Review on habitats-plant traits-vegetation of ephemeral wetlands – A global perspective - Deil 2005 by JPZ.

Phytocoenologia

35 (2Ð3)

533Ð705

BerlinÐStuttgart, August 26, 2005

A review on habitats, plant traits and vegetation of ephemeral wetlands Ð a global perspective by Ulrich Deil, Freiburg i. Br. (Germany) with 26 figures and 8 tables Abstract. Based upon a world-wide literature review and a database, which refers to 250 publications and documents about 8500 phytosociological relevés, the following questions are discussed: What are the common ecological parameters for temporary wetlands and which environmental conditions offer a niche for dwarf ephemerals? Which taxa have evolved and speciated within ephemeral wetland habitats? How do the relations between relief features, local hydrology and climatic conditions change in different parts of the world? Which global patterns in flora and vegetation do occur? The review is restricted to ephemeral freshwater ecosystems with the following two properties: Above-ground plant cover is seasonal, and the habitats are water-saturated or submerged only part of the year. For a better understanding of large-scale patterns, the results of studies about small-scale zonation, variability in time (phenology and year-to-year dynamics), ecophysiology and life strategies are briefly reported. Finally, conservation aspects and trends of floristic globalization are considered. Three habitat types can be distinguished according to relief, hydrology and climate: 1. Seasonal pools: They occur in semi-arid and subhumid climates at both sides of the Tropic of Cancer. The catchment areas are local or the ponds are purely rainwater systems. 2. Amphibic shorelines of permanent ponds, lakes and rivers: They concentrate in perhumid extratropical temperate zones and in orotropical climates. Along allochthonous rivers with extended catchments and with seasonal flood pulse, large temporary floodplains also occur in semi-arid regions. 3. Ephemeral flush habitats: In the perhumid tropics and in the subhumid subtropics, ephemeral wetlands are linked to runoff-habitats like the slopes of inselbergs and rock outcrops and to interflow habitats along intermittent streams. The distribution of some keystone taxa reflects the present climatic differentiation of the globe and to some extent also historical events (palaeogeography, speciation processes). Myosurus for example is linked to extratropical regions, Lilaeopsis to the New World and the Southern Hemisphere, Limnophila and Rhamphicarpa to the Palaeotropical region. Vicariance patterns are a common phenomenon. Examples can be seen in Isoetes, Marsilea, Ophioglossum, Juncus (sections Tenageia, Ozophyllum and Caespitosi), Limosella, Crassula (section Helophytum), Bacopa, Hydrocotyle, Eriocaulon and Xyris. These genera speciated within this environment and evolved habitat equivalent species. The reduced size and the spatial isolation of the habitat reduce gene flow and favour allopatric speciation. The variability in time and small-scale ecological gradients stimulate sympatric speciation by temporal separation of the populations. Niche-equivalent taxa replace each other in different parts of the world. The niche of dwarf ephemeroid annuals is occupied by Centrolepidaceae in the Australian region, by Restionaceae in the Capensis, by Eriocaulaceae in the Australian region and East Asia, by Juncaceae in the holarctic kingdom, by Orcuttieae in the Californian phytogeographical sector, and by Cyperaceae, DOI: 10.1127/0340-269X/2005/0035-0533 0340-269X/05/0035-0533 $ 43.25 ” 2005 Gebrüder Borntraeger, D-14129 Berlin · D-70176 Stuttgart

534

U. Deil

Crassulaceae, Gentianaceae, Elatinaceae and Apiaceae in all floristic kingdoms. Other predominant life forms are herbaceous perennials with the isoetid syndrome, geophytic ferns (Ophioglossum, Marsilea), carnivorous plants from the families Lentibulariaceae and Droseraceae, and poikilohydric vascular plants with the xyroid syndrome. The latter occur in the Tropics, with Xyridaceae (pantropical), Velloziaceae (neotropical region), Afrotrilepis, Craterostigma, Lindernia, Chamaegigas (palaeotropical region), Trilepis (neotropical region) and Borya (Australian region). The floristic kingdoms of the world are also reflected in the phytosociological classification of the ephemeral wetland communities. They are further differentiated according to climate zones and altitudinal belts. High ranked syntaxa in the New World are the Beckmannio syzigachne-Rumicetalia salicifolii (temperate regions of North America), Downingio bicornutae-Lasthenietea fremontii (Californian phytogeographical province), Mayacetea fluviatilis, Xyridetea savanensis and Leptocoryphio-Trachypogonetea (neotropical lowlands from Cuba via the Guiana Shield to northern Argentina), and Limoselletea australis (Andean belt in the neotropical region, lowlands in the extratropical parts of South America). The communities in the Western Palaearctis belong to the Isoeto-Nanojuncetea. Within this class, two orders can be separated according to species combination, ecology, predominant life form and phenology: Isoetetalia in the Mediterranean area and Cyperetalia fusci in the temperate zone of Eastern and Central Eurasia. Amphibic vegetation on mud soils in East Asia belongs to the Lindernion procumbentis, on nutrient poor soils to Eriocaulion atratae (Northern Japan) and Eriocaulion hondoensis (Southern Japan). Seasonal waterlogged soils in arctic and subarctic climates, often kept open by cryoturbation, are colonized by Koenigia islandica-communities. In subsaharan Africa, observations are scanty for the montane and subalpine zones of Eastern Africa (Limoselletea africanae) and preliminary for Southern Africa. In West Africa, the vegetation of ephemeral flush sites on inselbergs and of seasonal ponds in plains is better known. Communities on meso- and eutrophic sites there belong to the Rhamphicarpo fistulosae-Hygrophiletea senegalensis, on oligotrophic sites to the Drosero-Xyridetea. The latter class ranges throughout inselbergs in Central and Eastern Africa. Seasonal waterlogged soils in Central African lowlands are colonized by the Microchloetea indicae. Southwestern outposts of this class occur in Namibia. A high degree of endemism characterizes the Centrolepidi aristatae-Hydrocolyletea alatae, distributed in the mediterranean climate of SW Australia, and the Crassulo sinclairii-Hydrocotyletea hydrophilae, which occur in New Zealand. Communities with Lilaeopsis polyantha are distributed from Tasmania to SE Australia. Vegetation zonation according to water depth, periods of inundation and time of emergence is a characteristic feature of temporary ponds and emergent shorelines. Other differentiating gradients can be soil depth and water storage capacity (on rock outcrops), duration of seepage water flow (on inselbergs), wave respectively ice scour intensity (in the shoreline habitat), frost-heaving intensity (in subarctic and oreotropical climates) and salinity (in endorheic playa lakes in arid and semi-arid climates). These environmental gradients result in repetitive patterns of contact series of plant communities (= zonation complexes). Inundation experiments and seed bank analysis show that in a given year, only part of the seeds are stimulated to germinate. At a given place different plant communities can be awakened by different flooding regimes. The seed bank makes the temporary wetland ecosystems resilient to the interannual variability of ponding. Seasonal dynamics and year-to-year variability are prominent attributes of ephemeral wetland vegetation. A high species turnover in the growing season allows to separate ecophases respectively chronocoenoses. Plant response to drought is individualistic and

535

Habitats, plant traits and vegetation of ephemeral wetlands

depends largely on the timing of meteorological events in relation to life-stages. Such a germination and sprouting ecology can explain the year-to-year fluctuations of vegetation zones. Interannual variability is greater on shallow soils and more accentuated in the summer ecophases respectively increases from the pool centre to the margins. The habitats are not submitted to progressive succession, when they are of primary nature and when the natural dynamic of the hydrological or geomorphological process continues. Temporary wetlands shelter extremely rare and isolated taxa. The habitats are sensitive to human impact and they are threatened in many parts of the world. A strong decline can be stated for many species in Central Europe. The main reasons are missing dynamics of the river systems, abandonment of extensive pasturing and Ă? in consequence Ă? rare soil disturbance. Some species shift from primary to man-made habitats such as drained fish-ponds, arable land, rice fields and irrigated turfs. First tendencies of a globalization of the ephemeral wetland flora can be observed. Keywords: vernal pool, temporary pond, evolution, Isoetes, Isoeto-Nanojuncetea, hydrophytes, amphiphytes. Table of contents 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Terms and definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.1 Data sources and literature overview . . . . . . . . . . . . . . . . . . . 3.2 Nomenclature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.3 Restrictions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.3.1 Excluded habitats . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.3.2 Treatment of cryptogams . . . . . . . . . . . . . . . . . . . . . . 4 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.1 Habitat typology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2 Distribution of selected diagnostic taxa . . . . . . . . . . . . . . . . . . 4.3 Floristic composition, distribution and ecology of vegetation types . . 4.3.1 North America . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.3.2 Central and South America . . . . . . . . . . . . . . . . . . . . . 4.3.3 Western Palaearctic region . . . . . . . . . . . . . . . . . . . . . . 4.3.4 Central and Eastern Asia . . . . . . . . . . . . . . . . . . . . . . 4.3.5 Tropical Africa . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.3.6 Other Paleotropical regions . . . . . . . . . . . . . . . . . . . . . 4.3.7 Southern Africa and Madagascar . . . . . . . . . . . . . . . . . . 4.3.8 Australia and New Zealand . . . . . . . . . . . . . . . . . . . . . 4.4 Small-scale zonation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.5 Plant traits and germination ecology . . . . . . . . . . . . . . . . . . . 4.5.1 Life forms and life cycles . . . . . . . . . . . . . . . . . . . . . . 4.5.2 Reproductive biology . . . . . . . . . . . . . . . . . . . . . . . . 4.5.3 Photosynthetic pathways . . . . . . . . . . . . . . . . . . . . . . 4.6 Dynamic processes in ephemeral wetland vegetation . . . . . . . . . . 4.6.1 Seasonal dynamics . . . . . . . . . . . . . . . . . . . . . . . . . . 4.6.2 Year-to-year variability . . . . . . . . . . . . . . . . . . . . . . . 4.6.3 Long-term dynamics . . . . . . . . . . . . . . . . . . . . . . . . . 4.7 Evolutionary aspects of the ephemeral wetland flora . . . . . . . . . . 4.7.1 Niche-equivalent families . . . . . . . . . . . . . . . . . . . . . . 4.7.2 Vicarious taxa in the Tropics and their linkage to trophic levels

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

536 539 540 540 550 551 551 552 553 553 561 567 567 572 584 592 595 602 603 606 611 619 620 624 629 629 631 637 639 641 641 642

536

U. Deil

4.7.3 Preference of families and genera to ephemeral wetland habitats 4.7.4 Vicariance patterns within selected genera . . . . . . . . . . . . . 4.7.5 Relict species and recent speciation processes . . . . . . . . . . . 4.7.6 Terrestrial or aquatic ancestors? . . . . . . . . . . . . . . . . . . 4.8 Conservation aspects . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.8.1 Rare species and new records . . . . . . . . . . . . . . . . . . . . 4.8.2 Human impact . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.8.3 Habitat loss and population extinctions . . . . . . . . . . . . . . 4.8.4 Restoration projects . . . . . . . . . . . . . . . . . . . . . . . . . 4.8.5 Globalization of the flora and invasive species . . . . . . . . . . 4.8.6 Primary and secondary habitats for ephemeral wetland species . 4.8.7 Pasturing and other plant-animal interactions . . . . . . . . . . . 5. Further studies and open questions . . . . . . . . . . . . . . . . . . . . . . Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . .

642 643 651 652 653 653 654 656 657 658 659 661 663 667 667

Abbreviations (used in singular and plural): CS = character species, EFH = ephemeral flush habitat, EFV = ephemeral flush vegetation, EWF = ephemeral wetland flora, EWH = ephemeral wetland habitats, EWS = ephemeral wetland species, EWV = ephemeral wetland vegetation, I-N = Isoeto-Nanojuncetea, SHH = shoreline habitat, SWH = seasonal wet habitat, TP = temporary pond, SPH = seasonal pool habitat, VP = vernal pool.

Introduction

This contribution represents an attempt to work out some common characters of ephemeral wetland vegetation (= EWV), and to outline the variability in flora, life forms and ecology in seasonally wet habitats (= SWH). A first unifying character of the plant cover in SWH was stated by Diels in 1906, in a study of seasonal floodplains in Southwestern Australia: The plants are dwarfish (a few centimetres high), above-ground biomass is ephemeral and the vegetation cover is open. He coined the term â&#x20AC;&#x153;Zwergfloraâ&#x20AC;? (dwarf flora) and discovered that the members of the Centrolepidaceae are characteristic taxa for this vegetation type in the Australian floristic kingdom. Aphelia brizula (Fig. 1) is an example. Further tiny annuals illustrated in Fig. 1 come from the families Stylidaceae, Haloragaceae, Lentibulariaceae and Asteraceae. In other parts of the world, vegetation stands occur with similar physiognomic characters of the plant cover and life forms. The representative taxa however are from other families like Juncaceae and Eriocaulaceae, or are vicarious species within the same genera like Isoetes, Ophioglossum, Drosera, Hydrocotyle etc. Evolutionary aspects and vicariance patterns in the flora of EWV were presented in earlier papers, when authors compared their local results with other parts of the world. Oberdorfer (1960), who was familiar with the holarctic type of EWV (I so et o- Na no ju nc et ea -communities = I-N), was fascinated by the striking convergence and vicariance pattern, when studying EWV in Chile. Vicariance patterns have been discussed by Eskuche (1975) for the example of Lindernia and other genera of the Gratioloideae, and by Cleef (1981) (annual Crassula species). de Foucault (1988) raised the question of niche-equivalent families in the tropical and temperate zones. QueĚ zel

Habitats, plant traits and vegetation of ephemeral wetlands

537

Fig. 1. Character species of the ephemeral dwarf flora in SW Australia (from Diels 1906). Ă? A Selaginella preissiana (Selaginellaceae); B Triglochin calcitrapa (Juncaginaceae); C Schoenus apogon (Cyperaceae); D Aphelia brizula (Centrolepidaceae); E Haloragis nodulosa (Haloragaceae); F Hydrocotyle alata (Apiaceae); G Utricularia multifida (Lentibulariaceae); H Stylidium calcaratum (Stylidiaceae); J Rutidosis argyrolepis (Asteraceae).

(1998) pointed out the common floristic character in EWF at the genus level between the Mediterranean basin, California and Australia. It is only the global viewpoint which permits to ask for the effects of convergent and divergent evolution processes, for vicariance patterns, speciation processes and adaptive radiation in the ephemeral wetland flora (= EWF). Beyond aspects like convergence, co-evolution, niche equivalence and strategy types, EWH are also interesting objects for vegetation ecologists. These habitats offer an extreme environment: Favourable edaphic conditions exist only for a very short time within the growing season and year-to-year variability is high. It is a plant life between inundation and desiccation, every year shifting from flooding to water shortage. However, an up-to-date syn-

538

U. Deil

opsis of the ephemeral wetland ecosystem in a world-wide perspective is not available. Recent reviews have been restricted either to a certain area or to a thematic aspect. This can be demonstrated by three examples: 1. The topics seed bank analysis, germination ecology, nature conservation and habitat restoration have been discussed during some workshops in France and Germany (for Southern France see QueĚ zel (1998), MeĚ dail et al. (1998), Grillas et al. (2004a, 2004b); for Central Europe see Deil et al. (1999)). Results from germination studies in Central Europe are summarized by Poschlod et al. (1999). 2. Californian vernal pools (= VP) and their flora have been considered in early papers as quite unique for the state. These habitats have therefore received much attention. A first synopsis was presented by Jain (1976) and Holland & Jain (1977/88), followed by a community profile (Zedler 1987) and some symposia proceedings and compilations (Jain & Moyle 1981/84, Ikeda & Schlising 1990, Witham et al. 1998). A general characterization of VP from the Californian viewpoint with an outlook to other mediterranean regions of the world is given by Keeley & Zedler (1998). A bibliography was compiled by Fiedler (2001). Photosynthetic pathways in SWH are reviewed by Keeley (1998, 1999). 3. The vegetation mosaic on rock outcrops and on inselbergs in tropical and subtropical regions very often includes seasonal water-filled rock pools and/or ephemeral flush vegetation (= EFV). Such outcrop habitats have been investigated more intensely in the last decade, because they shelter endemic species and are umbrella habitats for rare phyto- and zoocoenoses. For several parts of the world, a synopsis of this habitat mosaic is available, e. g. for Western Australia (Hopper et al. 1997), North America (Quarterman et al. 1993, Anderson et al. 1999, Shure 1999), and the Tropics (Porembski & Barthlott 2000a). The aim of this contribution is to review the literature on EWV available to the author at the present time and to summarize current knowledge. Different aspects of ephemeral dwarf plant ecosystems will be taken into consideration and the following questions will be discussed: 1. Can we typify SWH according to the hydrological, geomorphological and pedological situation? Are such types linked to certain climatic zones of the earth and to specific pedo-geomorphological processes? 2. What is the distribution of some keystone species? Does the phytochorology of diagnostic taxa reflect the present climatic differentiation of the globe, and to what extent are such spatial patterns the result of palaeogeography and plate tectonics? 3. From which parts of the world are phytosociological releveĚ s or other plot-related floristic data available? 4. What are the results of a classification according to floristic similarity at the species level? What are the characteristic species and ecological conditions? This topic will be restricted to high-ranked syntaxa (classes, orders and alliances in the sense of Braun-Blanquet (1964)). 5. Are there common life forms and strategy types like dwarf ephemerals in EWV in all parts of the world? Are there niche-equivalent families or

Habitats, plant traits and vegetation of ephemeral wetlands

539

genera in different floristic kingdoms? What are the unifying characters of herbaceous perennials with the Isoetid syndrome or of annuals germinating in the amphibic phase? 6. Which taxa have evolved and speciated within the EWH? Were the ancestors aquatic or terrestrial? Is speciation and evolution of narrow-endemics favoured by the scattered occurrence of the semi-terrestrial environment? For a better understanding of large-scale patterns, the results of studies about small-scale zonation and ecological gradients, variability in time (phenology and year-to-year dynamics), and ecophysiology (photosynthetic pathways, seed bank analysis, germination experiments, etc.) will be briefly reported. Finally, conservation aspects, trends of floristic globalization and open questions will be considered.

Terms and definitions

The synthesis is restricted to “ephemeral wetland vegetation” (= EWV). This term encompasses two selective criteria: 1) The plant species (annual or perennial) are visible above-ground for only part of the year. 2) The habitats are water-saturated or submerged during an ecologically relevant part of the growing season. A third criterion is that the review is restricted to fresh waters. These restrictions shall be discussed now in detail. Ephemeral character of the plants: The predominant life forms are annual amphiphytes, germinating in the aquatic phase and reproducing in the terrestrial ecophase (so-called tenagophytes) or semi-terrestrial geophytes. Plant communities dominated by perennial helophytes and by rooting pleustophytes with floating leaves (= hydrogeophytes) are included only if they show an ephemeral behaviour in seasonal or semi-permanent water. Wetland vegetation dominated by perennial plants with permanent aboveground biomass, like bogs, reed marshes, floating meadows and Papyrus swamps, and seasonally inundated permanent grasslands (often called “herbaceous swamps”) such as Dambo vegetation in Africa (Mäckel 1974, Acres et al. 1985) are excluded, even if they occur in or around seasonal lakes. The same is true for communities with the following matrix life forms: Free-floating pleustophytes on the water surface, permanent submerged rooting pleustophytes and hydrophytes restricted to permanent water bodies. Cyclical wetlands sensu Tiner (1999) like prairie potholes, “playas” and vernal pools are only included, when the above-ground vegetation is not permanent. The definition of “ephemeral wetlands“ applied here is similar to that of Johnson & Rogers (2003). Water conditions: This review is restricted to non-tidal systems and nonpermanent freshwater ecosystems. Short-living halophytic vegetation subjected to daily inundations is not taken into consideration. Seasonally submerged habitats with brackish or saline water in the aquatic phase are ex-

540

U. Deil

cluded, even if they are dominated by annual plants. Ephemeral vegetation in salt-pans, very common in South Africa for example (Cilliers & Bredenkamp 2003), is not considered when the emergence occurs under saline conditions. Terminology: The following terms are used to describe the duration, frequency, and periodicity of water available for the plant cover: 1) permanent, 2) near permanent, 3) seasonal (an annual change of wet and dry conditions; the predictable wet season is the growing season), 4) intermittent (several short wet phases per year, without detectable periodicity), 5) episodic (rare, unpredictable wetting, often linked to erratic precipitation). Classes 2 to 5 are temporary wetlands, 3 is rhythmic, 4 and 5 are arhythmic. Lateral water movement separates inflow, throughflow and outflow systems. In the landscape dimension, catchments can be exo- and endorheic, water courses autochtonous or allochthonous. Surface waters can be standing (= stagnant) or flowing. Rising water-level can be the result of raising groundwater level (ponding) or lateral inflow of surface water (flooding). Additional characters can include the nutrient content of water and/or soil (oligotrophic, mesotrophic, eutrophic), salinity (freshwater, brackish water = oligosaline, (eu)saline) and variability of the salinity (stasosaline, poikilosaline). This terminology is partly identical or similar to terms and typologies proposed by Cowardin et al. (1979), Norwick (1991), Semeniuk & Semeniuk (1995), Finlayson & Van der Valk (1995), Johnson & Rogers (2003) and Grillas et al. (2004a). To some extent it differs considerably from previous proposals. Grillas et al. (2004a) for example apply the term “ephemeral” only to a rare and erratic flooding regime, Cowardin et al. (1979) classify first lacustrine, riverine and palustrine systems, and within these categories distinguish according to the periodicity of the water. Concerning the amplitude of water-level fluctuations in relation to soil surface, we separate aquatic (deep or shallow submerged), amphibic, waterlogged, and dry conditions. A well thought out and detailed typology of within-year variations of the water-level was proposed by Czech authors (Hejný 1957, 1962, Hejný & Husák 1978): They separate the following ecophases: hydrophase (limnic phase), littoral, limosal and terrestial ecophase. The sequence of ecophases is called the ecoperiod.

Materials

3.1.

Data sources and literature overview

At the moment, about 682 constancy columns, taken from 250 publications, are stored in a database. They represent 8521 relevés. In most cases, these data are phytosociological relevés, in some cases they are from transect plots or just local species lists. The number of relevés per region can be seen in Fig. 2. The locations of permanent plot studies are mapped in Fig. 3, the relevant publications are listed in the legend to this figure. The report about the available vegetation data is given here region by region, starting

Habitats, plant traits and vegetation of ephemeral wetlands

541

Fig. 2. Available data on ephemeral wetland vegetation around the world.

Fig. 3. Locations of permanent-plot studies in ephemeral wetlands. Ð1 = Crowe et al. (1994); 2 = Holland & Jain (1981/84), Bauder (2000); 3 = Burbanck & Platt (1964), Burbanck & Phillips (1983), Houle & Phillips (1989b); 4 = Isichei & Longe (1984), Porembski & Barthlott (1997), Krieger et al. (2003); 5 = Nègre (1956), Rhazi et al. (2001b); 6 = Rudner (2005a); 7 = Ballesteros (1984); 8 = Grillas & Tan Ham (1998); 9 = Barbéro et al. (1982); 10 = Müller (1996), Urban (2005); 11 = Poschlod (1996), Poschlod et al. (1996); 12 = Sumberová et al. (2005); 13 = Bergmeier (2001); 14 = San Martı́n et al. (1998).

542

U. Deil

with both Americas and ending up with Australia, New Zealand and Polynesia. North America: Vegetation science in North America was for a long time not oriented to vegetation classification in the sense of the European BraunBlanquet-approach, i.e. classification according to floristic similarity, based upon plot-related complete floristic data sets (Braun-Blanquet 1964). From the temperate climate zone, only a few studies are available. Looman (1982) analysed semi-aquatic vegetation in Canada in the Prairie Provinces, and Galiano (1957) and Géhu & Géhu-Franck (1985) at lakes in the Province of Quebec respectively in the St. Laurence-floodplain. VP in the Mediterranean climate of the Southwestern United States have received much attention, especially in California. The investigations started with Purer (1939). She monitored year-to-year variability over three growing seasons. Studies of the flora, small-scale zonation, ecology and ecophysiology were presented for example by Jain (1976), Holland & Jain (1977/ 88), Schlising & Sanders (1982), Lathrop & Thorne (1983), Zedler (1987), Keeley (1998, 1999), Heise & Merenlender (1999), and Bauder (2000). Further papers are included in syntheses and compilations (Ikeda & Schlising 1990, Jain & Moyle 1981/84, Witham et al. 1998) like the contributions of Thorne (1984), Abbott (1984), Cox (1984), Rosario & Lathrop (1984), Zedler (1984), Bauder & McMillan (1998), and Barry (1998). These symposium proceedings also include population studies of selected taxa such as Downingia, Pogogyne and Orcuttia (Martin & Lathrop 1986, Griggs 1984, Stagg & Lathrop 1984, Griggs & Jain 1983, Bauder 1989, Zammit & Zedler 1990, Zedler 1990, Zedler & Black 1992). A bibliography for Californian VP was compiled by Fiedler (2001). A preliminary floristic list and deductive classification of the order D ow ni ng io -N av ar re ta li a was presented by Knapp (1957, 1965). Plotrelated floristic data from California were offered by Kopecko & Lathrop (1975) and Holland & Jain (1981/84). Quite recently, a comprehensive floristic classification based upon more than 600 phytosociological relevés has been presented by Barbour et al. (2003, 2005). Crowe et al. (1994) studied vegetation zonation and soil characteristics in vernal pools of Eastern Washington, Clausnitzer & Huddleston (2002) in Southeastern Oregon. VP in Baja California are neglected and little known (Moran 1984). For other parts of the United States, the publications available in this field are scanty. Vegetation dynamics and soils in buffalo wallows in the Great Plains were studied by Uno (1989), Polley & Collins (1984) and Polley & Wallace (1986), the vegetation mosaic on glades in the Ozarks (Northern Arkansas and Southern Missouri) by Baskin & Baskin (2000) and Ware (2002). EWV in playa lakes in the southern high plains was studied in a very preliminary way (Reed 1930, Bolen et al. 1989, Haukos & Smith 1994a) or concentrated upon perennial vegetation types (Willen & Tiner 1993, Hoagland & Collins 1997). For the Southeastern part of the USA, knowledge is better: Comprehensive studies about the

Habitats, plant traits and vegetation of ephemeral wetlands

543

vegetation mosaic on granitic outcrops on Mount Arabia (Piedmont of the Appalachian Mountains, Northern Georgia) respectively the Cedar Glades (Tennessee) are given by Shure (1999) and Baskin & Baskin (1999), both having been included in the compilation of plant communities on outcrops and barrens in North America (Anderson et al. 1999) and based on earlier papers like McVaugh (1943), Burbanck & Platt (1964), Quarterman (1950) and Quarterman et al. (1993). Further papers deal with endemism (Murdy 1966, Baskin & Baskin 1988), flora (Wyatt & Fowler 1977), life forms (Phillips 1982), succession (Shure & Ragsdale 1977, Phillips 1981, Burbanck & Phillips 1983, Kirkman et al. 1998), seed bank (Haukos & Smith 1994b) and reproductive ecology (Wyatt 1981, 1983, 1997, Wyatt & Allison 2000). Central America and the Carribean region: EWV is not treated in the synopsis about the wetlands of Mexico (Olmsted 1993). Preliminary observations about the vegetation of seasonal dune slacks at the Gulf of Mexico are recorded by Martı́nez et al. (1997). EWV in TP in the white sand savannas of Cuba was studied by Borhidi et al. (1979, 1983) and Balátová-Tulácková & Capote (1985), a syntaxonomic synopsis is given in the Cuban vegetation monograph (Borhidi 1996a). Amphibian vegetation on mud soils in Guadeloupe was studied by de Foucault (1978, 1983). South America: Except the synopses of aquatic vegetation in Peru (Galán de Mera 1995, Galán de Mera et al. 2002), no summarizing publications about EWV are available from South America. The papers either deal with EWV of a restricted region or concentrate upon one of the following habitats: rock outcrops, inselbergs and savannas of the Guiana shield, lakeshores in the Andean Paramo belt, floodplains in the tropical lowlands and TP in the mediterranean parts of South America. Inselberg vegetation in French Guiana is recorded by Sarthou & Villiers (1998) and Sarthou (2001), and minor observations come from Hoock (1971), Raynal-Roques & Jérémie (1980) and Sarthou & Grimaldi (1992). Ephemeral types of Amazonian savannas have been studied by Duivenvoorden & Cleef (1994) in Colombia and by Heyligers (1963) in Surinam. Minor observations come from the Atlantic coast of Brazil, dealing with swamp rock vegetation (Pires-O’Brien 1992), penumbral rock communities (Alves & Kolbek 1993) and the vegetation mosaic in the outcrop area of Serra dos Carajás (Pará) (Cleef & da Silva 1994). The vegetation of granitic outcrops in the Cordoba Mountains in Northern Argentina is recorded by Cabido & Acosta (1986) and Cabido et al. (1990). The phytosociological data from temporarily inundated white sand savannas in the Guianas (Van Donselaar 1965, 1969) and Venezuela (Susach 1989), which are dominated by perennial plants, have not been included into the database. The same is true for papers focussing on perennial vegetation on inselbergs in Brazil like Meirelles et al. (1999), Porembski et al. (1998) and further contributions in Porembski & Barthlott (2000a).

544

U. Deil

Savanna vegetation, dominated by annuals, was integrated in the database. This concerns “Llanos” in Venezuela (Castroviejo & López 1985, Galán de Mera in lit.). Lakeshore and mire vegetation in the Andean Paramo belt was studied by Berg (1998) in Venezuela, by Cleef (1981) in Colombia, by Gutte (1980, 1986, 1988), Galán de Mera (1995) and Galán de Mera et al. (2003) in Peru, by Seibert & Menhofer (1991, 1992) in Bolivia, by Ruthsatz (1995) and Luebert & Gajardo (2005) in Chile, and by Ruthsatz (1977) in Argentina. EWV in one of the largest floodplains of the world, the Pantanal of Mato Grosso, was studied by Pinder & Rosso (1998), Prado et al. (1994), Schessl (1997, 1999) and Zeilhofer & Schessl (1999) in Brazil, by Eskuche (1975, 1986), Lewis et al. (1985, 1987), Franceschi & Lewis (1991), Franceschi et al. (2000) and Fontana (1991) in Argentina, and by Wolf (1990) in Paraguay. Janssen (1986) deals with inundated savannas in Humaitá (Brazil). The floodplain vegetation in the Pacific lowlands of Peru is documented by Müller & Gutte (1985), in the Amazonian lowlands of Peru by Seidenschwarz (1986), in Bolivia by Beck (1983, 1984) and Haase (1989). A floristic checklist of herbaceous plants in the “varzea” near Manaus (Brazil) is provided by Junk & Piedade (1993), and tenagophytes are noted by these authors. The first phytosociological records on vernal pool vegetation in Chile were taken by Oberdorfer (1960). More recently, Ramı́rez et al. (1994, 1996, 2000), San Martı́n et al. (1998) and Bliss et al. (1998) studied this kind of vegetation. Europe: The description of dwarf Juncus-Isoetes-communities started in the holarctic region with observations by Allorge (1922) in France and North Africa. An early approach to summarize the knowledge about vegetation typology, ecology, periodicity and dispersal was presented by Moor (1936, 1937) for Europe and North Africa, followed by a bibliography of the I-N by Tüxen & Zevaco (1973). A first synopsis of the EWV was realized by Pietsch (1973a) on the basis of 5238 relevés, sampled in Europe. He used literature published before 1965. More recently, Brullo & Minissale (1998) presented a syntaxonomic scheme and constancy tables (reduced to frequent respectively diagnostic species), based upon 4249 relevés from the Western Palaearctic region (Europe and Northern Africa). For Central Europe, Brullo & Minissale mainly adopted the older data from Pietsch. For Southern Europe and Northern Africa, they added a lot of their own, new and to some extent unpublished data; the literature until 1998 was exploited quite exhaustively. As a protected habitat in the directive of the European Community (EUR-OP 1992, Anonymous 1999), EWV vegetation has been a focus of interest in many plant sociological studies in recent years and a huge amount of new data, not yet considered by Brullo & Minissale in 1998, is available now. Nationwide syntheses have been compiled for Great Britain (Rodwell 2000), the Netherlands (Lemaire et al. 1998), Germany (Täuber & Petersen 2000; with addi-

Habitats, plant traits and vegetation of ephemeral wetlands

545

tional data from NE Germany by Berg & Bolbrinker 2004), Poland (Popiela 1999), Lithuania (Rasomavicius & Biveinis 1996), Norway (Vevle 1989), Slowakia (Valachovic et al. 2001) and Romania (Coldea 1997). The regional literature for these countries is summarized in these national synopses and not further listed here. Phytosociological data come from Ireland (Braun-Blanquet & Tüxen 1952), Hungary (Bagi 1987, 1991, Pietsch 1973b, Ubriszy 1961), Bosnia (Jasprica & Caric 2002) and Yugoslavia (Slavic 1951, Horvatic 1954). A syntaxonomic synopsis (without tables) of all the ephemeral plant communities occurring in the country is presented by Traxler (1993) for Austria, by Borhidi (1996b, 2003) and Molnár & Borhidi (2003) for Hungary, by Hejný & Husák (1978) for the former Czechoslovakia, and by Hejný (1995) and Vicherek (1973) for non-saline respectively halotolerant communities of the Czech Republic. The classification for the I-Ncommunities of the Czech Republic was evaluated by Chytry & Tichy (2003). Vegetation on exposed pond bottoms, first studied by Klika (1935), is investigated in more detail by Sumberová et al. (2005). A comprehensive account for France is missing (but see de Foucault 1988 for earlier data). Such a synthesis would be important. It would offer the opportunity of analysing I-N-communities in the transition from temperate climate (communities belonging to the order C yp er et al ia fu sc i) to those adapted to the mediterranean precipitation regime (the order I so et et al ia ). Géhu (1992) and Julve (1993) present syntaxonomic schemes for France. Many local studies are available for the southern parts of mainland France (Aubert & Loisel 1971, Barbéro 1965, 1967, Barbéro et al. 1969, 1982, Braun-Blanquet 1935, Braun-Blanquet et al. 1952, Molinier 1937, Molinier & Tallon 1948, 1949/50, Moor 1937, Poiron & Barbéro 1965, 1966, Vanden Berghen 1969) and for Corsica (Gamisans 1976, Gamisans et al. 1996, Lorenzoni & Paradis 1997, 1998, 2000, Malcuit 1962, Paradis 1992, Paradis & Lorenzoni 1994, Paradis et al. 2002). Material for the atlantic part of France is provided by de Foucault (1988) and by Clément & Bouzille (1996), for the Upper Rhine Valley by Moor (1937), Rastetter (1967) and Stalling (2005). Most observations about I-N-communities in Switzerland date back to the beginning of phytosociological studies in Europe (Koch 1926, 1934, Moor 1936, 1937, 1958, Braun-Blanquet & Moor 1935). A recent review is not available. The Iberian Peninsula is a focal point for EWV (see Fig. 2). A first synopsis of I-N-communities in Spain was presented by Rivas Goday (1970), summarizing former local studies (Rivas Goday 1955, 1956, 1964, 1968). Since that time, many papers dealing with EWV have been published. The study areas range from Catalonia (de Bolòs 1979, Ballesteros 1984, Molero 1984), the Pyrenees, Basque Country and other Northern Provinces (Biurrun 1999, Braun-Blanquet 1967, Dı́az González 1976, Géhu 1975, Loidi et al. 1997, Molero & Romo 1988, Nozeran & Roux 1958, Rodrı́guez et al. 1997, Vives 1964), the Central Iberian Mountains and Mesetas (Arnaiz & Molina 1985, Garcı́a Rı́o & Navarro 1994, Navar-

546

U. Deil

ro & Valle 1984, Rivas Martı́nez 1963, Rivas Martı́nez & Izco 2002, Sánchez Mata 1989, Sánchez Rodrı́guez & Fernández Dı́ez 1987, Sardinero 2004) to Andalusia (Gómez Mercado & Valle 1992, Martı́nez Parras et al. 1988, Melendo et al. 1996, Melendo & Cano 1997, RivasMartı́nez et al. 1980, Rudner et al. 1999, Rudner 2005a, 2005b, Ruiz & Valdés 1987, Salazar et al. 2001, Tamajón Gómez & Muñoz Alvarez 2001). Subhalophytic habitats around endorheic playas on the Meseta have been studied by Cirujano (1981) and Velayos et al. (1989), similar environments in coastal regions in SW Andalusia by Rivas-Martı́nez et al. (1980). Molina & Casado Álvaro (1997) reviewed the alliance A gr os ti on po ur re ti i, Molina (2005) the communities with Isoetes, and Molina & Pertiñez (2000) communities with Eryngium corniculatum. EWV of the Balearic Islands is documented by de Bolòs et al. (1970), de Bolòs (1996) and Llorens (1979). VP vegetation in mainland Portugal was studied by Jansen & Sequeira (1999) in the Serra da Estrela, by Espı́ritoSanto & Arsénio (2005) in the Alentejo, by Rudner (2005a, 2005b) in the Serra de Monchique, and by Pinto-Gomes et al. (1999) in the lowlands of the Algarve province. A syntaxonomic synopsis (including the class IN) for the whole Iberian Peninsula is presented by Rivas-Martı́nez et al. (2002). The synthesis of Brullo & Minissale (1998) included most of the phytosociological data available from Italy at that time. Besides some studies in Central Mainland Italy (Anzalone & Caputo 1975, Blasi et al. 2002, Biondi et al. 2002, Foggi & Grigioni 1999, Filipello & Sartori 1981, Lucchese & Pignatti 1990, Pedrotti 1982, Pedrotti et al. 1982), many data come from Sicily and surrounding islands (Bartolo et al. 1990, Brullo et al. 1976, 1977, 1994, Brullo & Di Martino 1974, Brullo & Grillo 1978, Brullo & Marcenò 1974, Brullo & Minissale 1998, Marcenò & Raimondo 1977, Marcenò & Trapani 1978, Minissale & Spampinato 1987) and from Sardinia (Brullo & Minissale 1998, Camarda et al. 1995). Observations in Northern Italy are rare (Piccoli & Merloni 1989, Cortini Pedrotti 1992), and most papers are oriented to rice field vegetation (Koch 1954, Pignatti 1957a, 1957b). Bergmeier & Raus (1999) summarized the state of knowledge for Greece. Further contributions come from Bergmeier (2001), de Bolòs et al. (1996), Oberdorfer (1952), Krause et al. (1963) and Sarika-Hatzinikolaou et al. (2003). Asia: EWH are very local and scattered in the subhumid and semi-arid regions of Southwest Asia. Kürschner & Parolly (1999) give an overview for Turkey. Depressions in the alpine belt of the Taurus Mountains have been studied by Quézel (1975). The observations from Israel (Eig 1946, Zohary & Orshansky 1947) and Yemen (Deil & Müller-Hohenstein 1985) are very preliminary. EWH in Central Asia are quite common along the shores of big rivers in Siberia and around Lake Baikal. Ünal (1999) gave a first synopsis (including the data from Taran 1994, 1995, 1998, and presenting some new data). There are further papers by Klotz & Köck

Habitats, plant traits and vegetation of ephemeral wetlands

547

(1984), Taran (1993, 2000, 2001) and Taran et al. (2004). A few relevés, taken in the Russian Far East, were published by Sinelnikova & Taran (2003). Mongolia (Hilbig & Schamsran 1981, Hilbig 1995, 2000), China (Nakamura 1994, Kürschner 2004, Wang et al. 2002), Taiwan (De Vol 1972, Chang & Hsu 1977) and India (Lavania et al. 1990, Watve 2003, Porembski & Watve 2005) are poorly studied. The state of knowledge is much better for Japan. A synopsis is presented by Shimoda (2005), relevés are also documented in Miyawaki & Okuda (1972) and Shimoda (1983, 1985, 1986, 1987, 1993). Atlantic Islands: Phytosociological data from EWH and vegetation descriptions are available for Greenland (Fredskild 1998), Iceland (Sörensen 1942, Hadač 1971, 1985, Mörsdorf 1989, Devillers-Terschuren & Devillers 2001), Madeira (Costa et al. 2003), the Azores (Lüpnitz 1975) and the Canary Islands (Sunding 1972, Reyes-Betancort et al. 2001, Rivas-Martı́nez et al. 1993, Stierstorfer 2005). Africa: The state of knowledge is quite good for the “dayas” in the Maghreb countries (Morocco, Algeria and Tunisia), for the “mares temporaires” in Senegal and Niger and for the Inselbergs in Benin, Ivory Coast and Nigeria, less satisfactory for Central Africa, and very preliminary for South Africa and the East African Mountains. Phytosociological relevés from Morocco have been published by Quézel (1957), Titolet (1989), Deil (1997), Brullo & Minissale (1998) and Rudner et al. (1999), a detailed analysis of the year-to-year variability of vegetation and environment in a Moroccan daya near Casablanca and a seed bank analysis of this site are presented by Rhazi (2001) and Rhazi et al. (2001a, 2001b). Observations in Algeria date back to Braun-Blanquet (1935). More recent studies are Chevassut & Quézel (1956, 1958), Daumas et al. (1952), Géhu (1992) and Géhu et al. (1994). Freshwater EWV in Northwestern Tunesia (Kroumerie Mountains) is considered by Nègre (1952), Pottier-Alapetite (1952, 1954), Debazac (1959), subhalophytic habitats in coastal regions by Barbagallo et al. (1990) and Vanden Berghen (1979a). I-N-communities in the coastal area of Libya (Cyrenaica) were studied by Brullo & Furnari (1994), ephemeral wetlands in the Central Sahara (Tibesti and Jabal Uweinat) by Leredde (1954), Quézel (1958) and Léonard (2001). Tropical West Africa: A synopsis of the literature, a documentation of the available phytosociological records and a classification including the typification of many syntaxa are presented by Müller & Deil (2005). This review is based on material from different countries and is restricted to EWV of seasonal ponds and semi-permanent freshwater lakes. Inselberg vegetation in West Africa is outlined by Porembski (2000a). Information about EWV is available from the following regions: Senegal (Vanden Berghen 1979b, 1982a, 1982b, 1984, 1990a, 1990b, 1997), Mali (Aberlin 1986a, 1986b), Burkina Faso (Müller 2003, Wittig 2005 (data mainly

548

U. Deil

taken from Müller 2003), Raynal & Raynal 1961, Guinko 1984), Niger (Roberty 1946), Guinea Bissau (Catarino et al. 2002a, 2002b), Guinea (Schnell 1951Ð52, Porembski et al. 1994), Sierra Leone (Gledhill 1970), Ivory Coast (Adjanohoun 1964, Porembski & Brown 1995, Porembski & Barthlott 1997, Dörrstöck et al. 1996, Krieger et al. 2000, 2003), Ghana (Hall 1971), Togo (Guyot et al. 1994), Benin (Oumorou & Lejoly 2003a, 2003b), and Nigeria (Richards 1957, Hambler 1964, Isichei & Longe 1984). EWV in rice fields was studied by Ataholo (2001) in several countries of the Sudan zone. Central Africa: A first and very preliminary draft of higher syntaxonomic units for Central and Eastern Africa is presented by Knapp (1968), a more detailed study for Central Africa (DR Congo, Rwanda, Burundi) by Schmitz (1988). Local and regional observations come from Cameroon (Léonard 1996), Congo (Duvigneaud & Symoens 1951, Lejoly & Lisowski 2000), Zaire (= DR Congo) (Fischer 1996, Léonard 1950, 1951, Mandango & Ndjele 1986, Mandango 1988, Masens 2000, Nyakabwa 1988, Schmitz 1963, Szafranksi & Apema 1983, Taton 1948, Taton & Risopoulos 1955), and Uganda (Eggeling 1935). Inselberg vegetation including ephemeral flush habitats was studied in Equatorial Guinea by Lejoly & Lisowski (1999), Parmentier (2002, 2003), and Parmentier et al. (2001, 2005), in Gabun by Reitsma et al. (1992). East Africa: Preliminary observations from EWH in the afroalpine belt of Eastern Africa are delivered by Hedberg (1964) and Fischer (1996). The vegetation of inselbergs in Ruanda and Zaire was studied by Porembski et al. (1997), in Malawi by Porembski (1996), in Zimbabwe by Seine (1996) and Seine et al. (1998). An overview for East and Southeast Africa is given by Seine & Becker (2000). Several aspects of inselberg flora and vegetation in different parts of Africa are discussed by Porembski (1999), Porembski (2000b, 2000c), Porembski & Barthlott (2000a), Porembski et al. (1995, 2000), a global synopsis about inselberg vegetation is presented by Porembski & Barthlott (2000b). Barthlott & Porembski (1998) outline some phytogeographical links between tropical Africa and Madagascar. However, a summarizing classification of inselberg vegetation based upon phytosociological data and in a broader geographical context is still missing. Namibia and Zambia: Preliminary floristic observations from the Southern Kalahari (Leistner 1967) and Northeastern Namibia (Hines 1990/93) are supplemented by ecophysiological studies of ephemeral pool plants (Gaff & Giess 1986, Heilmeier et al. 2005). Phytosociological data are given by Volk & Leippert (1971) and Volk (1984). A detailed phytosociological and ecological study of the Kafue Flats in Southern Zambia is provided by Ellenbroek (1987), a comparison with floodplains in Northern Australia by Howard (1985).

Habitats, plant traits and vegetation of ephemeral wetlands

549

South Africa: EWH are common in the Capensis (Breen et al. 1993, Taylor et al. 1995) and their floras are rich in endemics (Cook 2004). Vegetation studies in these habitats however are rare and more oriented to the perennial vegetation of vleis and swamps (see for example Kooij et al. 1991). Halotolerant and nitrophilous vegetation of endorheic pans of the NW Province was recently studied by Cilliers & Bredenkamp (2003). Observations in temporary freshwater habitats are available from Natal (Furness & Breen 1980, Eckhardt et al. 1996), the Cape region (Taylor 1972, Campbell et al. 1980), Lesotho (van Zinderen Bakker & Werger 1974, van Zinderen Bakker 1965), and Marion Island (Gremmen 1981). Madagascar: Observations about EWV are preliminary (Morat 1973, Rauh 1973, Fischer & Theisen 2000). Australia: Diels (1906) was the first to study EWH in SW Australia. A detailed analysis of the ephemeral vegetation in winter wet sandy depressions, along water courses and on rock outcrops in the subhumid parts of SW Australia was performed by Pignatti & Pignatti (1994). Further contributions are restricted to inselberg vegetation (OhlemĂźller 1997, Hopper et al. 1997, Hopper 2000a, 2000b) or discuss the invasion of holarctic species (Doing 1994). Knowledge about a SW Australian class in the Mediterranean part is extended to the desert areas by Pignatti & Pignatti (2005). In SE Australia temporary wetlands are widespread (Jacobs & Brock 1993). Most contributions however do not offer plot-related and complete floristic data, but deal with seed bank (Brock 1998, Brock & Casanova 1997, Casanova & Brock 2000, Nicol et al. 2003), population biology of single plant species (Coates et al. 2002) and phenology of zoocoenoses (Lake et al. 1989). A recent synthesis of outcrop vegetation is oriented to perennial plants (Hunter & Clarke 1998). Temporarily flooded interdune depressions in Victoria are considered by Thannheiser (2001), in Tasmania by Haacks & Thannheiser (2000, 2003). A synopsis of Tasmanian wetlands including EWV is presented by Kirkpatrick & Harwood (1983). Some information about coastal wetlands in floodplains of the Northern Territory is provided by Taylor & Dunlop (1985) and Whitehead et al. (1990), for Queensland by Blackman & Locke (1985). For most of the Australian provinces, only rough classifications based upon hydrologic characters or vegetation formations are available according to Pressey & Adam (1995). New Zealand: For a long time, the knowledge about EWV was restricted to fragmentary notes (Cockayne 1958, Sykes & Wilson 1987, Wardle 1991). The situation has been improved considerably by Johnson & Rogers (2003). The authors offer a nationwide study of EWH. Further contributions are Haacks (2003), Rogers et al. (2002), Wells et al. (1998), and Wilson et al. (1993).

550

U. Deil

Pacific Islands: Hoff & Brisse (1990) studied SWH on the Polynesian Islands Wallis and Futuna. Observations in Papua New Guinea are fragmentary (Conn 1983). 3.2.

Nomenclature

Using vegetation data from all over the world and publications ranging over the time span of a century of scientific research (starting with Diels 1906 and ending with papers from 2005), the floristic nomenclature is a major and to some extent unsolvable problem. At a national and Ð in a few cases Ð continental scale, floras and checklists with a standardized nomenclature and with a consistent species concept are available (like Flora Europaea for the Western Palearctis). In a global perspective, such a database is missing. An effort to document accepted names is for example Species 2000. This list however is uncomplete and the taxonomic concept varies from region to region and from taxon to taxon. The same is true for The International Plant Names Index = IPNI (2005). Both data banks help to solve some problems of synonymy. Another problem is that the delimitation of the species changes through time. A consistent species concept however is a “conditio sine qua non” for the analysis of vicariance patterns and for the phytosociological classification. The syntaxa should reflect the floristic (dis)similarity of the stands and not author-specific nomenclature and species concepts. When a recent global treatment of a genus is available, and when the species of that genus are not sympatric, we can conclude from such a monograph which name is for example used today for “Limosella australis”, mentioned by author X in 1960 for EWV in area Y. Such monographs however are available only for a few taxa (see chapter 4.7.). A modern taxonomic treatment is missing for many keystone taxa in EWF such as Limosella. For this review and for the database “ephemeral wetlands”, the following pragmatic approach was applied: Isoetes-species are named according to Desfayes (2005), Lemnaceae after Landolt et al. (1998). For all other taxa, the nomenclature is adopted from the following regional checklists (in this sequence): Alston (1959) for ferns and fern allies and Lebrun & Stork (1991Ð1997) for flowering plants of tropical Africa, O’Shea (2003) and Wigginton (2004) for mosses respectively liverworts and hornworts of sub-saharan Africa, Cook (2004) and Johnson & Brooke (1998) for wetland plants of Southern Africa respectively New Zealand, the Western Australian Herbarium Florabase (1998 ff) for Southwestern Australia and Australia in general, Lavania et al. (1990) for aquatic plants in India and the surrounding countries, Corley et al. (1981) and Corley & Crundwell (1991) for mosses in Europe, Grolle & Long (2000) for liverworts and hornworts in Europe. The nomenclature of vascular plants in the Western Palearctis follows Tutin et al. (1968Ð1993) and Halliday & Beadle (1983), with a few modifications for Mediterranean species according to Médail (2004). Further species have been checked with the data

Habitats, plant traits and vegetation of ephemeral wetlands

551

banks of Species 2000 (2003) and The IPNI (2005) (in this sequence). In all other cases, the names used by the authors are kept. Naming and typification of plant communities and higher syntaxa are not validated and corrected according to the ICPN (Weber et al. 2000), but names used in the publications are applied (except for some obvious misspellings). 3.3.

Restrictions 3.3.1. Excluded habitats

Microecosystems with temporary waters, occurring in leaf sheaths of epiphytes in the tropics and in tree hollows: They are too different in size and dynamics to be compared to plant communities in the ecosystem dimension. Permanently submerged habitats: They are often in contact with the plant communities studied here and share some ecological conditions, life forms and taxa (like Isoetes). In the Palaearctic region, this vegetation type Ð not further considered here Ð is classified within I so et o- Li tt or el le te a. Ruderal vegetation of wet ground: Open habitats, which offer wet, nutrient-rich soils and favourable temperatures at the end of the growing season, are colonized by annuals of high productivity. Such species often occur also on ruderal sites or are common weeds. In the holarctic region, this vegetation type is placed in the class B id en te te a t ri pa rt it ae (Mucina 1997), in the Palaeotropical region in the R ud er al i- Ma ni ho te te a (order B id en te ta li a p il os ae ) (Schmitz 1988). The floristic links and the life cycles of this kind of vegetation are close to ruderals and therefore it is not considered in detail here, but mentioned when these communities are the final group in the annual sequence on emerging ground. Rheophytic vegetation: Podostemaceae (pantropical) respectively Hydrostachyaceae (Madagascar and Southern Africa) colonize rocks in rapidly flowing tropical and subtropical rivers. These species need a terrestrial phase for sexual reproduction and are mostly annual or biennial species. With these characteristics they generally fit into the framework of ephemeral wetlands. For the following three reasons they are not considered in this review: 1) The terrestrial phase is very short. 2) These plants attached to rocks and boulders in freshwater rapids and waterfalls comprise an evolutive world of its own with extreme adaptations in morphology and life cycle (Schnell 1998, Jäger-Zürn 1998, Cook 1990, 2004). 3) They often occur in monospecific stands. Most species are stenoendemics, sometimes restricted to a single cataract or river system.

552

U. Deil

3.3.2. Treatment of cryptogams EWV is often regarded as a vegetation type of simple vertical structure with one stratum. A closer look however shows, that in many situations a cryptogam layer is growing under the vascular plant stratum. In the holarctic region for example, liverworts of the genera Riccia, Anthoceros, Phaeoceros, Fossombronia and Riella and mosses from the genera Ephemerum, Pseudephemerum, Physcomitrium, Aphanorhegma (= Physcomitrella), Pohlia, and Archidium, a.o., often colonize ponded soil and muddy amphibic substrates, before vascular plants germinate, and they continue to grow under these plants (Dierssen 2001, Sérgio et al. 1997/98, Hugonnot & Hébrard in Grillas et al. 2004a, p. 19). Some vegetation scientists, when dealing with EWV, ignore the cryptogams, although they can contribute considerably to the total biomass of EWV and change the germination conditions for the vascular plants. Other authors do include cryptogams in their floristic samples, and such data are treated in three different ways: 1. Cryptogams are part of a multilayered association. An example for this synusial concept is the Centunculo minimi-Anthocerotetum agrestis, an association colonizing temporary inundated soils in arable land in Central Europe (see for example Popiela 1999, 2005 and Stalling 2005). 2. When mosses and liverworts dominate in the beginning of the amphibic phase, they are considered as an early phenophase. Leredde (1954) for example separates a Riccia crystallina-Funaria saharae-stade within a Cotula anthemoides-Vahlia oldenlandoides-community in the Tassili Mountains (Sahara). 3. Colleagues with a bryologist’s eye describe cryptogam communities. Examples for this approach are the R ic ci et um jo ve t- as ti i- ar ge nt ol im b at ae in briefly flooded rock depressions in Southern Yemen (Kürschner 2003), the P le ur id io ac um in at i- Op hi og lo ss et um l us it an ic i as winter ecophase of a C ic en di o- So le no ps io n-community in Northwestern Spain (Rodrı́guez-Oubiña et al. 2001), the R ie ll et um no ta ri si i in wet dune hollows in Tunisia (Vanden Berghen 1979a), or associations colonizing emergent pond bottoms in Western and Central Europe like R ic ci o c av er no sa e- Ph ys co mi tr el le tu m e ur ys to mi , R ic ci o h ue be ne ri an ae -P se ud ep he me re tu m n it id ae and Ph ys c om it re ll et um py ri fo rm is (for more details see von Hübschmann 1986, Dierssen 2001). These cryptogam communities can be part of an annual succession series, like the sequence B ot ry di et um gr an ul at i, R ic c io ca ve rn os ae -P hy sc om it re ll et um , Cy pe ro -L im os el le tu m, B id en ti on -community, which colonizes dessicating pond bottoms in Germany (Ant & Diekjobst 1967); the series R ic ci o h ue be ne ri an ae P se ud ep he me re tu m n it id ae , El eo ch ar it et um ac ic ul ar is and P ol yg on o h yd ro pi pe ri -B id en te tu m t ri pa rt it ae , observed by Duvigneaud et al. (1986) in drained fish ponds in the French Ardenne Mountains; and quite a similar series, studied by Cortini Pedrotti & Aleffi (1990) and Cortini Pedrotti (1992) at lake shores in the Italian Alps: B ot ry di et um gr an ul at i, R ic ci o c av er no sa e- Ph ys co mi tr el le t um , El eo ch ar it et um ac ic ul ar is , Bi de nt io n.

Habitats, plant traits and vegetation of ephemeral wetlands

553

In the synopsis about EWV presented here, cryptogams are excluded from the analysis for two reasons: 1. In most of the available data sets, cryptogams, algae and fungi are ignored or sampled incompletely. 2. The spatial distribution and ecological requirements of the cryptogam flora are only partially congruent with those of the vascular plants. Because of their smaller size and faster growth-cycle in comparison to vascular plants, they react to microenvironmental gradients at a still finer spatial scale. On a global scale, mosses and liverwort often show a much broader distribution. An example is the C ry ps io va gi ni fl or ae -E ra g ro st ie tu m h um if us ae in the Eastern Sahara Mountains (LeĚ onard 2001). Riccia cavernosa, a constituent member of this community, is very eurychorous. It occurs in seasonal wet or flooded habitats all over the world. The vascular plants are stenochorous: Crypsis vaginiflora and Eragrostis aegyptiaca ssp. humifusa are of saharo-arabian distribution. In conclusion: The survey presented here deals with patterns in the taxocoenoses of vascular plants, not with phytocoenoses including all taxonomic groups.

Results

4.1.

Habitat typology

This chapter should give answers to the following questions, raised in the introduction: 1) Can we typify SWH according to the hydrological, geomorphological and pedological situation? 2) Are such types linked to certain climatic zones of the earth and to specific pedo-geomorphological processes? The typology will be based upon physical factors. The aim of such a typology is to look for correlations between macroclimatic zones and the local water regime, which is modified by relief, soil and plant cover (see Semeniuk & Semeniuk 1995 for a similar approach). The variety of situation is illustrated by four figures (Figs. 4 to 7): In perhumid extratropical climates, EWV occurs at the shores of permanent rivers, lakes and artificial ponds with fluctuating water-level. The shores of these freshwaters are mostly emerging in summer, when precipitations are low. Artificial ponds are drained in summer from time to time and the exposed pond bottoms offer a niche for the EWF. This situation is illustrated by Fig. 4. It shows a carp pond in Germany, situated near a medieval monastery. As part of this cultural world heritage object, the basin is drained off in the traditional way in summer at an interval of ten years, and annual mud vegetation can establish on the pond floor. The inverse periodicity (terrestrial Ă? littoral sequence during the growing season) takes place at the shores of the Lake Constance: Snow smelting in the European Alps results in a maximum of the water-level in summer. There, the EWF uses the temporal niche in spring for its short life cycle. When we pass to a climatic zone with seasonal rainfall, rainfed ponds are seasonal, too. In Mediterranean areas with a winter maximum of precip-

554

U. Deil

Fig. 4. Rossweiher near Maulbronn (Germany). An artificial carp pond during summer drainage.

itation like in Northern Morocco (Fig. 5), the depressions are ponded in winter and dry out in summer. The favourable period is spring and therefore the term â&#x20AC;&#x153;vernal poolâ&#x20AC;? is often used for this kind of habitat. At the southern fringes of the Sahara, the cycle is inverse with submersion in summer and an amphibic phase in fall (autumnal pond). In semi-arid and arid regions with short, torrential and unpredictable rainshowers, ephemeral vegetation occurs along intermittent streams. Fig. 6 shows a carpet with Bacopa monnieri in the Yemeni lowlands in Southern Arabia. When we go to the subhumid or perhumid tropics, short-living annual plants are restricted to run-off hydrological systems like rock outcrops (Inselberg, Bonhardts). Ephemeral vegetation either colonizes temporarily flooded rock pools or occurs on the slopes of inselbergs, furthered by water seeping from mats with perennial plants. Such throughflow systems rarely occur also in extratropical regions like on a rock outcrop in the southern part of Portugal (Fig. 7). Ephemeral wetlands can be roughly classified in three types of habitats (Fig. 8): the shoreline habitat, the seasonal pool habitat and the ephemeral flush habitat. The global distribution of these habitats, defined according to landform and hydrology, is illustrated in Fig. 9. Fluctuations of the water-level are the results of variations in precipitation, evapotranspiration, surface and groundwater inflow and outflow, infiltration rate, and drainage

Habitats, plant traits and vegetation of ephemeral wetlands

555

Fig. 5. Vernal pool near Tangier (Morocco).

intensity. There is a clear geographical pattern of these habitat types, which will be explained now. The shoreline habitat (= SHH) dominates in the perhumid extratropical temperate climatic zones along the shores of shallow freshwater lakes, artificial ponds and rivers. It further occurs in mountainous regions of the Tropics. In both situations, the fluctuating water-level reacts to increased evapotranspiration and reduced precipitation in summer respectively in short dry seasons. Man-made pond-landscapes, created for Carp cultivation, are known from different parts of Central Europe, such as South Bohemia (Czech Republic), Franconia (Germany), and la Dombes in Burgundy (France). When the catchments are very extended, the SHH can be found along allochthonous rivers in semi-arid and even arid climatic zones: A pronounced seasonal precipitation regime in the adjacent climatic zone creates a floodpulse which inundates vast plains. The largest ephemeral wetland of this type is the Pantanal of Mato Grosso in South America (Schessl 1997, Eskuche 1975, Wolf 1990) and the floodplains of rivers from the Andes entering the Amazon basin (Beck 1983, Seidenschwarz 1986, Janssen 1986, Haase 1989). The flat watershed between the Indian and Atlantic Ocean in SE Africa is covered by seasonal ponded swamps (so-called â&#x20AC;&#x153;damboâ&#x20AC;?) of very large size (Taylor et al. 1995). Seasonal floodplains also occur in Southern Siberia: Melting snow in late spring and still frozen estuaries in the Arctic Ocean result in a high waterlevel of big rivers running to the north like the Ob and the Irtysh. Ephem-

556

U. Deil

Fig. 6. Bacopa monnieri-carpet along intermittent stream in the At Tur Basin (Yemen).

eral wetlands establish in summer along these river shores, when the waterlevel declines (Taran 1993, 1994, 1995, 2000, 2001, Klotz & Köck 1984). The seasonal pool habitats (= SPH) are concentrated in the subhumid areas on both sides of the Tropic of Cancer. In the subtropical regions, the wet season is mostly spring and the pools desiccate in early summer. The widely used terms “vernal” and “autumnal pool” in geobotanical literature are correct from the viewpoint of vegetation scientists, focussing on the developing plant cover in spring respectively fall. In the hydrological sense, the pools are “hibernal“ respectively ”aestival” (Norwick 1991), because they are water-filled throughout the winter and spring seasons respectively summer and fall. In the dry tropics, flooding occurs in summer and the pools become dry in autumn. The SPH include periodically inundated depressions in sandy soils with an impermeable bedrock in the underground,

Habitats, plant traits and vegetation of ephemeral wetlands

557

Fig. 7. Chaetopogon fasciculatus bordering a cushion of rock debris on a syenite outcrop in the Serra de Monchique (Portugal).

Fig. 8. Geomorphological and hydrological situations with ephemeral wetland vegetation.

558

U. Deil

Fig. 9. Global distribution of ephemeral wetland habitats.

depressions over lateritic crusts, deflation hollows on volcanic ash and shallow rainfed rock pools. VP landscapes occur in California (Holland 1998) and along the Moroccan coast around Ben Slimane (see the geological map by Destombes & Jeanette 1966). The size of the TP ranges from a few square metres in rockpools to several hectares in Moroccan dayas. In semi-arid areas, rainfall is more episodic and catchments are endorheic. Vleis (= temporary marshes), and pans (= endorheic shallow depressions) are for example widespread in a belt surrounding the Karoo in Southern Africa (Breen et al. 1993, Taylor et al. 1995) and at the southern fringes of the Sahara Atlas in Algeria (Barry & Faurel 1973). Thousands of â&#x20AC;&#x153;playasâ&#x20AC;? are scattered over the Southern Great Plains in the USA. The temporary waters in endorheic basins in semi-arid regions are often poikilohaline, with a freshwater phase after flooding and saline or alkaline conditions before drying out. Intermittent rivers are mostly of endorheic nature, ending in salt pans. Pure rainfed ponds are often poorly buffered with dramatic diurnal changes of dissolved carbon dioxide, oxygen and pH. Water chemistry is similar to oligotrophic lacustrine habitats. Seasonal inundation can be the direct result of seasonal rainfall and surface drainage or the indirect effect of a fluctuating groundwater level, rising above the surface during the wet season. The latter phenomenon often occurs in dune slacks. Until now, VP hydrology has been poorly studied. Two experimental sites in California show that the pools are mostly rainfed there. At the Central Great Valley site, subsurface outflow in winter and inflow in spring reduces the amplitude of the water-level fluctuations and retards desiccation in early summer (Hanes & Stromberg 1998). The VP hydrology is better described by a mini-catchment system than by a pure

Habitats, plant traits and vegetation of ephemeral wetlands

559

rainwater-evapotranspiration system. In the Santa Barbara region, the frequency of heavy rainfall events is an important factor explaining the waterlevel fluctuations (Pyke 2004a). The soil-forming processes of the stagnant layer were studied by Hobson & Dahlgren (1998) in VP in California. The ephemeral flush habitat (= EFH) concentrates on rock outcrops in the Subtropics and on tropical inselbergs, and along river shores of intermittent rivers, flowing after torrential rainfall. Runoff and interflow create episodically wet conditions in coarse-grained cushions of rock debris (“paluslope” sensu Semeniuk & Semeniuk 1995). The accumulation of the substrate is often biogenic. The term ephemeral flush vegetation (= EFV) was coined by Richards (1957) in Western Africa for a short-living plant cover, irrigated by interflow water from the adjacent Afrotrilepis mats, and has been accepted by scientists studying inselberg vegetation (see for example Hambler 1964 and many papers of Porembski and co-workers). Both habitats are restricted to inselbergs. Inselbergs and EFH are common in subhumid tropical climates. Rare outliers occur in the extratropical regions like in the Southeastern United States, in Southern Portugal, and on rock outcrops in Southwestern Australia. The hydrology of this interflow-system is not well known (but see first observations by Rudner 2005a, 2005b). The role of geomorphodynamic processes and physical disturbance: When the water respectively the precipitation regime is very variable and soil water is not available for perennials in the dry season, the relief can be stable and above-ground destruction of the plant cover is not necessary to maintain the EWV in the long run. In subhumid and semi-arid climates, temporary ponds can be extremely stable structures in the geomorphological sense. They can persist in the same location for centuries or millenia and fill with sediments very slowly. The persistence seems to be the result of rapid oxidation of organic matter during the dry phase, which substantially reduces the rate of biogenic sediment accumulation (Collinson et al. 1995). In perhumid climates, which allow permanent plant growth, a local destruction of the plant cover might be necessary to exclude the competition of perennial species. The disturbance factors can be different: 1. Geomorphodynamic processes like remodelling of surface by floodings, bank erosion, and ice scour destroy the high-growing perennial plant cover and create patches of open soil. Local destruction of EWH ensures in the long term the stability of the EWV at a regional scale. EWH are often shuttle habitats in alluvial landscapes. 2. In subarctic regions cryoturbation and lifting of the perennials by needle ice is a precondition for the existence of “flags” (EWV in Iceland) (Sörensen 1942). The same is true for patches of bare soil and mud in the paramo steppes and the hard cushion mires in the orotropical bioclimates of the Andes and the East African Mountains. 3. Pawing and wallowing by bison destroy the perennial plant cover in the Great Plains in North America. This creates ephemeral pools and deepens playa lakes. Rooting by wild boar and by pigs created germi-

560

U. Deil

nation niches for short-living ephemerals in permanent grassland in Europe. Soil transport and modelling of a pool Ð hummock microrelief by pocket gophers is recorded by Cox (1984) from a mima-moundlandscape in California. The role of pasturing is discussed in detail in chapter 4.8.7. Scientific and vernacular names: Seasonal ponds occur in many parts of the world. Besides frequently used terms in English scientific literature like “vernal pools” (California), “playa lakes” (Southern Great Plains), “potholes“ (Northern Great Plains, USA), kettle holes in moraines in New Zealand (Johnson & Rogers 2003) and ”mares temporaires” in French speaking countries, many local names are used for this habitat. Examples are “dayas” and “merjas” for vernal pools respectively amphibian habitats in Maghreb countries (Morocco, Algeria, Tunesia), “padule” in Corsica, “bonales“ in Spain (Rivas Goday & Rivas-Martı́nez 1963), ”niayes“ in Senegal, “Himmels-Teiche” for precipitation-filled ponds in Germany, “Sölle” for potholes in Pleistocene landscapes in NE Germany, “flags” in Iceland (Sörensen 1942), “vleis“ in South Africa, ”palanganas“ in the Argentinian pampa and “ñadis” for depressions over soils with hydromorphic character in Chile. Stream beds in deserts with periodic to episodic water flow are called “oued” or “wadi” in Arab speaking countries, “omuramba“ and ”oshana” in the Namib Desert (Lindeque & Archibald 1990/91, Hines 1990/93), “creek” in North America, and “vazantes” in the floodplain of Mato Grosso in South America (Schessl 1997). “Barlkarra“ is the aboriginal name for seasonal and intermittent floodplains in NW Australia (Semeniuk & Semeniuk 1995). Temporary water-filled rock pools and dolines are called ”gnammas” on granite rock outcrops in SW Australia, “kamenitzas” respectively “pozzi” on karstic plateaus on Malta and Corsica, “turloughs“ in Ireland (Ivimey-Cook & Proctor 1966) ”polje” in the Balkan region, “bowals” over lateritic crusts in the Sahel zone and “dalles rocheuses” in French literature. Temporarily flooded depressions in biogenic mats on inselbergs in French Guiana are named “mares gravillonaires“ (de Granville 2002). In the SE USA, Ware (2002) distinguishes inselbergs (island hills), rock outcrops, glades (open patches with shallow soil or bedrock) and cedar glades, when supporting Juniperus trees. All these relief types can include small-scale temporary wetlands. Not biologists, but indigenous people have developed the most detailed classification system for EWH (Shepard et al. 2001). To perceive the habitats according to time, depth, and duration of flooding and dominant plant species and to communicate such a typology is essential for Indians in seasonal floodplains in the Amazonian basin of Peru. “Apamankera nia” are areas flooded during the rainy season, “osateni” seasonally waterlogged depressions in the floodplain, and “yogetsapini“ shoreline habitats with Ludwigia. A very detailed terminology is also applied by the Toba-Pilagá people, an Indian group living in the Gran Chaco alluvial plain in Argentina (see Scarpa & Arenas 2004).

Habitats, plant traits and vegetation of ephemeral wetlands

4.2.

561

Distribution of selected diagnostic taxa

EWH are distributed nearly all over the world (Fig. 9). A first insight into the floristic data set (Fig. 2) however shows, that most of the species are restricted to a certain floristic kingdom. Even eurychorous species like Juncus bufonius (Fig. 10) are not cosmopolitan. In this chapter we present distribution maps of some keystone taxa of EWF and we discuss the question, to what extent the phytochorology of diagnostic taxa reflects the present climatic differentiation of the globe and to what extent such spatial patterns are the result of historical events (palaeogeography and plate tectonics, evolution and speciation processes). The distribution of EWS has been poorly analysed. Most information has to be taken from different floras. An important bibliographic resource is Cook (1990): He outlines the global distribution of all genera of aquatic plants. Casper & Krausch (1980, 1981) mention the distribution of genera and species of vascular plants, which occur in fresh waters in Central Europe, Meusel et al. (1965, 1978) and Meusel & JĂ¤ger (1992) provide maps for selected taxa of the European flora with an outlook to the global distribution of some genera. A very informative chorological analysis for the Palaearctic region, focussing on the class I so et o- Na no ju nc et ea , was realised by von Lampe (1996): She presented distribution maps for 33 species, which are diagnostic for the alliance N an oc yp er io n sensu lato, and she discussed correlations between distribution, growth form, phenology and germination ecology. The areas of some species are good indicators for the distribution of high ranked syntaxa. Juncus bufonius (Fig. 10) for example is a very constant

Fig. 10. Distribution of Juncus bufonius (from von Lampe 1996).

562

U. Deil

member of the holarctic class I so et o- Na no ju nc et ea . The populations in the Southern Hemisphere are mostly regarded as synanthropic. Myosurus minimus s.str. (Ranunculaceae) is holarctic too, but with a clear preference to the western parts of the continents in the Northern Hemisphere (Fig. 11) (for the coenology see Vicherek 1968). The other taxa of that genus are stenochorous and speciation is still under way: Myosurus minimus is splitting into M. minimus s.str. (holarctic region; synanthropic in Australia = M. minimus ssp. australis) and M. minimus ssp. novae-zelandiae (New Zealand). The closely related taxa M. apetalus (South America), Myosurus patagonicus (Southern Argentina and Chile) and M. sessilis (Mediterranean region) seem to be bona fide species. Myosurus is linked to ephemeral wet habitats in extratropical climates. The distribution map with the vicarious and habitat equivalent Myosurus patagonicus in South America indicates the synareal of an extratropical class in South America, and the synanthropic occurrence of Myosurus minimus in the Australian region shows the risk of invasions to niche-equivalent habitats in other floristic kingdoms. Further vicariance patterns, restricted to the Western Palaearctic region, occur for example in Mentha sect. Pulegium and Centaurium subsect. Parviflora (von Lampe 1996) and in Elatine triandra s.l., Rumex maritimus s.l. and Veronica peregrina (HulteĚ n 1971). The areas of the I so et o- Na no ju nc et ea -species are heterogeneous regarding oceanity and zonality. A number of taxa have a distribution similar to Cicendia filiformis (Gentianaceae) (Fig. 12): Radiola linoides, Juncus capitatus, Hypericum humifusum, Illecebrum verticillatum, Montia fontana ssp. chondrosperma, Corrigiola litoralis and Exaculum pusillum (= Cicendia pusilla) are, like Cicendia filiformis, restricted to the atlantic parts of Europe

Fig. 11. Distribution of the genus Myosurus (from von Lampe 1996).

Habitats, plant traits and vegetation of ephemeral wetlands

563

Fig. 12. Distribution of Cicendia filiformis (from von Lampe 1996).

and NW Africa (the Teesdalia-chorotype sensu Meusel et al. 1965). They are associated in depressions in oceanic heathland on acidic sandy soils (R ad io li on sensu Pietsch 1973a) and they are dormant in winter. The exogenous dormancy is induced by low temperatures (von Lampe 1996). In the New World, Cicendia filiformis is replaced by C. quadrangularis, a species also strictly linked to VP and to an oceanic subtype of the mediterranean and temperate climates of California, Chile, Argentina and Peru (Meusel et al. 1978). EWS colonize habitats with little competition, the dispersal capacity of the species is high. One can therefore suppose that the areals are more or less an expression of the physiological valence of the species (von Lampe 1996). There is a clear correlation between the distribution and the kind of hibernation, the start of germination, first sprouting in spring etc., all factors which reflect the thermal requirements. Westside species have an autumnal maximum of germination and sprouting. Character species of mud vegetation in the temperate zone of the Palaearctic region (E la ti ni -E le oc ha ri ti on ov at ae sensu Pietsch 1973a) range from Central Europe to Central Asia, some of them further to East Asia such as Cyperus fuscus, Coleanthus subtilis, Gypsophila muralis, Potentilla supina and Carex bohemica. The European taxon Elatine hydropiper is replaced in Central and East Asia by E. spathulata. Eleocharis ovata, Coleanthus subtilis and Myosurus minimus are facultative perennials or winter annuals with endogenous dormancy. Summer annuals with endogenous winter dormancy of Eurasian distribution are Lindernia procumbens and Cyperus michelianus, of holarctic distribution Limosella aquatica, Cyperus flavescens, Eleocharis acicularis,

564

U. Deil

E. ovata and Anagallis minima. E. ovata is replaced in the western part of the North American continent by E. obtusa. Some species of the latter chorotype are considered in Northern America as synanthropic (Filaginella uliginosa for example). In the holarctic region, the EWF impoverishes more and more towards the boreal zone. A phytogeographical element restricted to circumarctic and subarctic distribution with southern outliers in the alpine belt of the Central Asian Mountains (Yunnan) and the Rocky Mountains is Koenigia islandica (Polygonaceae) (see map 55 in Hultén 1971). A closely related taxon (K. fuegiana) occurs in Tierra del Fuego. Limosella, a cosmopolitan genus of Scrophulariaceae with about 11 species comprises rosulate, creeping, dwarfish annual herbs (Cook 2004). The genus name “mud wort” indicates already the habitat preference (limose = muddy). Some species are widespread like L. aquatica (Northern Hemisphere, see map 6 in von Lampe 1996), L. africana (African Mountains from Ethiopia and Cameroon to South Africa), L. australis (= L. major = L. subulata = L. minuta) (mountains of Africa, Namibia, Australia, Eastern North America, Great Britain), L. grandiflora (= L. capensis) (from Ethiopia to South Africa), L. longiflora (= L. lineata) (Southern Hemisphere), L. major (Central and Southern parts of Africa). Other mud worts are stenochorous and stenoic like L. inflata and L. vesiculosa (endemic in rock pools of South African mountains), and L. pubiflora (Arizona). Limosella africana is name-giving for a class of EWV in Eastern and Southern Africa, L. australis for a syntaxon in South America (see chapter 4.3.) (the taxonomic delimitation of L. australis and of Limosella-species in general however is unclear according to Cook 2004). Lilaeopsis is a perennial Apiaceae of juncoid aspect. All the 13 known species colonize muddy substrate in fresh and brackish water by creeping stolons. The distribution of the genus was originally restricted to the New World and to the Southern Hemisphere (Affolter 1985, Cook 1999) (Fig. 13, left part). L. attenuata (= L. carolinensis?) is naturalized for some decades in estuaries in NW Spain (Géhu 1975, Rodrı́guez et al. 1997). The species occurs in EWH in Argentina, Florida and along the Atlantic coast of North America (an amphitropical and bi-temperate distribution sensu Raven 1963). Lilaeopsis macloviana (syn. L. andina, Crantzia lineata, L. patagonica, L. sinuata, L. hillii and L. exigua) outlines the range of a EWV syntaxon, which is related to emergent pond shores in the Paramo belt in the Andes, and further to the south Ð in the temperate climate Ð declines to sea level (Fig. 13, right part) (see for example Ruthsatz 1995 for Argentina, Galán de Mera 1995 and Galán de Mera et al. 2003 for Peru). L. novaezelandiae and L. ruthiana are endemic in New Zealand. Both species occur in seasonally inundated dune valleys (Sykes & Wilson 1987, Wilson et al. 1993, Haacks 2003, Johnson & Rogers 2003). The vicarious L. polyantha is endemic in Tasmania and SE Australia. It also occurs in dune slack communities (Haacks & Thannheiser 2003, Nicol et al. 2003). Limnophila (Lindernieae) and Rhamphicarpa (Rhinanthoideae) are genera of palaeotropical distribution (see Fig. 14). Limnophila has its centre of

Habitats, plant traits and vegetation of ephemeral wetlands

565

Fig. 13. Lilaeopsis E. L. Greene (Apiaceae). Ă? Left: World-wide distribution of the genus with number of species. Right: Areal of L. macloviana (open dots: identity uncertain) (adopted from Affolter 1985).

diversity in Asia (Philcox 1970), Rhamphicarpa in Africa (Hansen 1975). Both genera of the family Scrophulariaceae characterize mud vegetation in the tropical and subtropical regions of the Old World. Limnophila ceratophylloides for example occurs in amphibic environmental conditions in the Congo basin (Masens 2000), L. indica in Papua New Guinea (Conn 1983). Rhamphicarpa is a semi-parasite on wild and cultivated Oryza as host plants. Rhamphicarpa fistulosa (syn. R. australiensis and R. longiflora) characterizes a West African class of mud vegetation, the R ha mp hi ca rp o f is t ul os ae -H yg ro ph il et ea se ne ga le ns is (MĂźller & Deil 2005). The highest rates of endemism in the EWF can be found in EWS in California and in SW Australia. Many stenochorous species, associated in the EWH, result in endemic phytosociological classes. VP in the californian floral province (California, Baja California, SE Washington, SW Oregon) contain two elements: widespread aquatic and amphibic cosmopolitans and specialized VP endemics (Keeley & Zedler 1998). Widespread are for example the genera Callitriche, Crassula, Elatine, Eleocharis, Isoetes, Juncus, Lilaea, Marsilea, Myosurus and Ranunculus. In most cases, the species in California have close relatives in the European-North African Mediterranean area. The vernal pool specialists however are endemic to California (55 % of VP flora according to Barbour et al. 2005). Genera like Limnanthes and Pogogyne, furthermore all members of the tribus Orcuttieae within Poaceae (Neostapfia, Orcuttia and Tuctoria) characterize the D ow ni ng io b ic or nu ta e- La st he ni et ea fr em on ti i. Other genera like Lasthenia, Psilocarphus, Downingia and Navarretia are of amphi-neotropical distribution (see Tab. 1 in Keeley & Zedler 1998). They are shared with the mediterranean part of Chile, with either identical or vicarious species (Raven 1963, Bliss et al. 1998). These taxa are the basis for the class-group D ow ni ng io N av ar re te a (see chapter 4.3.).

566

U. Deil

Fig. 14. Distribution of Rhamphicarpa Benth. emend. Engl. (adopted from Hansen 1975) and Limnophila R.Br. (from Philcox 1970).

The ephemeral dwarf plant vegetation in winter wet sandy depressions, along intermittent water courses and on rock outcrops in SW Australia belongs to the class C en tr ol ep id i- Hy dr oc ot yl et ea al at ae (Pignatti & Pignatti 1994). This vegetation type is endemic to SW Australia (56 % SW Australian endemics), and characterized by Centrolepidaceae, Asteraceae, Apiaceae (Hydrocotyle), Cyperaceae, Juncaginaceae and Stylidaceae. Remarkable is the nearly total absence of Juncaceae (besides some introduced species like Juncus bufonius). The dwarf rush niche is occupied by the Centrolepidaceae. They have been discerned as the character family of this vegetation type already by Diels (1906). In a global perspective, the EWF shows remarkable geographical patterns. Azonal distribution and cosmopolitan areals are rare in this group of plants. Historical events like the splitting of the Australian plate from Gondwanaland respectively the separation of Africa and South America and speciation processes in Cretaceous and Tertiary times are visible in the endemic EWF in SW Australia and in the floristic contrast between the neotropical and the palaeotropical regions. Close floristic links between Eurasia and Eastern North America show that the concept of a common holarctic kingdom is also supported by the EWF. The present climatic differentiation of the globe, first of all the contrast between extratropical regions with frost and winter rain and tropical, frost-

Habitats, plant traits and vegetation of ephemeral wetlands

567

free conditions with summer rain, is very obvious when comparing the EWF north and south of the Sahara. The delimitation between the palaeotropical and the palaearctical region is in the EWF as accentuated as in the flora in general. 4.3.

Floristic composition, distribution and ecology of vegetation types

This world-wide review is restricted to high-ranked syntaxa. It presents a synopsis of the hitherto described classes, orders and alliances, lists some characteristic species and outlines the ecological conditions of the plant communities. Associations are mentioned only exceptionally. Rankless communities are only considered when they are distributed over a broader geographical area and when they have a pronounced floristic individuality. The sequence of the presentation follows Fig. 2 and chapter 3.1. Annotations to the distribution of the syntaxa (their synareal) are tentative (see Figs. 15 and 16). 4.3.1. North America Mud vegetation in the Canadian Prairie Provinces and in the zone with temperate climate in Eastern Canada and NE USA belongs to the B ec km an ni o s yz ig ac hn e- Ru mi ce ta li a s al ic if ol ii (Looman 1982) with

Fig. 15. Tentative distribution of ephemeral wetland syntaxa in the New World.

568

U. Deil

Tab. 1. Syntaxonomic survey of EWV in Northern America. Temperate and boreal zones Isoeto-Nanojuncetea Br.-Bl. & Tx. ex Westhoff et al. 1946 Beckmannio syzigachne-Rumicetalia salicifolii Looman 1982 mud-vegetation of NE Northern America and the Canadian Prairie Provinces Nanocaricion Looman 1982 Northern Parkland and Boreal zone Rumicion fuegini Looman 1982 Southern Parkland and Prairie zone Mediterranean zones Downingio bicornutae-Lasthenietea fremontii Barbour et al. 2003 vernal pool vegetation of the Californian Floristic Province Downingio bicornutae-Lasthenietea fremontii Barbour et al. 2003 communities at the upper fringes of vernal pools, with short inundation period Downingio bicornutae-Lasthenion fremontii Barbour et al. 2003 Lasthenietalia glaberrimae Solomeshch & Holland in Barbour et al. 2005 communities in long ponded pool bottoms Lasthenion glaberrimae Solomeshch & Holland in Barbour et al. 2005 Southern Great Plains (Oklahoma) Coreopsis tinctoria-Croton lindheimerianus-Agrostis elliottiana-community Ozarks glades (Arkansas and Missouri) Leavenworthia uniflora-Hypericum gentianoides-Sedum nuttallianum-community Granite outcrops of the Appalachian Piemont (Georgia) Isoetes melanospora-Amphianthus pusillus-Sedum pusillum-community

two alliances, separated according to region and climate: N an oc ar ic io n in the Northern Parkland and in the Boreal zone, R um ic io n f ue gi ni in the Southern Parkland and in the Prairie zone (Tab. 1). CS are Beckmannia syzigachne, Rumex salicifolius, Eleocharis acicularis, Plagiobothrys scoulieri and Veronica peregrina. Looman states a high similarity of EWV in the Neoarctis with corresponding vegetation units in Europe. I-N CS, common between North America and Eurasia, are Juncus bufonius, Elatine triandra, Anagallis minima, Limosella aquatica, Myosurus minimus, Alopecurus aequalis a.o. Some taxa are vicarious at an infraspecific level such as Rumex maritimus var. fueginus and Veronica peregrina ssp. xalapensis. The neoarctic B ec km an ni oR um ic et al ia are replaced in the Palaearctic region by the Cy pe re ta li a f us ci . EWV on the mud banks of big rivers in Siberia like the Amur, Ob and Irtysch have many taxa in common with Canada such as Alopecurus aequalis (incl. A. amurensis), Rumex maritimus (incl. R. ucrainicus) and Beckmannia syzigachne (Ünal 1999, Klotz & Köck 1984, Taran, 1994, 1995). In the continental climate of Canada (Looman 1982), Central Asia (Hilbig 1995, Ünal 1999) and at the eastern side of the Eurasian continent in

Habitats, plant traits and vegetation of ephemeral wetlands

569

Japan (Shimoda 1983), I-N- and B id en te te a-communities are difficult to separate. This results from a steep increase of the temperature in late spring and a short vegetation period. As a consequence, the life cycles of early (cold) and late (warm) germinating species overlap. Bidens cernua, Polygonum lapathifolium, P. hydropiper a.o. occur with high constancy in the B ec km an ni o- Ru mi ce ta li a-communities in Canada. Beyond the associations P ri mu le tu m m is ta ss in ic ae and Gr at io le t um ne gl ec ta e, Looman (1982) mentions further undescribed communities with Navarretia leucocephala ssp. minima, Lilaea scilloides and Polygala paucifolia. Open patches in Scirpus americanus tall herb communities along the St. Lawrence river are colonized by the L im os el lo su bu la ta eC yp er et um ri vu la ri s (GeĚ hu & GeĚ hu-Franck 1985). It has some ecological and floristical similarities with European N an oc yp er io n communities. Plant communities, colonizing shorelines of oligotrophic waters in the Province of Quebec, and characterized by Eriocaulon aquaticum, Eleocharis acicularis, Subularia aquatica, Littorella uniflora, Juncus brevicaudatus and Lobelia dortmana (Galiano 1957), are more or less identical with the E ri oc au lo -L ob el ie tu m, described by Braun-Branquet & TĂźxen (1952) from Ireland. They belong to the I so et o- Li tt or el le te a, a class of shallow oligotrophic waters in the holarctic kingdom. Millions of prairie potholes occur in Northern America. Hydrologically, they range from temporal to permanent wetlands. They are not considered here, because even in the temporary wetlands the above-ground vegetation is predominantly permanent. VP vegetation in California has a few species in common with EWV in the temperate parts of Northern America and Eurasia such as Juncus bufonius, Eleocharis acicularis, Veronica peregrina, Myosurus minimus, Lythrum hyssopifolia and Eleocharis palustris (incl. E. macrostachya). A large number of species however occurs exclusively in the californian phytogeographical province. Based upon these species, Barbour et al. (2003) recently described the D ow ni ng io bi co rn ut ae -L as th en ie te a f re mo nt ii . This class is quite congruent to what has been outlined by Knapp (1957) as D ow ni ng io -N av ar re te ta li a. Californian VP vegetation is adapted to a winter rain climate and colonizes VP, dessicating in late spring and early summer. According to pool depths, inundation period and surface temperatures during the amphibic phase, two orders can be distinguished: D ow ni ng io -L as th en ie ta li a f re mo nt ii in the middle and upper part of the pools, and L as th en ie ta li a g la be rr im ae in deep parts and in long submerged pools (Tab. 1) (Barbour et al. 2003, 2005). CS are Alopecurus saccatus, Callitriche marginata, Crassula aquatica, Deschampsia danthonioides, Downingia bicornuta, D. ornatissima, Elatine californica, Croton setigerus, Eryngium vaseyi, Gratiola ebracteata, Isoetes orcutii, I. howellii, Juncus uncialis, Lasthenia fremontii, Lilaea scilloides, Pilularia americana, Plagiobothrys stipitatus, Pogogyne ziziphoroides, Psilocarphus brevissimus a.o. With preference for the margin of the pool (= CS D ow ni ng io -L as t he ni et al ia fr em on ti i) one can mention: Blennosperma nanum, Cicendia quadrangularis, Chlorogalum angustifolium, Downingia cuspidata, Hemi-

570

U. Deil

zonia fitchii, Juncus capitatus, Lasthenia californica, L. platycarpha, Layia fremontii, Limnanthes douglasii, Microseris acuminata, Navarretia tagetina, Plagiobothrys chorisianus var. undulatus, P. greenii, Plantago elongata, Psilocarphus oregonus, P. tenellus, Trifolium depauperatum. This order is further differentiated by transgressive “upland” species. Some are natives such as Lupinus bicolor and Castilleja campestris. Most of these invaders however are introduced annuals from the Western Palearctic Mediterranean area like Aira caryophyllea, Vulpia bromoides, Taeniatherum caput-medusae, Erodium botrys and Leontodon taraxacoides. OC of L as th en ie ta li a g la b er ri ma e are: Eleocharis palustris (incl. E. macrostacha), Lasthenia glaberrima, Pogogyne douglasii, Plagiobothrys leptocladus, Legenere limosa, Lythrum portula, Navarretia leucocephala and Trifolium variegatum. The results of earlier papers and local studies in California (Holland & Jain 1977/88, 1981/84, Kopecko & Lathrop 1975, Schlising & Sanders 1982, Heise & Merenlender 1999) fit into this scheme. Observations outside the State of California are preliminary. The D ow ni ng io -L as th en ie te a occur also in Baja California (Mexico) (Moran 1984), in Oregon and in Eastern Washington. The vegetation in depressions in the Lava Plains of Southeastern Oregon, called “upland playas”, resembles the Northern basalt flow ponds in California (Clausnitzer & Huddleston 2002) and fits into the same Californian class. Eastern Washington shelters northern outposts of the D ow ni ng io -L as th en ie te a (Crowe et al. 1994): TP situated in the Artemisia tridentata ssp. wyomingensis-steppe are characterized in their deeper parts by taxa like Navarretia spp., Plagiobothrys spp., Psilocarphus spp., Epilobium torreyi and Deschampsia danthonioides. Some EWV-types in California are not well known, like a community with Marsilea vestita, Eleocharis parishii and Alopecurus saccatus on the Santa Rosa plateau and a variant on alkaline soils with Cressa truxillensis, Crypsis schoenoides, Distichlis spicata (Kopecko & Lathrop 1975) and with Pleuropogon californicus (Barbour et al. 2005). VP with oligosaline conditions at the end of the ponding period are differentiated by halotolerant species like Lilaea scilloides, Crypsis schoenoides, Polypogon monspeliensis, Cotula coronopifolia, Downingia insignis, Cressa truxillensis, Distichlis spicata, Psilocarphus tenellus and Frankenia salina (Holland & Jain 1981/ 84, Barbour et al. 2005). There are obvious vicariance patterns between California and Southern Europe respectively Northern Africa, where I-Ncommunities are in spatial or seasonal contact with communities of the orders C ry ps ie ta li a a cu le at ae and F ra nk en ie ta li a, characterized by Cressa cretica, Crypsis spp., Frankenia spp., Polygonum monspeliensis. The flora of the Californian VP has two elements: widespread cosmopolitans and specialized endemics (Keeley & Zedler 1998). Widespread are for example the aquatic and amphibic genera Callitriche, Crassula, Elatine, Eleocharis, Isoetes, Lilaea, Marsilea, Myosurus and Ranunculus. In most cases, the Californian species of these genera have close relatives in the European-North African Mediterranean area. The true vernal pool specialists however are endemic in California such as the genera Limnanthes, Leg-

Habitats, plant traits and vegetation of ephemeral wetlands

571

enere and Pogogyne, and further all members of the tribus Orcuttieae within Poaceae (Neostapfia, Orcuttia and Tuctoria). Other genera like Lasthenia, Psilocarphus, Downingia and Navarretia are of amphi-neotropical distribution (Raven 1963, Thorne 1984, Keeley & Zedler 1998). These taxa occur also in the mediterranean part of Chile, either with identical or with vicarious species. These taxa characterize the New World class group D ow ni ng io -N av ar re te a. The information about ephemeral vegetation in playa lakes in the southern high plains of the Midlands is fragmentary (Bolen et al. 1989). Better known are buffalo wallows in SW Oklahoma. Polley & Collins (1984), Polley & Wallace (1986) and Uno (1989) studied these depressions, which are created during the rutting season by bison bulls, pawing the ground and then wallowing repeatedly. The number of pools must have been tremendous in prehistoric times. Buffalo wallows have a unique assemblage of annual species, differing from the surrounding perennial prairie. Ephemeral spring vegetation is dominated by Coreopsis tinctoria, Croton lindheimerianus, Myosurus minimus, Veronica peregrina, Agrostis elliottiana and Alopecurus carolinianus. The summer ecophase is a mixture of annuals (Ambrosia psilostachya, Ammannia coccinea) and perennials (Lythrum californicum, Bothriochloa saccharoides, Juncus torreyi). The vegetation mosaic on glades (openings in woodlands) in the Ozarks, an outcrop area in Northern Arkansas and Southern Missouri, was studied by Ware (2002). Superficial soils over impermeable bedrock, saturated in winter and submitted to frost-heaving, are colonized by small annual herbs (Leavenworthia uniflora, Hypericum gentianoides, Minuartia patula, Sedum nuttallianum, S. pulchellum), annual grasses (Sporobolus neglectus, S. ozarkanus, S. vaginiflorus) and perennial succulents (Talinum calycinum, T. parviflorum). The deeper parts of playa lakes in Texas are colonized by Marsilea vestita, Heteranthera limosa, Myosurus minimus, Ambrosia grayi and Veronica peregrina, the outer fringes by Lippia nodiflora, Verbena bracteata, Oenothera canescens and Nothoscordum striatum (Reed 1930). The vegetation of seasonal flooded karstic sinkholes in the coastal plain of Georgia is outlined by Kirkman et al. (1998). Elements of an EWF occur in the LudwigiaRhexia-, Gratiola-Justicia- and the Leersia-Panicum-group with species such as Ludwigia linearis, L. linifolia, Eriocaulon decangulare, Eryngium prostratum, Rhexia aristosa, Gratiola brevifolia, G. ramosa, Bacopa caroliniana, Eleocharis minima, Justicia ovata, Leersia hexandra a.o. The vegetation mosaic of outcrop areas can include EWH of the temporary rockpool type, in a few cases EFV. Several such outcrop systems occur east of the Mississippi. The main areas are sandstone glades of Northern Alabama, limestone glades from Middle Tennessee and Alabama to Kentucky, shale-barrens in the Mid-Appalachians, serpentine barrens in Pennsylvania and Maryland and granite flatrocks from Georgia to Virginia (Quarterman et al. 1993, Ware 2002). Outcrop areas in the SE of the USA shelter geographically and phylogenetically isolated taxa such as Amphianthus pusillus, a monospecific genus of the Scrophulariaceae, and Dia-

572

U. Deil

morpha (= Sedum) smallii (McVaugh 1943, Murdy 1966, Baskin & Baskin 1988). Shure (1999) provides a comprehensive study about the vegetation on Mount Arabia, a granitic outcrop area at the Piedmont of the Appalachian Mountains in Northern Georgia. The main vegetation types are temporary pools with Isoetes melanospora, I. tegetiformans and Amphianthus pusillus (all endemic), coarse debris layers with Sedum pusillum, Cyperus granitophilus, Juncus georgianus, Rhynchospora globularis var. saxicola, and dry turfs with Diamorpha smallii, Minuartia godfreyi and Agrostis elliottiana. In its physiognomic character, this mosaic is quite similar to the rock outcrop vegetation complex in the Monchique Mountains in Portugal (Figs. 8 and 9 in Rudner 2005b). Baskin & Baskin (1999) record a community with Leavenworthia spp., Isoetes butleri and Ophioglossum engelmannii from Cedar glades in Tennessee, Northern Alabama and Kentucky. An EWV in seasonal flooded interdune depressions at the Gulf of Mexico with Hydrocotyle bonariensis, Lippia nodiflora, Cyperus articulatus and Trachypogon gouini can be concluded from the permanent plot studies of Martı́nez et al. (1997). 4.3.2. Central and South America Mayacaceae-species characterize shallow oligotrophic ponds and temporary submerged shores of rivers in Cuba. These sites are surrounded by shorter submerged depressions in white sand savannas, characterized by members of the families Eriocaulaceae, Xyridaceae, and Scrophulariaceae, and carnivorous plants from the genera Utricularia, Drosera and Pinguicula. This hydroseries, first pointed out by Knapp (1965), was studied in detail in Cuba by Borhidi et al. (1979, 1983) and on the Isla de Juventud by BalátováTulácková & Capote (1985), and later summarized by Borhidi (1996a). An extension of these EWV types from the Carribean region to the Amazonian lowlands of Peru was stated by Galán de Mera (1995). The same author (Galán de Mera et al. 2002) validated these syntaxa and presented a syntaxonomic synopsis from the Peruvian viewpoint. We follow here his classification and nomenclature (Tab. 2). Mayacetea fluviatilis: Seasonal oligotrophic ponds and temporarily flooded riversides in the neotropical region belong to the M ay ac et ea fl uv ia ti li s Galán de Mera & Rosa in Galán de Mera et al. 2002 (Fig. 15). For the moment, this species-poor class includes one order and one alliance, with two communities recorded from Western Cuba: M ay ac et um fl uv ia ti li s along small rivers in the montane belt and M ay ac et um wr ig ht ii in coastal areas (Borhidi et al. 1983). In this class can further be included the Mayaca fluviatilis-variant of the Paratheria prostrata-Eleocharis minima-community in the Amazonian lowland of Bolivia (Haase 1989), the Bacopa salzmannii-Mayaca fluviatilis-community sensu Eskuche (1986) from the Paraná floodplain near Corrientes in Argentina, and the Mayaca fluviatilis-subtype of the Paspalum delicatulum-Echinodorus tenellus-community, observed by Schessl (1997) in seasonal rivulets (“vazantes”) in the

Habitats, plant traits and vegetation of ephemeral wetlands

573

Tab. 2. Syntaxonomic survey of EWV in tropical lowlands of Latin America. Submerged turfs in the Caribic and in the Amazonian basin Mayacetea fluviatilis Galán de Mera & Rosa in Galán de Mera et al. 2002 submerged or long flooded oligotrophic ponds and riverbanks Mayacetalia fluviatilis Borhidi in Borhidi et al. (1979) 1983 Mayacion fluviatilis Borhidi 1983 White sand savannas in the Caribic and NW South America Xyridetea savanensis Galán de Mera 1995 Rhynchosporo filifoliae-Xyridetalia Borhidi in Borhidi et al. 1979 Rhynchosporo podospermae-Xyridion bicarinatae Borhidi in Borhidi et al. 1979 shortly submerged depressions from Cuba to Peru ? Rhynchospora tenuis-confinis-bog (Eskuche 1986) Northern Argentina Hydrolaeetalia nigricaulis Balátová-Tulácková & Capote 1983 Hydrolaeion nigricaulis Balátová-Tulácková & Capote 1983 long submerged temporary ponds in Cuba White sand savannas on the Guiana Shield and flooded savannas in the Amazonas basin and the Pantanal of Mato Grosso Leptocoryphio-Trachypogonetea Van Donselaar 1965 Paspaletalia pulchellii Van Donselaar 1965 seasonal wet savannas Syngonantho-Xyridion (from Suriname to Colombia) on nutrient-poor white sand, drained soils Bulbostylidion lanatae on sandy loam, stagnant soils Panicetalia stenodis van Donselaar 1965 very wet, in depressions, on heavy soils Axonopodion chrysitidis van Donselaar 1965 in Suriname Curtion tenuifoliae Janssen 1986 in Humaitá (Brasil) shortly submerged Schizachyrion brevifolii Janssen 1986 in Humaitá (Brasil) submerged several months Hyptis lorentziana-Diodia kuntzei-community-group (Schessl 1997) seasonally flooded savannas in the Pantanal of Mato Grosso ? Schizachyrium sulcatum-Cuphea odenellii-community-group (Haase 1990) seasonally flooded savannas in the Bolivian Amazonas basin ? Eleocharis filiculmis-Rhynchospora corymbosa-community-group (Haase 1989) seasonally flooded savannas in the Bolivian Amazonas basin Pioneer vegetation in stream beds and on river banks in the Amazonian Lowlands of Peru Lindernietalia crustaceae sensu Seidenschwarz (1986) Pioneer vegetation on sandy floodplains at Rio Paraná in Northern Argentina Tripogon spicatus-Cienfuegosia sulphurea-turf (Eskuche 1986) Mud vegetation in tropical lowlands Bacopa monnieri-communities (De Foucault 1978, 1983, Müller & Gutte 1985) Mud vegetation at Rio Parana in Northern Argentine Lindernio dubiae-Mecardonietum herniarioides Eskuche 1975 Alternanthera ficoides-Eragrostis hypnoides-community (Fontana 1991)

574

U. Deil

Pantanal of Mato Grosso in Brazil. Mayaca longipes colonizes rock pools near Cayenne (French Guiana) (Raynal-Roques & Jérémie 1980), Mayaca fluviatilis a “swamp rock savanna on a sandstone escarpment near the Atlantic coast at Javi (Pires-O’Brien 1992) and in the Serra dos Carajás (Brazil) (Cleef & da Silva 1994). CS of the M ay ac et ea are several Mayacaspecies (Mayaca fluviatilis s.l., M. longipes and M. sellowiana). This EWV of stagnant and slow flowing oligotrophic waters is in contact with seasonally submerged white sand savannas. Xyridetea savanensis: Amphibic turfs, dominated by dwarfish Eriocaulaceae, Cyperaceae and Xyridaceae, occur in seasonally submerged depressions in white sand savannas. They belong to the neotropical class X yr id et ea sa va ne ns is Galán de Mera 1995 (syn. Pa rv or hy nc ho sp or et o- Er i oc au le te a Borhidi in Borhidi et al. 1979), a vegetation type on acid, nutrient-poor soils. The duration of the inundation period is the most important differentiating factor and results in three orders: H yd ro la ee ta li a n ig ri c au li s, R hy nc ho sp or o- Xy ri de ta li a and P ae pa la nt ho -E ri oc au le ta li a. The communities of the last order are not considered here, because they are dominated by dwarf perennials (Tab. 2). The E nc op el lo te nu if ol ia e- Hy dr ol ae et um ni gr ic au li s (Cuba, Balátová-Tulácková & Capote 1985) is a TP community and belongs to the H yd ro la ee io n n ig ri ca ul is . This association is rich in Cuban endemics such as Encopella tenuifolia, Eriocaulon fuliginosum, Elephatopus pratensis and Xyris bicarinata. The following associations are known at the moment from the R hy nc ho sp or o- Xy ri di on : Ba rm an ni o b ic ol or is H yp er ic et um fa sc ic ul at i (Isla de Juventud, Balátová-Tulácková & Capote 1985), C ha et ol ep id i- Rh yn ch os po re tu m f il if ol ia e (Cuba, Borhidi et al. 1979), L in de rn io cr us ta ce ae -X yr id et um sa va ne ns is (Peru, Galán de Mera 1995), and S pi la nt ho ul ig in os ae -P as pa le tu m o rb ic ul at um (Venezuela, Castroviejo & López 1985, Galán de Mera in lit.). The Rhynchospora tenuis-confinis-bog (Eskuche 1986) is a southern outlier of the X yr id et ea sa va ne ns is , ranging to Corrientes in Argentina. Other white sand savannas: Seasonally submerged dwarf savannas occur also on sandy, nutrient-poor alluvium, on sandstone outcrops and on inselbergs surrounding the Amazonian basin. They are dominated by the same families and genera as in Cuba and Peru. The X yr id et ea sa va ne ns is are ecologically and floristically very similar to the white sand savanna class L ep to co ry ph io -Tra ch yp og on et ea , described from the Guiana Shield by Van Donselaar (1965), the orders first of all comprising the wet variants (P as pa le ta li a p ul ch el li i and P an ic et al ia st en od is ) (Tab. 2). The main difference is that X yr id et ea sa va ne ns is are dominated by annuals, L ep to co ry ph io -Tra ch yp og on et ea by perennials. Here we focus on communities dominated by annuals. They are embedded into the perennial white sand savannas. The EWV belongs in flat situations to the TPH, on inselbergs and outcrops to the EFH. The syntaxon-

Habitats, plant traits and vegetation of ephemeral wetlands

575

omy (Tab. 2) is very preliminary and follows to a large extent Van Donselaar (1965, 1968) and Heyligers (1963) for Surinam and French Guiana, Duivenvoorden & Cleef (1994) for Colombia, Janssen (1986) for Humaitá in Brazil, Sarthou & Villiers (1998) and Sarthou (2001) for French Guiana. Further rankless communities are described from French Guiana (Hoock 1971), Bolivia (Haase 1989, 1990) and Brazil (Schessl 1997). Minor observations come from the savannas along the Orinoco in Venezuela (Susach 1989). The S yn go na nt ho -L ag en oc ar pe tu m t re mu li Van Donselaar 1965 (syn. Lagenocarpus tremulus-community sensu Heyligers 1963), a widespread association of the S yn go na nt ho -X yr id io n, includes some variants on open sites with seeping water or on shallow turfs with ephemeral character. Diagnostic species are for example Xyris guianensis, X. spathacea, Drosera capillaris and Utricularia fimbriata (Heyligers 1963, Kramer & Van Donselaar 1968). Floristic similarities to the S yn go na nt ho -X yr id io n, known for Surinam, have some associations on seasonally flooded sandstones in the Columbian part of the Amazon basin (Duivenvoorden & Cleef 1994), the A xo no po sc hu lt es ii -S ch oe no ce ph al ie tu m m ar ti an i, the X yr id o w ur da ck ii -P as pa le tu m t il le tt ii and the Si ph an th er o h or st ma nn ii -X yr id et um pa ra en si s. These communities are open ephemeral turfs, colonizing superficial soils over sandstone. The U tr ic ul ar i et um ne ot ti oi di s is a EFV of unclear syntaxonomic position. A Utricularia adpressa-Nymphoides humboldtiana (= N. indica)-community, surrounded by a Cyperus haspan-Rhynchospora cyperoides-marsh, is mentioned by Hoock (1971) for French Guiana. Seasonally flooded savannas in Northern Bolivia (Haase 1990) with Rhynchospora globosa, Syngonanthus densiflorus; Schizachyrium sulcatum, Cuphea odenellii, Ludwigia nervosa, Xyris macrocephala and mire-pools with Rhynchospora tenuis and Utricularia amethystina might belong to the P as pa le ta li a p ul ch el li i. Inselberg vegetation: Nutrient-poor soils and a common flora, at least on the genus and family level, link white sand savannas and herbaceous vegetation on inselbergs. EWV on inselbergs in South America is poorly known. Most of the studies dealing with inselbergs and other rock outcrops have been oriented either towards the lichen and cyanophycean crusts, colonizing the rock surface (Büdel et al. 1994), or towards the perennial vegetation, rich in endemics from the families Bromeliaceae, Velloziaceae, Orchidaceae and Cyperaceae (see for example Porembski et al. 1998, Ibisch et al. 1995). These mats, dominated by poikilohydric, clonally growing Monocotyledonae, are ecosystem engineers, donating seeping water for the EFV. Other publications merely provide floristic lists (Meirelles et al. 1999) or fragmentary observations (Raghoenandan 2000, Safford & Martinelli 2000). The vegetation mosaic, analysed by Sarthou & Grimaldi (1992), Sarthou & Villiers (1998) and Sarthou (2001) on the inselberg complex “Nouragues” in French Guiana, is dominated by perennial grasses (Axonopus ramosus) and by the mat-forming Guiana-endemic Bromeliaceae Pepinia (= Pitcairnia) geyskesii. During the amphibic phase, an annual synu-

576

U. Deil

sium develops with Utricularia subulata, U. amethystina, Selaginella producta, Perama hirsuta und Paepalanthus lamarkii (the subassociations A xo no pe tu m r am os i u tr ic ul ar ie to su m and P ep in ie tu m g ey sk es ii u tr ic ul ar ie to su m). The cyanophycean crusts change the water chemistry by N- and C-fixation and by raising the pH from 4 and 5 in rock pools to 6.5 and 7 in the runoff water (Sarthou & Grimaldi 1992). EFV is rare on inselbergs of Venezuelan Guiana. Utricularia oliverana emerges on a water film soaking from Pitcairnia-mats. Annuals in seasonal rock pools and on wet shallow deposits are Acisanthera crassipes, Bacopa callitrichoides, Eleocharis cellulosa, Eriocaulon cinereum, Paepalanthus lamarckii, Utricularia subulata, Xyris stenostachya a.o. (Gröger 2000). Seasonal rock pools with oligotrophic waters in French Guiana are inhabited by Ophioglossum ellipticum (= O. nudicaule), Isoetes ovata, Stylosanthesand Xyris-species (Raynal-Roques & Jérémie 1980). A southeastern outlier of ephemeral Eriocaulacean turfs occurs as synusium in penumbral rock communities, dominated by perennial Velloziaceae and Xyridaceae, in campo rupestre sites in Brazil (Alves & Kolbek 1993), with Eriocaulon cipoense, Paepalanthus spp. and Syngonanthus spp. Dwarf annual turfs with Echinodorus tenellus, Syngonanthus caulescens, Eleocharis minima a.o. are mentioned by Cleef & da Silva (1994) for the Serra dos Carajás (Pará, Brazil). Pantanales and flooded savannas: In contrast to the extremely nutrientpoor substratum of white sand savannas and inselbergs, which is wetted by rainwater respectively runoff from the rock surface, the alluvial plains and the terraces along big rivers, running from the Eastern Andean Escarpment to the Amazon, Orinoco and Parana basins, are richer in nutrients. These floodplains are the biggest wetlands of the world. The Pantanal de Mato Grosso for example, in the upper reaches of the Rio Parana, covers about 200000 square km during the maximum of the flood pulse (Por 1995, Heckman 1998), annual flooding peaks at the end of the rainy season in March and April. The seasonal hydromorphic savannas in the Bolivian province of Beni range between 100000 and 150000 square km (Beck 1983), the inundation period ranges from December to June. The Lower Amazon River near Manaus shows the maximal fluctuation of a freshwater system of the world with a variability of the water-level of between 8 and 12 m. Varzéa-vegetation along the Amazonian rivers is among the world’s most productive ecosystems. Most of the herbaceous species are perennial C4-grasses like Paspalum fasciculatum and Echinochloa polystachya. The latter species produces about 100 t dry matter/ha/y. These highly productive meadows depend on a monomodal flood pulse and are not reported from the upper reaches of the rivers, where floodplains are subjected to less predictible and rapid pulses (Junk & Piedade 1997). Tenagophytes in the floodplain near Manaus are according to Junk & Piedade (1993): Hymenachne amplexicaulis, H. donacifolia, Luziola spruceana, Oryza grandiglumis, Rhynchospora schomburgkiana, Vesicularia vesicularis, Limnocharis flava, Marsilea polycarpa, Ludwigia spp. a.o.

Habitats, plant traits and vegetation of ephemeral wetlands

577

Most of the floodplains are seasonal or intermittent wetlands in the hydrological sense, but only smaller areas are seasonal also in respect to plant cover. Only the latter habitats are further considered here. Sites flooded more than 6 months in the Pantanal de Mato Grosso are grassland-dominated (Zeilhofer & Schessl 1999).The synthesis is mainly based upon the following vegetation studies: Beck (1983, 1984) and Haase (1989, 1990) for Bolivia, Seidenschwarz (1986) for Peru, Janssen (1986) for HumaitaĚ in Brazil, Schessl (1997, 1999) and Pinder & Rosso (1998) for the Pantanal de Mato Grosso in Brazil and Eskuche (1975) for the floodplain of Rio Parana in Argentina. Many taxonomic problems of diagnostic taxa are unsolved. The syntaxonomy is in an initial stage. Several types of EWV are recorded by Beck (1983) from the inundation savannnas in Bolivia: Seasonal ponds with ferns (Marsilea polycarpa, Ceratopteris pteridioides) and Neptunia oleracea, emerging river bank with Polygonum hydropiperoides and P. densiflorum and semi-terrestrial turfs. The latter community is a mixture of annuals, germinating in the amphibic phase (Bacopa monnierioides, Sporobolus indicus, Eleocharis minima, Paratheria prostrata) and perennials, resprouting after the inundation (Cyperus haspan, Leersia hexandra, Paspalum plicatulum, Eragrostis acutiflora). A dwarf short-living Paratheria prostrata-Eleocharis minima-community is also recorded by Haase (1989). Further EWV is clustered in the Eleocharis filicaulis-Rhynchospora corymbosa-community-group and in the Schizachyrium sulcatum-Cuphea corymbosa-group (Haase 1989, 1990). CS of these alliances are a.o. Ludwigia nervosa, Rhynchospora corymbosa, R. tenuis, Syngonanthus densiflorus, Utricularia amethystina, Xyris macrocephala. Some genera indicate relations to the white sand savannas. Marsilea polycarpa-ponds and Polygonum hydropiperoides-stands are also recorded from Mato Grosso (Schessl 1997). Seidenschwarz (1986) proposes the L in de rn ie ta li a c ru st ac ea e for pioneer vegetation in seasonally flooded riverbeds and streamsides of the Amazonian lowlands of Peru. The following associations are known: L ep t oc hl oe tu m s ca br ae , Ro ri pp et um pa lu st ri s, R hy nc ho sp or o p ol ys ta ch yi -B id en te tu m c yn ap if ol ia e, P or op hy ll et um ru de r al is in the Kyllinga-variant. The syntaxonomic position of the high ranked syntaxa described by Seidenschwarz (1986) and their delimitation must be regarded as preliminary. The savannas at the Rio Madeira (HumaitaĚ , Brazil) in the western Amazon basin have been studied by Janssen (1986). She describes two alliances, which can be included into the P an ic et al ia st en od is : Cu rt io n t en ui f ol ia e-communities are shortly submerged, S ch iz ac hy ri on br ev if ol ii communities are flooded for several months. Some associations of these alliances are dominated by ephemerals: The U tr ic ul ar ie tu m h ir te ll ae occurs in shortly inundated depressions without organic matter, the N eu r ot he ce tu m l oe se li oi de s in longer water-filled TP with an organic topsoil. To the S ch iz ac hy ri on br ev if ol ii belong the associations Sc hi za c hy ri et um br ev if ol ia e, C yp er et um ha sp an i and R hy nc ha nt he re t um gr an di fl or ae . Local character species are the name-giving taxa and

578

U. Deil

for the latter association Drosera sessilifolia, Burmannia spp., Genlisea spp., Utricularia myriocysta, Herpestis reflexa and Limnosipanea spruceana. The plant communities and the vegetation mosaic in the Pantanal de Mato Grosso, the giant floodplain in the upper reaches of Rio Parana in SE Brazil, close to the Bolivian border, were studied by Schessl (1997, 1999), the seasonal cyclic succession by Prado et al. (1994). Beside free-floating Salvinia auriculata-Pistia stratiotes-Eichhornia azurea-pleustophyte communities, floating meadows with Oxycarium cubense, swamps with hydrogeophytes (Discolobium pulchellum, Cyperus giganteus, Thalia geniculata) and tussock grassland with perennials (Axonopus spp., Andropogon spp., Panicum stenodes), shortgrass floodplains are the most common physiognomic vegetation type. The last element is EWV in the definition of this contribution. It is composed of prostrate herbs such as Diodia kuntzei, Hyptis lorentziana, Ludwigia inclinata, Caperonia castaneifolia, Lipocarpha humboltiana, by annual tussock taxa (Echinochloa spp.) and by graminoid annuals (Panicum laxum, Paspalum delicatulum, Setaria parviflora, Reimanochloa acuta, Eleocharis minima, Eragrostis tenella). The associations of the Hyptis lorentziana-Diodia kuntzei-group (they include the short grassland formation sensu Pinder & Rosso 1998) are permanent pioneer-communities in an annual cycle of an allogenous succession series. The colonization starts in spring. Precipitation culminates in December and January, the peak of the flood pulse is from February to April. Schessl (1997) classifies 8 community-groups and 19 communities. The following vegetation units, characterized by a short period of above-ground vegetation in the amphibic and early terrestrial phase, should be mentioned: The Echinodorus tenellus-Bacopa dubia-community and the Heliotropium lagoense-Ophioglossum crotalophoroides-Schizosepala matogrossensis-community are dominated by tenagophytes, colonizing dystroph sands. Organic crusts, decomposing when the water-level has declined, are inhabited by the Utricularia meyeri-amethystina-community with Utricularia ssp., Drosera sessilifolia, Burmannia capitata, Eragrostis tenella and Anagallis minima. The Hyptis lorentziana-Diodia kuntzei-communitygroup can be included into the P an ic et al ia st en od is (Tab. 2). It is vicarious to the Paspalum ionanthum-subdivision sensu Haase (1990) with the following species-pairs (Pantanal/Bolivia): Paspalum stellatum/P. ionanthum, Axonopus purpusii/A. fissifolius, Trachypogon spicatus/T. plumosus. The syntaxonomic position of the Tripogon spicatus-Cienfuegosia sulphurea dwarf turf (Eskuche 1986) is unclear. This community includes some elements of the M ic ro ch lo et ea in di ca e. Mud-vegetation in tropical lowlands: A few observations are available from floodplains at the Pacific Coast of Peru and from Guadeloupe in the Carribean. The ephemeral plant communities in frost-free lowlands of the neotropical region are often characterized by Bacopa species. MĂźller & Gutte (1985) and GalaĚ n de Mera (1995) record communities with Bacopa monnieri, Eclipta prostrata and Ludwigia adscendens from the Pacific coastal plain of Peru. de Foucault (1978, 1983) describes the E le oc ha ro g en ic ul at ae -B ac op et um mo nn ie ri from the French Antilles. Other

Habitats, plant traits and vegetation of ephemeral wetlands

579

EWV with Bacopa spp. have already been mentioned for Bolivia (Bacopa monnierioides-Sporobolus spicatus-community) (Beck 1983) and Brazil (Echinodorus tenellus-Bacopa dubia-community) (Schessl 1997). Bacopa monnierioides and B. salzmannii occur in the S pi la nt ho ul ig in os ae P as pa le tu m o rb ic ul at um in Venezuela (Castroviejo & López 1985, Galán de Mera in lit.). Emerging riversides of the Rio Paraná in Northern Argentina are the habitat for the L in de rn io du bi ae -M ec ar do ni et um he rn ia ri oi de s (Eskuche 1975). Both name-giving species are Scrophulariaceae and Eskuche underlines the role of annual taxa from the tribus Gratioleae as colonizers of muddy substrate in different parts of the world (see chapter 4. 7. 4.). The chorospectrum of this unique association includes endemics (Mecardonia herniarioides, Scoparia aemilii, Plagiocheilus tanacetoides), taxa ranging to Mexico (Eragrostis hypnoides, Cypsela humifusa), and species widespread in the warm tropical and subtropical regions (Lindernia dubia, Fimbristylis squarrosa, Rorippa islandica, Alternanthera paronychioides). Seasonal wetlands in the Santa Fe province of Argentina include communities with Echinochloa heliodes, Luziola peruviana, Paspalum distichum, Eleocharis macrostachya, E. viridans, Lilaeopsis attenuata, Ludwigia peploides, Leersia hexandra, Juncus microcephalus a.o. (Lewis et al. 1985). In dessicating ancient stream beds of the Panará River in Argentina grow dwarf seasonal turfs with Alternanthera ficoides, Eragrostis hypnoides, Plantago myosurus, Eryngium chubutense, Rorippa islandica a.o., replaced later in the season by a tall ruderal community, the P ol yg on o p un ct at iR um ic et um pa ra gu ay en si s (Fontana 1991). A pioneer community, dominated by short-living annuals such as Eragrostis hypnoides, Scoparia montevidensis, Gamochaete subfalcata and Echinodorus spp. colonizes open sites, where the Panicum prionitis-tall grassland has been destroyed by an extraordinary long-lasting flood (Lewis et al. 1987, Franceschi & Lewis 1991, Franceschi et al. 2000). Neotropical EWV on nutrient-poor sites: When comparing the floristic data sets from seasonally submerged white sand savannas, EFV on inselbergs and ephemeral turfs on nutrient-poor alluvial sands in the tropical parts of Latin America, a common stock of genera emerges as keystone taxa. The vicariance pattern between S yn go na nt ho -X yr id io n and R hy nc ho sp or o- Xy ri di on bi ca ri na ta e has already been mentioned. The classes X yr id et ea sa va nn en si s and L ep to co ry ph io -Tra ch yp og on et ea form a group of classes, linked by common genera, subgenera or sections. It would be interesting to look for common elements with the Paleotropical class D ro se ro -X yr id et ea . Raynal-Roques & Jérémie (1980) stated these parallels. They are based upon the families Droseraceae, Cyperaceae, Eriocaulaceae (Eriocaulon, Paepalanthus, Syngonanthus), Lentibulariaceae, Xyridaceae and Ophioglossaceae. de Foucault (1988) pointed out the contrast between the Xyridaceae-Eriocaulaceae-family pattern on nutrient-poor tropical EWH and the Scrophulariaceae-LythraceaeElatinaceae-family-group in nutrient-rich environments.

580

U. Deil

At the moment, the taxonomy of many species is too unclear for such an approach even for the neotropical region. Some patterns of vicariance however can be outlined. Galán de Mera et al. (2002) mentions the following CS for the X yr id et ea sa va ne ns is in Peru: Drosera montana, Hyptis brevipes, H. savannarum, Lindernia crustacea, L. diffusa, L. dubia. L. microcalyx, Syngonanthus densiflorus, Tonina fluviatilis, Utricularia pusilla, U. subulata, U. triloba, Xyris guianensis, X. jupicai, X. laxifolia, X. savanensis, X. subulata, X. tristis. In Suriname occur a.o. Drosera capillaris, Paepalanthus polytrichus, Rhynchospora arenicola, R. graminea, Syngonanthus umbellatus, Utricularia guianensis, U. fimbriata, Xyris guianensis, X. longiceps, X. spathacea, X. surinamensis (Heyligers 1963). Sarthou & Villiers (1998) record in French Guiana Rhynchospora tenuis, R. globosa, Stylosanthes guianensis, Utricularia hispida, U. subulata. Janssen (1986) mentions from Humaitá in Brazil: Drosera sessilifolia, Hyptis goyazensis, Paepalanthus myocephalus, Rhynchospora nervosa, Syngonanthus caulescens, Utricularia subulata, U. viscosa, Xyris savanensis. Limoselletea australis: When studying the vegetation of the Paramos of the Eastern Cordillera in Colombia, Cleef (1981) separated the communities, colonizing amphibic habitats and emerging mineral soil at lakeshores in the orotropical belt, in the provisional class L im os el le te a a us tr al is . This type of vegetation is dominated by Isoetid and Callitrichid growth forms, by Limosella-, Crassula- and Lilaeopsis-species. With this combination of growth forms and taxa it has close relationships with the N an oj un ce te a a us tr al is , described by Oberdorfer (1960) from the temperate climate zone of Chile. Both classes are more or less synonymous. The syntaxonomy adopted here (Tab. 3) follows mostly the proposals of Galán de Mera (1995) and Galán de Mera et al. (2002, 2003). The L im os el le te a a us tr al is include the vegetation of amphibic habitats around Lagunas in the Andean belt (2200Ð4000m asl.), of rivers and lakes in temperate Chile and of TP in mediterranean Chile. The water bodies can be either seasonal or permanent with fluctuating water-level. The synareal ranges along the Andean Cordillera from Venezuela to Argentina and in the extratropical lowlands from the temperate zone of Chile to Southern Argentina and the Falkland Islands (see Fig. 15 and the distribution of Lilaeopsis macloviana, Fig. 13). CS of the class and order are: Crassula peduncularis (incl. C. paludosa and C. bonariensis, see Bywater & Wickens 1984), C. venezuelensis, Eleocharis albibracteata, Gratiola peruviana, Isoetes andicola (= Stylites a.), I. palmeri, Juncus bufonius, J. stipulatus, Lilaeopsis macloviana (= L. andina), Limosella aquatica, L. australis, Ranunculus limoselloides, Scirpus inundatus. Two alliances can be outlined at the moment (Tab. 3): Til la ei on pa lu do sa e Cleef 1981 (syn. L il ae op si d io n a nd in ae Seibert & Menhofer 1991) in the Andes and Ju nc io n p la ni fo li i Oberdorfer 1960 in the temperate zone of Chile. The alliance D it ri ch o- Is oe ti on le ch le ri Cleef 1981, often in contact with the Ti ll a ei on pa lu do sa e and including the communities on more or less permanently submerged shores of oligotrophic lakes in the Paramos, is better

Habitats, plant traits and vegetation of ephemeral wetlands

581

Tab. 3. Syntaxonomic survey of EWV in the extratropical lowlands of South America and in the Paramo- and Puna-belt of the Andes. Amphibic habitats in the Andean belt and seasonal wetlands of the temperate lowlands Limoselletea australis Cleef 1981 Tillaeetalia Cleef 1981 Tillaeion paludosae Cleef 1981 lakeshores in the Puna and Paramo-belt Juncion planifolii Oberdorfer 1960 lakeshores, riverbanks and seasonal ponds in temperate Chile Hard cushion mires with temporary moorland pools in the Andes Plantagini rigidae-Distichietea muscoidis Rivas-Martı́nez & Tovar 1982 Plantaginetalia tubulosae Gutte 1985 in the dry puna from Peru and Bolivia to Chile and Argentine Hypsello reniformis-Plantaginion tubulosae Galán de Mera et al. 2003 mires including moorland pools with freshwater, Northern Altiplano Oxychloion andinae Ruthsatz 1995 mires including muddy patches and moorland pools, Southern Altiplano Oritrophio-Wernerietalia Cleef 1981 Paramos of Colombia, Venezuela, Ecuador and Northern Peru

placed into an undescribed class (L it to re ll et ea au st ra li s sensu Oberdorfer 1960), which is equivalent to the I so et o- Li tt or el le te a of the holarctic region. A floristic differentiation according to the trophic level of the substrate can be expected from the indicator values, established by San Martı́n et al. (2003) for some Chilean water plants (with Lilaeopsis macloviana, Limnobium laevigatum, Ludwigia palustris and Phyla nodiflora on rich soils, Crassula peduncularis, Isoetes savarieri, Centella asiatica and Lythrum borystenicum on nutrient poor sites). The following communities of the Til la ei on pa lu do sa e are hitherto known from the Northern and Central Andes: C ra ss ul et um co nn at ae from Bolivia (Seibert & Menhofer 1991), I so et et um an di co la e, Til la ee tu m p al ud os ae and Limosella australis-community from Venezuela (Cleef 1981). The Til la ei on -communities are part of a hydroseries from the limnic H yd ro co ty lo ra nu nc ul oi de s- My ri op hy ll et um el at in oi de s, near-permanently submerged Isoetetum lechleri, amphibic Til la ei on to helophytic marshes with the perennials Juncus ecuadorensis and Eleocharis palustris. Southeastern outliers of the Til la ei on -communities occur in the Cordoba Mountains in NW Argentina (Cabido et al. 1990, Cabido & Acosta 1986). Shallow, temporarily water-filled depressions on rock outcrops in an altitude of 1900 m asl. are colonized by the Crassula peduncularis-Limosella lineata-community. Predominant are annuals like Crassula peduncularis and Muhlenbergia peruviana. These dwarf turfs are surrounded by a perennial rush marsh with Juncus uruguensis, J. achalensis, Eleocharis albibracteata and Alchemilla pinnata. In pools with poor drainage, where water per-

582

U. Deil

sists for a longer period, Lilaea scilloides and Callitriche heteropoda develop conspicuous mats. Non-forest vegetation in the temperate climatic zone of Chile is in most cases man-made. The grasslands in the IXth and Xth Región (the surroundings of Temuco, Osorno and Cautin) are dominated by adventitious species of holarctic origin (Leontodon taraxacoides, Mentha pulegium, Agrostis capillaris). In TP, however, indigenous grassland species can be found (Ramı́rez et al. 2000). TP and the shores of oligotrophic lakes seem to be primary habitats for these openland-species. Oberdorfer (1960) was the first to study these plant communities and to discover the striking convergence between extratropical South America and the Western Palaearctic region with vicarious taxa in the hydroseries from L it to re ll et ea au st ra li s/ Is oe to -L it t or el le te a to L im os el le te a a us tr al is /I so et o- Na no ju nc et ea respectively. The following communities are hitherto described, all belonging to the J un ci on pl an if ol ii and all recorded from Chile: S ci rp o i nu nd at i- Li m os el le tu m a qu at ic ae on lakeshores, Ju nc et um pl an if ol ii in furrows and ditches (Oberdorfer 1960), E le oc ha ri te tu m m ac ro st ac hy ae (Contreras et al. 1991), Lyt hr o p or tu la e- El eo ch ar it et um pa ch yc ar pa e in TP (San Martı́n et al. 1998), L eo nt od o- Pi pt oc ha et et um n av ar re ti et os um and Eryngium pseudojunceum-Centipeda elatinoidescommunity (both in depressions on alluvial terraces along Rio Chol-Chol near Cautin, Ramı́rez et al. 1994), and P ol yg on o- Cr as su le tu m p al ud o sa e (Osorno, Ramı́rez et al. 1996). Characteristic species are Callitriche turfosa, Centipeda elatinoides, Cicendia quadrangularis, Crassula paludosa, Dichondra sericea, Eryngium pseudojunceum, Eleocharis humifusum, E. pachycarpa, Juncus stipulatus, Navarretia involucrata, Nierembergia repens, Lythrum portula, Piptochaetum montevidense, Plagiobothrys fulvus, Scirpus inundatus. The G na ph al io cy ma to id is -P ol yg on et um hy dr op ip er o id is and the Phyla nodiflora-community (San Martı́n et al. 1998) characterize the late spring and summer-ecophases (for the zonation, see Fig. 18c). Some species and genera relate the J un ci on pl an if ol ii -communities floristically to TP-vegetation in California. This floristic linkage is still stronger, when passing from the temperate to the mediterranean climatic zone in Chile. In the latter region, VP have not yet been studied in detail. A first floristic survey (Bliss et al. 1998) confirms the role of amphitropical taxa sensu Raven (1963) such as Centipeda elatinoides, Cicendia quadrangularis, Crassula spp., Downingia pusilla, Eryngium pseudojunceum, Lasthenia kunthii, Navarretia involucrata, Plagiobothrys spp., Psilocarphus brevissimus. These taxa are the basis for a class-group D ow ni ng io -N av ar re te a. Further species in TP in Central Chile are: Amphibromus scabrivalvis, Anagallis minima, Bromidium anomalum, Callitriche lechleri, Deschampsia airiformis, Elatine triandra, Eryngium depressum, E. rostratum, Hydrocotyle cryptocarpa, Isoetes savatieri, Lilaea scilloides, Limosella australis, Lythrum hyssopifolia, Marsilea mollis, Micropsis nana, M. pygmaea, Pilularia americana, Ranunculus bonariensis (Bliss et al. 1998). Mud patches and seasonal pools in hard cushion mires: EWV occurs in seasonal waterlogged depressions and in temporary pools, included as

Habitats, plant traits and vegetation of ephemeral wetlands

583

microhabitats in the hard cushion mires (= P la nt ag in i r ig id ae -D is ti c hi et ea mu sc oi di s Rivas-Martı́nez & Tovar 1982) of the Andean Mountains. Seibert & Menhofer (1991, 1992) describe a hummock-pool-mosaic from the Altiplano in Bolivia north of Lake Titicaca. The dwarfish perennials Plantago tubulosa, Werneria pygmaea, Eleocharis tucumanensis, and Azorella diapensioides form the hummocks, the annuals Limosella australis, Muhlenbergia minuscula, M. peruviana, and Calamagrostis heterophylla emerge in the amphibic phase in the muddy depressions. The mire ecosystems occur in an altitude of 4300 m asl. They are submitted to diurnal frost and to an extreme pasture pressure by Alpacas and Lamas. Cryoturbation and trampling by the large herbivores creates open muddy patches. Andean mires from Central Peru to Bolivia (in the humid Puna) belong to the C al am ag ro st io -D is ti ch ie ta li a m us co id is (Rivas-Martı́nez & Tovar 1982), and the mires from Southern Peru to Central Argentina to the P la nt ag in et al ia tu bu lo sa e (Galán de Mera et al. 2003). Moorland pools with freshwater in the aquatic phase are recorded from the H yp s el lo re ni fo rm is -P la nt ag in io n t ub ul os ae , primarily from the El eo c ha ri to tu cu ma ne ns is -P la nt ag in et um tu bu lo sa e Seibert 1993, distributed in the Northern Altiplano of Bolivia and Peru. Also the following variants of mires in NE Argentina are linked to the L im os el le te a by Limosella lineata and Crassula peduncularis: The Hypsella oligophylla-, the Muhlenbergia fastigiataÐDistichlis humilis- and the Marsilea punae-Eleocharis acicularis-community (Ruthsatz 1977). Muddy patches and moorland pools with freshwater and brackish water occur further in the O xy c hl oi on an di na e Ruthsatz 1995 (= Wer ne ri on py gm ae ae Ruthsatz 1977 ex Galán de Mera et al. 2002), a dwarfish geophytic turf in the Southern Andes. Elements of the L im os el le te a are transgressive into the following microassociations of hard cushion mires: D is ti ch ie tu m m us co id is , variant with Lilaeopsis macloviana; Ox yc hl oe tu m a nd in ae , variant with Lilaeopsis macloviana (Ruthsatz 1977, Luebert & Gajardo 2005) (both on the Altiplano of Northern Chile); Scirpus hieronymii-Limosella aquatica-Isoetes (= Stylites) andicola-community (Central Peru, Gutte 1980); A lc he mi ll a d ip lo ph yl la e- Li la eo ps id et um an di na e sensu Rivas-Martı́nez & Tovar 1982 (Peru); Plantago tubulosa-community, variant with Limosella australis (Bolivia, Seibert & Menhofer 1992), the Muhlenbergia ligularis-Cotula minima-Scirpus cernuus-community on river shores and the C al li tr ic ho he te ro po da e- Al op ec ur et um hi tc hc oc ki i l il ae et os um su bu la ta e in seasonal freshwater ponds between 4200 and 4400 m asl. (Peru, Gutte 1986, 1988). The mud-communities R an un cu le tu m l im os el lo id is and Ra nu nc ul et um ma nd on ia ni in Peru (Galán de Mera 1995, Galán de Mera et al. 2003) and R an un cu le tu m f la ge ll if or mi s in Bolivia (Seibert & Menhofer 1992) might be better considered as fragments of the L im os el l et ea au st ra li s than included into N ym ph ae et al ia . They are linked to the first syntaxon for example by the presence of Lilaeopsis macloviana. Fragments of ephemeral communities on amphibic histosols occur in the superparamo-belt (between 4000 and 4800 m asl.) in the Venezuelan Sierra

584

U. Deil

Nevada de Mérida (Berg 1998) with Ophioglossum crotalophoroides, Carex bonplandii, Oritrophium venezuelense, Werneria pygmaea, Lachemilla sprucei and Gentiana sedifolia. These communities are vicarious to the O ri tr op hi o l im no ph il ae -Wer ne ri et um py gm ae ae Cleef 1981 from Colombia, and belong to the same order (O ri tr op hi o- We rn er ie ta li a Cleef 1981). 4.3.3. Western Palaearctic region EWH in the temperate and mediterranean climate zones of Europe and in the mediterranean part of Northern Africa are colonized by plant communities which are dominated by geophytic Isoetes spp. and by dwarf and short-living Juncus spp. and Cyperus spp. This kind of vegetation is classified as Isoeto-N an oj un ce te a (including I so et et ea ve la ta e and J un ce t ea bu fo ni i sensu de Foucault 1988). The synopsis presented here (Tab. 4) follows to a large extent the syntaxonomic scheme proposed by Brullo & Minissale (1998), with some modification according to Mucina (1997), Täuber & Petersen (2000) and Rivas-Martı́nez et al. (2001, 2002). A classification based upon the new phytosociological data available now from Europe is under preparation. Annual ruderal communities of periodically flooded, nutrient-rich alluvial soils and related synanthropic habitats such as hypertrophic pond bottoms belong to the B id en te te a t ri pa rt it ae , a class not further considered here. The transitional position of poikilosaline temporary waters will be discussed after presenting the freshwater communities. CS of the I-N are Antinoria agrostidea, Elatine macropoda, Hypericum humifusum, Juncus bufonius, J. capitatus, J. hybridus, J. pygmaeus, J. tenageia, Lythrum hyssopifolia, L. tribracteatum, Myosurus minimus a.o. According to floristic composition, predominant life forms and distribution of the CS, two orders can be distinguished: I so et et al ia and Cy pe re ta li a f us ci (= Na n oc yp er et al ia ) (Tab. 4, Fig. 16). The Is oe te ta li a are dominated by therophytes and geophytes, the C yp er et al ia by therophytes and hemicryptophytes. A number of character species occur in both areas. They show a very different life cycle (winter and spring annuals) in the mediterranean respectively (summer annuals) in the temperate climatic zones of Europe. These differences in life forms and life cycles between the EWV in the mediterranean and the temperate climate of the Western Palaearctic region were already discovered by Braun-Blanquet (1935) and by Moor (1937). A neoarctic order, vicarious to the C yp er et al ia fu sc i, is B ec km an n io -R um ic et al ia sa li ci fo li i (see chapter 4. 3. 1.). The ecological equivalent of the South European-North African order I so et et al ia in the mediterranean climate of California is the endemic class D ow ni ng io -L as t he ni et ea . This syntaxonomic difference is the expression of the higher rate of endemism in the Californian region in comparison to the Old World Mediterranean EWF, a fact, which has been underlined by Quézel (1998). The I so et et al ia are of circum-mediterranean distribution, with a higher density of the habitats and a richer flora in the Western parts of the

Habitats, plant traits and vegetation of ephemeral wetlands

585

Tab. 4. Syntaxonomic survey of EWV in the western palaearctic region. Dwarf rush communities in the Holarctic kingdom, in non-saline amphibic environments Isoeto-Nanojuncetea Br.-Bl. & R. Tüxen ex Westhoff et al. 1946 Isoetetalia Br.-Bl. 1935 em. Rivas Goday 1970 Mediterranean to submediterranean-atlantic zones of Southern Europe and Northern Africa; dominance of spring annuals and winter to spring green geophytes Isoetion Br.-Bl. 1935 Circummediterranean distribution; soils dessicating in early spring Cicendio-Solenopsion Brullo & Minissale 1998 (= Cicendion auct. mediterran.) Mediterranean-atlantic distribution; on acid soils, dessicating in late spring Agrostion pourretii Rivas Goday 1958 em. Rivas-Martı́nez et al. 1986 (= A. salmaticae) West-Iberian distribution; acid soils, long waterlogged in spring Preslion cervinae Br.-Bl. ex Moor 1936 (= Menthion cervinae) Mediterranean distribution; nutrient-rich soils, desiccating in summer Cyperetalia fusci Pietsch 1963 (= Nanocyperetalia) submediterranen, temperate and subboreal zones of Eurasia dominance of summer annuals and hemicryptophytes Nanocyperion flavescentis Koch ex Lippert 1936 central alliance of the order, Eurosiberian distribution Radiolion linoidis (Rivas Goday 1961) Pietsch 1973 sandy, nutrient poor soils; preference for atlantic-subatlantic climate Elatino triandrae-Eleocharition ovatae (Pietsch & Müller-Stoll 1968) Pietsch 1973 muddy, eutrophic to hypertrophic soils; Eurosiberian distribution Verbenion supinae Slavnic 1951 muddy, nutrient rich soils; submediterranean-subcontinental distribution EWV in nutrient-rich, saline or brackish conditions in the amphibic phase Thero-Salicornietea Tx. in Tx. & Oberdorfer ex Géhu & Géhu-Frank 1984 Crypsietalia aculeatae Vicherek 1973 on salt and alkali soils Crypsis aculeata-Heliotropium supinum-community group Mediterranean area Puccinellion peisonis Wendelberger 1943 corr. Soó 1957 inland salt-marshes in the surroundings of the Neusiedler See Cypero-Spergularion salinae Slavnic 1948 Pannonian Basin Polygono salsuginei-Crypsion aculeatae Korzhenevskii & Klyukin 1990 mud soils on volcanish ash flows, Crimea area Wahlenbergia tibestica/bernardii-Crypsis aculeata/schoenoides-community-group Central Sahara Mountains EWV on cryoturbate soils in the northern boreal and arctic zone ? ? Koenigio-Microjuncion arcticum sensu Sörensen (1942) Koenigio islandicae-Sedetum villosi Sörensen 1942 on “Flags” in Greenland, Iceland, Faroer Islands, Norway Junco-Ranunculetum hyperborei Mörsdorf 1989 seasonal ponds and lakeshores on Iceland Koenigio islandicae-Saginetum intermediae Fredskild & Daniels 1998 solifluidal moving clay and melt water runnels on Greenland

Fig. 16. Tentative distribution of ephemeral wetland syntaxa in the Old World, Australia and New Zealand.

Habitats, plant traits and vegetation of ephemeral wetlands

587

Mediterranean area. In the oceanic climate of Western Europe, this order ranges far to the North (Britanny, Southern England) (Fig. 16). The vernal pool habitat is the most common habitat type. Most of the species have a preference to oligotrophic, well drained soils. Many species are rare and on Red Lists (see Tab. 2 in Grillas et al. 2004a), because nutrient input and changes in the hydrology threaten the populations. CS are for example Isoetes velata, I. setacea, Airopsis tenella, Centaurium maritimum, Crassula vaillantii, Damasonium alisma, D. bourgaei, Scirpus cernuus, Juncus tingitanus, Lotus angustissimus, Lythrum borysthenicum, L. thymifolia, Marsilea strigosa, Oenanthe silaifolia, Pilularia minuta, Veronica acinifolia. Within the order, the trophic level of the substrate and the duration of inundation are the most important differentiating factors. Within the I so et et al ia , four alliances (Tab. 4) can be classified according to floristic similarity (the S er ap io n sensu Aubert & Loisel (1971) is excluded, because it is dominated by perennials): 1. I so et io n: The alliance is of circum-mediterranean distribution. The associations belonging to I so et io n occur in the thermomediterranean and mesomediterranean bioclimate. The amphibic phase is in March and April. Geophytic quillworts are a major component of the biomass. CS are Isoetes histrix, I. duriaei, I. velata, Antinoria algeriensis, Lotus conimbricensis, Myosurus sessilis, Polygonum arenastrum, P. romanum, Ranunculus revelieri a.o. 2. C ic en di o- So le no ps io n (= C ic en di on auct. medit.): This alliance is of mediterranean-atlantic distribution (see KĂźrschner & Parolly 1999 for the tentative synareal), with a clear preference to acid soils. The habitats are waterlogged longer than the I so et io n-habitats, the pools become dry in May and June. In early summer, the I-N-species are replaced by H el ia nt he me te a-species (see Rudner 2005b). CS of the C ic en d io -S ol en op si on are for example Cicendia filiformis, Laurentia gasparrinii, Exaculum pusillum, Illecebrum verticillatum, Scirpus pseudosetaceus, Ophioglossum lusitanicum, Radiola linoides, and Silene laeta. 3. A gr os ti on po ur re ti i (= A gr os ti on sa lm an ti ca e): This alliance is represented by the unique association P ul ic ar io pa lu do sa e- Ag ro st ie tu m p ou rr et ii (Molina & Casado AĚ lvaro 1997). It grows on acid, well aerated, long water-saturated soils and is endemic in the western parts of the Iberian Peninsula. CS are Agrostis pourretii, Chaetopogon fasciculatus, Chamaemelum fuscatum, C. nobile, Molineriella laevis and Trifolium spp. Later in the season, the P ul ic ar io -A gr os ti et um is replaced by Tuberaria guttata-communities. 4. P re sl io n c er vi na e (= M en th io n c er vi na e) (incl. E la ti no ma cr op od ae -D am as on io n a li sm ae sensu de Foucault 1988): Long submerged depressions, often over clay or with muddy substrate, are colonized by Mentha cervina (= Preslia cervina), Artemisia molinieri, Callitriche spp., Baldellia ranunculoides, Eryngium corniculatum, E. galioides, Juncus foliosus, Marsilea batardae, Ranunculus lateriflorus, R. nodiflorus, Sisymbrella aspera, and Veronica anagalloides. The maximum of the phenological development is in June and July.

588

U. Deil

The C yp er et al ia fu sc i are distributed in the temperate zone of Europe (Fig. 16). Southern outposts of this ephemeral dwarf-cyperoid vegetation occur in mountainous regions of the Mediterranean area. The habitats enter into the amphibic phase in summer, most of the character species have a summer-autumnal life cycle. CS are Cyperus fuscus, C. michelianus, Centaurium pulchellum, Corrigiola litoralis, Eleocharis acicularis, Filaginella uliginosa, Gnaphalium luteo-album, Gypsophila muralis, Isolepis setacea, Ludwigia palustris, Lythrum portula, Plantago major ssp. intermedia, Potentilla supina, Scirpus supinus a.o. Four alliances (Tab. 4) can be outlined at the moment in a Europeanwide perspective: 1. N an oc yp er io n f la ve sc en ti s: This alliance ranges throughout the distribution of the order. CS are for example Cyperus flavescens, Blackstonia spp., Carex serotina, Fimbristylis annua, Juncus tenuis, J. ranarius and Sagina nodosa. 2. R ad io li on li no id is (Ci ce nd io n sensu Brullo & Minissale 1998): This alliance is restricted to sandy, nutrient-poor soils. It has a preference to atlantic-subatlantic climates. CS such as Anagallis minima, Cicendia filiformis, Illecebrum verticillatum, Radiola linoides and Montia fontana are often found in heathland ponds and in seasonally submerged dune valleys. The delimitation of the alliances R ad io li on and Ci ce nd io S ol en op si on is unclear. 3. E la ti no -E le oc ha ri ti on ov at ae (incl. El eo ch ar it io n s ol on ie ns is and E la ti no -L in de rn io n p ro cu mb en ti s): In this broad sense this Central-European-Eurasiatic alliance includes EWV of exposed pond bottoms, emerging river banks, floodplains, and rice fields in the amphibic phase. CS are for example Carex bohemica, Elatine alsinastrum, E. hydropiper, Eleocharis ovata, and Limosella aquatica. 4. Ver be ni on su pi na e: Brullo & Minissale (1998) define this alliance in a very broad sense, including F im br is ty li di on di ch ot om ae , D ic ho st yl io n m ic he li an i, H el eo ch lo o- Cy pe ri on and Ly t hr io n b ra ct ea ti sensu auct. Borhidi (2003) includes all the mentioned syntaxa in a broadly defined N an oc yp er io n. However, it seems better to exclude communities, characterized by obligate halophytes such as Crypsis spp. and Heleochloa spp., from Ver be ni on s up in ae and Cy pe re ta li a f us ci and place them in the separate order C ry ps ie ta li a. The following species are characteristic for the Ver be ni on su pi na e in a stricter sense: Centaurium spicatum, Coronopus squamatus, C. navasii, Cyperus glomeratus, Eryngium barrelieri, Fimbristylis bisumbellata, Glinus lotoides, Lythrum baeticum, L. flexuosum, Paspalum paspalodes, and Verbena supina. The C yp er et al ia fu sc i-communities are becoming more and more impoverished in Northwestern, Northern and Eastern Europe (see Rodwell 2000 for Great Britain, Vevle 1989 for Norway, Dierssen 1996 for Scandinavia, Rasomavicius & Biveinis 1996 for Lithuania, Popiela 1997, 1999, 2005 for Poland; Coldea 1997 for Romania; Traxler 1993 for Austria). Outposts on Iceland are linked to special local climatic conditions such as

Habitats, plant traits and vegetation of ephemeral wetlands

589

the surroundings of fumaroles and hot springs (Subularia- and Limosellaflag) (Sörensen 1942, Dierssen 1996). Marginal, species-poor communities of dwarf rush vegetation (= basalcommunities of C yp er et al ia fu sc i) are recorded from the Canary Islands (Gran Canaria, Sunding 1972; El Hierro; Stierstorfer 2005; Lanzarote, Reyes-Betancort et al. 2001; Tenerife, Rivas-Martı́nez et al. 1993), from Madeira (Costa et al. 2003), and from the Azores Islands (Lüpnitz 1975). In a Western Palaearctis perspective, the classification results in a number of floristically clearly separated clusters, which can also be characterized ecologically very well. There are however two groups of communities with transitional character, ordered by a climatic respectively an edaphic environmental gradient: 1. On nutrient-poor, acid soils, and in the atlantic climate of Western Europe (coastal areas from the Basque country to the Netherlands), we can state a gradual floristic shift from C ic en di o- So le no ps io n to R ad io li on -communities. This area is well reflected by the distribution of Cicendia filiformis (Fig. 12). Both alliances are united by some authors in C ic en di on sensu lato, because they have a considerable number of species in common. These species make a consistent classification of the MidEuropean-Eurosiberian C yp er et al ia fu sc i and the Mediterranean-Atlantic order I so et et al ia difficult. Täuber & Petersen (2000) underline the fact, that the sociological character has to be defined within one biome and is valuable only for a particular phytogeographical region. This is reflected in the separation of the two orders, I so et et al ia with preference in the mediterranean, C yp er et al ia with preference in the temperate region. When the phenology of the species is included as a differentiating factor, the separation becomes more distinct: Cicendia filiformis and associated species are spring annuals in the mediterranean climate, summer annuals in the temperate climate. 2. In the steppe areas of Eastern and Southeastern Europe, temporary pools are often filled with freshwater in winter and spring. Under high evapotranspiration rates in summer, the water body can get brackish or saline at the end of the growing season and the poorly drained, nutrient-rich substrates Ð salt-free mud in spring Ð become alkaline in summer. This results in an intermingling of glycophytic and halophytic species. These transitions from C yp er et al ia fu sc i to C ry ps ie ta li a-communities will be discussed below. An introgression of glycophytic and halotolerant EWV can also be observed in California. Barbour et al. (2003) mention Crypsis schoenoides, Polypogon monspeliensis, Cressa truxillensis, Cotula coronopifolia and Distichlis spicata as differential species in brackish pools and on alkali soils. The time of emergence and the temperature of the substrate in the amphibic phase are factors, which influence the species composition via temperature preferences during germination. Seed ecology seems to be an important explaining factor for species composition. This has been studied by Pietsch (1999) for the example of 20 C yp er et al ia species. He stated close

590

U. Deil

correlations between the germination requirements and the phytosociological diagnostic groups: The Juncus bufonius-group includes the class and order species: With a brief superficial wetting, independently from the substrate type and even with constant temperatures, high germination rates are exhibited for these species in a few days. The other species are stimulated by fluctuating temperatures. The Limosella aquatica-group germinates within five days in submerged or waterlogged conditions, the Lythrum portula-group within 10 days. Both are E la ti no -E le oc ha ri ti on -species. The CS of the R ad io li on germinate only on nutrient-poor substrate and after long inundation. The different ecological requirements of the R ad io li on -species are confirmed by a numerical analysis of the Czech phytosociological database (Chytry & Tichy 2003) and by a data set from NE Germany (Kiesslich et al. 2003): R ad io li on is clearly separated, El at i no -E le oc ha ri ti on and Na no cy pe ri on overlap each other and also with B id en te te a-communities. Halo-nitrophilous amphibious vegetation: When the habitats are wetted by freshwater in the beginning of the growing season and by brackish water at the end of the amphibic phase, the I-N-communities are substituted (temporarily or spatially) by halotolerant communities, belonging to the C ry ps ie ta li a. This order is included by some authors (Mucina 1997, Rodwell et al. 2002 and Borhidi 1996b, 2003 for example) in a continental salt-marsh-class (T he ro -S al ic or ni et ea respectively Pu cc in el li o- Sa li c or ni et ea ), by others elevated to its own class (Cr yp si et ea ac ul ea ta e sensu Vicherek 1973). Some authors treat it as part of the IĂ?N. There is a considerable overlap in floristic composition between the C yp er o- Sp er gu la ri on sa li na e (C ry ps ie ta li a a cu le at ae ), the He lo ch l oo -C yp er en io n sensu Borhidi (2003) and some communities within E la ti ni -E le oc ha ri ti on ov at ae and Ve rb en io n s up in ae (all in Cy p er et al ia ). Species in common in these syntaxa are for example Crypsis aculeata, C. schoenoides, C. alopecuroides, Cressa cretica, Heliotropium supinum and Verbena supina. The delimitation of both orders should be clarified by further studies. These communities have their main occurrence on alkali soils in the Sarmato-Pannonian phytogeographical region (= Southeastern Europe). The diversity of the communities and the floristic richness are for example documented by Borhidi (1996b, 2003) and MolnaĚ r & Borhidi (2003) for Hungary, by Vicherek (1973) for former Czechoslovakia, by Korotkov et al. (1991) for the Black Sea region, and by Mucina (1993) for the Pannonian part of Austria. The European alliances of the C ry ps ie ta li a are listed in Tab. 4, following the concept of Rodwell et al. (2002). C ry ps ie ta li a-communities also occur scattered throughout the Mediterranean area (see for example Paradis 1992 and Paradis & Lorenzoni 1994 for Corsica). The habitat density becomes higher in semi-arid climates, like in the continental parts of the Iberian Peninsula and in Northern Africa. Examples are the Lyt hr o b ib ra ct ea ti -H el io tr op ie tu m s up in i and the H el io tr op io su pi ni -H el eo ch lo et um sc ho en oi di s in La

Habitats, plant traits and vegetation of ephemeral wetlands

591

Mancha and in the Guadalquivir basin in Spain (Cirujano 1981, Tamajón Gómez & Muñoz Alvarez 2001), and the D am as on io al is ma e- Cr yp s ie tu m a cu le at ae in SW Andalusia (Rivas-Martı́nez et al. 1980) and Tunesia (Barbagallo et al. 1990). Southernmost outposts of the C ry ps ie ta li a, intermingled with I-Nspecies, occur in the Central Saharan Mountains. Quézel (1958) documents from the Tibesti EWV with Crypsis aculeata, Cressa cretica, Wahlenbergia tibestica, Coelachyrum brevifolium, Triraphis pumilio, Eleocharis atropurpurea, Tripogon minimus, Cyperus meeboldii. These holarctic taxa are mixed with tropical elements such as Ammania prieureana, A. senegalensis, Vahlia oldenlandioides, Bergia ammanioides a.o. In the Jebel Uweinat region (Libya, Egypt, Sudan) occurs the C ry ps io va gi ni fl or ae -E ra gr os ti et um hu mi fu sa e (Léonard 2001). EWH in the Tassili and the Hoggar Mountains are colonized by Cotula anthemoides, Crypsis schoenoides, Wahlenbergia bernardii, Juncus bufonius, Marsilea aegyptiaca, Spergularia rubra, Blackstonia perfoliata, Centaurium pulchellum a.o. (Leredde 1954). At the Eastern fringes of the Mediterranean basin, in the Jordan Valley, occur the C yp er o p yg ma ei -G li ne tu m l ot oi de s (Zohary & Orshansky 1947) and the Crypsis minuartioides-Heliotropium supinum-community (Eig 1946). EWV in the northern boreal zone and in the arctic region: In the Northern Palaearctic region and in the alpine zone of Scandinavia, the I so et oN an oj un ce te a are replaced by communities characterized by Koenigia islandica (Tab. 4, Fig. 16). This annual Polygonaceae colonizes soils, opened by cryoturbation and needle ice. Such sites, called “flags” on Iceland, are often in contact with snowbeds or springs. Flags are flat areas with a scarce vegetation cover, covered with clay and opened by frost heaving. They occur in climates with temperatures oscillating around zero for a long period of the year. Sörensen (1942) studied flag-vegetation on Iceland and proposed the K oe ni gi o- Mi cr oj un ci on . This alliance (not yet validated!) might be better not included into spring vegetation (E pi lo bi et al ia a ls in if ol ii , M on ti o- Ca rd am in et ea ), as proposed by Sörensen (1942). Fredskild (1998) includes the K oe ni gi o i sl an di ca e- Sa gi ne tu m i nt er me di ae into the Sa xi fr ag o- Ra nu nc ul io n n iv al is , but the floristic distance to snowbed vegetation is obvious (see Tab. 36 in Fredskild 1998). The inclusion of the K oe ni gi o- Mi cr oj un ci on into the Is oe to -L it to r el le te a by Devillers-Terschuren & Devillers (2001) is also not convincing. The K oe ni gi o- Mi cr oj un ci on might be better promoted to a separate class. The following associations belong to the boreo-arctic K oe ni gi o- Mi c ro ju nc io n (for the outposts of Koenigia-communities in Central Asia see chapter 4. 3. 4.): 1) K oe ni gi o i sl an di ca e- Se de tu m v il lo si with records from Greenland (Fredskild 1998), Iceland (Sörensen 1942, Hadač 1971, 1985) and the Scandinavian Fjell (Dierssen 1996). The associations K oe ni gi oA gr os ti et um st ol on if er ae and Eq ui se to pa lu st ri s- Se de tu m

592

U. Deil

v il lo si sensu Hadač (1971, 1985) might be included into a broadly defined K oe ni gi o- Se de tu m. 2) J un co -R an un cu le tu m h yp er bo re i (= D re pa no cl ad o- Ra nu nc ul et um hy pe rb or ei Hadač 1989) in seasonal ponds and at lakeshores on Iceland (Mörsdorf 1989). 3) K oe ni gi o i sl an di ca e- Sa gi ne tu m i nt er me di ae : The community seems restricted to the East Coast in Greenland between 73o and 78o30⬘ North. It colonizes stony, locally moving clay, runnels in river deltas, and slopes below snow drifts, which are wetted by melt water (Fredskild 1998). Characteristic species are dwarf annuals such as Koenigia islandica, Alopecurus alpinus, Festuca hyperborea, Deschampsia brevifolia, Saxifraga hirculus, S. platysepala, Sagina intermedia, Sedum villosum (Sörensen 1942, Fredskild 1998). The perennial plants, which establish in flag-vegetation, are eradicated every year. Their rosettes and propagules take root again in the next growing season. Sörensen (1942) called this life form “ambulatorian” plants. Examples are Triglochin palustris, Parnassia palustris, Polygonum viviparum and Poa alpina. 4.3.4. Central and Eastern Asia EWH have been intensely studied in Japan. Artificial ponds, constructed for rice field irrigation, occur all over the country. On nutrient-poor soil, ecologically equivalent communities to the European R ad io li on sensu Pietsch (1973a) are two alliances, described from Japan: E ri oc au li on at r at ae in Northern Japan and Er io ca ul io n h on do en si s in Southern Japan (Shimoda 1983, 1985, 1986, 1987, 2005). CS of the latter alliance are Eriocaulon japonicum, E. hondoense, E. nakasimianum, E. decemflorum, E. sikokianum, Deinostema violaceum, Utricularia bifida, Coelachne japonica a.o. (Shimoda 2005). The Eriocaulaceae, a pantropical-subtropical family, seem to replace the Juncaceae there. The Eriocaulon-communities emerge on bare soil at the fringes of irrigation ponds, when the water table recedes in summer. A widespread association is the D ei no st em at o- Er io ca ul et um ho nd oe ns is Shimoda 1983, documented for the Prefectures of Oita, Yamaguchi, Hiroshima and Okayama. The high percentage of stenochorous taxa indicates an undescribed, Japan-endemic class of “E ri oc au le te a” (Tab. 5, Fig. 16). Nutrient-rich substrates in Japan and China are colonized by L in de rn io n p ro cu mb en ti s-communities (Miyawaki & Okuda 1972), impoverished outliers occur in Siberia (Ünal 1999). This vegetation type, germinating in summer on desiccating muddy alluvium, on the bottom of irrigation ponds, at the fringes of permanent ponds with fluctuating water-level and in the post-harvest phase of rice fields, corresponds to N an oc yp er io n-communities in Europe. CS are short-living dwarf plants such as Lindernia procumbens, Ludwigia epilobioides, Centipeda minima, Fimbristylis squarrosa, Cyperus orthostachys, C. difformis and Eclipta prostrata. The L in de rn io n p ro cu mb en ti s is in an intermediate position between B id en te te a (A lo -

Habitats, plant traits and vegetation of ephemeral wetlands

593

Tab. 5. Syntaxonomic survey of EWV in Central and Eastern Asia. EWV on sandy soils, at shorelines of oligotrophic ponds in Japan ? ? Eriocaulion hondoensis Shimoda 1983 Southern Japan Eriocaulion atratae Ohba 1974 Northern Japan Emerged shore vegetation of nutrient-rich substrates in Japan and China ? ? Lindernion procumbentis Miyawaki et Okuda 1972 nutrient-rich muddy alluvium, pond bottom and emerging pond shores Outliers of Western Palaearctic EWV in Siberia, Russian Far East and Mongolia Isoeto-Nanojuncetea Br.-Bl. & R. Tüxen ex Westhoff et al. 1946 Cyperetalia fusci Pietsch 1963 Elatino triandrae-Eleocharition ovatae (Pietsch & Müller-Stoll 1968) Pietsch 1973 Cypero fusci-Limoselletum aquaticae (Oberdorfer 1957) Kornek 1960 Lower and Middle Ob-river, Lower Irtish Eleochario ovatae-Caricetum bohemicae Klika 1935 em. Pietsch 1961 Juncus bufonius-Limosella aquatica-community (Hilbig 1995) Eleocharis acicularis-Schoenoplectus supinus-community (Hilbig 1987) Cyperus fuscus-community (Hilbig 1987) Radiolion linoidis (Rivas Goday 1961) Pietsch 1973 Androsaco filiformis-Blasietum pusillae Taran 2000 Lower Ob-river Southern outposts of subarctic Koenigia islandica-communities Koenigia islandica-Veronica rubrifolia-community (Hilbig & Schamsran 1981) Mongolia Koenigia islandica-Ranunculus natans-community (König & Rilke 2004) Central Altai, Western Siberia Isoetes-communities in mainland China and on Taiwan Isoetes yunguiensis-community (Wang et al. 2002) Yunnan Plateau, SW China Isoetes taiwanensis-community (De Vol 1972) on vulcanic ash, Taiwan Halotolerant EWV in the Alashan Gobi, Inner Mongolia, NW China Halerpesto cymbalariae-Crypsietum aculeatae Kürschner 2005 Halotolerant EWV in the Black Irtish floodplain, Siberia Marisco hamulosi-Crypsietum schoenoidis Taran 1993

p ec ur io n a mu re ns is ) and Cy pe re ta li a f us ci sensu lato. The following associations are hitherto known: F im br is ty le tu m v er ru ci fe ra e and Van de ll ie tu m a ng us ti fo li ae from the surroundings of Tokyo (Miyawaki & Okuda 1972), the Juncus leschenaultii-Lindernia procumbens-, Fimbristylis squarrosa-, Ludwigia prostrata-Lindernia procumbens- and Cype-

594

U. Deil

rus haspan-communities from Hiroshima Prefecture (Shimoda 1983, 1985, 1986), and the Fimbristylis diphylloides-Cyperus michelianus-community in Anhui province, China (Nakamura 1994). EWV in mainland China and on Taiwan is nearly unknown. Wang et al. (2002) record an Isoetes yungiensis-community from the upper reaches of Yangtse on the Yunnan Plateau (SW China). At an altitude of 1200 to 1900 m asl. there grow together: Isoetes yungiensis, Juncus bufonius, Leersia hexandra, Rotala rotundifolia, Eriocaulon schochianum, Hypericum japonicum, Hippuris vulgaris and Mariscus umbellatus. With the first record of the genus Isoetes on Taiwan, De Vol (1972) outlines an Isoetes taiwanensiscommunity on volcanic ashes at 1000 m asl., with Blyxa echinosperma, Sphaerocarum malacense, Abildgaardia ovata, Schoenoplectus mucronatuus, Eriocaulon formosanum, Monochoria vaginalis, Juncus effusus, and Nymphoides cristata. The species list shows some floristic resemblance with the B ly xo -M on oc ho ri et um va gi na li s l in de rn ie to su m p yx id ar ia e, described by Miyawaki (1960) from rice fields in Japan with well drained sandy soils. With the data available now for Central and Eastern Asia, it becomes clear, that the C yp er et al ia fu sc i have a much wider geographical range than previously assumed by Pietsch (1973a). They extend from Byelorus and the Caspian Sea to Central Asia, to Mongolia and to the Russian Far East (Fig. 16) (Taran 1993, 1994, 1995, 1998, 2000, 2001, Taran et al. 2004, Sinelnikova & Taran 2003, Ünal 1999, Hilbig 1995). This is already indicated by the areals of diagnostic species such as Myosurus minimus, Limosella aquatica and Coleanthus subtilis (see Fig. 11 here and additional maps in von Lampe 1996). Comparing the I so et o- Na no ju nc et ea over the Palaearctis, the communities are more and more impoverished to the East (Popiela 1999, Hilbig 1995, Taran 1995, Ünal 1999). The most widespread association is the C yp er o f us ci -L im os el le tu m a qu at ic ae . It is recorded in different subtypes (with Coleanthus subtilis, Rumex ucranicus, Scirpus lateriflorus) from the river banks of the Lower and Middle Ob and Irtish, from the surroundings of Lake Baikal and from the Sajan Mountains. The A nd ro sa co f il if or mi s- Bl as ie tu m p us il la e occurs along the Lower Ob River (Taran 2000), the E le oc ha ri o o va ta e- Ca ri ce tu m b oh em ic ae in the Baikal area (Ünal 1999). The latter region is an “oceanic island” in Siberia. This is reflected in exclaves of atlantic-subcontinental C yp er et al ia fu sc i-CS. In the Russian Far East and in Mongolia, the observations are fragmentary (Fig. 16). Sinelnikova & Taran (2003) document the C yp er o f us ci -L im os el le t um aq ua ti ca e for the coastal area at Magadan (Ochotsk Sea) as an easternmost outpost of the C yp er et al ia fu sc i. Impoverished outliers of this order in Mongolia are mentioned by Hilbig (1995, 2000) (see Tab. 5), in Siberia by Taran (1995) and Ünal (1999). The Koenigia islandica-Veronica rubrifolia-community (Mongolia) (Hilbig & Schamsran 1981) and the Koenigia islandica-Ranunculus natans-community (Central Altai, West Siberia) (König & Rilke 2004) belong to the Koenigia islandica-syntaxon with main distribution in the boreal and subarctic regions of the holarctic kingdom.

Habitats, plant traits and vegetation of ephemeral wetlands

595

In the steppe and semi-desert zones of Central Asia, EWH become brackish before drying up completely. The following associations, colonizing poikilosaline waters and alkali soils, are known: The M ar is co ha mu l os i- Cr yp si et um sc ho en oi di s in the floodplains of the Black Irtish, Ural, Don and Dnjeper Rivers, the E ra gr os ti et um su av eo le nt is from the lower reaches of the Volga River, the D am as on io -M ar si le et um s tr ig os ae east of the Volga River and in Kasachstan (Taran 1993), and the H al er pe st o c ym ba la ri ae -C ry ps ie tu m a cu le at ae in the Alashan Gobi Desert of Inner Mongolia (Kürschner 2004). All these communities are easternmost outposts of the Palearctic C ry ps ie ta li a-communities. 4.3.5. Tropical Africa This area will be treated very briefly here, because Müller & Deil (2005) summarize the present knowledge for West Tropical Africa. Some of the higher syntaxa described respectively validated in this publication seem to range further to Central, Eastern and Southern Africa. The syntaxa in Tropical Africa outside West Africa can be only outlined for the moment (Tab. 6), and the synareals given in Fig. 16 must be considered as tentative. For Central and Eastern Africa, the synopsis presented here follows more or less Schmitz (1988). This author validates a number of syntaxa by selecting type-relevés. Comparative tables however are missing in this publication. A summarizing study of the wetland vegetation on inselbergs in West Tropical Africa is under way (Müller, submitted). An overall synthesis of inselberg vegetation in Tropical Africa and Madagascar, based upon floristic similarity, is not possible, because complete floristic datasets and plot-related data are not available for most of the areas. Seasonal ponds and lakes in West Tropical Africa: Seasonal ponds and semi-permanent freshwater lakes are a common landscape element there. The vegetation, emerging in temporary waters and colonizing the amphibic shorelines of lakes with fluctuating water-levels, is an important resource for man and his livestock. From the Sudanian to the Sahelian zones, water level fluctuations become stronger and the dry period is more extended. The dominant life forms are free-floating respectively rooting submerged pleustophytes, hydrogeophytes and short-living amphibic and terrestrial plants. Superimposition of several communities, dominated by different life-forms, is a common phenomenon. Water depth, duration of flooding, and the trophic level are the most important differentiating ecological factors. Floating leaf communities (N ym ph ae io n m ic ra nt ha e, N ym p ha ei on gu in ee ns is ), submerged macrophytic vegetation (Ce ra to p hy ll io n d em er si ) and free-floating communities (Pi st io n s tr at io ti s) are concentrated in deeper ponds. The associations colonizing the amphibic environments around shallow lakes and the bottom of temporary ponds in West Africa are combined in the R ha mp hi ca rp o- Hy gr op hi le te a s en eg al en si s (Tab. 6, Fig. 16). The communities of the E ch in oc hl oi on ca ll op i occur in rapidly drain-

Tab. 6. Syntaxonomic survey of EWV in Tropical Africa. EVW of West Tropical Africa, mesotrophic and eutrophic, sandy and muddy soils Rhamphicarpo fistulosae-Hygrophiletea senegalensis J. Müller & Deil 2005 Echinochloetalia callopi J. Müller & Deil 2005 Echinochloion callopi J. Müller & Deil 2005 rapidly draining, mesotrophic depressions over lateritic crusts Eragrostietalia squamatae J. Müller & Deil 2005 Eragrostion squamatae J. Müller & Deil 2005 depressions in coastal dune fields ? Sagittario guayanensis-Nymphaeion maculatae J. Müller & Deil 2005 nutrient-rich muddy shorelines in the North Sudanian and Sahelian zones ? Brachiario muticae-Cynodontion dactyli J. Müller & Deil 2005 eutrophic, shortly inundated shorelines of Sahelian seasonal lakes, heavily grazed ? ? Glinus lotoides- and Glinus oppositifolius-communities Shortly submerged or waterlogged sandy soils in Central Africa Microchloetea indicae Schmitz (1971) 1988 Sporoboletalia festivi Lebrun 1947 Nanocyperenalia teneriffae Mullenders 1954 deep soils, shortly waterlogged Nanocyperion teneriffae Lebrun 1947 seasonal (shortly) flooded sands, from Eastern DR Congo to Northern Namibia Ilysanthenalia schweinfurthii Mullenders 1954 superficial soils Indigoferion schweinfurthii Mullenders 1954 in rock pools and over lateritic depressions, from the Sudanian to the Zambesian zones Ilysanthion pulchellae Taton 1948 Eastern fringes of the Congo Basin, on granite outcrops and vulcanites Swamps, reeds, and floating meadows in Tropical Africa ? Phragmitetea Cyperetalia papyri (= Papyretalia) Lebrun 1947 em. Schmitz 1988 Magnocyperion divitis (Lebrun 1947) em. Schmitz 1988 lakeshores, shallow water, submerged in the rainy seasons Eriochloion nubicae Schmitz 1988 shallow ponds with periodically emergent floor EWV of tropical Africa, oligotrophic sites on inselbergs, in rock pools and over lateritic crusts Drosero-Xyridetea Schmitz 1988 Drosero indicae-Utricularietalia subulatae J. Müller submitted Eriocaulo pumili-Ophioglossion gomezianum J. Müller & Deil 2005 in West Africa Genliseo africanae-Sporobolion pauciflori J. Müller submitted Inselbergs in Guinea, Sierra Leone and Liberia ? Drosero madagascariensis-Rhynchosporion candidae Duvigneaud & Symoens 1951 Central Africa, waterlogged sands Utricularion schweinfurthii Mullenders 1954 Eastern parts of Central Africa, rock and moorland pools Loudetiopsis glabratae-Utricularion andongensis ined. Western and Central parts of Central Africa, rock pools and EFV on Inselbergs Floating vegetation in seasonal ponds over laterite ? ? Pistion stratiotes Schmitz (1971) 1988 Marsileetum minutae Schmitz 1971 Mire pools and bare, cryoturbate soils in the afro-alpine zone of the East African Mountains Limoselletea africanae ined. ? ? Subularia monticola-Limosella africana-Crassula granvikii-communities (Hedberg 1964) Isolepis setacea-Callitriche oreophila-community (Fischer 1996) Coelachne africana-Anagallis angustiloba-community (Fischer 1996)

Habitats, plant traits and vegetation of ephemeral wetlands

597

ing depressions over lateritic crusts with mesotrophic soils. This alliance is documented for the moment from Senegal to the Lake Chad region. The E ra gr os ti on sq ua ma ta e is found in seasonally waterlogged depressions in coastal dunes. This alliance is recorded from the Guinean zone of Senegal, but can be expected in other coastal regions of West Africa, too. Nutrient-rich shorelines with muddy substrate in the North Sudanian and Sahelian zones are colonized by the S ag it ta ri o g ua ya ne ns is -N ym ph ae io n m ac ul at ae . The creeping swards of the Br ac hi ar io mu ti ca e- Cy no d on ti on develop on eutrophic, shortly inundated wet places around Sahelian seasonal lakes, subjected to heavy grazing. The diagnostic species of all the mentioned syntaxa are listed by MĂźller & Deil (2005). Similarities in life strategies, habitat conditions and floristics (on the family and genuslevel) exist with EVH in other tropical regions of the world. Vicarious taxa occur for example in the families Scrophulariaceae (Gratioloideae), Acanthaceae (Hygrophila), Apiaceae (Hydrocotyle), Elatinaceae (Bergia, Elatine), Lythraceae (Ammannia), Menyanthaceae (Nymphoides) and Alismataceae (Limnophyton, Sagittaria). The communities of the R ha mp hi ca rp o- Hy gr op hi le te a s en eg al en si s can be in spatial contact with permanent reed and papyrus-swamps (C yp er et al ia pa py ri ). The latter order occurs at the margins of big lakes (Lake Chad for example), where water-level fluctuations are small and groundwater is always close to the surface. Many species, which have their primary habitats in ephemeral ponds, settle also in rice fields. Rice weed communities in West Africa, belonging to the order M el oc hi et al ia co rc ho ri fo li ae (Lu dw ig io oc to va lv is E ch in oc hl oe te a c ol on um ), are not further considered here, but are presented by MĂźller & Deil (2005). E ch in oc hl oe te a c ol on um sensu Wittig (2005), described on the basis of a small data set from Burkina Faso, will be better included in the pantropical wetland class L ud wi gi oE ch in oc hl oe te a c ol on um sensu Hoff & Brisse (1983). Shortly submerged or seasonally waterlogged soils in Central Africa: Such sites are colonized in the amphibic phase by the communities of the M ic ro ch lo et ea in di ca e (Schmitz 1988). This class is differentiated ecologically by soil deepness and field capacity of the substrate (Tab. 6). Sporobolus festivus, Pycreus capillifolius, Microchloa indica, M. ensifolia, Ophioglossum gramineum, Bulbostylis spp. a.o. occur on deeper soils. They characterize the S po ro bo le ta li a f es ti vi with the suborder and alliance Na n oc yp er en al ia te ne ri ff ae respectively Na no cy pe ri on te ne ri ff ae . These syntaxa are documented from Eastern DR Congo, southernmost outliers occur in Namibia. They include the associations S po ro bo le tu m s pi ca ta e, P or tu la ce tu m k er me si na e and C ra te ro st ig me tu m n an o- la nc eo la ti (Lebrun 1947) with diagnostic species such as Cyperus teneriffae, Portulaca kermesina, Sporobolus iocladus, S. homblei, Chrysochloa hubbardiana, Portulaca centrali-africana, Craterostigma plantagineum, C. lanceolatum, C. purpureum, Indigofera parvula, Cycnium tubulosum ssp. montanum, and Abildgaardia ovata.

598

U. Deil

Ephemeral dwarf turfs on shallow soils on granite rock outcrops have first been described by Taton (1948) from Eastern DR of Congo. The associations I ly sa nt ho pu lc he ll ae -A eo ll an th et um re pe nt is and I ly sa nt ho tr ic ho to ma e- Bu lb os ty le tu m p ol yt ri ch ae belong to the I ly sa nt he na li a s ch we in fu rt hi i, a suborder distributed from the southern Sudanian and the Guinean to the Sambian climatic zones, with two alliances: I nd ig of er io n s ch we in fu rt hi i in rock pools and lateritic depressions in the region of Kaniama, Lumumbashi and Katanga, and I ly s an th io n p ul ch el la e on granite outcrops. Character species of the suborder and the alliances are Lindernia schweinfurthii, L. madiensis, L. pulchella), Aeollanthus repens, Aspilia subpandurata, Bulbostylis angolensis, Abildgaardia congolensis), Brachiaria scalaris, Cyanotis kaniamae, Cyperus difformis, Hygrophila crenulata, Lipocarpha sinensis, Oldenlandia corymbosa var. caespitosa, Pycreus flavescens, Schyzachyrium flaccidum, Senecio ruwenzorensis a.o. Westernmost outliers are recorded by Oumorou & Lejoly (2003) from Benin (Sporobolus festivus-Microchloa indica-community). Mares over laterite near Lumumbashi are colonized by the M ar si le et um mi nu ta e Schmitz 1971. The inclusion of this community into the floating communities of the P is ti on st ra ti ot es /N ym ph ae et al ia lo ti by Schmitz (1988) must be regarded as preliminary. The R or ip po -B er g ie te a and Tor en io -O ld en la nd ie ta li a, proposed by Knapp (1966) for long submerged river banks in Central and West Africa, are not yet confirmed by plot-related floristic data. The C yp er et al ia pa py ri , arranged by Schmitz (1988) preliminarily into the P hr ag mi te te a, include a broad spectrum of formations: floating meadows (J us si ae io n and P ap yr io n), rooting water meadows (E ch in oc hl oi on cr ur is -p av on is ), sedge swamps (Ma gn oc yp er io n d iv it is ) and short-living amphibic vegetation (E ri oc hl oi on nu bi ca e). Most of the associations are dominated by tall and perennial helophytes. However, some communities within M ag no cy pe ri on and Er io ch lo io n are dominated by annuals such as L ud wi gi o a by ss in ic ae -R hy nc ho sp or et um c or ym bo sa e (Szafranski & Apema 1983), L ee rs io he xa nd ra eR hy nc ho sp or et um co ry mb os ae (Mandango 1988), De sm od io hi rt ae -B ra ch ia ri et um ru zi zi en si s (Germain 1952), L ip oc ar ph o c hi ne ns is -C yp er et um ha sp an (Szafranski et al. 1986), Er io ch lo et um n ub ic ae (Lebrun 1947, Germain 1952). Communities with Oryza barthii respectively O. longistaminata and Asteracantha longifolia (= Hydrocotyle auriculata) are recorded from the floodplain north of Lake Tanganika by Germain (1952) and from a freshwater lagoon in Guinea-Bissao by Catarino et al. (2002a, 2002b). The floristic and ecological relationships of the E ch in oc hl oe tu m p yr am id al is (LeĚ onard 1951) from the Congo basin to the Vossia cuspidata-water meadows at Lake Chad (Iltis & Lemoalle 1983), the Vos si et um cu sp id at ae (Lebrun 1947) and a plant community with Oryza longistaminata, Vossia cuspidata and Echinochloa pyramidalis in Burkina Faso (Guinko 1984) must be clarified. Valley grassland on badly drained soils is widespread in Eastern Africa (Tanzania, Zambia, Malawi).

Habitats, plant traits and vegetation of ephemeral wetlands

599

This highly productive vegetation is dominated by robust perennials, disappearing above-ground in the dry season and resprouting from rhizomes after flooding. Character species are Echinochloa pyramidalis, E. stagnina, Hyparrhenia rufa, Leersia hexandra, Eriochloa nubica, Vossia cuspidata a.o. (Vesey-Fitzgerald 1963, 1970, Ellenbroek 1987). The inclusion of the B ac op et um cr en at ae , observed by Lejoly & Lisowski (2000) on hydromorphic soils in open patches of the rain forests in the Congo Basin into the M ag no cy pe ri on di vi ti s must be regarded as preliminary. The L im no ph il o c er at op hy ll oi di s- Sa lv in ie tu m n ym ph el lu la e, described by Masens (2000) for desiccating former rice fields and pond margins in Central Africa, would be better separated into different communities or at least eco-phases, with Salvinia dominating in the aquatic and Limnophila in the amphibic phase. Pond slopes in Central Africa are colonized by the L ud wi gi o- En hy d re tu m (Schmitz 1988). Northernmost outliers occur in Southern Togo (L ud wi gi et um st ol on if er ae ) (Guyot et al. (1994). These communities belong to the Central African alliance J us si ae io n LeĚ onard 1950 (= L ud w ig io n s to lo ni fe ra e (LeĚ onard 1950) Schmitz 1971). The L ud wi gi oE ch in oc hl oe tu m c ru s- pa vo ni s, recorded by Masens (2000) from Congo, might be included in this alliance. The syntaxonomic position of the J us si ae io n in the C yp er et al ia pa py ri and Ph ra gm it et ea is doubtful. The L ep to ch lo o- Ec hi no ch lo et um st ag ni na e (Mandango 1988), recorded for Central Africa, shows some floristic similarity with the Sahelian and North Sudanian communities of the S ag it ta ri o g ua ya ne ns is -N ym ph ae io n m ac ul at ae . EWV on inselbergs and other nutrient-poor substrates: Representatives of the magnoliat families Eriocaulaceae, Xyridaceae, Lentibulariaceae, Scrophulariaceae and Droseraceae and vicarous species within the fern-genera Ophioglossum, Marsilea and Isoetes occur in nutrient-poor, moist habitats in the tropical parts of Africa. On the basis of a few common species and many vicarious taxa, this vegetation can be included into the class D ro se ro -X yr id et ea , described by Schmitz (1988) from Central Africa (= E ri oc au lo -U tr ic ul ar ie te a sensu Knapp 1966). Plant communities with closely related taxa occur in the neotropical region (X yr id et ea sa v an en si s and other white sand savannas). According to periodicity and duration of flooding and wetting, its habitats range from seasonally inundated lateritic depressions, rock pools, ephemeral wet rocky slopes and rock pools on inselbergs to permanently wet bogs. The EWV on inselbergs is often in contact with perennial mats of poikilohydric Cyperaceae, Afrotrilepis pilosa in West Africa, Coleochloa setifera in Eastern Africa and Madagascar (Porembski et al. 1996a, Porembski 1999). These species-poor communities with Cyperaceae and Velloziaceae (genus Xerophyta) are ecosystem engineers for the adjacent EFV, because they provide soaking water for a certain period after the end of the rainy season.

600

U. Deil

Inselberg-vegetation in West Africa: EFV and rock-pool communities in West Africa belong to the D ro se ro in di ca e- Ut ri cu la ri et al ia su bu la t ae . Diagnostic species are the name-giving species and Lindernia schweinfurthii, Xyris anceps, Utricularia pubescens and Ophioglossum costatum (Müller, submitted). Two alliances are hitherto known: E ri oc au lo pu m il i- Op hi og lo ss io n g om ez ia nu m (Müller & Deil 2005) and G en l is eo af ri ca na e- Sp or ob ol io n p au ci fl or i (Müller, submitted). The first alliance is so far documented for the Ivory Coast, Guinea and Mali (Schnell 1951Ð52, Adjanohoun 1964, Aberlin 1986a). The associations I so et o n ig ri ti an ae -O ph io gl os se tu m g om ez ia nu m and D op at ri o s en eg al en se -M ar si le et um po ly ca rp ae belong to this alliance (Müller & Deil 2005), as well as a number of rankless communities such as the “Groupement à Andropogon africanus et Ophioglossum costatum” from Benin (Oumorou & Lejoly 2003a, 2003b). Through joint species like Eriocaulon pumilum, Xyris straminea, and X. capensis, the E ri oc au lo O ph io gl os si on can be included into the Dr os er o- Xy ri de te a. The only association within the G en li se o a fr ic an ae -S po ro bo li on pa uc if lo ri hitherto known is the Ut ri cu la ri o s ub ul at ae -E ri oc au le tu m p um il i, confirmed for the Nimba mountains in Guinea (Schnell 1951Ð 52) and for the Ivory Coast (Dörrstöck et al. 1996). Inselberg vegetation in Central and Eastern Africa: Earlier publications about rock pool vegetation and seasonal waterlogged nutrient-poor sands in Central Africa are summarized by Schmitz (1988). Some of the communities of the alliances D ro se ro ma da ga sc ar ie ns is -R hy nc ho sp or io n c an di da e and U tr ic ul ar io n s ch we in fu rt hi i listed there are ephemeral (Duvigneaud & Symoens 1951). More recently, Lejoly & Lisowski (1999, 2000) describe the M es an th em o r ad ic an ti s- Se la gi ne ll et um co ng oe ns is from the Congo basin, which can be included into the Dr os er oR hy nc ho sp or io n c an di da e. Parmentier (2002, 2003) presents lists of diagnostic species for TWINSPAN-groups from samples on inselbergs in Equatorial Guinea. The following clusters are of ephemeral character: 1) A seasonally wet turf in rock pools with Lindernia diffusa, Lipocarpha chinensis, Heterotis rupicola, Ischaemum timorense, Kyllinga erecta, Diodia sarmentosa a. o., 2) An EWV with Loudetiopsis glabrata, Eragrostis invalida, Burmannia madagascariensis, Utricularia andongensis, Scleria spiciformis, S. melanotricha, Otomeria micrantha. A community-group (alliance?) characterized by Loudetiopsis glabrata, Utricularia andongensis and Burmannia madagascariensis might turn out to be a syntaxon for EFV in this part of Africa. Inselbergs in Zimbabwe shelter Drosera indica, Lindernia monroi, L. conferta, L. pulchella, Aponogeton macrostachyus, Dopatrium junceum, Isoetes spp., Utricularia spp., Genlisea spp., Ludwigia leptocarpa, Burmannia spp., etc. in seasonal rock pools and EFH (Seine 1996, Seine & Becker 2000).

Habitats, plant traits and vegetation of ephemeral wetlands

601

Mire pools and cryoturbate sites in the afro-alpine belt: Observations about EWV on open patches in the alpine moorland of the East African Mountains are scanty. Bare ground in Carex runssoroensis-tussock grassland in an altitude between 3750 and 4100 m asl. at Mt. Elgon and Ruwenzori is colonized by Subularia monticola, Crassula granvikii, Callitriche stagnalis, Lobelia deckenii, and Limosella africana (Hedberg 1964). Carex monostachya-tussock grassland at Mt. Kenya and Kilimanjaro (between 4200 and 4400 m asl.) shelters EWV with Subularia monticola, Sagina afroalpina, Cardamine obliqua, Ranunculus volkensii, and Montia fontana. The genus Subularia and the life form of the “solifluction floaters” link these habitats with cryoturbate patches in the arctic zone on Iceland (flagvegetation) and Scandinavia. Representatives of this life form are unattached specimens of mosses and lichens, lifted by needle ice. Subularia monticola remains intact in small cavities in the ice, Limosella africana avoids the perils of solifluction by growing below the water surface. Fischer (1996) mentions from the Kahnzi-Biéga National Park in Eastern Zaire mires with Cyperus latifolius. In open patches at 2200 m asl. occur the dwarf annuals Coelachne africana, Lythrum rotundifolium, Anagallis angustiloba, Smithia elliotti, Alchemilla ellenbeckii, Pycreus nigricans, and Polygonum salicifolium, at 2400 m asl. Isolepis setacea, I. costata, Alchemilla ellenbeckii, Callitriche oreophila and Polygonum salicifolium. Some of these communities belong to the L im os el le te a a fr ic an ae , a class first proposed by Knapp (1966), but not validly described. Supraregional floristic contrast: The floristic separation of seasonal pond vegetation over base-poor substrates between West and Central Africa is not sharp. The syntaxonomic position of the suborder I ly sa nt he na li a s ch we in fu rt hi i Mullenders 1954 for example, subordinated by Schmitz (1988) to the Central African class M ic ro ch lo et ea in di ca e Schmitz (1971) 1988, is unclear. These communities have some species in common with the seasonal pools on rock outcrops and on lateritic crusts in West Africa (E ri oc au lo -O ph io gl os si on go me zi an um ) and Central Africa (U tr ic ul ar io n s ch we in fu rt hi i) and with the vegetation of ephemeral flush vegetation on inselbergs in general (D ro se ro -X yr id et ea ). Apart from some common elements at the genus level (Marsilea, Ophioglossum), the floristic contrast between the ephemeral wetland vegetation in the southern parts of the holarctic kingdom and the northern margins of the Palaeotropical region results in different syntaxa of high rank (I so et oN an oj un ce te a, C ry ps ie ta li a etc. in extratropical regions, R ha mp hi c ar po -H yg ro ph il et ea , Dr os er o- Xy ri de te a, M ic ro ch lo et ea in di c ae etc. in the tropical parts of Africa). In the Central Saharan Mountains of the Tassili (Leredde 1954) and Tibesti (Quézel 1958), the holarctic and the palaeotropic geoelements come together. Ephemeral wetland vegetation there shelters for example Cressa cretica and Crypsis aculeata (at their southern limit), and Ammannia spp., Bergia ammannioides and Vahlia oldenlandioides (at their northern limit). The ecological background for this floristic contrast between the temporary wetland vegetation North and

602

U. Deil

South of the Sahara is the different seasonality (vernal / autumnal phenological optimum respectively zenithal precipitation regime). 4.3.6. Other Paleotropical regions Arabian Peninsula: Most of the rivers running from the Yemeni Escarpment in SW Arabia through intramountainous basins to the coastal plain (= Tihama) and the Red Sea are intermittent. When the catchments are not too big, the floods do not devastate the plant communities in the river bed. In such a situation, Deil & MĂźller-Hohenstein (1985) observed a community in the At Tur Basin with Bacopa monnieri, Eclipta prostrata, Phyla nodiflora, Marsilea aegyptiaca, Echinochloa colona, Dactyloctenium aegyptium, Fimbristylis cymosa, Cyperus laevigatus a.o. (Fig. 6). There is a common stock of species with floodplains in other tropical regions like Peru, Bolivia and Guadeloupe (see chapter 4. 3. 2.). India: According to the checklist of water plants in India, recorded by Lavania et al. (1990), the subcontinent is rich in endemic elements specialized to the amphibic environment, for example in the genera Isoetes, Marsilea and Aponogeton. Watve (2003) and Porembski & Watve (2005) provide preliminary observations about the flora of EFH and rock pools on the outcrops of the Western Ghats and on ferricretes and inselbergs in Southern India. They mention taxa such as Utricularia spp., Eriocaulon spp., Lindernia ciliata, Murdannia spp., Burmannia pusilla, Rhamphicarpa longiflora, Trithuria konkanensis, Fimbristylis spp., and Sopubia delphinifolia. Rock pools are colonized by Marsilea quadrifolia, Limnophila indica, Dopatrium junceum, Rotala indica a.o., flat depressions by Lindernia crustacea, L. parviflora, Drosera indica, deeper depressions by Rhamphicarpa longiflora, Hygrophila serpyllum and Aeschynomene indica. There are obvious vicariance patterns of these unknown plant communities with the classes D ro se ro -X yr id et ea and Rh am ph ic ar po -H yg ro ph il et ea s en eg al en si s from Tropical Africa, and with the inselberg vegetation (X yr id et ea sa va ne ns is ) in the neotropical region. Polynesia: The ruderal- and oldfield-communities, described by Hoff & Brisse (1990) from Wallis and Futuna, include some units of EWV. These islands are located 400 km W of Samoa and have a tropical climate. The L in de rn io pr oc um be nt is -E le oc ha re tu m o ch ro st ac hy s develops on mud soil in irrigated Taro-plantations, the L ud wi gi o o ct ov al vi sE ch in oc hl oe tu m c ol on ae in ruderalized seasonal ponded depressions. Further associations of amphibic ruderal sites and trampled grounds are K yl li ng o n em or al is -E ch in oc hl oe tu m c ol on ae , Ip om oe o f im b ri os ep al ae -K yl li ng et um br ev if ol ia e and Ver on ic o- Fi mb ri st yl et um to me nt os ae . The syntaxa of higher rank are unclear. Papua New Guinea: Observations about EWV are fragmentary. Conn (1983) mentions extensive Limnophila indica-communities in shallow

Habitats, plant traits and vegetation of ephemeral wetlands

603

swamps and roadside ponds. Hydrogeophytic Cryptocoryne-species (Araceae) colonize stream margins and muddy areas in the lowlands. Semiaquatics in the lower alpine zone are Nymphoides hydrochoroides, Villarsia spp., Xyris capensis, Utricularia racemosa, Eriocaulon hookerianum and Haloragis halconensis. TP in the hard cushion bogs in the alpine zone (> 3500 m asl.) are colonized by Centrolepis philippinensis, Myriophyllum pedunculatum, Gentiana piundensis, Ranunculus ssp., Eriocaulon spp. and Astelia alpina. Open Scirpus crassiusculus-fens and dwarf Isoetes stevensiitarns are recorded at Mt. Giluwe. 4.3.7. Southern Africa and Madagascar Namibia: Volk & Leippert (1971) and Volk (1984) described three plant communities from EWH near Binsenheim. At an altitude of 1850 m asl. and under summer rainfall conditions (about 350 mm between November and April) occur the X er op hy te tu m h um il is (on runon-habitats with coarse sand at the base of rock outcrops), the Eriocaulon welwitschii (= E. aristatum)-Riccia volkii-community (on rock debris, seasonally wetted by soaking water) and the Gnaphalium stenolepis-Riccia angolensis-community (on alluvial soils). These communities are dominated by annuals, but also rich in perennial poikilohydric resurrection plants such as Xerophyta humilis (Velloziaceae), Oropetium capense, Microchloa caffra (Poaceae), Craterostigma plantagineum (Scrophulariaceae) and bryophytes (Riccia okahandjana, Bryum argenteum, Exormotheca holubii). The following species are in common with EWV in the Congo-basin: Microchloa indica, Cyperus teneriffae, Lindernia nana, Sporobolus festivus, and Utricularia arenaria. Volk (1984) therefore includes these communities into the N an oc yp er io n t en er if fa e. They seem to be a southwestern outpost of the Central African S po ro bo le ta li a f es ti vi (Mi cr oc hl oe te a i nd ic ae ) (Tab. 7). Further ephemeral communities, not yet documented by phytosociological data, are the Aponogeton junceus-Marsilea macropoda-community in the eastern Kalahari (Leistner 1967), floodplains in NE Namibia with Sporobolus spp., Marsilea unicornis, Elytrophorus globularis, Leptochloa fusca, Aponogeton desertorum, Eragrostis spp., Oryzidium barnardii, Melinis repens a.o. (Hines 1990/93), and rock-pool vegetation in the Namibian desert with Chamaegigas intrepidus, Limosella grandiflora, Aponogeton desertorum and Lindernia monroi (Gaff & Giess 1986, Heilmeier et al. 2005). Southern Africa: EWH are common in South Africa and the surrounding countries. According to Taylor et al. (1995), large areas are covered by seasonal wetlands (pans and vleis) in Botswana and South Africa, by seasonal floodplains (dambos) in Angola, Malawi, Zimbabwe and Zambia. Plantsociological data are rare. Non-saline habitats have been studied in the Cape region (Taylor 1972, Campbell et al. 1980), in Natal (Furness & Breen 1980, Eckhardt et al. 1996), in Lesotho (van Zinderen Bakker &

604

U. Deil

Tab. 7. Syntaxonomic survey of EWV in Southern Africa and Madagascar. EWV on rock outcrops and floodplains in subhumid parts of Namibia Microchloetea indicae Schmitz (1971) 1988 Sporoboletalia festivi Lebrun 1947 Nanocyperion teneriffae Lebrun 1947 Seasonal floodplain and rock pool vegetation in the Namib and Eastern Kalahari Deserts ? Elytrophoretea globularis sensu Knapp (1968) ? Chamaegigas intrepidus-Aponogeton desertorum-community-group ined. Vernal pool vegetation in the Cape Region ? Satyrio-Gladioletea sensu Knapp (1968) ? Satyrio coriifolii-Lachenalietalia contaminatae sensu Knapp (1968) Isoetes capensis-Sparaxis bulbifera-community (Campbell et al. 1980) Seasonally wet grasslands in Natal and Zambia Gunnero perpensae-Eragrostidion planae (Eckhardt et al. 1996) seasonal wet grasslands in the montane zone of Kwa Zulu (Natal) Cyperus fastigiatus-Echinochloa pyramidalis-community (Furness & Breen 1980) floodplain of the Pongolo river in NE Natal Acroceras macrum-water meadows, Echinochloa pyramidalis-variant (Ellenbroeck 1987) floodplain of the Kafue river in S Zambia Mire pools in afro-alpine tussocky bogs Limoselletea africanae ined. ? Scirpo fluitantis-Limosellion longiflorae Van Zinderen Bakker & Werger 1974 Limosella capensis-Crassula natans-community (van Zinderen Bakker & Werger 1974) EWV in Madagascar Isoetes schweinfurthii-Cyperus leucocephalus-community-group ined. seasonal wetlands in the savannas of SW Madagascar Drosera madagascariensis-Genlisea incurva (= G. margaretae)-community ined. EFV on inselbergs in Madagascar

Werger 1974, van Zinderen Bakker 1965) and in Zambia (Ellenbroek 1987). Dambo-vegetation, which is widespread in Southeastern Africa (Acres et al. 1985), is excluded by definition, because it is mainly perennial. Knapp (1968) suggested the E ly tr op ho re te a g lo bu la ri s for dwarf annual turfs in seasonally wet depressions with E ly tr op ho re ta li a in vleis in the Karoo and P ri on an th et al ia ph ol iu ro id is in VP in the SW Cape region. For both orders, solid data are missing. A series of communities, characterized by local endemics of the genera Isoetes, Marsilea, Oxalis, Crassula and eurychorous members of the genera Eriocaulon, Utricularia and Xyris can be concluded from the wetland flora of Southern Africa for the Cape region (Cook 2004). The only available

Habitats, plant traits and vegetation of ephemeral wetlands

605

data are from the Cape Flats near Cape Town. A seasonal submerged turf with Scirpus nodosus and Juncus krausii is mentioned by Taylor (1972). Campbell et al. (1980) describe a Triglochin bulbosa-Romulea tabularisSparaxis bulbifera-community colonizing the margins of vleis, and an Aponogeton angustifolius-Sporobolus pungens-community in the deeper parts. The habitat shelters the rare species Isoetes capensis and Restio sabulosus. For sandy soils, waterlogged in the rainy season and completely dry in summer, Knapp (1968) proposed the order S at yr io co ri if ol ii -L ac he na li et al ia co nt am in at ae (Sa ty ri o- Gl ad io le te a). With genera like Romulea and Sparaxis, the community observed by Campbell et al. (1980) might belong to this syntaxon. The E ly tr op ho re te a, dominated by annuals, and the S at yr io -G la di ol et ea , rich in geophytes, might be united in the future. A Cyperus fastigiatus-Echinochloa pyramidalis-community grows in the floodplain of the Pongolo river in NE Natal (Furness & Breen 1980). The community is dominated by the rhizome-geophyte Cyperus fastigiatus, which resprouts in the amphibic phase, and by creeping annuals such as Centella asiatica, Grangea maderaspatana, Glinus lotoides and Ludwigia stolonifera. Seasonal wetlands in higher altitude (1500 to 2000 m asl.) with Eragrostis plana, Leersia hexandra, Fimbristylis ferruginea a.o. characterize the G un ne ro pe rp en sa e- Er ag ro st id io n p la na e (Eckhardt et al. 1996) with the associations L im os el lo gr an di fl or ae -L eu co si de tu m s er ic ea e (near to springs, opened by trampling and grazing) and the I so l ep id o f lu it an ti s- Pa ni ce tu m s ch in zi i (long submerged depressions). The syntaxa of higher rank are unclear (Tab. 7) and do not fit in any of the orders or classes derived by Knapp (1968) in a deductive way for South Africa. Wetland vegetation, analysed by Ellenbroek (1987) on the Kafue Flats in Zambia, has some species in common with the Pongolo river floodplains in Natal. The water meadows in Zambia are dominated by perennial grasses (Acroceras macrum, Panicum repens, Leersia denudata, Paspalidium obtusifolium and Sacciolepis africana), which resproute after the dry period. In the amphibic phase, they offer open sites for annuals such as Echinochloa pyramidalis, Setaria sphacelata, Hygrophila prunelloides, H. auriculata, Rhamphicarpa tubulosa and Caperonia serrata. The ecological and floristic similarities (common respectively vicarious species) between the Kafue Flats in Zambia and the floodplains in Northern Australia are underlined by Howard (1985). The vegetation mosaic of afro-alpine tussocky bogs in the Drakensberge (Lesotho) and Basutoland (Oranje) includes small patches with muddy soils, openend by cryoturbation and needle ice (van Zinderen Bakker 1965, van Zinderen Bakker & Werger 1974). A Limosella capensis-Crassula natans-community with stagnant water is in contact with R an un cu l et um me ye ri and Se ne ci on et um cr yp to la na ti (both in Sc ir po fl ui ta nt is -L im os el li on lo ng if lo ra e) in flowing water. Further characteristic taxa besides the name-giving species are Aponogeton spathaceum, Eriocaulon sonderianum, Landtia spec., Eleocharis dregeana, Lagarosiphon

606

U. Deil

muscoides, and Utricularia spp. These communities might be an exclave of the afro-alpine syntaxon L im os el le te a a fr ic an ae ined. Subantarctic islands: The C ra ss ul o m os ch at ae -C la sm at oc ol ee tu m v er mi cu la ri s, recorded by Gremmen (1981) from the Marion and Prince Edward Islands, can be interpreted as an extremely impoverished outlier of the South American class L im os el le te a a us tr al is . Madagascar: EWV occurs in seasonally flooded depressions in the Savanna zone and on inselbergs. The vegetation mosaic on inselbergs Ð a common landscape element in Madagascar Ð includes EFH. The plant communities are not yet studied and the syntaxonomy is unknown (Tab. 7), but we can conclude from the floristic annotations in Rauh (1973) and Fischer & Theisen (2000), that seasonal rock pools and EFH are inhabited by taxa such as Drosera madagascariensis, Fimbristylis spp., Utricularia spp., Genlisea margaretae, Eriocaulon spp., Rotala spp., Lindernia rotundifolia, Microchloa kunthii, Antherotoma naudinii, Emilia graminea, and Cyanotis nodiflorum. The species Utricularia caerulea and U. subulata are distributed on inselbergs from Madagascar to India, others are endemic in Madagascar like Genlisea margaretae and Cyanotis nodiflorum. The observations of Morat (1973) in the “mares temporaires” and “savanes marécageuses” in SW Madagascar allow to outline an Isoetes schweinfurthii-Cyperus leucocephalus-community-group (alliance?). Character species of this EWV-type are the name-giving species and Scirpus corymbosus, Kyllinga pumila, Cyperus spp., Fuirena glomerata, and widespread helophytes such as Eleocharis caduca. Stagnant soils over limestone crusts are colonized by widespread sub-ruderal species such as Sporobolus pyramidalis, Tragus berteronianus, Chloris virgata, Echinochloa nubica, Cynodon dactylon a.o. The semiterrestrial communities are in contact to shallow respectively seasonally submerged vegetation with Nymphoides indica, Aponogeton decaryi, Neptunia oleracea, Nymphaea stellata, Utricularia spp., Salvinia hastata, Pistia stratiotes, Azolla africana, Lemna aequinoctialis, Spirodela polyrhiza, and Lagarosiphon madagascariensis. 4.3.8. Australia and New Zealand EWV in SW Australia: The scientific analysis of EWV in the world started 100 years ago with Diels (1906) in SW Australia. He was not only the first to coin the term “dwarf flora” (Fig. 1) and discovered, that Centrolepidaceae are a character-family of this habitat in the Australian region, but he also outlined already both alliances known today from SW Australia, with tiny annual Centrolepis-species on seasonally waterlogged sandy and muddy alluvial soils, and with Campylopus bicolor and Utricularia multifida on rock outcrops. A detailed analysis of the ephemeral vegetation in winter wet sandy depressions, along water courses and on rock outcrops in the subhumid parts of SW Australia by Pignatti & Pignatti (1994) and

Habitats, plant traits and vegetation of ephemeral wetlands

607

an extension of these studies to the deserts of Western Australia (Pignatti & Pignatti 2005) gave the following results: All the communities belong to the C en tr ol ep id i a ri st at ae -H yd ro co ty le te a a la ta e, a class which is endemic in SW Australia (56 % SW Australian endemics) (Fig. 16), and characterized by Centrolepidaceae, Asteraceae, Apiaceae (Hydrocotyle), Cyperaceae, Goodeniaceae, Haloragaceae, Juncaginaceae, Lentibulariaceae, Droseraceae and Stylidiaceae (Stylidium, Levenhookia). Remarkable is the nearly total absence of Juncaceae (beside some introduced species like Juncus bufonius). CS are for example: Centrolepis aristata, C. polygyna, Hydrocotyle alata, H. callicarpa, H. diantha, Calandrinia granulifera, Aphelia brizula, A. cyperoides, Eragrostis dielsii, Goodenia filiformis, Levenhookia pusilla, L. stipitata, and Triglochin calcitrapa. 66 % of the species are annuals, some are spring green geophytes (Chamaescilla corymbosa, Wurmbea dioica) or poikilohydric subshrubs (Borya spp.). The differentiating factors within the EWH in SW Australia are the climatic gradient from the subhumid coastal areas to the arid deserts and the edaphic contrast between the rock outcrop localities and the floodplain habitat (see Tab. 8). The following associations, all recorded from seasonal wet depressions on granite outcrops, belong to the C am py lo po bi co lo r is -C en tr ol ep id io n a ri st at ae : Ap he li o c yp er oi di s- Ce nt ro le pi d et um (subhumid climate), Ca mp yl op o- Dr os er et um ra me ll os ae and C am py lo po -P ol yp om ph ol yd et um mu lt if id ae (semi-arid areas). The C en tr ol ep id et um po ly gy na e, the unique association of the C en tr ol ep id io n p ol yg yn ae , occurs on moist sand near rivers and lakes in the semi-arid parts of SW Australia. The Centrolepis eremica-Cyperus rigidellus- and the Drosera indica-Stylidium desertorum-communities emerge after erratic rainfall on claypans in the arid Great Victoria Desert, Gibson Desert and Sandy Desert. Both units belong to the Drosera indicaLipocarpha microcephala-community-group (Pignatti & Pignatti 2005). A therophyte community in statu nascendi, characterized by a mixture of indigenous therophytes (Triptilodiscus pygmaeus, Hydrocotyle laxiflora) and species introduced from the Mediterranean area (Juncus bufonius, Cicendia filiformis, Sagina apetala, Ophioglossum lusitanicum) and from California (Cicendia quadrangularis) is recorded from SW Australia by Doing (1994). EWV in the Northern Territories, SE Australia, and Tasmania: Big rivers drain to the Timor Sea near Darwin. From the TWINSPAN-groups, mentioned by Whitehead et al. (1990) for the floodplains of the Mary River, EWV occurs with species like Marsilea mutica, Phyla nodiflora, Alternanthera nodiflora, Eriochloa procera, Eleocharis dulcis, Ludwigia adscendens, Oryza rufipogon etc. The study of outcrop communities on the New England Bartholith (from Queensland to New South Wales) by Hunter & Clarke (1998) was oriented to open forests and heathlands. From the list of additional species one can conclude, that EW-elements occur in the sampled vegetation mosaics, for example in the Isotoma axillaris-Gonocarpus teretioides-, Calytrix

608

U. Deil

Tab. 8. Syntaxonomic survey of EWV in Australia and New Zealand. Mediterranean and desert zones of SW Australia Centrolepidi aristatae-Hydrocotyletea alatae Pignatti & Pignatti 1994 Centrolepidi aristatae-Hydrocotyletalia alatae Pignatti & Pignatti 1994 Campylopo bicoloris-Centrolepidion aristatae in wet depressions on rocky outcrops/inselbergs in subhumid and semi-arid areas Centrolepidion polygynae on moist sand near rivers and lakes, semiarid SW Australia Drosera indica-Lipocarpha microcephala-community-group on claypans, arid climate, Great Victoria Desert, Gibbson Desert, Sandy Desert EWV in New Zealand, impoverished outliers in Tasmania and SE Australia Crassulo sinclairii-Hydrocotyletea hydrophilae ined. ? Lilaeopsidion novae-zelandiae ined. in seasonal waterlogged dune hollows in New Zealand Lilaeopsidion ruthianae ined. turfy, muddy and sandy margins of freshwaters, mires and kettle holes in New Zealand ? Lilaeopsis polyantha-communities in seasonal waterlogged dune hollows in Tasmania and SE Australia

tetragona- and Cheilanthes sieberi-Isotoma axillaris-communities with species such as Isotoma axillaris, Gonocarpus teretioides, Isolepis hookeriana, Hydrocotyle spp., Centrolepis strigosa, Schoenus apogon, Fimbristylis dichotoma, Ophioglossum lusitanicum and the introduced species Gratiola peruviana and Juncus bufonius. No vegetation data are available for the seasonal wetlands, widespread in New South Wales (Jacobs & Brock 1993), but some floristic annotations are included in the seed bank studies and inundation experiments of Brock & Casanova (1997), Casanova & Brock (2000) and Nicol et al. (2003). From the species, which are listed in these publications (for example Lilaeopsis polyantha, Limosella australis, Selliera radicans, Triglochin striata, Crassula helmsii, Isolepis platycarpa, Cyperus sanguinolentus), one can draw the following conclusions: 1) EWH of the SHH and TPH exist there. 2) The water bodies are to some extent brackish. 3) There are no floristic links to EWV in SW Australia, but to Tasmania and New Zealand. The description of perennial dune vegetation in Victoria (Thannheiser 2001) and Tasmania (Haacks & Thannheiser 2000, 2003) reveals some floristic similarity with New Zealand also in the ephemeral flora. Isolepis aucklandica and Lilaeopsis polyantha for example are recorded by Haacks & Thannheiser (2000) from the Tasmanian coasts, included there in open and seasonally waterlogged patches of the S el li er et um ra di ca nt is and Distichlis distichophylla community. When more plot-related data become available, a syntaxon (alliance?) with Lilaeopsis polyantha might be

Habitats, plant traits and vegetation of ephemeral wetlands

609

defined in the future, summarizing ephemeral mud vegetation in Tasmania, Victoria and New South Wales. The Tasmanian wetland types, differentiated by Kirkpatrick & Harwood (1983), include EWH. Short-living and dwarfish annuals occur in the â&#x20AC;&#x153;marginal herblandsâ&#x20AC;? (Wilsonia rotundifolia- and Selliera radicansherbland, both units with halotolerant species) and in sedgelands (Eleocharis acuta- and Juncus kraussii-sedgeland for example). The sample plots of the authors are obvious a mosaic of perennial and annual vegetation. Juncus kraussii-sedgeland and Selliera rotundifolia-marginal herbland are more or less identical with vegetation units described by Haacks & Thannheiser (2000). The EWV of Tasmania might belong to the Lilaeopsis polyantha-alliance or to a vicarious syntaxon with Lilaeopsis brownii, Pratia platycalyx, P. surrepens, Mimulus repens, Limosella lineata, Neopaxia australasia, Scirpus cernuus, Centella cordifolia, Eryngium vesiculosum, Centrolepis fascicularis and Drosera pygmaea. A dwarf turf, seasonally submerged by brackish water, is recorded by Kirkpatrick (1975) from a coastal lagoon of the Tasman peninsula. Diagnostic species are Schoenus nitens, Samolus repens, Pultenaea dentata, Gnaphalium candidissimum and Hydrocotyle hirta. EWH in New Zealand: EWH range over broad spectra of altitudes, relief types, substrates, duration of ponding and climatic conditions (Johnson & Rogers 2003). The main landforms are dune hollows, deflation hollows in ash-covered plateaus, and kettle holes (= depressions on hummock moraine surfaces). Annual precipitations vary from 350 mm in Central Otago to 3000 mm in Western Fjordland, with a pronounced dry season as a common character. 419 indigenous and 171 introduced species are recorded by Johnson & Rogers (2003) from EWH. 88 are obligate EWS. All New Zealand members of Gratiola, Lilaeopsis, Hypsela, Limosella, and Glossostigma are linked to this environment. Some species are endemic on the Northern Island (Selliera rotundifolia, Crassula manaia), some on the Southern Island (Iti lacustris, Ranunculus recens). Naturalized EWS are Lythrum hyssopifolia, L. portula, Juncus tenuis, J. bufonius and Isolepis spp. 18 % of all protected vascular plant species of NZ occur in EWH. Because of a small number of sites, small population size and habitat vulnerability to invasive weeds and land-use changes, conservation efforts are necessary for some species such as Myosurus minimus ssp. novae-zelandiae, Myosotis pygmaea (Rogers et al. 2002), Amphibromus fluitans, Carex uncifolia, Isolepis basilaris, Crassula ruamahanga a.o. (Johnson & Rogers 2003). Available vegetation studies about EWH in New Zealand are not oriented towards classification in a national context. The very profound and nationwide analysis by Johnson & Rogers (2003), a series of publications restricted to dune ecosystems (Sykes & Wilson 1987, Wilson et al. 1993, Haacks 2003) respectively the submerged environment (Wardle 1991, Wells et al. 1998) and a study of some rare spring annuals in the Otagoarea (Rogers et al. 2002) allow a preliminary and tentative classification.

610

U. Deil

The description of habitat preferences of New Zealand wetland plants by Johnson & Brooke (1989) was very useful for that purpose. EWV in New Zealand belongs to the C ra ss ul o s in cl ai ri i- Hy dr oc ot yl et ea hy dr op hi la e ined. (Tab. 8). The class is endemic in New Zealand (Fig. 16), with impoverished outliers in Tasmania and SE Australia. The following species, endemic in New Zealand, characterize this undescribed syntaxon: Crassula sinclairii (= Tillaea s.), Hydrocotyle hydrophila, H. microphylla, H. sulcata, Centrolepis minima, Plantago triandra, Isolepis basilaris, I. habra, Ranunculus limosella, Pilularia novae-zelandiae, Gunnera dentata, Juncus pusillus, and Pratia perpusilla. The following character species of the class occur also in Tasmania respectively SE Australia: Isolepis aucklandica, Limosella lineata, Elatine gratioloides, Gratiola sexdentata, a.o. The class is dominated by annuals and by dwarf, creeping perennial herbs. A few geophytes contributed to the seasonal plant cover, such as Iphigenia novae-zelandiae and Isoetes spp. Two community groups (alliances?) can be distinguished at the moment: L il ae op si di on no va e- ze la nd ia e ined. in seasonal waterlogged dune hollows and L il ae op si di on ru th ia na e ined. on turfy, muddy and sandy margins of inland freshwaters, mires and kettle holes from the lowlands to the montane belt. CS of the communities in seasonal wet interdune depressions are: Lilaeopsis novae-zelandiae, Epilobium billardiereanum and Scirpus cernuus. Lilaeopsis novae-zelandiae and Scirpus cernuus tolerate brackish water (Partridge & Wilson 1987). The L il ae os id io n n ov ae z el an di ae is further differentiated by the introgression of halotolerant dune and salt marsh species from the adjacent communities J un ce tu m k ra us si i, S el li er et um ra di ca nt is and Ap od es mi et um si mi li s (Haacks 2003). Such species are for example Apodasmia similis (= Leptocarpus s.), Selliera radicans, Triglochin striata, Cotula coronopifolia, Lobelia anceps, Samolus repens, Apium prostratum, Gunnera dentata, Crassula moschata, Schoenus nitens, Crassula manaia, Lepidium tenuicaule. The turfy margins of freshwaters and the amphibic bottom of kettle holes are inhabited by the L il ae op si di on ru th ia na e-communities. CS are Lilaeopsis ruthiana, Leptinella maniototo, Hypsela rivalis, Schizeilema cockaynei, Tetrachondra hamiltonii, Parahebe canescens, Glossostigma diandrum (= G. submersum), G. elatinoides and Utricularia monanthos (incl. U. novae-zelandiae). The distribution of the latter two species extends also to Australia, the other taxa are New Zealand endemics. Transgressive taxa in montane bogs and kettle holes are Centrolepis pallida, C. ciliata and Hydrocotyle novae-zeelandiae var. montana. All the communities recorded by Johnson & Rogers (2003) from the Wanganui Coastal Dune hollows and from the Chatham Islands belong to the alliance L il ae op si di on no va e- ze la nd ia e, as well as open variants of the Apodasmia similis-community, S el li er et um ra di ca nt is and Le pt in el le tu m d io ic ae sensu Haacks (2003), the Hydrocotyle sulcata-Lilaeopsis novae-zelandiae-swamp, Triglochin striata-Lilaeopsis novae-zelandiae-swamp and Gunnera monoica-Ophioglossum coriaceum-moist-slack sensu Sykes & Wilson (1987), the Sea machair and Transitional machair

Habitats, plant traits and vegetation of ephemeral wetlands

611

sensu Wilson et al. (1993) and the Selliera rotundifolia-Crassula manaiaZoysia minima-turf sensu Rogers et al. (2002). Most of the communities, described by Johnson & Rogers (2003) under various names, belong to the L il ae op si di on ru th ia na e. Name-giving species for these communities are for example Lilaeopsis ruthiana, Hypsela rivalis, Galium perpusillum, Juncus pusillus, Leptinella maniototo, Alopecurus geniculatus, Neopaxia linearifolia, Hydrocotyle hydrophila, H. novae-zeelandiae, Muehlenbeckia axillaris, Glossostigma elatinoides, Lythrum portula, Carex rubicunda, Eleocharis gracilis, and Pratia perpusilla. The syntaxonomic positions of the Myosurus minimus-community and the Dichondra brevifolia-Crassula sinclairii-Carex breviculmis-community sensu Rogers et al. (2002) have to be clarified. 4.4.

Small-scale zonation

Vegetation zonation according to water depth, period of inundation and time of emergence is a well known character of TP and emergent shorelines. Other differentiating gradients can be salinity (in endorheic playa lakes in arid and semi-arid climates), soil depth and water storage capacity (on rock outcrops), duration of seepage water flow (on inselbergs, depending on the distance to the water-storing perennial mats), wave respectively ice scour intensity (in the shoreline habitat) and frost-heaving intensity (in subarctic and oreotropical climates). These environmental gradients result in repetitive patterns of contact series of plant communities (= zonation complexes) respectively catenal series in the pedological sense. Some examples from various parts of the world, representing different hydrological and geomorphological situations, will be briefly outlined. California: The zonation in Californian VP was first studied by Kopecko & Lathrop (1975) on the Santa Rosa Plateau. From the pool centre to the pool margins, the following zones are distinguished: 1. Dry marsh bed zone with Alopecurus howellii, Marsilea vestita, Navarretia prostrata, Orcuttia californica, Isoetes howellii, I. orcuttii, Eryngium aristulatum a.o. 2. Standing water zone with Callitriche longipedunculata, Elatine chilensis, Lilaea scilloides, Isoetes orcutii, Ranunculus aquatilis a.o. 3. Muddy margin zone with Crassula aquatica, Callitriche marginata, Anagallis minima, Eleocharis acicularius, Juncus bufonius, Pilularia americana, Elatine californica, Downingia cuspidata a. o. 4. Vernally moist zone with Bromus hordeaceus, Plagiobothrys undulatus a.o. 5. Dry grassland zone with Bromus hordeaceus, Avena barbata, Erodium cicutarium, Plagiobothrys nothofulvus, Lasthenia californica, Lythrum hyssopifolia a. o. Deschampsia danthonioides and Psilocarphus brevissimus range over a broad pool depth gradient. This pattern is confirmed by transect studies in other parts of California, for example in the Sacramento region (Schlis-

612

U. Deil

ing & Sanders 1982) and in San Diego County (Zedler 1984). In alkaline pools in the San Joaquin Valley, Lilaea scilloides, Downingia bella, Callitriche marginata, Plagiobothrys leptocladus and Psilocarphus tenellus are restricted to the pool centre, Elatine californica, Myosurus minimus, Spergularia marina, Plagiobothrys bracteatus and Hemizonia pungens to the margins (Holland & Jain 1977/88, 1981/84). Classification of some hundred releveĚ s according to floristic similarity subdivided the Californian VP vegetation class D ow ni ng io bi co rn ut ae L as th en ie te a f re mo nt ii into two orders. These orders correspond with different periods of inundation respectively different times of emergence. Pool edges and the centres of shallow pools are colonized by the associations of the D ow ni ng io -L as th en ie ta li a f re mo nt ii , bottoms of the deepest or the longest-duration pools of the L as th en ie ta li a g la be rr im ae (Barbour et al. 2003, 2005). Vegetation zonation in Californian VP in relation to inundation was studied in detail by Zedler (1984, 1987) and Bauder (2000). Fig. 17 (left side) illustrates the sequence of the species according to weighted average inundation classes. The bottom of the pool is colonized by Pilularia americana, Lilaea scilloides and by Isoetes spp. A second group grows in the inner zone of the pool. Vernal pool specialists like Myosurus minimus, Crassula aquatica, Pogogyne abramsii and Psilocarphus brevissimus concentrate there. California vernal pool endemics like Navarretia hamata and Ophioglossum californicum cluster in a third group, characteristic for the shortly flooded margins. Introduced annuals from the Palaearctic region like Bromus madritensis and Vulpia myuros are restricted to the non-inundated upper fringes. The preference to a specific inundation period is confirmed by inundation-frequency-profiles for selected taxa (Fig. 17, right side). The inundation in the pool basin eliminates true terrestrial species. The dessication in the terrestrial phase excludes obligate wetland taxa from the outer margin. The amphibic habitat offers a unique habitat quality, the evolutionary result is the VP-specific flora (Keeley & Zedler 1998). Mean species density is maximal in the outer margin zone. The low diversity at the long duration end of the gradient is interpreted by Zedler as a smaller number of species adapted to extended ponding. This presumption is confirmed by Bauder (1989, 2000). She tested species response patterns and distribution along soil moisture and relative elevation by inundation and competition experiments. Long inundation increases the mortality of non-pool- (Bromus spp., Vulpia myuros) and of edge-species (Juncus bufonius, Anagallis minima, Eryngium aristulatum, and Deschampsia danthonioides), but is tolerated by the pool species Crassula aquatica, Isoetes orcuttii, Downingia cuspidata, Psilocarphus brevissimus a.o. Wetting permits the establishment of Pogogyne abramsii at the dry end even in competition with non-pool species. Very long inundation excludes this mint species from deep pools, insufficient soil moisture excludes it from the pool margins. Species distribution along the inundation gradient is overlapping, with a strong spatial species turnover occurring in the five centimetres below the mean inundation level (see Fig. 3 in Bauder 2000).

Fig. 17. Average inundation duration (left) and inundation-frequency-profiles (right) for vernal pool species in California (from Zedler 1984, 1987).

614

U. Deil

Washington: Vegetation zones and soils in vernal pools in Eastern Washington have been studied by Crowe et al. (1994). When species abundance is included into the analysis, the zonation becomes clearer than with presence/absence data. The vegetation patterns can be explained by the microtopography. Soil characteristics like particle size, soil moisture potential, pH and other chemical parameters are seen by the authors as dependent parameters from the elevation gradient. Six vegetation zones have been identified (see Fig. 18 A). Appalachian Piedmont (Georgia): TP with Isoetes melanospora, I. teretiformis and Amphianthus pusillus are in contact to coarse debris layers with Sedum pusillum, Cyperus granitophilus, Juncus georgianus and Rhynchospora globularis var. saxicola, surrounded by a dry resistant turf with Diamorpha smallii, Minuartia godfreyii, Agrostus elliottiana and a lichen-moss pioneer community on the rock surface (Shure 1999). Guianas: The white sand savanna grassland (L ep to co ry ph io -Tra ch yp og on et ea ) in the Guianas was classified by van Donselaar (1965, 1969) according to floristic similarity. This typology reflects the inundation periodicity in the field in a sequence of wet depressions (P an ic et al ia st en od is ) to wet savannas (P as pa le ta li a p ul ch el li i) further on to dry savannas (Tra c hy po go ne ta li a p lu mo si ). This pattern is confirmed and refined by Janssen (1986) for the Rio Madeira-floodplain in HumaitaĚ (Western Brazil). Brazil: In the Pantanal of Mato Grosso, one of the largest floodplains in the world, the following hydroseries is outlined by Schessl (1997, 1999). 1. Free floating pleustophytes (Salvinia auriculata, Pistia stratiotes) 2. Floating meadows (Oxycarium cubense) 3. Permanent submerged tall swamps (Cyperus giganteus, Thalia geniculata) 4. Ephemeral short grass floodplain (Panicum laxum, Setaria parviflora, Reimarochloa acuta, Cyperus haspan, Eleocharis minima, Mecardonia procumbens, Marsilea polycarpa) 5. Tall tussock grassland (Andropogon hypogymnus, Axonopus leptostachyus) 6. Small tussock grassland and earthmound savanna (Panicum stenodes, Axonopus purpusii, Andropogon selloanus) Bolivia: The mosaic at Rio ParanaĚ in Brazil (Schessl 1997, 1999), Paraguay (Wolf 1990) and Argentina (Eskuche 1975) is somewhat similar to the Rio Yumaca floodplain in NE Bolivia (Beck 1983, 1984) with free floating communities (Azolla filiculoides, Pistia stratiotes, Eichhornia azurea), rooting floating leaf plants (Hydrocotyle ranunculoides, Sagittaria guayanensis, Nymphaea blanda, Nymphoides indica), Cyperus giganteus swamps, grassland of medium inundation period (Thalia geniculata, Polygonum hydropiperoides, Hymenachne amplexicaulis, Leersia hexandra, Cyperus haspan, Eleocharis atropurpurea), temporary pools with Marsilea polycarpa, Neptunia oleracea and Ceratopteris pteridioides, prostrate mudflat communities

Habitats, plant traits and vegetation of ephemeral wetlands

615

Fig. 18. Schematic hydroseries with ephemeral wetlands in different parts of the world.

616

U. Deil

(Heteranthera limosa, Bacopa monnierioides), Sida ciliaris-shrubland and Machaerium isadelphum-Tabebuia heptaphylla-woodlands. The sequence at clearwater rivers west of the Llanos de Moxos in NE Bolivia was studied by Haase (1989) and is illustrated for the terrestrial ecophase in Fig. 18 B. Colombia: The hydroseries in the Paramos of Colombia is H yd ro co ty lo r an un cu lo id es -M yr io ph yl le tu m e la ti no id es (permanent water), Isoetes spp.-communities (all Isoetes from section Laeves) (nearly permanent shallow water), Til la ee tu m p al ud os ae (amphibic) and a perennial marsh zone with Juncus ecuadoriensis and Eleocharis palustris (Cleef 1981). The sequence of the syntaxa D it ri ch io su bm er si -I so et io n and Til la ei on is very similar at the genus level to the contact between Is oe to -L it t or el le te a (permanent submerged nutrient poor waters) and I so et o- Na n oj un ce te a (semiterrestrial pond margins) in the Palaearctic region. This congruence was stated already by Cleef. Peru: A freshwater zonation in the high Andean belt (3600 to 4400 m asl.) in Peru is M yr io ph yl le tu m q ui te ns e (permanent water), R an un cu le t um li mo se ll oi de s (amphibic moorland pools) and E le oc ha ri to tu cu m an en si s- Pl an ta gi ne tu m t ub ul os ae (terrestrial hard cushion moorland) (Galán de Mera et al. 2003). Further observations about the zonation pattern in the Paramo belt come from Bolivia (Seibert & Menhofer 1991, 1992). Chile: The zonation around TP in the temperate climate of Southern Chile (IXth region) was studied by San Martı́n et al. (1998) (see Fig 18 C). It ranges from ephemeral vegetation with different Eleocharis species via a perennial grassland (M en th o p ul eg ii -A gr os ti et um ca pi ll ar is ) to a perennial juncaceous marsh (J un ce tu m p ro ce ri i). Shallow depressions in the alluvium of Rio Chol-Chol near Temuco are colonized by the L eo nt od on to ta ra xa co id is -P ip to ch ae te tu m m on te vi de ns is na va rr et ie t os um in vo lu cr at ae , surrounded by perennial turfs with Mentha pulegium, Juncus rigidus and J. microcephalus (Ramı́rez et al. 1994). VP in the mediterranean part of Chile have not yet been studied in detail. From a first floristic survey and from a few transects through pools, Bliss et al. (1998) infer the following sequence (from the pool centre to the edges): Lilaea scilloides Ð Marsilea mollis Ð Plagiobothrys spp. Ð Navarretia involucrata. Lasthenia kunthii and Crassula peduncularis occur over a broad pool-depth range. When passing from the subhumid to the semi-arid regions of Chile, Psilocarphus brevissimus and Ranunculus bonariensis shift more to the pool centre. Argentina: In the high Andean belt of NW Argentina, the raised hard cushion bogs are characterized by Hypsella oligophylla, Werneria pygmaea and Distichia muscoides (Fig. 48 in Ruthsatz 1977). Small runnels within this dwarf geophyte turf shelter Lilaeopsis andina and Ranunculus cymba-

Habitats, plant traits and vegetation of ephemeral wetlands

617

laria. The bogs are surrounded by a tussock grassland with Festuca scirpifolia, Alchemilla pinnata, Eleocharis albibracteata and Muhlenbergia peruviana, and further away, by a Festuca orthophylla-Baccharis incarum semidesert shrubland. The vegetation in ephemeral pools in the Pampa de Achala (Argentina) is zonated in the following way: Limosella lineata-Crassula pedunculariscommunity (pool centre), Muhlenbergia peruviana-turf (inner margin), Alchemilla pinnata-Eleocharis albibracteata-sedge swamp (outer margin) (Cabido & Acosta 1986). France: Zonation in rock pools and around TP was studied by Barbéro et al. (1982) and Loisel et al. (1994), some additional notes come from Quézel (1998), Médail et al. (1998) and Grillas et al. (2004a). Plant species in small temporary rock pools over ryolite in the Provence are arranged in the following way (for a comparison with rock pools on Gavdos/South Aegean see also Fig. 22): 1. Crassula vaillantii 2. Calliergon sp., Drepanocladus sp., Callitriche stagnalis 3. Isoetes velata, Lythrum borystenicum (= Peplis erecta) 4. Ophioglossum lusitanicum, Isoetes duriaei. The hydroseries in larger TP in the Maures Massif is illustrated in Fig. 18 D. Portugal: Due to the high seasonal dynamics of TP vegetation in the Alentejo-region, Espı́rito Santo & Arsénio (2005, Fig. 4) distinguish an early spring and an early summer zonation. In March, the hydroseries is P ep li do er ec ta e- Ag ro st ie tu m s al ma nt ic ae (aquatic), Ju nc o c ap it at iI so et et um hi st ri ci s (late emergent) and L ot o s ub bi fl or i- Ch ae to po g on et um fa sc ic ul at i (early emergent). In May, the long submerged J un co py gm ae i- Is oe te tu m v el at i is surrounded by the E ry ng io co rn ic ul at i- Pr es li et um ce rv in ae (amphibic) and the Pu li ca ri o u li gi n os ae -A gr os ti et um sa lm an ti ca e (terrestrial). The only ephemeral flush habitat, where zonation was studied in detail, is in the Serra de Monchique in Southern Portugal (Fig. 7 here, Figs. 8 and 9 in Rudner 2005b). By a biogenic accumulation of weathered material, inclination on syenite rock outcrops is reduced from 10 to 5 degrees. Coarse sediment is transported by surface water and accumulated at the upper end of the slack cushion. The lower end can be eroded by heavy rainfall events. The soils are well drained and do not show any hydromorphic characters. At a long time scale, the whole gravel stair is migrating upwards on the rocky slope. The different soil depth, the better and longer water supply at the lower end and the decreasing proportion of macropores in this direction results in the following catenal vegetation complex: 1. An accumulation zone with coarse debris, colonized by the H el ia nt he mo -P la nt ag in et um be ll ar di i a re na ri et os um co ni mb ri ce ns is . 2. A shallow soil layer with less input of coarse gravel and a humic horizon, dominated by Isoetes histrix and Cicendia filiformis.

618

U. Deil

3. A thick soil layer, consolidated by a perennial herb community with Hyparrhenia hirta, Asphodelus aestivus, Iris xiphium and Elaeoselinum gummiferum. 4. A thick layer with finer material, rich in micropores, covered by the L ot o- Ch ae to po go ne tu m f as ci cu la ti . Water supply is ensured until early summer by seeping water. 5. An erosion zone with maximal humus content: Pinguicula lusitanica is located there. This is a remarkable system in several respects: 1) In the hydrological sense, as an interflow water supply ecosystem. 2) In the geomorphodynamic aspect, by the feedback between geomorphological processes and a temporary stabilization by the plant cover. By these characters, it resembles the runon-runoff-system on tropical inselbergs and on rock outcrops in subtropical zones in Georgia (USA) and SW Australia. The distribution of dominant life forms in relation to soil depth in the Serra de Monchique (Portugal) resembles the zonation on gravel cushions in the Appalachian Piedmont (USA): Wyatt & Allison (2000) report annual monospecific communities on shallow soils (2Ð9 cm), species-rich annual herb communities mixed with lichens at medium soil depth (7Ð15 cm) and annual-perennial communities on thicker soils (14Ð41 cm) (Rudner 2005a). Morocco: TP in the Ben Slimane region in Morocco have been studied by Rhazi et al. (2001a, 2001b) and Grillas et al. (2004a). A central zone with Nitella translucens, Callitriche brutia, Myriophyllum alternifolium, Glyceria fluitans and Ranunculus baudotii is surrounded by a perennial Scirpus maritimus marsh. The emergent pool shores are colonized by ephemeral plants like Elatine brochonii, Isoetes velata, Juncus pygmaeus, J. bufonius and Lythrum thymifolia, the outer margins by Hypericum tomentosum, Polypogon monspeliensis and ruderal non-pool species like Asphodelus aestivus, Cynara humilis and Cistus spp. West Africa: The hydroseries in seasonal lakes with small catchment areas in the Sahelian zone starts in deep and open water with the free floating pleustophytic L em no -P is ti et um over submerged Potamogeton-communities, followed by N ym ph ae io n m ic ra nt ha e-communities (leaf-floating, but rooting), superimposed to submerged C er at op hy ll et um de m er si . The amphibic zone is colonized by communities of the Rh am ph ic ar po fi st ul os ae -H yg ro ph il et ea se ne ga le ns is , with the associations of the S ag it ta ri o g ua ya ne ns is -N ym ph ae io n m ac ul at ae closer to the lake centre and associations of the B ra ch ia ri o m ut ic ae -C yn od on ti on d ac ty li on the earlier emergent surroundings (see Fig. 4 in Müller & Deil 2005). Temporary ponded hollows in the Casamance dune field (Western Senegal) show the following zonation: M ar si le et um co ro ma nd el ia na e h yg ro ph il et os um se ne ga le ns is , M. c. ty pi cu m, M . c . e ly ma nd re to s um go ss we il er i, Aristida sieberiana-community (Vanden Berghen

Habitats, plant traits and vegetation of ephemeral wetlands

619

1990b). The sequence over impermeable ferrallitic crusts in Eastern Senegal is illustrated by Fig. 18 E (Vanden Berghen 1990a). Namibia: Niche partitioning according to water depth results in a zonation of monospecific communities in rock pools of the Namibian desert (Heilmeier et al. 2005). The less dessication-tolerant Limosella grandiflora is restricted to deeper parts of the pools, Chamaegigas intrepidus colonizes the shallow water zone. Japan: An example for a pond-zonation in oligotrophic conditions is described by Shimoda (2005) (Fig. 18 F) The permanent submerged communities with Nymphaea tetragona and Myriophyllum ussuriense are substituted by the S ci rp et um la nc eo la ti (amphibious) and the De in at os te mo -E ri oc au le tu m h on do en si s (emergent), surrounded by the terrestrial marsh with Rhynchospora fujiana. Zonation patterns on eutrophic mud with L in de rn io n p ro cu mb en ti s communities are different (Miyawaki & Okuda 1972). New Zealand: Zonation patterns in kettle systems, lake shores, tephrabased depressions and coastal sand dune hollows have been studied by Johnson & Rogers (2003) over the whole altitudinal range of both islands. A simplified zonation pattern for a kettle system is presented in Fig. 18 G. The vegetation mosaic in coastal dunes and salt marshes was sampled and analysed by Haacks (2003). This is the only available study using the SIGMA-approach to document the vegetation mosaic in EWH: Sample plots are chosen in the landscape dimension, all plant communities are noted, cover values are estimated, and these so-called SIGMA-releveĚ s are classified according to similarity in community-composition. The results are documented in tables and in schematic transects. The EWV S el li er et um ra di ca nt is for example is inserted in the following salt-marsh hydroseries: Z os te re tu m n ov a- ze la nd ic ae , Sa rc oc or ni et um qu in qu ef lo ra e, S am ol et um re pe nt is , Se ll ie re tu m r ad ic an ti s, J un ce tu m k ra us ii . The ephemeral Apodasmia similis-community colonized open patches in the perennial J un ce tu m k ra us ii . 4.5.

Plant traits and germination ecology

The comparison of life forms and strategy types allows to ask for convergent evolution processes and for niche-equivalent taxa. This can give an answer to the question of why EWH are a preferred habitat for dwarf plants with low productivity. The analysis can be oriented toward the whole life cycle of the species and the classification can include morphological and ecophysiological characters as well as aspects of reproductive biology. Other studies and classification systems focus on a single aspect as for example photosynthetic pathways; or they concentrate on a particular developmental phase such as ger-

620

U. Deil

mination. Here, we will first review the results of life form and life cycle studies and describe the syndromes (= co-evolved adaptive traits) of the strategy types, which characterize the EWH, and in further subchapters briefly review our knowledge about seed bank, reproductive biology and photosynthetic pathways. 4.5.1. Life forms and life cycles A comprehensive classification system of life forms in a global perspective, as is available for true hydrophytes (see Scultorpe 1967 as an early approach) does not exist for semi-terrestrial plants. For temperate climatic zones, a quite detailed system for aquatic and amphibious plants was developed by Hejný (1957, 1962). According to their capability to resist inundation, he distinguishes tenagophytes (= shallow water plants) and pelochtophytes (muddy littoral plants). The first group (for example Limosella aquatica) germinates in the littoral and reproduces in the terrestrial phase, the second group (Carex bohemica, Cyperus flavescens, Juncus bufonius etc.) germinates in the limose phase and completes its life cycle under terrestrial conditions. Brock & Casanova (1997) and Casanova & Brock (2000) studied 60 wetland species in New South Wales (Australia) in a flooding experiment. They classified seven functional groups according to the reaction of the plant species when passing from the aquatic to the terrestrial phase and vice versa. “Amphibious fluctuation responders” are the heterophyllous species Limosella australis and Myriophyllum variifolium, a “fluctuation tolerator” is Cyperus sanguinolentus. Heterophylly is a common phenomenon in the EWF in many regions. Further life cycle studies and life form typologies have been realized from EWS in different parts of the world. During (1980, 1994) analysed N an oc yp er io n-species and bryophytes in the Netherlands, Vogel (1997, 1999) Corrigiola littoralis and Illecebrum verticillatum in Central Europe, Grillas et al. (2004b) a number of I-N-species in the Mediterranean, von Lampe (1996) growth form and phenology of I-N-species in Central Europe, and Zedler (1990) vernal pool plants in California. In a world-wide perspective, three plant strategy types predominate in EWV: 1) dwarf annuals, 2) dwarf geophytes and 3) poikilohydric vascular plants. All these will be presented and analysed now in detail. Dwarf annuals with the ephemeroid syndrome: von Lampe‘s (1996) studies about the morphology and phenology of I-N-species revealed several structural adaptations to the ephemeroid life form. All species show an extremely high phenological plasticity, a tendency to nanism (“Zwergflora” sensu Diels 1906, see Fig. 1), the ability to flower with a very small vegetative apparatus and to fructify within a few weeks after germination. Favourable conditions lead to continuous ramification and a high diaspore output. Further characteristics are autogamy or cleistogamy, assimilatory sepals and sprouting from dormant buds. These short-living shuttle species are stress

Habitats, plant traits and vegetation of ephemeral wetlands

621

avoiders. They germinate in an opportunistic way from a permanent seed bank. The tendency to nanism can also be confirmed for the EWF in other parts of the world. In New Zealand for example, the most dwarfish species of several taxa occur in this habitat, like Juncus pusillus, Eleocharis pusilla, Ranunculus limosella, Carex rubicunda and Crassula spp. (Johnson & Rogers 2003). Representatives of the dwarf ephemeroids come from the families Cyperaceae and Scrophulariaceae (all floristic kingdoms), Juncaceae (holarctic kingdom), Eriocaulaceae (Australia, East Asia), Centrolepidaceae (Australia), Orcuttieae within Poaceae (Californian sector), Gentianaceae, Crassulaceae, Apiaceae, Callitrichaceae, Ranunculaceae, and Elatinaceae (most floristic kingdoms). Some of these annuals are succulents (Crassula, Diamorpha). Geophytic perennials: Herbaceous species with below-ground perennial organs can be separated into different subtypes: slow-growing, stress-tolerant perennials with the Isoetid syndrome (Isoetes), bulbous spring green Monocotyledonae (Scilla, Dipcadi in the Mediterranean, Chamaescilla and Wurmbea in Australia, Iphigenia in New Zealand) and geophytic ferns (Ophioglossum). Convergence in isoetid growth is stated by Keeley & Zedler (1998) for Isoetes, Orcuttia, Lilaea, Navarretia and Eryngium. All these genera, which can be found in Californian vernal pools, have a rosette of terete leaves with lacunal air spaces. An extreme adaptation is realized in tropical Isoetes species: they colonize the amphibic margins of oligotrophic lakes in the tropical-alpine belt (Paramos). Examples are I. andicola (Peru), I. novogranadensis (Ecuador) and I. hopei (New Guinea). These long-living, evergreen taxa have no stomata. CO2 is recycled by CAM or taken from the sediment by an extensive root system. Above-ground green biomass makes for only 4 % of their total biomass (Keeley et al. 1994). The niche for dwarf plants: Ephemeral wetlands are the preferred niche for dwarfish annuals and for geophytic perennials with low and only seasonal above-ground biomass. Competitive perennials with higher productivity and permanent above-ground biomass are excluded through various effects (see also chapter 4.1.): 1. Soil water is not sufficient (shallow soils, low precipitation, strong waterlevel fluctuations) to support a perennial plant cover. Under such environmental conditions, EWH are spatially stable. This is the situation in semi-arid and subhumid climates and in the seasonal pool habitat. In these situations, both dwarf annuals and geophytic perennials are keystone species in EWV. 2. Soil water is sufficient for perennial vegetation. The plant cover, however, is destroyed from time to time by physical disturbance events such as fluvial erosion and sedimentation, wave exposure, ice scour, cryoturbation, uprooting by animals, labouring by man etc. The dwarfish annuals

622

U. Deil

re-colonize the open space for some years. EWV is the pioneer phase. The EWS either survive the late succession phases in the seed bank and wait for the next disturbance event or the populations shift around from year to year. This is true for humid climates. Urban (2005a) explains the niche for short-living annuals in the shoreline habitat by the water-level fluctuations and proposes the oscillation model. Competitive terrestrial plants are excluded from the amphibic habitat because they do not tolerate flooding. Perennial aquatic macrophytes are excluded because they need the uplift by a permanent water body. A special case are EWH kept open by cryoturbation. The so-called “flags” on Iceland are colonized by summer annuals like Sedum villosum and by ambulatorian perennials (Sörensen 1942). The latter are uprooted by needle ice. They hibernate as bulbs (Triglochin palustris), bulbils (Sagina nodosa) or rosettes. They take root in the next spring at another place. The whole plant functions like a diaspore. Kautski (1988) modified the triangular C-S-R-model for aquatic macrophytes by a square model with four basic strategies. Besides ruderals and competitors, she proposed two types of stress-tolerators, i.e. “stunted” and “biomass storer”. The dwarfish annuals fit into her category of “ruderals“ with characteristics like a short life span, large reproductive effort, small growth form, short period of leaf production in a season of high potential productivity, dormant seeds, rapid nutrient turnover rates, rapid curtailment of vegetative growth and diversion of resources into reproduction. Most of the Isoetes species fit well into the category of ”stunted” with the parameters of small stature, long-lived leaves, relatively high root biomass and inherent slow growth. The Isoetes andina-group already show some characteristics of “biomass storers”. Poikilohydric vascular plants: 90 % of the world-wide species with this water budget strategy occur on inselbergs in the Tropics (Porembski & Barthlott 2000b, Biedinger et al. 2000). Other life forms there are succulents, carnivorous plants (Lentibulariaceae, Droseraceae) and cryptogamic crusts (Porembski et al. 2000). Seasonal rock pools are the preferred habitat of desiccation-tolerant plants. For Southern Africa for example, Gaff (1977) mentions members of the genera Craterostigma (see Fig. 19), Chamaegigas, Lindernia (Scrophulariaceae), Myriothamnus (Myriothamnaceae), Xerophyta (Velloziaceae), Cyperus, Coleochloa, Kylligia (Cyperaceae), Microchloa and Oropetium (Poaceae). An increasing desiccation tolerance from Aponogeton desertorum to Limosella grandiflora and further on to Chamaegigas intrepidus is stated by Gaff & Giess (1986) for rock pools in Namibia. This spatial sequence corresponds with a habitat preference from deep pools to shallow pools, i.e. an increasing desiccation frequency. Niche partitioning between Chamaegigas intrepidus and the less desiccation-tolerant Limosella grandiflora in temporary pools in Namibia is studied by Heilmeier et al. (2005). Limosella grandiflora colonizes deep pools. This slow-growing stress tolerator recovers from rhizomes. Chamaegigas intrepidus, the “fearless giant

Habitats, plant traits and vegetation of ephemeral wetlands

623

Fig. 19. Poikilohydric plants in rock pools of the Yemeni Escarpment (SW Arabian Peninsula): Craterostigma pumilum and Selaginella yemenensis.

dwarf”, colonizes shallow pools or the margins of deep pools. This resurrection plant has constitutive characters of desiccation tolerance, in leaves as in shoots and roots. It supports up to 20 desiccation-wetting-cycles per rainy period and can flower two days after resurrection (Heilmeier et al. 2005). The strategy of resurrection is however no longer successful when the active period is too short, because respiration metabolism starts earlier and ends later than photosynthesis (productivity trade-off hypothesis) (Alpert 2000). A “Chamaegigas-strategy” of desiccation tolerance and recovering within some minutes after reflooding is recorded by McLachlan & Cantrell (1980) for Chironomid-larvae in tropical rock pools. Resurrection species are numerous in the neotropical region within the families of Xyridaceae, Velloziaceae and Bromeliaceae. Poikilohydric Cyperaceae occur in the neotropical region (Trilepis) and in the palaeotropical kingdom (Afrotrilepis, Coleochloa). Pepinia geyskesii and Ananas anassoides-mats (Bromeliaceae), observed by Sarthou & Villiers (1998) on inselbergs in French Guiana are a niche equivalent to Afrotrilepis- and Coleochloa-mats (Cyperaceae) in Africa (Seine & Becker 2000, Barthlott & Porembski 2000b). Velamen radicum is a common character in mat-forming poikilohydric Monocotyledonae (Velloziaceae, Cyperaceae), and has now also been recorded for Scrophulariaceae (Chamaegigas intrepidus) (Heilmeier et al. 2005) and Borya (Liliaceae) (Porembski & Bartlott 2000b). Vegetative reproduction is widespread among the inselberg species (Porembski et al. 1998) and very important for some resurrection

624

U. Deil

plants. The whole population of Borya mirabilis on an outcrop in Australia seems to be a single clone (Coates et al. 2002). Convergence and niche equivalence: The obvious convergence in growth forms is also expressed in plant names such as Ranunculus limosella, Elatine gratioloides, Glossostigma elatinoides etc. (Johnson & Rogers 2003). We know of some families with convergent life forms that replace each other in different parts of the world (see also chapter 4. 7. 1.). These are for example in the juncoid annual niche Juncaceae, Centrolepidaceae and Eriocaulaceae, and in the niche for poikilohydric perennials with the xyroid syndrome the families Xyridaceae, Cyperaceae, Velloziaceae and Bromeliaceae. The xyroid families are not only niche-equivalent, but also have the same ecosystem function in the catenal context: These mat-forming species store the precipitation water and accumulate soil, and the continuous supply of seepage water out of the monocotyledon mats allows the development of the ephemeral flush vegetation. 4.5.2. Reproductive biology Seed bank and germination ecology: The importance of the seed bank for species of amphibic habitats was first studied by Darwin (1859). He counted 537 seedlings from three table spoonsful of mud after a six-monthgermination experiment. The knowledge of seed bank characteristics and germination ecology of EWS varies a lot for different parts of the world. A broad spectrum of habitats and many species have been analysed for Central and Western Europe. Results from that area are presented in the following papers: Albrecht (1999), Bauer & Poschlod (1994), Bekker et al. (1999), Bernhard (1993, 1999), Bissels et al. (2005), Jansen et al. (2004), von Lampe (1996), Matus et al. (2003), MĂźller (1996), Nagler (1999), Oesau (1972), Pietsch (1999), Poschlod (1996), Poschlod et al. (1993, 1999), Salisbury (1968, 1970), TĂ¤uber (1999a, 1999b) and Vogel (1999). Observations in the Mediterranean regions of Europe and North Africa are restricted to a few sites in France and Morocco (Bonis et al. 1996, Grillas et al. 2004a, Rhazi et al. 2001b, 2005). Better known are seasonal wetlands in SE Australia (Brock 1998, Casanova & Brock 2000, Nicol et al. 2003), in California (Bliss & Zedler 1998, Griggs 1984, Schlising 1989, Zammit & Zedler 1990, Zedler 1990, Zedler & Black 1992), in the Midwest and the temperate zones of North America (Haukos & Smith 1993, 1994a, 1994b, Jurik et al. 1994, Le Page & Keddy 1998, Schneider 1994, Seabloom et al. 1998, Uno 1989, Wienhold & van der Valk 1989) and in the Southeastern USA (Baskin & Baskin 1972, 1979, 1998, Houle & Phillips 1988, 1989a). The observations in Scandinavia (Milberg & Stridh 1994), South Africa (Brock & Rogers 1998), India (Sharma et al. 1984, Amritphale et al. 1989) are restricted to selected vegetation types respectively to single species. A world-wide synopsis about seed bank, germination and dormancy, including data from EWH, is presented by Baskin & Baskin (1998). The knowledge about soil seed

Habitats, plant traits and vegetation of ephemeral wetlands

625

banks in Northwest Europe is summarized by Thompson et al. (1997), for EWS in Central Europe by Poschlod et al. (1999). There are four major trends in seed bank characteristics and reproductive strategy: 1. A persistent seed bank: Seeds are viable for decades or even more than one hundred years. This is the result of adaptation to short-term availability and temporal unpredictability of the habitats. 2. Seed production and population size show dramatic fluctuations from year to year. The seed bank buffers these variations of above-ground vegetation and reproductive success. 3. A high plasticity in germination: Secondary dormancy is enforced by unfavourable conditions like darkness or anaerobiosis (imposed by water). Spring annuals have evolved a summer dormancy cycle and are able to remain dormant for several years. Physiological dormancy is the most common type of dormancy in amphibious plants (Baskin & Baskin 1998). 4. A high vegetative plasticity of adults: The number of established seedlings is not decisive for the reproductive success of a generation because individuals show enormous plasticity. A small population is not reduced by self-thinning; rather, it produces larger individuals and total diaspore production can be greater than in a dense population of small individuals (Bonis et al. 1996). We now present some details for selected areas and species groups respectively. Most species of EWS in Europe have very small propagules; their germination being stimulated by light (Salisbury 1968, 1970). These species exhibit vernal and quasi-simultaneous germination, a small number of seeds e. g. of Anagallis minima and Lythrum hyssopifolia germinating in autumn. The overwintering individuals may produce enormous quantities of seeds. Variability in plant size and in fruitset is striking. Average seed output per plant, seed production by the largest plant and ratio maximum/average vary in the following way: Cicendia filiformis (510; 2700; 5.4), Juncus bufonius (17000; 175000; 10.3), Anagallis minima (250; 6380; 25,8) and Lythrum hyssopifolia (2550; 74500; 29.0). All the I-N-species analysed by Bissels et al. (2005) in the Upper Rhine Valley in Germany have a persistent seed bank and produce enormous numbers of seed. The highest seed density ever measured is 700.000 seeds per square metre for Juncus bufonius. Annual mudflat species in a freshwater lake in Central Sweden all have a permanent seed bank, with 5400 seeds per square meter for Limosella aquatica and 156000 for Elatine-species (Milberg & Stridh 1994). Up to 10000 seeds per individual were recorded by Oesau (1972) for Limosella aquatica. According to von Lampe (1996), most of the N an oc yp er io n-species are able to germinate under water. Species with continental distribution show an endogenous winter dormancy and frost resistance. Oceanic phytogeographic elements are frost-sensitive, their winter dormancy is exogenous. Atlantic I-N-species exhibit a lower germination rate at high temperatures (TĂ¤uber 1999a, 1999b). Permanent waterlogged conditions during

626

U. Deil

the germination phase are essential for Anagallis minima and Cicendia filiformis. In a world-wide perspective, physiological dormancy is the most common type of dormancy in amphibic plants (Baskin & Baskin 1998). Flooding can be a stimulating factor for some taxa like Lilaea and Pilularia in Californian VP, and at the same time a stress factor for other species (Bliss & Zedler 1998). Flooding stimulates germination of Carex bohemica (Poschlod 1996), though the cause for this might be anaerobiosis and not the flooding itself. Anaerobiosis breaks the dormancy of Orcuttiaspecies and of Tuctoria greenei (Griggs 1984, Stagg & Lathrop 1984, Keeley 1988). Heteranthera limosa germinates to high percentages only under a low oxygen level, as associated with flooding (Baskin & Baskin 1998). A combination of anaerobic conditions and light is an environment specific to the uppermost soil level overlaid by water. Limosella aquatica can germinate submerged and emerged, Carex bohemica, Cyperus fuscus and Eleocharis ovata only emerged (Poschlod et al. 1999). Poschlod (1996) and Poschlod et al. (1993, 1999) demonstrate the importance of seed banks for the survival of mud vegetation from fish-ponds in Southern Germany. Even rare and endangered species that have not occurred in the apparent vegetation for decades can be recorded in the seed bank (underground floristics). Summer drainage in 10- to 20-year intervals seems to be sufficient to preserve for example Carex bohemica in the seed bank. Bauer & Poschlod (1994) showed that the seed bank is a â&#x20AC;&#x153;memoryâ&#x20AC;? of historical land use and reflects the different management history of ponds in Southern Germany. Anagallis minima and Juncus capitatus are more often documented in the seed banks of arable land in Bavaria (Southern Germany) than in the apparent vegetation (Albrecht 1999). Pietsch (1999) studied the germination ecology of Cyperetalia fusci-species. He states close correlations between germination behaviour and phytosociological diagnostic groups. A brief superficial wetting, independent from the substrate type and even at constant temperature conditions elicits high germination rates within a few days in the Juncus bufonius-group. This group includes the class and order species. The other species are stimulated by fluctuating temperatures. The Limosella aquatica-group germinates within 5 days in submerged or wet conditions, the Peplis portula-group within 10 days. Both are Elatino-Eleocharition-character species. The Radiola liniodesgroup includes character species of the alliance R ad io li on . These species germinate only on oligotrophic substrates and after longer inundations. Dormancy and life cycle of Diamorpha cymosa were studied in detail by Baskin & Baskin (1972). This annual germinates in autumn, passes the winter in a vegetative stage and flowers and sets fruits in the following spring. Dead plants remain erect until the late summer and retain the mature seeds in the folicles until autumn. Seeds are dormant at maturity and require a period of after-ripening that ends in August. High summer temperatures break dormancy and inhibit germination. Diamorpha cymosa is an obligatory light germinator. Even small amounts of sediments (0.25 to 0.5 cm) can reduce the number of seedlings and the number of germinating species considerably (Jurik et al. 1994, Baskin & Baskin 1998).

Habitats, plant traits and vegetation of ephemeral wetlands

627

Seed yield, seed size and germination behaviour of the Lamiaceae Pogogyne abramsii, endemic in Californian vernal pools, was studied by Zammit & Zedler (1990). There, seed number is correlated with above-ground biomass of the mother plant. A high fertility of the mother plant results in seeds with a thin seed coat and in a higher rate of seed dormancy. Hygrophila auriculata, a EWS in India, has a germination optimum of 28 degrees (Amritphale et al. 1989). High germination optima are recorded also for other EWS of tropical regions, such as Bacopa acuminata, Hygrophila auriculata, Heteranthera limosa, and Eclipta prostrata (Baskin & Baskin 1998). Fluctuating temperatures in the dry phase increase the germination rate for a number of EWS, for example for Neptunia oleracea (Sharma et al. 1984). A dormancy break during the dry period means that seeds can germinate at the beginning of the wet season. Another adaptation of seeds to seasonally de-watered habitats is that high temperatures in summer do not cause flooded seeds to re-enter dormancy. Seed can germinate as soon as the water recedes (Baskin & Baskin 1998). EWS can be stimulated from the seed bank for restoration projects through the removal of the top soil layer and above ground vegetation (see Rhazi et al. 2005 for Isoetes ponds in Southern France, Bekker et al. 1999, Van Beers & Dirkse 2000, Jansen et al. 2004, and Matus et al. 2003 for heathland ponds and dune slacks in the Netherlands, Nagler 1999 for heath ponds in Northern Germany). Long-living seeds (viable for some decades) are recorded for the mud-species Lindernia dubia, Limosella aquatica and Elatine triandra from North America (Wienhold & van der Valk 1989). Like plant seeds, the cyst stage of vernal pool shrimps can survive for decades (Belk 1998). Seed bank pattern and above-ground zonation: The expectation of many authors of earlier papers (see for example NeĚ&#x20AC;gre 1956, BarbeĚ ro et al. 1982, Holland & Jain 1981/84), that the zonation of the species in the seed bank is less accentuated than the apparent vegetation, has been verified by recent studies. Seed bank analyses in EWH in Morocco (Rhazi et al. 2001b), California (Bliss & Zedler 1998), New York (Schneider 1994), Oklahoma (Uno 1989), Texas (Haukos & Smith 1994b), Georgia (USA) (Houle & Phillips 1988), temperate North America (Wienhold & Van der Valk 1989, Seabloom et al. 1998), New South Wales (Australia) (Nicol et al. 2003), and Australia and Transvaal (South Africa) (Brock 1998, Brock & Rogers 1998, Casanova & Brock 2000) confirmed that upland species (specialized to the edges of the vernal pools) and lowland taxa (restricted to the pool centre) are distributed over a broad range of inundation periods and microrelief. At a given place and in a given year, only part of the seeds are stimulated to germinate. Wetland succession in spring is to some extent predictable from the seed bank, but becomes more and more unpredictable in later ecophases (Haukos & Smith 1993). Inundation experiments with sediments from temporary wetlands in SE Australia (Casanova & Brock 2000, Nicol et al. 2003) and California (Bliss & Zedler 1998) show, that from an identical soil sample, different

628

U. Deil

plant communities can be awakened by different flooding regimes. Final species combination is correlated with the water regime (location along the elevation gradient and draw-down rate) irrespectively of the initial seed bank composition. Rapid drawdown eliminates amphibious species. The results support the hypothesis of Moore & Keddy (1988), that zonation along the elevation gradient at shorelines is shaped by the water regime and is not due to differences in the seed bank. This was confirmed by experiments. Vivian-Smith (1997) tested the establishment of twenty wetland species in plots within a microtopographic heterogeneity of a few centimetres. The results confirmed habitat preferences in respect to flooding regime. The regeneration niche is close to the water depth niche of the adults (Seabloom et al. 1998). The feedback between the zonation of the reproductive mother plants, the survival rate of the seedlings and the seed densities of the species in relation to water depth results in quite sharp zonations. Long distance dispersal: Studies about this aspect are rare. Endozoochorous dispersal by birds is largely a matter of speculation (see LawalreĚ e (1969) for the transport of Isoetes and Cruden (1966) for amphitropical VP-species in both Americas). Reviews about the current state of knowledge are presented by Figuerola & Green (2002), Green et al. (2002), and Figuerola et al. (2003). The main focus of these papers, however, is on aquatic macrophytes and water birds, not on temporary wetlands. Rabbits as dispersal vector for VP plants in California are documented by germination studies from the faeces (Zedler & Black 1992). Exozoochorous transport of Carex bohemica by mud, attached to the feet of mallards, was verified by Hohensee & Frey (2001). Studies about the role of migrating mammals for exozoochorous diaspore transport on hooves are missing. Champeau & ThieĚ ry (1990) observed the transport of crustacean eggs through Saharan winds from North Africa to Southern Europe. They explain the existence of a south-north-gradient in the distribution of some VP-species as the result of a gradient in the fallout rates according to the egg-mass. Egg dispersal of Anostraca is also recorded from rock pools in Botswana (Brendonck & Riddoch 1999). Studies about wind dispersal of plant propagules in EWH could not be found. Pollination: A contrasting pollination and breeding strategy for two Crassulacean-species, endemic on rock outcrops in Georgia (USA), was recorded by Wyatt (1981, 1983, 1997). Diamorpha smallii is an obligatory outbreeder, pollinated by ants. Sedum pusillum is autogamous. Autogamy occurs in Lindernia procumbens and Elatine spp. (Taran 1995). Limosella aquatica can be pollinated underwater in air-bubbles. Schiller et al. (2000) compared the insect visits in Pogogyne abramsii in ancient and newly created pools. Foraging by insects is density-dependent. Recently created pools have less dense populations and smaller plants, but more visits per flower. Seedset was significantly lower in new pools (smaller

Habitats, plant traits and vegetation of ephemeral wetlands

629

plant size), but great enough for a positive population growth rate. Fructification in created pools is not limited by pollination. 4.5.3. Photosynthetic pathways Carbon dynamics, exploitation of the CO2-pool of the sediment and active dystrophication have been studied intensively in the permanently submerged isoetid-environment (see for example Gacia & Ballesteros 1993, Madsen et al. 2002, Smolders et al. 2002). These phemomena occur however also in TP and a variety of photosynthetic pathways is used by aquatic and amphibic plants. This was studied in detail by Keeley (1999) with species taken from Californian VP. CAM is recorded for a number of Isoetes and Crassula-species. It is not an adaptation to the scarcity of water, but to a temporary CO2-shortage. The moderately fertile or even oligotrophic shallow temporal pools are often rainfed and their water is poorly buffered. The pools have an extreme diurnal fluctuation of carbon availability (Keeley 1996, 1998a, 1999), oxygen, pH, and temperature (Arle 2002, Scholnik 1994, Heilmeier et al. 2005, ThieĚ ry 1987 in Grillas et al. 2004a, p. 51). Due to the photosynthetic activity of the photoautotrophic organisms that live in the pools, the CO2-concentration decreases to such an extent that it becomes a limiting factor for photosynthetic carbon acquisition (Keeley 1996, 1998a, Newman & Raven 1995). The high diffusional resistance of water is a barrier to CO2-leakage, coupled with the sink provided by extensive intercellular gas space. Isoetes has air chambers in the leaves, where endogenous CO2 is accumulated at night. In the temperate zone, semi-terrestrial species switch from CAM to C3 in the terrestrial stage and produce functional stomata (no functional stomata on submerged foliage!). Strongly terrestrial species like Isoetes duriei and I. stellenbossensis are obligate C3-species, even when artificially submerged (Keeley 1999, Richardson et al. 1984). CO2-uptake from the sediment and not from the water is recorded for Eriocaulon decangulare and other taxa with the isoetid-syndrome such as Subularia, Littorella, Isoetes and Lobelia (Raven et al. 1988). EWH are carbon-limited ecosystems in the aquatic phase, water-limited systems in the terrestrial phase (Keeley 1999). There are both tolerance and avoidance strategies, and the response by the same species may be different according to the phase. 4.6.

Dynamic processes in ephemeral wetland vegetation

By a short life cycle and Ă? in the case of perennials Ă? ephemeral development of above-ground biomass, the EWV shows a pronounced annual dynamic, in phenological parameters of single species (germinating, sprouting, flowering and fruiting period) as well as in the seasonality of the plant cover as a whole. The ability of many species to germinate under water and to finish their life cycle in the terrestrial phase (tenagophytes), and the ecological requirements of other species, which germinate in the amphibic

630

U. Deil

phase (pelochtophytes sensu Hejný 1957, 1962) or even under pure terrestrial conditions, can result in a high species turnover of the apparent vegetation in one vegetation period. Besides the water factor, temperature (of substrate, water and air) is another important ecological factor, differentiating early and late germinating species. When the life cycles of the species overlap considerably, we can separate ecophases (aquatic = limnic phase = hydrophase; amphibic = limose phase; terrestrial phase) (Hejný & Husák 1978) within one plant community. When the life spans are very short and the temporal separation between cold and warm germinating/sprouting species is more accentuated, we can consider the temporal sequence of the plant assemblages as distinct communities, because species composition, ecological conditions during the active period, and spatial distribution at the local and the regional scale all are different. We have a temporal sequence of communities (an ecocycle sensu Hejný 1962), not interacting with each other, at the same locality. This is quite obvious when including short-living cryptogams (see chapter 3. 3. 1.), but can also be observed in plant communities dominated by vascular plants. De Foucault (1988) applied this approach in a very rigid sense by defining synusia as communities of their own. He thus separated the class I so et o- Na no ju nc et ea into two different classes, the Is oe te te a v el at ae (a vegetation unit dominated by winter and spring green perennial geophytes) and the J un ce te a b ul bo si (dominated by spring-germinating annuals). A very different concept is applied for example by Masens (2000): He includes all the different species combinations to be observed on desiccating rice fields and on pool margins in Central Africa into one community, the L im no ph il o c er at op hy ll oi di s- Sa lv in ie tu m n ym ph el lu l ae . Taking into account the enormous seasonal changes of the ecological conditions, species combination and dominant life forms, it seems more appropriate to split this vegetation unit into different communities or at least ecophases, with Salvinia dominating in the aquatic and Limnophila in the amphibic phase. An intermediate approach between the concept of De Foucault (1988) (every phase with other dominating life forms is a community of its own) and Masens (2000) (all phases round the year belong to one community) is the proposal by Barkman (1973) to separate within a broadly defined association “chronocoenoses”, characterized by a common phenology, similar life cycle and physiognomy of the species. Beside the seasonal dynamics, the year-to-year variability of the hydrological conditions is another prominent attribute of EWH. Nègre (1956) stated a spatial fluctuation of the zonation belts bordering dayas in Morocco. Subhumid and semi-arid climates, where most of the SPH and EFH are located, have a higher interannual rainfall variability than perhumid regions. EWV in desert areas depends on erratic rainfall and unpredictible La Niña events (Pignatti & Pignatti 2005). The small catchment area makes rock pools, SPH and EFH sensitive to local and regional variability of rainfall. SHH depend more on the regional rainfall pattern. The water regime in floodplain habitats, which are flooded by allothonous rivers (for example those starting in humid mountainous areas and advancing into

Habitats, plant traits and vegetation of ephemeral wetlands

631

dry lowlands), depends on the precipitation pattern in a remote area. The sensitivity of the EWV to year-to-year changes in the water supply is enhanced by superficial soils and the small root horizon of the matrix species. All these factors favour a shifting pattern of the communities at the local scale and year-to-year fluctuations of the vegetation mosaic. A series of wet or dry years can initiate succession processes. All these dynamic phenomena (phenophases, intra-annual sequence, interannual fluctuations, longterm trends) will be discussed now in more detail, based upon the few case studies available (see Fig. 3). 4.6.1. Seasonal dynamics Herbarium specimens are sampled, when the specimens are in an optimal phenological phase. Keeping this in mind, Bergmeier & Raus (1999) have checked the herbarium material from Greece as a very rough approach to the phenology of I-N-species in the Mediterranean climate. This allows to separate vernal flowering (early germinating) species like Juncus capitatus and Isoetes histrix from autumnal (late germinating) species like Cyperus flavescens and C. fuscus (Fig. 20). Because many species are reacting in the same way, we can separate in the planar vegetation belt of the Mediterranean basin a vernal vegetation type (the alliance C ic en di o- So le no ps io n) from an autumnal unit (the Ver be ni on su pi na e = H el eo ch lo io n). The mediterranean climate with the sequence of mild, wet winters, wet springs with fluctuating temperatures, and hot, dry summers initiates a distinct phenology and a clear separation of cold and warm germinating / sprouting species. On nutrient-poor sites in the Southwestern part of the Iberian Peninsula for example, a phenological sequence of late autumnal and winter green perennial geophytes (Isoetes spp., Scilla autumnalis,

Fig. 20. Flowering phenophase of selected Isoeto-Nanojuncetea-species in Greece, derived from herbarium specimens (adopted from Bergmeier & Raus 1999).

632

U. Deil

Ophioglossum lusitanicum), early spring annuals (Juncus spp., Isolepis spp., Cicendia filiformis, Solenopsis laurentia), late spring annuals (Chaetopogon fasciculatus, Lotus subbiflorus, Lythrum spp.) and early summer annuals (Tuberaria spp., Anthoxanthum ssp., Agrostis pourretii, Trifolium spp.) is documented in the permanent plot studies of Rudner (2005a) (see also Fig. 4 in Espı́rito Santo & Arsénio 2005 for the Alentejo region in Portugal). This confirms the following sequence of chronocoenoses: S ci ll o a ut um na li s- Op hi og lo ss et um lu si ta ni cu m (autumn and early winter), J un co ca pi ta ti -I so et et um hi st ri ci s (early spring), L ot o s ub bi fl or iC ha et op og on et um fa sc ic ul at i (late spring) and H el ia nt he mo an n ua e- Pl an ta gi ne tu m b el la rd ii (early summer). Within one plot, about one third of the species is replaced by other species during one vegetation period. When the sites are not water-saturated throughout the winter period, the earlier phenophases are missing and spring flowering starts with the Tuberaria-group. These species colonize a much broader range of habitats than the earlier Chronocoenoses. Most authors therefore separate the classes I-N and H el ia nt he me te a a nn ua e. Another detailed study was realized by Ballesteros (1984). He observed three I-N-communities in Catalonia over a two-year period. Soil water, as the supposed triggering environmental factor, was measured. The communities are not replacing each other at the same site. His results show (see Fig. 21) that there are two communities, where above-ground biomass, the number of epigean species and the number of fertile plants are unimodal per year and concentrate in early spring (I so et et um du ri ae i) respectively summer (C yp er et um fl av es ce nt is ). A third community, which is characterized not only by annuals, but also by geophytes (S ci ll o- Op hi og lo ss et um lu si ta ni cu m), has two peaks per year. A sequence of plant communities in small karstic rock pools on an island south of Crete (Gavdos Island, Greece) was studied by Bergmeier (2001). There is a clear relationship between pool depth/size and inundation period, reflected in different plant communities (see Fig. 22). Shallow pools drying up already in February are the habitat for a Tillaea (= Crassula) alata-Crepis pusilla community. The Zannichellia pedunculata-Callitriche pulchra-community (Z an ni ch el li on pe di ce ll at ae , Po ta mo ge to ne t ea ) is restricted to deeper and larger cavities, which store water until May. The Tillaea vaillantii (= Crassula v.)-community (I so et io n, I so et o- Na n oj un ce te a) and the transitional units occur in rock pools of moderate depth or at the margins of deeper ones. In fairly deep pools with gradually sloped margins and decreasing water-level during springtime, this temporal sequence results at the same time in a small-scale zonation. In the mediterranean region of the Southern Hemisphere, the following sequence in the centre of dessicating VP is reported by San Martı́n et al. (1998) from the surroundings of Temuco (Chile): P ot am og et on et um p us il la e, L ud wi gi o p ep lo id is -S ag it ta ri et um mo nt ev id en si s, Lyt hr o p or tu la e- El eo ch ar it et um pa ch yc ar pa e, G na ph al io cy ma t oi di s- Po ly go ne tu m h yd ro pi pe ro id is and Ph yl ae tu m n od if lo r ae . Concerning vertical structure, biomass, and floristic similarity at the

Fig. 21. Seasonal changes in soil water content, species numbers and above-ground biomass of three I s o e t o - N a n o j u n c e t e a -communities in Catalonia (adopted from Ballesteros 1984).

Habitats, plant traits and vegetation of ephemeral wetlands

633

634

U. Deil

Fig. 22. Relation between pool depth, seasonal water-level, and vegetation type in rock pools of Gavdos (Greece) (from Bergmeier 2001).

genus level, the Lyt hr o- El eo ch ar it et um has some common characters with the holarctic I-N-communities, the G na ph al io -P ol yg on et um with B id en te te a-communities. A similar pattern like in Mediterranean Europe with cold and warm germinating species can be stated for Central Europe, based on germination experiments (Fig. 23): The early germinating spring annuals Cicendia filiformis and Illecebrum verticillatum with a winter dormancy (induced by deep temperatures) and the late germinating summer annuals Lindernia procumbens and Cyperus michelianus with endogenous winter dormancy are character species of two different syntaxa (R ad io li on li no id es respectively E la ti no -E le oc ha ri ti on ov at ae ) (von Lampe 1996, TĂ¤uber & Petersen 2000). On nutrient-rich sites in the temperate Eurosiberian region, the C yp er et al ia fu sc i-communities are replaced by B id en te t ea -commmunities in late summer and autumn. The vegetation dynamics on exposed carp pond bottoms in the Czech Republic were studied by SumberovaĚ et al. (2005) in two-week intervals

Habitats, plant traits and vegetation of ephemeral wetlands

635

Fig. 23. Phenology of selected Isoeto-Nanojuncetea-species in Central Europe (adapted from von Lampe 1996).

over two years. According to the different management of nursery ponds and storage ponds, the fish basins are drained in spring or summer. Crassula aquatica, Sagina procumbens, Potamogeton pusillus a.o. species are associated with ponds drained in spring, Lindernia procumbens, L. dubia, Limosella aquatica, Lythrum portula, Eleocharis ovata, Bidens bipartita a.o. with summer-drained ponds. Nursery fish-ponds are exposed for a very short period (April to June). Therefore, annual species with extremely short life cycles like Coleanthus subtilis and Elatine triandra occur there. Thermophilous species, germinating in May and June, and plants with longer life cycles are eliminated from the latter pond type (see also the life cycle analyses and phenological studies about Carex bohemica and other mud pond species in Southern Germany by Poschlod 1996, Poschlod et al. 1993). A pronounced phenology shows the spontaneous vegetation in rice fields. Species turnover in relation to the season and to management was for example studied in Northern Italy by Pignatti (1957a) and in Hungary by Ubriszy (1961). In the continental climate of Central Asia (Hilbig 1995, Ă&#x153;nal 1999) and Canada (Looman 1982), I-N- and B id en te te a-communities are difficult to separate. The reason might be the steep increase of the temperature in late spring and a shorter vegetation period. As a consequence, the life cycles of early (cold) and late (warm) germinating species overlap to a larger extent. The same is true for Great Britain and Japan, where extremely equable and permanently moist climatic conditions allow a similar phenology of N an oc yp er io n respectively L in de rn io n and B id en ti on species (Rodwell 2000, Shimoda 1983). TĂ¤uber (2000) demonstrates quite convincingly, that by the additional annotation of phenophases in plant sociological sampling, the separation between I-N and B id en te te a becomes clearer. In granite outcrop plant communities in Georgia (USA), a turf with spring annuals and winter green geophytes, dominated by Diamorpha smallii and Isoetes melanospora, is followed by a summer annual grassland with Cyperus granitophilus (Burbanck & Platt 1964, Matthews & Murdy

636

U. Deil

1969, Burbanck & Phillips 1983, Quarterman et al. 1993). The seasonal species turnover is significant in the Diamorpha smallii-community on shallow soils. On deeper soils, perennials dominate. Species composition is quite constant there, but abundance of species changes through the seasons (Houle & Phillips 1989b). A strong shift in species abundance was also observed by Crowe et al. (1994) in VP in Eastern Washington (USA). In the “small herb community” fringing seasonal water-saturated glades in the Ozark area in northern Arkansas and southern Missouri, Ware (2002) reports the sequence of Hypericum gentianoides (winter annual), Galium virgatum (spring annual) and Crotonopsis elliptica (summer annual). This differs slightly from the sequence recorded from Georgia with the spring annuals Diamorpha smallii, Minuartia godfreyi and Agrostis elliottiana, replaced later by the summer annuals Crotonopsis elliptica, Hypericum gentianoides and Helianthemum porteri (Quarterman et al. 1993). A sequence of an early spring phase with Isoetes melanopoda, Lindernia monticola and Gratiola neglecta to a late spring phase with Crotonopsis elliptica is further reported from rock outcrops in the Appalachian Piedmont (Matthews & Murdy 1969). Buffalo wallows in Oklahoma are first dominated by spring annuals (Myosurus minimus, Coreopsis tinctoria, Agrostis elliottiana, Alopecurus carolinianus, Croton lindheimerianus a.o.). This ephemeral plant cover is replaced after inundation in early summer by resprouting perennials (Bothriochloa saccharoides, Dicanthelium oligosanthus, Lythrum californicum, Ambrosia psilostachya etc.) (Uno 1989). In tropical regions, phenological studies in EWH are rare. Reekmans (1982) distinguishes the following phenophases in EWV of the Rusizi-plain (Burundi), north of Lake Tanganika: Bulbine abyssinica-Sporobolus pyramidalis-phase (FebruaryÐMarch), Hygrophila auriculata-Isoetes abyssinicaAeschynomene indica-phase (MarchÐApril), Ageratum conyzoides-Heliotropium ovalifolium-Oldenlandia affinis-phase (May). The interannual succession in the Mato Grosso floodplain of Brazil was studied one year by Prado et al. (1994). The growing season can be differentiated according to water-level fluctuations into four seasons: “enchente” (rising water-level), “cheia” (maximum), “vazante“ (falling waters) and ”seca” (minimum). At the same locality, a Salvinia auriculata-Eichhornia azurea-phase is followed by a Pontederia lanceolata-phase, later on replaced in the amphibic phase by Diodia kuntzei, Hyptis lorentziana and Polygonum punctatum. The short-living species Echinodorus tenellus, Eleocharis minima and Bacopa spp. are tenagophytes. Preliminary observations about seasonal changes in inselberg vegetation are recorded by Isichei & Longe (1984) from western Nigeria and by Porembski & Bartlott (1997) from the Ivory Coast. The latter authors mention, that the Afrotrilepis-mats are constant throughout the year. This vegetation type is a more or less monospecific assemblage of a core species. The ephemeral vegetation in rock pools and EFH show a strong seasonality, with a maximum of species diversity and flowering rate in June. In November, the communities have disappeared.

Habitats, plant traits and vegetation of ephemeral wetlands

637

4.6.2. Year-to-year variability Interannual variability of the floristic composition and of the abundance of EWS has been observed in many regions of the world. Holland & Jain (1981/84) for example monitored the vegetation in five vernal pools in California in 1976, 1979 and 1980. The maximum total-pool-species richness occurred in the wet year 1980. In the dry year 1976, many typical vernal pool species, which are common in a normal year, were totally missing. A more detailed study was realised by Bauder (2000) (Fig. 24). She monitored permanent transects throught TP near San Diego (California). The observation period from 1982 to 1986 included a normal, a wet and a dry vegetation period. On the basis of 679 small-plot samples, patterns of plant distribution in relation to length and frequency of inundation and relative elevation were examined. “Pool” species such as Downingia cuspidata and Pogogyne abramsii were more static on the elevation gradient than “edge” and “outside pool“ species like Hypochaeris glabra and Hemizonia fasciculata. ”Non-pool” species moved in the dry year towards the pool centre and responded to the wet year by shifting towards the dry end of the moisture gradient. Some annual pool-species had their highest frequency in the intermediate, moderately wet year. A four-year permanent-transect study through a VP in Morocco (Rhazi et al. 2001b) included two wet years (1996, 1997) and one dry year (1999). Myriophyllum alterniflorum, abundant in the pool centre in the wet years, is totally absent in 1999. Pilularia minuta was observed only in one year. Enormous changes in population densities were observed for annuals (Elatine brochonii) and perennials (Scilla autumnalis). Dry resistant ruderals and weed species invaded the outer fringes of the pool in the dry year, and the dry grassland species Polypogon monspeliensis became dominant in the middle position. Permanent-plot studies in dwarf rush communities in Southern Spain and Portugal revealed an interannual variability of the flora of equal dimension or exceeding the intra-annual species turnover (Rudner 2005a). The climatic variability can have a stronger impact on the species composition than the annual changes from wet soil conditions in spring to summer drought. The main reason is that the first drought events occur at different dates. Interannual species turnover in about 200 rockpools on Ivorian inselbergs was monitored between 1990 and 1999 by Krieger et al. (2003). The turnover rate in these extremely species-poor stands is higher in small pools, in pools with few residual soil and within the group of annual plants. The authors explain the small-scale fluctuations, the high number of accidental species and the enormous turnover rate within and between the pools with the variability of rainfall events in space and time, with vicinity effects (local and regional species pool!) and with recolonization events after local extinction of populations. The last point is more speculative, because seed bank analyses are missing. The rock pool vegetation is interpreted as a non-equilibrium system, ruled by stochastic events.

638

U. Deil

Fig. 24. Spatial fluctuations of species in Californian vernal pools from a wet (1982Ă?1983) to a dry year (1983Ă?1984) (cumulative frequency for 12 pools) (Bauder 2000).

Habitats, plant traits and vegetation of ephemeral wetlands

639

In the Sahel zone, zonation complexes, stable at a medium time scale, can show year-to-year fluctuations depending on the amount of precipitation (MĂźller & Deil 2005). Vegetation types, dominated by short-living annuals, shift more than plant communities with hydrogeophytes as keystone species (Vanden Berghen 1990b). The cover values of different EWV in NE Australia was monitored by Blackman & Locke (1985) over a period of four seasons, based on data from permanent transects, aerial photographs and ground check. The cover value of the plant communities changes considerably from year to year. This results in a changing carrying capacity for waterfowl. The seed bank makes the temporary wetland ecosystems resilient to the interannual variability of ponding. The upland and intermediate vegetation units, when dominated by annuals, shift in dry years closer to the pool bottom, and pool bottom species extend in wet years to the upper fringes of the ponds. The annuals shift around, the geophytes (Isoetes and Ophioglossum for example) and the hemicryptophytes form a spatially constant matrix (core species sensu Hanski 1982). The perennials react to the fluctuating water condition with a changing sprouting rate and a different period and duration of above-ground appraisal. The rare annuals behave like dynamic satellite species sensu Kammer (1997), the dominant and subdominant annuals like urban species sensu Hanski (1991). Houle & Phillips (1989b) monitored the spatial fluctuations and the variations in species composition and abundance in granite outcrop plant communities in Georgia (USA) over three years. Year-to-year-variability was greater on shallow soils and more accentuated in the summer ecophases. In general, plant response to drought is individualistic and depends largely on the timing of meteorological events in relation to life-stages (Houle & Phillips 1989b, Bauder 2000). Such a germination and sprouting ecology can explain the year-to-year-fluctuations of vegetation zones, observed by Rhazi et al. (2001b) in vernal pools in Morocco. If the seeds of early and late germinating species and the rhizomes and bulbs of the perennials are distributed over the whole topographic gradient of the depression, the actual performance of the plant communities is triggered for every year differently by the size and duration of the wetted area, in combination with the soil temperatures. We can see that interannual variability increases when we go from the pool centre to the margins (Fig. 25). The individualistic response of the EWF can explain the enormous variability in species combinations and the high number of communities (126 communities listed by Brullo & Minissale 1998) for the orders of I so et et al ia and N an oc yp er et al ia in Europe. This is a quite obvious contradiction to the number of observed habitat-specific taxa. 4.6.3. Long-term dynamics A good knowledge of the seasonal and year-to-year variability of a plant community is a precondition to separate fluctuations from pseudo-fluctuations (Kammer 1997), and fluctuations from succession. The extremely

640

U. Deil

Fig. 25. Year-to-year variability of three vegetation zones in a temporary pool in Morocco (shift in the centres of gravity on the plot of axes 1 and 2 of the CA) (Rhazi et al. 2001b).

high intra- and interannual dynamics of EWV in comparison to perennial vegetation types makes it very difficult to decide, what is fluctuation, what is trend. Only a few long-term permanent-plot studies exist, others are under way (Grillas & Tan Ham 1998). A first data set is available from rock outcrops in Georgia (USA). 34 test plots, documented in 1957, have been resampled in 1968 and once more between 1976 and 1978 (Burbanck & Platt 1964, Burbanck & Phillips 1983, Quarterman et al. 1993, Shure 1999). The plots dominated by Diamorpha smallii did not change within these 22 years. They perform as a permanent and stable pioneer community. In 16 test plots, mean soil depth increased slightly and vegetation changed. The change is interpreted as a succession from the Diamorpha smalli-community to a lichen-therophyte community (with Cladonia leporina, C. caroliniana, Campylopus spp., Diamorpha smallii, Minuartia godfreyi, Agrostis elliottiana etc.), followed by a perennial turf with Andropogon virginicus, Tradescantia ohiensis, Schoenolirion croceum a.o. Finally, seedlings of Pinus taeda and other lignified species are establishing. According to the authors, the small-scale zonation according to soil depths reflects the long-term dynamics of this vegetation complex. However, dead individuals of trees and shrubs indicate that in dry years this progressive succession is disrupted and pushed back to the earlier stage (see also Phillips 1981). Another possibility of a long-term stabilization of these outcrops systems can be, that the biogenically accumulated weathering substrate is removed by small-scale catastrophic splash events. Such a process has been observed on the rock outcrops in the Serra de Monchique (Portugal) (see Fig. 8 in Rudner 2005b). Fresh sediment accumulations at the upper part

Habitats, plant traits and vegetation of ephemeral wetlands

641

and bare bedrock material without Cyanobacteria at the lower edge of the vegetation patch indicate a long-term uphill migration. The role of crustforming Cyanobacteria (Scytonema spp., Stigonema spp.) for weathering of granite outcrops was studied by Sarthou & Grimaldi (1992) on tropical inselbergs in French Guiana and by Büdel et al. (1994) in Venezuela. Altogether, the occurrence of endemic open-ground specialists at rock outcrops, in temporary ponds and along shoreline habitats are strong arguments that these systems are not in general subjected to progressive succession, when these habitats are of primary nature and when the natural dynamics of the hydrological or geomorphological processes continues. The situation is different, when man has created secondary habitats for EWS like in sand pits. Müller (1996) and Müller & Rosenthal (1998) studied succession over 10 years in NW Germany. Litter removal from the poor sandy soils mobilizes R ad io li on species from the seed bank. These tiny annuals however are completely outcompeted after 5 years by perennial herbs, by regrowing tree-saplings and by proliferating carpets of hygrophytic mosses. Another succession study about the effects of topsoil removal in heathlands in NW Germany, oriented more to the I so et oL it to re ll et ea -milieu, is presented by Urban (2005b). EWV can find a temporal niche in the early phase of a regenerative succession sensu van der Maarel (1988). Such a situation is documented by a permanent plot study in the Rio Paraná-valley in Northern Argentina (Lewis et al. 1987, Franceschi & Lewis 1991, Franceschi et al. 2000). Extreme flooding events are destroying the Panicum prionitis-tall grassland community. The open sites are colonized by the Eragrostis hypnoides-Gamochaete subfalcata-association. After some years, this pioneer community is outcompeted by tall perennials such as Panicum prionitis, P. laxum and Eleocharis viridans, resprouting from subterranean organs and forming a highly resilient vegetation type. It persists until the next catastrophic flood. 4.7.

Evolutionary aspects of the ephemeral wetland flora 4.7.1. Niche-equivalent families

Evolution can be convergent, parallel or divergent. Convergent evolution results in similar growth form and life strategy in taxa of different origin. Within the EWF we have some niche-equivalent families, which replace each other in different parts of the world. Examples are the Juncaceae, Centrolepidaceae and Eriocaulaceae in the juncoid annual niche, and the families Xyridaceae, Cyperaceae (Afrotrilepis, Coleochloa in the Old World, Trilepis in the New World), Velloziaceae (Xerophyta in the palaeotropical, Vellozia in the neotropical region) and Bromeliaceae in the niche for poikilohydric perennials with the Xyroid syndrome (Barthlott & Porembski 2000). Two family groups (according to the families accepted by APG II 2003) play a major role in EWF: Centrolepidaceae, Restionaceae, Cyperaceae, Eriocaulaceae, Juncaceae, Mayacaceae, Xyridaceae, Bromeliaceae and Poaceae (all to Poales), and Alismataceae, Aponogetonaceae, Juncaginaceae,

642

U. Deil

and Limnocharitaceae (all to Alismatales). The Xyroid families are not only niche-equivalent, but also have the same ecosystem function in the catenal context: These mat-forming species store the precipitation water and accumulate soil, and the ephemeral flush vegetation depends on the water seeping from those mats (Biendinger et al. 2000, Porembski et al. 2000). 4.7.2. Vicarious taxa in the Tropics and their linkage to trophic levels A first synopsis about vicarious species in amphibic vegetation in Western Africa in particular and in the pantropical context in general is presented by MĂźller & Deil (2005). They analyse, which taxa have a preference to EWH and which families and genera are linked to a certain subset of environmental conditions. Examples from the eutrophic muddy environment can be noted in the families Acanthaceae (Hygrophila), Apiaceae (Hydrocotyle), Elatinaceae (Bergia, Elatine), Lythraceae (Ammannia, Nesaea), Menyanthaceae (Nymphoides), Onagraceae (Ludwigia, Jussiaea), and, within Liliopsida, in the families Alismataceae (Limnophyton, Sagittaria), Maranthaceae (Thalia), Pontederiaceae (Eichhornia, Heteranthera), Poaceae (Brachiaria, Echinochloa, Leersia, Oryza, Paspalidium, Paspalum, Vossia etc.) and Cyperaceae (the genera Cyperus, Eleocharis, Fuirena, Lipocarpha, Pycreus, Rhynchospora, Schoenoplectus, Scleria and Scirpus for example). In the nutrient-poor environment (oligotrophic ponds over lateritic crusts, granite rock outcrops, seasonally inundated white sand savannas), examples of vicarious species between the palaeotropical and the neotropical regions can be stated in the families Xyridaceae, Eriocaulaceae, Droseraceae, Utriculariaceae, Lentibulariaceae, Ophioglossaceae and Isoetaceae. This results in the vicarious classes D ro se ro -X yr id et ea (Africa) and X yr id et ea sa va ne ns is (the tropical parts of both Americas). Plant communities, vicarious in a stricter sense (with closely related taxa) to the West African E ri oc au lo pu mi li -O ph io gl os si on go me zi an um , can be inferred from a series of publications dealing with the neotropical region (see chapter 4.3.2.). 4.7.3. Preference of families and genera to ephemeral wetland habitats The database with floristic samples all over the world shows clearly, that some taxa adapted quite early in geological time to seasonally wet conditions and later on evolved and speciated within this environment without radiating into other habitats. This can be concluded from high ranked taxa (families, tribes, genera), linked exclusively to ephemeral wetland ecosystems, and from geographically vicarious species in this kind of environment. For the first case we can mention the families Marsileaceae, Centrolepidaceae, Hydatellaceae and Mayacaceae, the tribus Orcuttieae, and genera like Cicendia, Dopatrium, Navarretia, Downingia. A clear preference to the amphibic and limose environment is also expressed in generic names

Habitats, plant traits and vegetation of ephemeral wetlands

643

like Amphibromus, Amphianthus, Hygrophila, Hydrocotyle, Limosella, Limnophila, Limnophyton, Littorella, Limnocharis, a.o. The plant families belonging to Farinosae sensu Engler (Centrolepidaceae, Mayacaceae, Restionaceae, Eriocaulaceae, Xyridaceae) (see Stützel 1984) have a clear preference to EWH. A close relationship between Eriocaulaceae and Xyridaceae is confirmed by Stützel (1998), Stevenson & Loconte (1995), Bremer (2002) and by Coan & Scatena (2004). A first global analysis of the ephemeral wetland flora at the family- and genus-level was carried out by De Foucault (1988): The nutrient-poor environment is characterized by the Xyridaceae-Eriocaulaceae-family pattern, the nutrientrich habitat by the Scrophulariaceae-Lythraceae-Elatinaceae-family pattern. The early isolation of the Australian plate in Earth history is reflected in the very different family spectra of EWV in Australia and the holarctic region, and in the important role of Centrolepidaceae there (see Pignatti & Pignatti 1994, 2005). Centrolepidaceae seems to be a younger evolutionary line within Restionaceae (Kellogg & Linder 1995, Bremer 2002) on the Australian plate. It evolved into EWH. Mayacaceae, a family linked exclusively to EWH, is derived from Xyridaceae (Stevenson & Loconte 1995). In the water-depth gradient (see chapter 4.4.), the following sequence of high ranked taxa can be summarized for the monocot families (systematics following Stevenson & Loconte 1995): Najadales (Potamogetonaceae, Zannichelliaceae, Juncaginaceae) Ð Alismatales (Aponogetonaceae, Alismataceae, Limnocharitaceae) Ð Commelinales (Eriocaulaceae, Xyridaceaea, Mayacaceae) Ð Juncales (Cyperaceae, Juncaceae) and Poales (Poaceae, Restionaceae, Centrolepidaceae). 4.7.4. Vicariance patterns within selected genera Some examples of vicarious species linked to EWV will be analysed now in more detail. Very useful for this purpose proved to be some floras, dedicated to aquatic and semi-terrestrial plants like Cook (1990, world-wide synopsis), Cook (2004, Southern Africa), Johnson & Brooke (1989, New Zealand) and Casper & Krausch (1980, 1981, Europe). The analysis is restricted to vascular plants. The fern family Marsileaceae occurs in tropical and warm temperate regions of the world. All three genera (Marsilea, Pilularia, and Regnellidium) are adapted to the EWH (Cook 1990). They sprout from long-living (up to 100 years!) sporocarps. Dissemination takes place by water birds. Within the pools, clonal growth seems to be very important (Vitalis et al. 1998). Juveniles are submerged, adults floating, emergent or terrestrial. Some species are widely distributed, others are local endemics. In Southern Africa for example, the stenochorous species Marsilea apposita, M. burchellii, M. fenestrata, M. schelpeana, M. unicornis, M. vera a.o. occur in TP and vleis, beside the eurychorous species M. capensis, M. coromandelina, M. aegyptiaca, M. distorta, and M. minuta (Cook 2004). Niche partitioning in the genus Marsilea and the resulting zonation according to pool depth

644

U. Deil

were studied by Kornas (1988). Five species co-occur in the surroundings of Lake Chad, differing in the position of the sporocarp, in seasonality, dormancy, soil conditions and time of emergence. M. polycarpa (= M. berhauti) with fully exposed sporocarps is purely aquatic. The amphibic clover ferns M. minuta, M. nubica and M. subterranea are basicarpous, the purely terrestrial M. distorta is geocarpous. Kornas assumes a trend from aquatic ancestors to modern terrestrial forms, favoured by the evolution of basal sporocarps, and a tendency to ateleochorous characters in semi-terrestrial taxa. In Europe and Northern Africa, Marsilea species are allopatric: Examples are M. quadrifolia (Western Eurasia), M. azorica (Azores), M. strigosa (West Mediterranean), M. batardae (Western Iberian Peninsula), M. aegyptiaca (NW Africa, SW Asia), M. coromandelina (Senegal to the Arabian Peninsula and further to the east), and M. minuta (tropical origin, with outliers in Morocco, Algeria, Egypt and the Near East) (see distribution maps in Quézel 1998). Further examples of clover ferns in EWH are M. crenata in SE Asia, M. villosa on Hawaii (Wester 1994), M. punae in NE Argentina (Ruthsatz 1977), M. mollis in Chile (Bliss et al. 1998), and M. drummondii, M. glabra, and M. hirsuta in Australia (Pignatti & Pignatti 2005). Isoetaceae: Isoetes (= quillwort = Merlin’s grass) play a major role in EWV all over the world, with preference in nutrient-poor environments. Jermy (1990) for example records a density of 69.000 individuals per 500 square metres in Cornwall. The role of Isoetes as diagnostic taxon in the actual EWV is also expressed in names of high-ranked syntaxa like the holarctic class I so et o- Na no ju nc et ea or the West-Palaearctic order Is oe te ta li a. The monogeneric family is documented by fossils since the early Triassic (Jermy 1990, Pigg 2001), with isoetalian lycopsid ancestors since the Devonian era. The dominant plant habit of modern Isoetes originated at least by the Jurassic (Pigg 2001). The oldest fossil record, I. beestonii, has colonized the shorelines of oligotrophic lakes in Australia (Retallack 1997). It formed monospecific communities in amphibic habitats of TP and swamps. Further fossil Isoetales-communities are recorded for China (with Isoetes, Pleuromeia and Annalepis) (Wang 1996, Meng 1998), Germany (with Isoetes, Pleuromeia and Annalepis) (Fuchs et al. 1991, Grauvogel-Stamm 1993, Grauvogel-Stamm & Lugardon 2001, Schweigert 1993), NW United States (with Isoetites) (Ash & Pigg 1991), Southern Tunisia (with Isoetites) (Barale 1999) and New Zealand (Thorn 2001), from the Early and Middle Triassic to the Jurassic and Lower Cretaceous period and in most situations from habitats with fluctuating water-level. Many species and genera became extinct at the end of the Triassic. According to morphological (Hickey 1986, Taylor & Hickey 1992) and ecophysiological characters (Keeley 1998a), and as indicated by the fossil records (Retallack 1997), the amphibic environment seems to be the original habitat of Merlin’s grasses. They speciated and radiated in the Early Tertiary and in Cretaceous times into the oligotrophic lacustrine and the semi-terrestrial habitat (Hickey 1986, Pigg 1992, Keeley 1998a). Isoetes is the old-

Habitats, plant traits and vegetation of ephemeral wetlands

645

est clade of CAM plants (Keeley & Rundel 2003). Taylor & Hickey (1992) and Rydin & Wikstrรถm (2002) underline the role of the habitat in explaining the phylogeny of this taxon. The major clades of the genus radiated subsequently to environmental shifts. Initially, quillworts were seasonally submerged evergreen plants with non-sclerified leaves (presence of air chambers in the leaves of all recent and fossil taxa). Following the Cretaceous, they adapted to terrestrial habitats with ephemeral leaves, peripherous bundles in the leaves and hard leaf bases for protection of the corm from desiccation and grazing. By the loss of some of these characters, some evolutionary lines partly returned to aquatic habitats. The dormant corm is an adaptation to survive the dry ecophase of the TP habitat. An extremely adapted growth form evolved with Isoetes andicola (Stylites a.), a stembuilding species which forms hard cushions like Distichia muscoides at the fringes of lakes and moorland in the Paramos of the Andes and which is resistant to frequent frost change and cryoturbate movement of the soil (Rauh & Falk 1959a, 1959b, Gutte 1980, Cleef 1981, Karrfalt 1984, Keeley et al. 1994). A similar growth form and ecology are recorded from the subalpine zone of Papuasia for I. hopei (Croft 1980). Another adaptation to the extreme conditions of the orotropical climate is the proliferation of dry-resistant gemmae (protected by sclerified phyllopodia) on the leaves. This character can be observed in Isoetes eshbaughii, I. andicola var. gemmifera and I. novogranadensis, all distributed in the Andean Paramos (Hickey 1986, Karrfalt 1999). There is a clear separation of two speciation mechanisms, corresponding with the delimitation of the classes I-N and I so et o- Li tt or el le te a in the holarctic region respectively the separation of permanently submerged versus temporarily ponded environments. The semi-terrestrial species often occur in monospecific populations. They are usually diploids. A gradual speciation due to spatial isolation of ancestral population and no long-range dispersal ability results in a vicariance pattern. The aquatic species occur often in multispecies assemblages and show polyploidy series, long-distance dispersal through water is common. They are allopolyploids, which have evolved through interspecific hybridisation and chromosome number doubling (Taylor & Hickey 1992, Troia 2001; but see Cesca & Peruzzi 2001 for a different hypothesis). Current taxonomic research about the genus Isoetes multiplied the number of known taxa. According to Hickey (1997), the genus was estimated in the 1980s to encompass about 60 species worldwide. Today, estimates are about 200 to 250 species. The number of taxa recognized in North America alone has increased by 50 % in the last 15 years, many of them being local endemics on granite outcrops (Musselman et al. 1997). Further recent taxonomic studies are available for India (Shukla et al. 2002) and the Northern Andes (Small & Hickey 2001). A pattern of vicarious species in TP is recorded from the USA by Taylor & Hickey (1992). They list I. melanopoda, I. melanopoda, I. melanospora, I. tegetiformans, I. howellii, I. nuttallii and I. butleri. Plant communities with Isoetes are for example described from rock pools on the Cedar glades in Tennessee (with I. butleri) (Baskin & Baskin 1999), and from

646

U. Deil

California (with I. orcuttii respectively I. howellii) (Kopecko & Lathrop 1975, Barbour et al. 2005). When several species co-occur, they occupy different niches in the gradients of soil depth, soil fertility and inundation period. On rock outcrops in the Appalachian Piedmont (SE United States) for example, I. melanospora colonizes TP with superficial soil and is associated there with Amphianthus pusillus and Diamorpha smallii. I. melanopoda occurs along rock margins with seasonal seepage water and in deeper pools, associated with species germinating in mud like Lindernia monticola and Gratiola neglecta (Matthews & Murdy 1969). Cook (2004) mentions 9 species for Southern Africa. Besides the widespread taxa I. schweinfurthii, I. welwitschii and I. aequinoctialis, there occur some narrow endemic species, linked to temporary ponds and rock pools: I. capensis, I. giessii, I. stellenbossiensis, I. toximontana, I. transvaalensis, and I. wormaldii. Different requirements to soil conditions were stated by Hall (1971) for four Isoetes species in Ghana: I. nigritana (clay soil), I. abyssinica (silty soil), I. tenuifolia and I. aequinoctialis (sandy soil). Temporarily flooded pools, soakage areas and wet moss swards on rock outcrops in Australia shelter endemic Isoetes species like I. brevicula, I. caroli, I. inflata, I. mongerensis, I. tripus and the more widespread (southern Australia) I. drummondii (Johnson 1984). Vicarious Isoetes species are known from higher altitudes in tropical regions. Croft (1980) mentiones I. hopei, I. habbemensis, I. stevensii and I. neoguineensis for Papuasia. Further species related to the EWH are I. ovata on inselbergs in French Guiana (Raynal-Roques & Jérémie 1980), I. taiwanensis in Taiwan (De Vol 1972) and I. yungiensis from SW mainland China (Wang et al. 2002). Quillwort species, replacing each other according to substrate, period of submergence, altitude and climate, are recorded for the Iberian Peninsula by Prada (1983), Molesworth (1975), Quézel (1998), Rudner (2005b) and Molina (2005). This concerns the species I. setacea, I. histrix, I. duriaei, I. delilei, and I. velata. Ophioglossum: In many parts of the world, this geophytic fern genus occurs in EWH. Here are some examples: O. lusitanicum in Southern Europe (Ballesteros 1984), O. azoricum on the Azores and extrazonally on Iceland around fumaroles (Dierssen 1996), O. vulgatum on Lesbos, Greece (Bazos & Yannitsaros 1999), O. coriaceum in New Zealand (Johnson & Brooke 1989), O. costatum on inselbergs in Benin (Oumorou & Lejoly 2003), O. gomezianum, O. costatum, and O. thomasii in lateritic depressions in West Africa (Müller & Deil 2005), O. lancifolium in Botswana (Vega et al. 1997), O. ellipticum on inselbergs in French Guiana (RaynalRoques & Jérémie 1980), O. engelmannii around rock pools on the Cedar glades in Tennessee (Baskin & Baskin 1999) and O. crotalaphoroides at lakeshores in the Paramos of Venezuela (Berg 1998). Gratioloideae: Within the polyphyletic family Scrophulariaceae, the subfamily Gratioloideae seems to be a well defined monophyletic clade (Fi-

Habitats, plant traits and vegetation of ephemeral wetlands

647

scher 1992) (but see Ohnstead et al. 2001 for a different concept of Gratioleae, excluding genera like Mimulus and Subtribus Stemodiinae). The important role of the Gratioloideae (genera Amphianthus, Bacopa, Chamaegigas, Dopatrium, Gratiola, Limnophila, Limosella, Lindernia (= Ilysanthes), Mecardonia, Rhamphicarpa, Stemodia, etc.) was already discovered by Eskuche (1975) when studying mud vegetation at Rio Paraná in Argentina. This taxonomic group is also well represented in the same environment in West Africa (see Tab. 1 in Müller & Deil 2005) and in Western Australia (by Peplidium, Mimulus, Stemodia, Glossostigma, see Pignatti & Pignatti 2005). The speciation and evolution of the African taxa within the tribus Lindernieae in the rock pool environment and in seasonal ponds over lateritic crusts is evident from a recent taxonomic study (Fischer 1992). The role of Limnophila and Rhamphicarpa and the vicariance pattern in the genus Limosella have already been discussed in chapter 4.2. Life forms range from poikilohydric perennial hemicryptophytes (Craterostigma, Chamaegigas, Lindernia), succulent annuals and perennials (Bacopa) to dwarfish short-living annuals (Lindernia, Dopatrium, Gratiola, Limosella). Bacopa, a species-rich genus of the warm regions, dominates and characterizes some EWV, like C yp er o p ul ch el li -B ac op et um ha mi lt on ia na e Vanden Berghen 1990 corr. Müller & Deil 2005, B ac op o d ec um be nt is X yr id et um an ci pi di s Vanden Berghen 1997, and B ac op o f lo ri bu nd ae -H yg ro ph il en io n b ar ba ta e Müller & Deil 2005 (all syntaxa in West Africa, see Müller & Deil 2005), B ac op et um cr en at ae Lejoly & Lisowski 2000 in the Congo, or B. monnieri along intermittent streams in Yemen (Deil & Müller-Hohenstein 1985) (Fig. 6), on Guadeloupe (de Foucault 1978, 1983) and in the coastal lowlands of Peru (Müller & Gutte 1985, Galán de Mera 1995). Amphianthus, a monospecific genus (A. pusillus) of the Gratioleae, is known from rock pools in Georgia and South Carolina (Murdy 1966, Hilton & Boyd 1996, Shure 1999). Chamaegigas Ð also monospecific Ð (Ch. intrepidus), is endemic in temporary rock pools in the Namibian desert. Poikilohydric like Chamaegigas is the genus Craterostigma, occurring with preference in rock depressions in the Old World (see Fig. 19). Dopatrium has 14 species, most of them annuals on inselbergs and in depressions over lateritic crusts in Africa and Asia (Fischer 1997). The genus prefers oligotrophic sites. The genus Gratiola, distributed over temperate regions and tropical mountains, has a few tenagophytes, for example in NW North America G. ebracteata, G. heterosepala and G. aurea. Lindernia with about 80 species in the warm regions of the world, has its centre of diversity in East Africa (Fischer 1992, Cook 2004). Besides some eurychorous EWS like L. procumbens (widespread in East Asian regions with monsoon climate, scattered through Europe, see map 1 in von Lampe 1996), others are of medium range like L. dubia (South America), L. conferta, L. parviflora and L. monroi in Southern Africa, L. verbenifolia and L. crustacea in East

648

U. Deil

Asia. Some species have spread to other parts of the world by human activities (mostly rice cultivation), for example L. dubia to Europe. Orcuttieae is a tribus within Poaceae, exclusively found in VP (Crampton 1959, Reeder 1982, Griggs & Jain 1983). The tribus includes the genera Neostapfia (1 species), Tuctoria (3) and Orcuttia (5). These glandulous annual grasses are all endemic in the Californian floristic region. They maintain a permanent seed bank, germination is stimulated by submersion and anaerobiosis. Some monotypic genera are exclusively linked to EWH. Amphianthus and Chamaegigas have already been discussed. Further examples are Lilaea (L. scilloides, Juncaginaceae) and Coleanthus (C. subtilis, Poaceae) (for distribution and ecology, see von Lampe 1996). Subularia (Brassicaceae) has two species. Both are tufted annuals with Isoetes-like leaves (Subularia: with subulate leaves!), colonizing temporary emergent shorelines of oligotrophic ponds (Mulligan & Calder 1964). S. aquatica (incl. var. americana) is of circum-boreal-subarctic, S. monticola of afro-alpine distribution (see map 197 in Hulten 1958). Both members of the former genus Boisduvalia, section Currania (now often included in Epilobium) are vernal pool specialists. Epilobium cleistogamum is restricted to the Great Valley in California, Epilobium pygmaeum (= B. glabella) is of amphi-tropical distribution (NW North America, W South America) (Raven & Moore 1965). Downingia (Campanulaceae) comprises 13 species, distributed in NW North America and one extending to Chile. In California, 6 species are endemic. They are VP specialists (see Tab. 1 in Barbour et al. 2005). Niche partitioning of D. bella and D. cuspidata was studied by Martin & Lathrop (1986). Like within Marsilea, the sympatric growing species are separated by a different time of emergence and flowering period. Pollinators are different, too. Further annual Campanulaceae of the subfamily Lobelioideae occur in the closely related genera Isotoma, Laurentia, Porterella and Solenopsis (Cook 1990). Pratia angulata, P. perpusilla and Hypsela rivalis are Lobelioideae, endemic in VP in New Zealand (Johnson & Brooke 1989, Johnson & Rogers 2003). Navarretia belongs to the family Polemoniaceae. The genus includes 40 species, all restricted to NW North America, except N. involucrata, which is distributed in California, Chile and Argentina. All VP specialists belong to the monophyletic section Navarretia. Navarretia leucocephala for example characterizes the class D ow ni ng io -L as th en ie te a f re mo nt ii (Barbour et al. 2005). The species of section Navarretia are tenagophytes, germinating in the aquatic phase, flowering and fruiting in the terrestrial phase. The section evolved recently from terrestrial ancestors. Adaptive traits to the amphibic environment are an Isoetid growth form in the juvenile phase,

Habitats, plant traits and vegetation of ephemeral wetlands

649

outcrossing, reduced spininess, and indehiscent fruits, remaining on the mother plant during summer (achory). If occurring sympatrically, the species are arranged according to the ponding gradient (Spencer & Rieseberg 1998, Crampton 1954). Juncus, a genus with about 315 species, has some sections closely related to the EWH. Annual species with preference of temporary ponds, rock pools and shoreline habitats concentrate in the Juncus subgenus Agathryon, section Tenageia, in the subgenus Juncus, section Caespitosi and in the subgenus Juncus, section Ozophyllum (Kirschner et al. 1999, 2002, Kirschner & Orchard 2002a, 2002b). Section Tenageia is an evolutionary line, which speciated and diversified in the EWH. A few taxa like Juncus bufonius are of broader distribution (eurasiatic, with synanthropic occurrence in other continents, see Fig. 10), most of the members are stenochorous. The centre of diversity is in the Western Mediterranean area. 11 species belong to this section: J. tenageia (incl. ssp. perpusillus), J. foliosus, J. rechingeri, J. amuricus, J. sphaerocarpus, J. bufonius, J. minutulus, J. hybridus, J. turkestanicus, J. sorrentinii, and J. ranarius. Some other annual rushes occurring in I-N communities in Europe and Northwest Africa are J. bulbosus, J. pygmaeus and J. tingitanus. They belong to the section Ozophyllum. The 16 species of section Caespitosi are stenoendemic and occur in Southern Africa and NW North America except J. capitatus, distributed in Europe. From Oregon to Baja California, the following species can be found: J. triformis, J. leiospermus, J. kellogii, J. luciensis, J. tiehmii, J. capillaris, J. bryoides, J. uncialis and J. hemiendytus. Rock pools and fringes of rock outcrops with seasonal soaking water in South Africa and Namibia are the habitats of the following species: J. scabriusculus, J. obliquus, J. stenopetalus, J. rupestris, J. pictus and J. cephalotes. Crassula s.l. (incl. Tillaea): Annual members of the genus Crassula all belong to the section Helophytum (Ecklon & Zeyher) Tölken, a taxon sometimes classified as a separate genus or subgenus (Helophytum = Tillaea = Bulliardia = Disporocarpa). Most of these species are adapted to the EWH. Often annual Crassula-species are characterizing and name-giving for plant communities of EWV like M yo su ro mi ni mi -C ra ss ul et um va il la nt ii , Lyt hr o t hy mi fo li ae -C ra ss ul et um va il la nt ii and Is oe to -C ra ss ul et um in Southern France and Spain, Tillaea alata-Crepis pusilla- and Tillaea vaillantii-community on Gavdos/Greece (Bergmeier 2001), Til la ee tu m p al ud os ae in Colombia (Cleef 1981), Cr as su le tu m c on na t ae in Bolivia (Seibert & Menhofer 1991), Po ly go no -C ra ss ul et um p al ud os ae in Southern Chile (Ramı́rez et al. 1996), Cr as su le tu m n at an ti s in Lesotho (van Zinderen Bakker & Werger 1974), and C ra ss ul o m os ch at ae -C la sm at oc ol ee tu m v er mi cu la ri s on Marion Island (Gremmen 1981). When studying EWV in the Paramos of the Colombian Cordillera, Cleef (1981) described the alliance Til la ei on pa lu do sa e within the class L im os el le te a a us tr al is . And he pointed out the amaz-

650

U. Deil

ing vicariance of annual Crassula species in andean, afro-alpine, montane south-hemispheric and lowland subantarctic EWH. Examples are Crassula paludosa (from Columbia to Chile), C. connata (Chile), C. moschata (Marion Island, Southern Chile, Argentina and New Zealand), C. natans (Lesotho, Southern Africa, Western Australia) and Crassula granvikii (East Africa). A similar pattern of vicarious species can be seen in amphibic Ranunculus with floating leaves and in Limosella with L. americana, L. australis, L. lineata, L. aquatica, L. capensis and L. africana. All New World species of Crassula are annual tenagophytes (Bywater & Wickens 1984). The native species are C. moschata, C. saginoides, C. venezuelensis, C. minutissima, C. solierii (= Tillaea andicola), C. longipes, C. peduncularis, C. drummondii, C. viridis, C. decumbens, C. closiana, C. connata. C. tillaea has been introduced to California and to Southern Africa. In the latter region, amphibic annual Crassula species occur in rock pools, around shallow vleis and on open mud flats. Examples are the South African endemics C. aphylla, C. elatinoides, C. gemmifera, C. natans, and C. tuberella (Friedrich 1979, Cook 2004). In New Zealand 13 native and 6 naturalized annual Crassula-species occur (Johnson & Brooke 1989), all more or less related to EWH (Johnson & Rogers 2003). Apart from widespread subantarctic taxa like C. moschata, others are stenochorous like C. ruamahanga, C. manaia, C. kirkii, C. multicaulis, C. sinclairii and C. hunua (= C. pusilla), the latter all endemic to New Zealand. A Crassula sinclairiiLilaeopsis ruthiana-community is recorded for different parts of the country (Johnson & Rogers 2003). Eriocaulon (Eriocaulaceae) is a large genus (ca. 400 species) of tropicalsubtropical distribution, with a few outliers in the temperate zone. The annual species show a preference to seasonal submerged fringes of oligotrophic ponds, like for example E. pumilum, E. plumale, E. xeranthemoides, and E. afzelianum in the E ri oc au lo pu mi li -O ph io gl os si on go me zi a nu m (MĂźller & Deil 2005), a West African alliance occurring in seasonal pools on lateritic crusts and rock outcrops. Eriocaulon cinereum and E. meiklei colonize dune valleys and rice fields in Senegal (Vanden Berghen 1997). Another centre of diversity for this genus are emergent shores of oligotrophic ponds in Japan: Eriocaulon hondoense, E. japonicum, E. nakasimanum and E. decemflorum are character species of the alliance E ri oc au li on ho nd oe ns is Shimoda 1983 (Shimoda 2005). Annual Eriocaulon species with tenagophytic life cycle in Southern Africa are E. abyssinicum, E. cinereum, E. maculatum, E. mutatum and E. welwitschii (Cook 2004). An Eriocaulon aristatum (= E. welwitschii)-Riccia volkii-community is described from Namibia (Volk 1984). Further examples of vicarious species occur in the genera Lilaeopsis (Affolter 1985, Johnson & Rogers 2003), Eryngium and Hydrocotyle (all Apiaceae), Amphibromus (Johnson & Brooke 1989, Jacobs & Lapinpuro 1986) and Beckmannia (both Poaceae), Limnophyton (Alismataceae), Utricularia (Taylor 1989) and Genlisea (both Lentibulariaceae), Pogogyne (Lamiaceae), Aponogeton (Aponogetonaceae) (van Bruggen 1985), Isolepis

Habitats, plant traits and vegetation of ephemeral wetlands

651

(Cyperaceae) (Muasya & Simpson 2002), Hygrophila (Acanthaceae), Bergia and Elatine (both Elatinaceae), Alternanthera (Amaranthaceae), Paepalanthus and Syngonanthus (Eriocaulaceae), Cicendia (incl. Exaculum) and Sebaea (Gentianaceae), Aeschynomene, Neptunia and Sesbania (all Fabaceae), Ammannia, Lythrum, Nesaea, Peplis and Rotala (all Lythraceae), Ludwigia (incl. Jussiaea) (Onagraceae), Littorella (Plantaginaceae), Heteranthera (Pontederiaceae), Xyris (Xyridaceae), Centrolepis (Centrolepidaceae), Centipeda (Asteraceae), a.o. (see Cook 1990, Johnson & Brooke 1989, von Lampe 1996). Many of the above-mentioned taxa, which evolved into or within the amphibic environment, are listed as aquatic and semi-aquatic CAM plants by Keeley (1998a). Quite often they are the only representatives within their families exhibiting this photosynthetic pathway. The following taxa of the EWF perform CAM: Isoetes, Marsilea, Pilularia, Eleocharis, Eriocaulon, Hydrilla, Lagarosiphon, Lilaea, Orcuttia, Neostapfia, Tuctoria, Lythrum, Eryngium, Lilaeopsis, Lasthenia, Plagiobothrys, Subularia, Downingia, Crassula, Pogogyne, Littorella, Navarretia, Ranunculus, and Limosella. These genera belong to 19 different plant families, documenting the polyphyletic origin of CAM. 4.7.5. Relict species and recent speciation processes Moor (1937) was the first to underline that in the EWH, phylogenetically old taxa of trachaeophytes are associated. He mentioned Isoetes, Marsilea, Pilularia, Elatine, Corrigiola, Illecebrum, Anthoceros, Riccia a.o. Rock outcrops in Western Australia act as museums of evolutionary processes by harbouring relicts of the past such as Isoetes and Stylidium spp. (Bussell & James 1997). An explanation might be the extremely low productivity in EWH. At other sites, the dwarfish life form is outcompeted by advanced and more productive taxa. On the other hand, Barthlott & Porembski (2000) underline that rock outcrop vegetation is dominated by phylogenetically young families and they stress the role of inselbergs for recent speciation. An increasing proportion of endemic taxa can be stated when passing from the pool bottom to the pool edges (see for example the list of eurychorous (holarctic region) aquatics to stenochorous (Californian) VP specialists in Keeley & Zedler 1998, Tab. 2). This trend is confirmed by Cook (2004) for Southern Africa: A higher rate of local endemics can be stated in semi-terrestrial habitats in comparison to aquatic environments. In general, the reduced size of the habitats, the existence of small populations and the spatial isolation of EWH reduce gene flow and favour allopatric speciation. The variability in time and the small-scale ecological gradients within the pools stimulate sympatric speciation by temporal separation of the populations. The unpredictability of flooding and a high frequency of catastrophic events (for example a series of extremely dry years) result in local extinctions of populations and in founder effects. In some taxa, the evolution of infraspecific taxa is promoted by inbreeding and cleistogamy

652

U. Deil

(see for example Myosurus) (Stone 1959). All these processes explain the common phenomenon of vicariant species, as demonstrated above by numerous examples. Murdy (1966) distinguishes two ways of speciation by the example of rock outcrop endemics in the SE Piedmont (USA): 1) Gradual speciation via outcrop ecotypes, starting from broadly distributed lowland taxa (for example Rhynchospora saxicola and R. globularis). 2) Saltational speciation by hybridisation and polyploidization is postulated for the species pairs Sedum pusillum Ð S. smallii, Talinum mengesii Ð T. tegetiformans, and Cyperus granitophilus Ð C. aristatus. In some cases, the speciation is not yet completed and has advanced only to the infra-specific level. Examples from Southern France and Corsica are Ranunculus revelieri ssp. rodiei respectively R. revelieri s.str. (Oliver et al. 1995), Solenopsis minuta ssp. corsica and Polygonum romanum ssp. gallicum (Médail et al. 1996, 1998). Another example is Myosurus (see chapter 4.2.). Missing speciation in highly disjunct species can be the effect of recent dispersal, probably by water birds. Within the amphi-neotropical element for example, TP are a preferred habitat (Raven 1963). Common species in VP of California and Chile are Lasthenia kunthii, Psilocarphus brevissimus, Downingia pusilla, Crassula aquatica, Cicendia quadrangularis and Navarretia involucrata (Raven 1963, Bliss et al. 1998). A southern origin can be assumed in the genus Piptochaetium: The Chilean taxon is diploid, all North American taxa are polyploid. A northern origin is supposed by Raven (1963) for Lasthenia (about 20 species in California, 1 species in Chile) and Downingia (13 species in North America, all outcrossing; 2 autogamous species in South America). Intrapopulation differentiation along the inundation gradient was studied by Linhart (1988) in Californian VP for the example of Veronica peregrina, a VP species of New World origin, nowadays of nearly cosmopolitan distribution in EWH. The contrast between plants growing in the pool centre under optimal physical conditions and at the same time under high intraspecific competition, and pool-margin individuals, subjected to interspecific competition and to a stronger variability in abiotic factors, results in a genetic differentiation of the centre and margin populations, with a different growth strategy: The centre population is germinating early and simultaneously, earlier flowering and fruit setting, seeds and seedlings are large. They tolerate immediate and intensive intraspecific competition better than seedlings from the pool-edge population. The peripheral plants germinate later and over a prolonged period, seedlings are smaller and tolerate better extreme environmental conditions including interspecific competition. In favourable years, plants there grow to a much larger size (aboveground and root length) (Linhart 1988). Further studies about population genetics of Californian VP plants are reviewed by Elam (1998). 4.7.6. Terrestrial or aquatic ancestors? Except Isoetes, all the vascular plants are secondary aquatics respectively tenagophytes. The step back to the aquatic / amphibic environment hap-

Habitats, plant traits and vegetation of ephemeral wetlands

653

pened quite often, independently in different taxa and at different times (Cook 1999). In some genera like Crassula and Eryngium, which are predominantly adapted to arid and semi-arid conditions, a small number of species became aquatic or amphibic. Within Eryngium (Apiaceae sensu stricto), about 10 out of 240 species are tenagophytes or helophytes (Cook 1999). Examples from TP are Eryngium depressum in Central Chile (Bliss et al. 1998), E. pseudojunceum in Southern Chile (Ramı́rez et al. 1994), E. castrense (= E. vaseyi) in California (Barbour et al. 2005), E. corniculatum on the Iberian Peninsula (Molina & Pertiñez 2000), and E. vesiculosum in New Zealand (Johnson & Brooke 1989). A recent transition from the terrestrial to the amphibic environment is probable for Navarretia (Spencer & Rieseberg 1998) and the grasses from tribus Orcuttieae (Keeley 1998b). 4.8.

Conservation aspects 4.8.1. Rare species and new records

EWH shelter extremely rare and isolated taxa. In New Zealand for example, 18 % of all protected species occur in these habitats (Johnson & Rogers 2003) and a considerable part of the Red-List-species in France is specialized to EWH (Oliver et al. 1995). 90 % of the VP flora in California are native, and 55 % of these species are restricted to this state (Barbour et al. 2005). Even in regions, where the flora has been studied since centuries, new species are being discovered. A few examples from the Mediterranean should be mentioned: Artemisia molinieri, a local endemism in temporary water-filled karstic depressions in Southern France, was described in 1966 (Quézel et al. 1966). Naufraga balearica was discovered as a new species in 1967 on Mallorca and recorded in 1981 from Corsica in an I so et io n-community (Gamisans et al. 1996, Olivier et al. 1995). Since that time, it has not been reported again in Corsica. Another monospecific genus in Corsican and Sardinian VP is Morisia monanthos. It relatives are Raffenaldia species, endemic to Northwest Africa and also linked there to ephemeral wetlands (Gamisans et al. 1996, Quézel 1998). Lotus benoistii, discovered in dayas of Morocco in 1924, and Legousia juliana, once sampled in vernal pools near Constantine (Algeria), have not been observed any more in the last decades (Titolet & Rhazi 1998, Quézel 1998)). In all these situations, a seed bank analysis might be helpful. “Extinct” species are often still alive in the seed bank (Poschlod 1993). In tropical regions and in less explored parts of the Southern Hemisphere, still more new species and new records are to be expected, when floristic and vegetation studies become more detailed. Some examples from recent literature should be mentioned. Porembski et al. (1996b) discovered a new species of Genlisea (Lentibulariaceae) on inselbergs in West Africa, Heenan (1997) a new Selliera (Goodeniaceae) in dune slacks in New Zealand. In a survey of pteridophytes in Botswana (Vega et al. 1997), Isoetes schweinfurthii, Ophioglossum lancifolium and Marsilea minuta were first

654

U. Deil

encountered in this country. The floristic exploration of Chilean vernal pools by Bliss et al. (1998) recorded Hydrocotyle cryptocarpa as new for Chile. 4.8.2. Human impact EWH are rare, of reduced size, spatially separated from each other and unpredictable in timing. They are sensitive to all hydrological changes in the catchment area by direct and indirect human intervention. With these characteristics, they are vulnerable habitats per se. Direct destruction occurs by manipulating the relief and by perturbing the sensitive hydrological system (filling-in and drainage to avoid ponding or excavation and dammingup to achieve permanent water bodies), by urbanization, construction of golf courses etc. In many countries, there is an ongoing process of transformation of TP areas into arable land. The ephemeral flush type is not so threatened, because inselbergs are holy places in many societies and in general of low economic interest. Recent threats however are quarrying and diverting seepage water for human uses (Porembski & Watve 2005, Parmentier 2002). The main reason for the decline of shoreline habitats in temperate climates is the reduction of amplitude of the water table dynamics in lakes and old river beds by hydrological management. In the Upper Rhine Valley in Germany for example, the regression of the E le oc ha ri te tu m a ci cu la r is is documented by Philippi (1985). EWV like Cy pe ro fu sc i- Li mo s el le tu m a qu at ic ae , colonizing alluvial sediments along rivers on the leeward side of convex banks of meanders in Central Poland (the â&#x20AC;&#x153;marginal barâ&#x20AC;? physiotope), is replaced by high-growing annual (R or ip pe tu m a mp hi bi ae ) and perennial canary red grass communities (Ph al ar id et um a ru nd in ac ea e) after some years (Borysiak & Stachnowicz 2000). This fluvial mesoform and its vegetation mosaic became rare due to flood control and river straightening. In regions with perhumid to semi-arid climates, EWS are outcompeted by productive perennials, if relief and water table are stable. They depend on a disturbance regime, destroying from time to time the above-ground plant cover, or on strong fluctuations of the water table. Biomass destruction can be caused by geomorphodynamic processes or by anthropo-zoogenous impacts. By their short life span, EWS support high disturbance frequencies, but suffer from strong disturbance intensity, which destroys the seed bank. Traditional agricultural systems often show low intensity and small-scale disturbance. Agroindustrial landscapes are characterized on the one hand by missing dynamics of flooding or ponding, on the other hand by severe perturbations of the topsoil (for example deep ploughing). Therefore modernisation of landscapes reduces the niches for EWS. Zoogenic impact by grazing and trampling of herbivores is often strong in EWH. We can state a sharp contrast in the land-use trends between developing countries and highly industrialized regions. While the Moroc-

Habitats, plant traits and vegetation of ephemeral wetlands

655

Fig. 26. Intensively grazed “daya” in the Middle Atlas Mountains (Morocco).

can dayas (Fig. 26) are threatened by overgrazing and by transformation to arable land (Rhazi et al. 2001a), habitats in France suffer from the abandonment of traditional grazing (Quézel 1998, Trabaud 1998). The literature review confirms this contrast: The colleagues in Europe and North America deal with restoration projects, with creation of new pools for mitigating impacts on existing pools, and with the risks of invasive species (see for example Black & Zedler 1998 and further contributions in Witham et al. 1998, Wester 1994, Wacker & Kelly 2004, Grillas et al. 2004a, Rhazi et al. 2004, 2005), while colleagues in Africa make efforts to protect these systems from overuse by grazing or use for washing by the local population (Rhazi et al. 2001a) and they study the effects of insecticides, which are applied to combat malaria. Despite the outstanding plant species density in EWV (Hobohm & Petersen 1999, Hobohm et al. 2003) and the fact, that many plants and animals are exclusively linked to temporary waters (see for example Collinson et al. 1995, Blackstock et al. 1993 and Nicolet 2001 for macroinvertebrates in Great Britain, several papers in Witham et al. 1998 for California), these habitats have been neglected by the RAMSAR convention for a long time (Williams 2000), but have recently been included into vulnerable and protected wetland habitats (Anonyme 2002). In French Guiana, inselbergs and their specific habitats justify per se the declaration as protected sites (Gasc et al. 1998). In the European Union, a certain conservation status is guaranteed by designating EWV as priority habitats (see the documents “CORINE Bio-

656

U. Deil

topes” (EUR-OP 1992) and “Habitat directive” (Anonymous 1999)). A recent LIFE-project (1999 to 2004) was dedicated to TP in Mediterranean France (Grillas et al. 2004a, 2004b) to develop management tools and methods for EWH, to make an inventory of flora and fauna, to monitor threatened species, to study the effects of experiments like shrub-clearing, digging-out, restoration of filled-in pools, pulling up invasive exotic species etc., and to publish a management handbook suitable at the Mediterranean scale. There is a strong lobby with its own websites for vernal pools in California (www.vernal.pools.org/), where however about 60 to 90 % of the presettlement vernal pool landscapes have been lost by mineral extraction, agricultural or urban development (Holland 1986 in Barbour et al. 2005, King 1998). Mitigation projects in California’s Great Valley do not substitute edaphically rare pool types like volcanic mudflows (Wacker & Kelly 2004). Some risks and conservation aspects are discussed now in more detail. 4.8.3. Habitat loss and population extinctions The decline of stenoendemics in dwarf littoral turfs at Lake Constance in Central Europe and the extinction of Saxifraga oppositifolia ssp. amphibia in the last few decades is documented by Dienst et al. (2004). An enormous loss of vernal pool habitats for the last 70 years is documented for Southern California by Bauder & McMillan (1998). The narrow geographical distribution of VP communities and the stenochory of the character species make them vulnerable to extinction (Barbour et al. 2005). On the other hand, the persistent seed bank buffers shorter periods of unsuitable living conditions (Poschlod 1993). The only scenario of habitat loss by climate change is presented by Pyke (2004b). Recent setting-aside processes for unproductive arable land in the Central Valley of California compensate to some extent the direct loss of EWH by urbanization and intensification of agriculture (Holland 1998). Restoration projects and mitigation have to take into consideration the original occurrence of VP and the distribution of suitable soil types and landforms (Smith & Verrill 1998). In-situ conservation projects should cover the whole environmental range of EWH, ex-situ conservation for extremely rare taxa must take into consideration the variability of the gene pools (see Griggs 1984 for Orcuttia). An extended submersion period, the abandonment of summer drainage, liming or herbicide spraying of the exposed pond bottom, fertilization of the substrate and eutrophication of the water body have all caused a decline of I-N-taxa and an increase of I so et o- Li tt or el le te a-species in carp ponds in Austria (Traxler 1991) and in Germany (Franke 1987). Changes in fish-pond management in the 20th century resulted in a decline of species like Gypsophila muralis, Crassula aquatica and Illecebrum verticillatum in the Czech Republic (Prach et al. 1987, Sumberová 2003). The same tendency can be stated for Japan: EWH around irrigation ponds in rice land-

Habitats, plant traits and vegetation of ephemeral wetlands

657

scapes are threatened by urbanization and eutrophication. The E ri oc au l io n h on do en si s, an alliance linked to sandy and oligotrophic soils, is replaced by L in de rn io n p ro cu mb en ti s-communities, when the shorelines are covered by muddy eutropic substrate (Shimoda 1983, 1993, 2005). The importance of summer drainage for the conservation of EWF, especially Carex bohemica, and the necessity of refilling the seed bank after one or two decades, was studied in detail in Southern Germany (Poschlod 1996, Poschlod et al. 1993, 1999, Bauer & Poschlod 1994). 4.8.4. Restoration projects An up-to-date synthesis of restoration efforts and management tool for TP in mediterranean climates is presented by Witham et al. (1998) and by Grillas et al. (2004a, 2004b) for California respectively the Mediterranean basin. One of the best studied VP sites in Mediterranean Europe is RoqueHaute, a former basalt quarry in Southern France (Trabaud 1998), now a nature reserve. Since the abandonment of the traditional grazing 40 years ago and a reduction of the fire frequency, an enormous vegetation change took place with a colonization of the open pond floor by trees (Ulmus minor, Fraxinus angustifolia, Tamarix gallica) and bullrush (Typha angustifolia). This resulted in a regression of Isoetes setacea, I. duriaei and annual amphibious species by shading and litter accumulation. A restoration project (Rhazi et al. 2004, 2005) showed, that removal of trees and shrubs initiates the establishment of annual EWS from the seed bank and increases the abundance and vitality of Isoetes setacea. Sheep grazing combined with shrub clearing are proposed as management methods. Permanent plot studies in oligotrophic heathland ponds in the Netherlands and in Northern Germany proved the positive effects of litter removal and ribbon cutting for the establishment of I-N- (Van Beers & Dirkse 2000, MĂźller 1996, Nagler 1999) respectively I so et o- Li tt or el le te a-species (Urban 2005b). Prescribed burning in late spring proved to be an appropriate way to reduce invasive weedy annual grasses like Taeniatherum caput-medusae in Californian VP-landscapes (Pollak & Kan 1998). Monitoring of restoration and mitigation projects in California gave the following results: Restoration of damaged and creation of new VP was to some degree successful. Vegetation and avifauna show trends towards restoration of natural pool characteristics after some years, inoculation speeds up this process. Aquatic invertebrates need more time to reestablish (Ferren et al. 1998, Black & Zedler 1998). The creation of new VP must occur in a landscape context (Sutter & Francisco 1998). The project area must provide for example suitable habitats for flower visitors like oligolectic bees of the family Andrenidae, specialized for Downingia, Lasthenia, Limnanthes and Blennosperma as pollen sources (Thorp & Leong 1998). Highest priority should be given to the preservation of natural sites, because pools are to some extent unique in their long individual history (Black & Zedler 1998, Belk 1998).

658

U. Deil

The long-term trend in the sedimentation process and increasing inflow of calcium carbonate-rich waters resulted in the disappearence of Isoetes setacea in a TP in Southern France (Le Dantec et al. 1998). In Southern Portugal, the effects of drainage and ploughing in the surroundings of VP for fauna and flora were studied by Beja & Alcázar (2003) and Espı́rito Santo & Arsénio (2005). Buffer zones are proposed to reduce nutrient and sediment input. The impact of land use for VP was also studied in Morocco: TP, situated in woodland, shelter more EWS than dayas located in agricultural areas (Rhazi et al. 2001a). In Japan, well conserved E ri oc au li on -communities are restricted to ponds located in forests (Shimoda 2005). 4.8.5. Globalization of the flora and invasive species An opposite process to habitat loss and species extinction is the synanthropic expansion of EWH. The anthropogenous spread of EWF can show two different trends: An extension into similar habitats in other floristic regions, or the shift from primary to man-made habitats (a process called “apophytization”). The first process, the “globalization” of the EWF, will result in the long term in a certain trivialization of the communities. As such a loss of floristic specifity of EWV in the different floristic kingdoms of the world is evaluated as negative, we can understand, that species evaluated as threatened or vulnerable in their native area are classified as “agressive neophytes“ or ”invasive species” in other regions. This concerns for example species of palaearctic origin like Lythrum hyssopifolia and Ranunculus flammula in New Zealand (Johnson & Rogers 2003), or Lythrum hyssopifolia and Anagallis minima in California (Barbour et al. 2005, Gerhardt & Collinge 2003). The Australian EWS Centipeda cunninghamii has recently been introduced to Europe and now invades P re sl io n c er vi n ae -communities in Spain (Sánchez Rodrı́guez & Elı́as Rivas 1998). Some examples of neophytic ephemeral communities have been studied: 1. An association in statu nascendi, characterized by a mixture of indigenous taxa (Triplitodiscus pygmaeus, Hydrocotyle laxiflora, a.o.) and species introduced from the European Mediterranean area (I-N, M oe nc hi on and Tu be ra ri on species) and from California (Cicendia quadrangularis), is recorded from SW Australia by Doing (1994). 2. The L il ae op si do ca ro li ne ns is -Tri gl oc hi ne tu m s tr ia ta e occurs in estuaries in NW Spain (Rodrı́guez et al. 1997). Both name-giving species come from the New World. 3. The reverse happened in Southern Chile, where species from Southern Europe are associated in VP (the M en th o p ul eg ii -A gr os ti et um c ap il la ri s) (San Martı́n et al. 1998). Perennials from Europe like Agrostis stolonifera, Ammophila arenaria, Poa pratensis and Trifolium repens have successully invaded seasonally ponded depressions in coastal dune fields in New Zealand. They are strong competitors to the indigenous dwarf flora such as Lilaeopsis novae-zelandiae, Crassula moschata, Apium prostratum, Selliera radicans, Leptocarpus

Habitats, plant traits and vegetation of ephemeral wetlands

659

similis, a.o. (Wilson et al. 1993, Haacks 2003, Johnson & Rogers 2003). The annuals, mentioned by Gerhardt & Collinge (2003) as invasive in Californian VP, remain restricted to the pool edges, except Lythrum hyssopifolia, Hordeum marinum and Polypogon maritimus. This is not astonishing, because all these species behave in the inundation-gradient exactly as in their area of origin. Niche equivalence is a strong risk for successful competition. Ananas comosus, originating from neotropical inselbergs, escaped from cultivations in Western Africa, and is now replacing the indigenous species Afrotrilepis pilosa there (Porembski 2000b). It is unknown, whether the agryophytic Ananas-mats offers the same water quality and seeping regime for the dependent EFV like the original Afrotrilepis-mats. 4.8.6. Primary and secondary habitats for ephemeral wetland species Some characters of the EWF such as short life cycle, long living seed, enormous diaspore off-set and flexible growth form (the capacity of continuous ramification for example) are good preadaptions for being successful in habitats with high disturbance frequency or when taller growing competitors are removed by man. The dwarf EWS are not destroyed by mowing near the surface. In New Zealand for example, representatives of the genera Crassula, Lilaeopsis, Pratia and Hydrocotyle colonized lawns in parks and gardens (Johnson & Rogers 2003), and in the SE of the USA, rock outcrop species became weeds (Wyatt 1997, Wyatt & Allison 2000). Cyanotis lanata, a very common tropical weed today, has its primary habitats on inselbergs in Africa (Porembski 2000b). In frost-free subhumid and semi-arid regions, floodplains along big rivers and seasonally ponded depressions are preferred places for rice cultivation. Many tropical EWS, growing primarily at the shores of seasonal ponds, can colonize rice fields, taro plantations and wet ruderal sites (Ataholo 2001, Hoff & Brisse 1990, Shimoda 2005, Müller & Deil 2005). Post-harvested or abandoned rice fields offer environmental conditions quite similar to EWH. Many taxa originating from TP in the Tropics spread also to rice fields in the Subtropics (see Miyawaki 1960). The C yp er o d if fo rm is -A mm an ni et um co cc in ea e for example, a rice-field community described from Catalonia (Spain) by de Bolòs & Masclans (1955), has species of Palaeotropical origin (Bergia capensis, Cyperus difformis), and from the New World (Ammannia coccinea, Lindernia dubia) as constituent members. The same process of invasion was observed by Koch (1954) in rice fields in the Piemont (Italy), by Pignatti (1957b) in the Po basin (Northern Italy) and by Ubriszy (1961) in Hungary. The last author designates rice fields as a “floristic treasure casket”. One example studied in detail is Heteranthera limosa (Pontederiaceae). This species, originating from seasonally flooded playas in the Southern USA, became a troublesome weed in rice fields in the USA (Baskin et al. 2003). It has recently expanded to rice fields in Greece (Raabe & Raus 2001), Italy (Pignatti 1982), Spain (Rodrı́guez et al. 1995) and Portugal

660

U. Deil

(Vasconcellos et al. 1999). Germination requires light, high temperatures and water-saturated soils, and is stimulated by low oxygen level. Seeds buried in non-flooded soil during winter germinate to a higher percentage and over a wider range of temperatures than do those buried in flooded soil (Baskin et al. 2003). The life-cycles of Heteranthera limosa and Oryza sativa are well synchronized. The water regime associated with rice cultivation is optimal for dormancy break and germination for Heteranthera limosa seeds, and the species could expand from primary habitats in summerrain tropical and subtropical regions to rice fields in the Mediterranean climate. Among the recent invasive non-native plants in Spain, a considerable number originated from tropical temporary wetlands and are established in rice fields (Del Monte & Aguado 2003). Also in temperate climatic zones, agricultural land can be a substitutional habitat for EVS. A strong variability of the water table in potholes in East German farmland increases species diversity of the wetland flora (Brose 2001). The floristic composition of these man-made communities differs from the primary associations. Only EWS species with a broader ecological amplitude are able to spread to fields and associate there with weeds sensu strictu (Albrecht 1999, Nezadal 1999, Täuber & Petersen 2000). Limosella aquatica for example is able to colonize irregularly flooded arable land in the Rhine Valley near Frankfurt (Bissels et al. 2005). Lythrum hyssopifolia has its only survival locality in England in winter-flooded hollows in arable fields (Preston & Whitehouse 1986, Callaghan 1998). These secondary mudflat communities strictly depend on arable use. In Poland, many characteristic species of I-N are at their eastern range of distribution. A strong decline of the EWF in the last few decades is documented by Popiela (2005). Species specialized to river banks and old river beds have lost these habitats by river regulation. Some spread to secondary habitats on exposed bottoms of fish-ponds, others to arable land. The character species of the S pe rg ul ar io ru br ae -I ll ec eb re tu m v er t ic il la ti and the Ce nt un cu lo mi ni mi -A nt ho ce ro te tu m p un ct at i occur exclusively in fields (Spergularia segetalis (nomen!) for example), an anthropogenic extension of their synareal in historical time by ploughing is quite plausible (Popiela 2005). Currently, a strong decline of I-N-populations in agricultural land can be stated in Central Europe (e. g. Popiela 2005, Täuber & Petersen 2000, Täuber 1999a, 1999b, Täuber et al. 2002, Albrecht 1999, Nezadal 1999, Käsermann 1999). Main reasons are the loss of a stubble phase and the favouring of competitive weeds by fertilization. In the French part of the Upper Rhine Valley, a strong decline (about 90 %) of fully developed C en tu nc ul o- An th oc er ot et um -stands between 1930 (Moor 1937) and 2004 (Stalling 2005) can be stated. The opening of the landscape by man has expanded the areal of I-Nspecies from shorelines and river banks to seasonal flooded wheel tracks in fields and to unpaved forest roads. The C yp er o- Li mo se ll et um aq ua ti c ae sc ir pe to su m l at er if lo ri in the Ob valley and the Androsace filiformis-Juncus bufonius-community in the Siberian Taiga zone are examples from Central Asia (Taran 1995), the S te ll ar io ul ig in os ae -I so le pi de -

Habitats, plant traits and vegetation of ephemeral wetlands

661

t um se ta ce i from Central Europe (Täuber & Petersen 2000) and from Ireland (Braun-Blanquet & Tüxen 1952). Railroad grounds, fallow coal pit areas and other r-selecting habitats in North Rhine-Westfalia (Germany) are colonized by Illecebrum verticillatum and Corrigiola litoralis (Vogel 1999). Primary habitats have nearly disappeared with industrialization. In Central Germany, military training areas are sometimes located in inland-dune ecosystems. Soil mobilization and destruction of aboveground biomass favour the existence of EWV, if the frequency of disturbance is not too high (Baumann & Wahrenburg 1995, Täuber 1994, Manz 1997). River regulations have caused a decline for I-N-species in Europe, because flooding and sedimentation was reduced. Sand pits can offer suitable substitutional habitats, when exploitation occurs stepwise and creates continuously open soil for pioneer species (von Brackel et al. 1990). Artificial waters can offer suitable habitats for EWS, if the pond shores have gentle slopes and if the water table is fluctuating. Examples from the Mediterranean region are stock waterers, called “lavognes” in Southern France (Grillas et al. 2004b) and “guazzi”, dug for water bird hunting in coastal plains in Central Italy (Biondi et al. 2002). Examples from the perhumid temperate zone are irrigation ponds in rice fields in Japan (Shimoda 2005) and fish ponds in Central Europe. South Bohemia (Czech Republic) is the region with the highest concentration of fish-ponds in Europe. According to the different water regimes and trophic level of nursery fishponds and storage ponds, different plant communities emerge after drainage. Storage ponds still offer suitable conditions for vulnerable species (Sumberová 2003, Sumberová et al. 2005). 4.8.7. Pasturing and other plant-animal interactions EWV is an important resource for man and his lifestock, becoming more and more prominent with increasing aridity. Already before hominization and domestication of animals, herds gathered at TP. In the Namibian desert, even unproductive dwarf annual turfs are relevant for the survival of migrating large herbivores (Breen 1991) and for nomadic waterfowl (Hines 1990/93, Lindeque & Archibald 1990/91), using this resource in an opportunistic way. The EWS are adapted to a certain pasture pressure by nanism and creeping growth form (avoidance of grazing) or by a regeneration capacity (tolerance strategy) from subterranean parts and clonal growth. If above-surface biomass is also present in the dry season, the species are often protected from disastrous grazing by a strong smell (for example Artemisia molinieri and Mentha cervina (= Preslia c.) in Southern France (Grillas et al. 2004b)) or by toxic repellents like in the genus Ranunculus. The largest population of Lythrum hyssopifolia in Great Britain occurs around a lake. The site is heavily grazed by wildfowl throughout the year, but L. hyssopifolia remains untouched (Callaghan 1998). The northernmost outliers of the annual grass Beckmannia syzigachne in the Makenzie River Delta (Canada) occur on small deltas and wave-built shoals (Gill 1974). These open sites with fresh sediments are preferred locations

662

U. Deil

for resting waterfowl. A strong grazing pressure on the semi-aquatic boreoarctic perennial grass Arctophila fulva favours the ephemerophytic Beckmannia. Endozoochorous seed-transport by birds migrating northwards in spring may be another factor creating such arctic outliers of Beckmannia. Under heavy grazing and trampling, creeping swards of Bermuda grass (Cynodon dactylon) develop on eutrophic, shortly inundated wet places (B ra ch ia ri o m ut ic ae -C yn od on ti on da ct yl i around seasonal lakes in the Sahel zone in Western Africa (Müller & Deil 2005), Tri fo li o f ra gi f er i- Cy no do nt io n in the Mediterranean zone). Grazing by African buffalos in a Lindernia diffusa-Lipocarpha chinensis-community is mentioned by Parmentier (2002) from rock pools on inselbergs in Equatorial Guinea. While the original size of EWH has been extended by anthropo-zoogenous impact in historical time, a reintroduction of moderate pasturing is often recommended in European countries, where livestock declined in recent decades (Médail et al. 1998). Lorenzoni & Paradis (1998) for example recommend grazing by sheep to prevent the recolonization of Eryngium pusillum sites by trees and shrubs in Corsica, Rhazi et al. (2004, 2005) for the protection of Isoetes setacea populations and annual EWS in Herault (France), Espı́rito Santo & Arsénio (2005) to favour Isoetes spp., and Blanca et al. (1999) for “protecting” Coronopus navasii, a Cruciferae known from three TP in the Sierra del Gador in Spain. Trampling of wet surfaces creates open patches and germination niches for annuals in perennial grassland. Pawing and wallowing by the remaining bison in the Great Plains (USA and Canada) still creates ephemeral pools, deepens playa lakes, favours annual mudflat species versus perennials and facilitates the establishment of Marsilea mucronata (Uno 1989, Hoagland & Collins 1997). Rooting by naturalized Sus scrofa in floodplains in Central Florida creates niches for short-living mud-species like Bacopa caroliniana, B. monnieri, Fuirena pumila, Hydrocotyle umbellata and Luziola fluitans (Arrington et al. 1999). Ground disturbance by extensive cattle grazing and “rooting” by wild boar is for example recommended for the maintenance of Ranunculus revelieri populations in mainland France and Corsica (Grillas et al. 2004b). A positive effect for the C yp er o- Sa m ol et um va le ra nd i by pasturing with Galloway-cattle is stated by Wichmann & Burkart (2000) in NE Germany. Soil disturbance by pigs has been an important factor creating germination niches for EWS in wetlands in Central Europe. The last populations of Marsilea quadrifolia and Pilularia globulifera in the German part of the Upper Rhine Valley were linked to pig enclosures in alluvial grassland (Nebel et al. 1990). Many populations of Lindernia procumbens, Limosella aquatica, Elatine alsinastrum and Cyperus fuscus became extinct with the abandonment of outdoor pig-farming in Germany (Philippi 1969). It is introduced as a management tool in the Elbe-alluvium (Beinlich et al. 2001) and was an effective way to re-establishment of Lythrum portula and other I-N-species from the seed bank (Neugebauer 2003). A moderate pasturing impact can also be a relevant environmental factor for EWV by faeces deposition. Brower et al. (2001) studied nutrient re-

Habitats, plant traits and vegetation of ephemeral wetlands

663

quirements of ephemeral plants in The Netherlands. Vegetative growth and flowering rate of Cicendia filiformis and Juncus tenageia are promoted by phosphorus, but not by nitrogen. The anaerobic conditions during ponding favour denitrification processes and raise the availability of phosphorus. The high N-deposition in Northwestern and Central Europe has two negative effects: P-availability is reduced and competitors are favoured by Nfertilization. EWV specialized for oligotrophic conditions like C ic en di et um fi li fo rm is , Sp er gu la ri o- Il le ce br et um and Ju nc o b uf on ii G yp so ph il et um are more threatened than those adapted to meso- and eutrophic environments (C yp er o f us ci -L im os el le tu m a qu at ic ae ) (Rennwald 2000).

Further studies and open questions

EWH is a microcosmos of high interest for vegetation ecologists and evolutionary biologists. This has been stated at the end of many studies dealing with this ecosystem (see for example Moor 1936, Holland & Jain 1977/ 88, Quarterman et al. 1993, Keeley & Zedler 1998, MĂźller & Deil 2005). Ephemeral wetlands are suitable model ecosystems to study plantenvironment relationships and evolutionary processes, because the environmental conditions are extreme, selective forces are strong, flora and fauna are unique, and the habitats are islands in space and time. They are spatially well defined and offer the possibility for manipulative field experiments. By the removal respectively introduction of competitors we can for example study, to which extent the fundamental and the realized niches of the species differ. Despite their biotic uniqueness and the high degree of endemism in various parts of the world, EWH have some common fundamental ecological traits. This resulted in convergent evolution in many taxonomic groups. From the viewpoint of primary production, EWH are exceptionally unproductive: They are CO2-limited in the aquatic phase and water-limited ecosystems in the terrestrial phase. This combination offers niches both for small, short-living annuals and for dwarf and slow-growing perennials. Based upon this review, a number of open questions and some interesting fields of future research can be stated: 1. Assuming, that the number of phytosociological data documented in Fig. 2 mirrors indeed the state of knowledge and that most of the relevant literature has been exploited for this review (the author at least made an effort to do that), we can state, that the present knowledge of the ephemeral wetland plant communities varies a lot throughout different parts of the world. Whereas some regions such as the western palaearctic region, Japan, California and West Tropical Africa are well known and sufficiently documented by phytosociological releveĚ s, other areas are not explored enough or the knowledge is in a preliminary status. This concerns for example India and SE Asia, Southern Africa, NE and SE USA, China, and the Mediterranean part of Chile. The studies of Porembski & Watve (2005) and Bliss et al. (1998) can only be regarded as a first step to the study of EWV

664

U. Deil

in India respectively Chile. A new and an endemic class can be expected for the Cape region. This is indicated by the large number of endemic vernal poor specialists recorded in the South African wetland flora by Cook (2004). 2. The available floristic-sociological data set will be classified and ordinated in the near future, when some taxonomic and nomenclatural problems have been solved. The classification, which will be done at the species level, will allow to evaluate the syntaxonomic schemes, presented in Tables 1 to 8 and to verify the distribution of high-ranked syntaxa (classes and orders), mapped in Figs. 15 and 16. It should go further down to the level of alliances. At that level of floristic dissimilarity, edaphic factors such as the trophic situation of the soil and the duration of submersion should be the most important differentiating factors. 3. An ordination of the data should give more insight into floristic and ecological transitions. For the data set of the Western Palaearctis for example, it would be interesting to study the transition from temperate Europe to the Mediterranean basin, i.e. the transition from C yp er et al ia fu sc i to I so et et al ia hi st ri ci s, the delimitation between I so et o- Na no ju nc et ea and B id en te te a, and the overlapping of C yp er et al ia fu sc i and C ry ps ie ta li a a cu le at ae in Eastern and Southern Europe and Northern Africa. In the neotropical region, the available data seem to be suitable to clarify the delimitation between X yr id et ea sa va ne ns is and Le pt oc or yp hi oTra ch yp og on et ea respectively the gradient between communities on nutrient-poor substrates (X yr id et ea sa va ne ns is , Inselberg vegetation, white sand savannas) and amphibic vegetation on mud soils (communities with Bacopa and Lindernia species). 4. The occurrence of vicarious and habitat equivalent species encourages to search for coeno-syntaxa sensu Deil (1999). For such a purpose, the species-based data must be transformed into a data set with genera. We then can classify at a supraspecific level. When plant communities in different regions are characterized by a large number of vicarious species, we can draw the conclusion that these taxa have been associated for a long time and speciated in the same ecological and coenological context (parallel evolution). We can classify the vegetation, based on high rank taxa, in coenosyntaxa and class-groups with a common ancestor community. Such a proposal is made by Bliss and co-authors when comparing vernal pools of California and Chile: â&#x20AC;&#x153;amphitropical species . . . provide an excellent opportunity for testing ideas about community assemblage through evolutionary . . . timeâ&#x20AC;? (Bliss et al. 1998). This approach can be tested by the example of the L im os el le a-class-group (EWV in the high mountains of South America and Africa), the X yr id ea -class-group (inselberg vegetation throughout the Tropics) (see Porembski 1999 for common taxa and for the variability in species diversity patterns), the D ow ni ng io -N av ar re te a-group (vernal pools of California and Chile), and by a comparison of EWV in temperate regions (Eurasia and New Zealand). To reconstruct the ancestor communities, the taxonomic level of genera, subgenera and sections seems to be more appropriate than the family level (see de Foucault 1988 for family-pattern

Habitats, plant traits and vegetation of ephemeral wetlands

665

in EWV). When more faunistic data are available in the future, this approach would allow to test the hypothesis of Keeley & Zedler (1998), that the similarities within the Crustacean-fauna (Branchiopoda and Anostraca) tie together the ephemeral habitats in a world-wide perspective better than the floristic data. 5. The classification, based upon supraspecific taxa and reflecting a common evolutionary history, should be accomplished by a taxon-free approach. The latter method looks for convergent evolution and niche-equivalent taxa. Examples are the classifications of NE American wetland plants (Boutin & Keddy 1993) and NW European vascular hydrophytic plant species (Willby et al. 2000), based upon morphological and phenological characters. The results of the latter study are to a large part congruent with earlier classifications (see for example Den Hartog & Segal 1964, Wiegleb 1991). Both studies ignore more or less the short-living dwarf ephemerals. A similar approach, applied to plants in the amphibic environment and stretching over different floristic kingdoms, should be interesting. Patterns of morphological syndromes might emerge, not so closely linked to phylogenetic groups, as can be seen in the NW European data (Willby et al. 2000). An early comparative study of life forms in the aquatic milieu between The Netherlands, Czechoslovakia and India was realized by Hogeweg & Brenkert (1969), further studies with quite rough typologies are for example Denny (1985) and Brock & Casanova (1997). 6. Plant life in temporary waters is a life between inundation and desiccation. This requires special adaptations in ecophysiology, germination ecology, dispersal mechanisms and growth form. Evolution has favoured certain strategy types which co-evolved a syndrome of adaptive traits. Every strategy type found another solution to adapt to the short period of favourable conditions. If we apply the approaches and classification systems used by HejnyĚ (1971) and Barkman (1988) to name a combination of morphological, physiological, phenological and life-cycle characters after a representative taxon, we should look for growth forms and phenological plant types such as Isoetids, Ophioglossoids, Marsileids, Pilulariids, Peplids, Tillaeids, Radiolids, Echinochloids, Eriocaulids, Xyroids, Droseroids, Lindernioids, Juncoids etc. It would be interesting to extend the system of Barkman (1988), developed for European plants, to the vegetation of ephemeral wetlands in general. The system must consider the fact, that many amphibic plants are heteromorphic and change their habit from the aquatic to the terrestrial growth form. For a better understanding of the competition and the productivity in these ecosystems, such studies should include investigations about photosynthesis and CO2 assimilation strategies, as realized by Keeley (1999) for vernal pool systems in California. 7. When comparing the flora of the Mediterranean regions of the world at the species level, a high rate of endemism can be stated for California, SW Australia, and South Africa, a lower level for Chile and the EuropeanNorth African Mediterranean area. The reasons are unclear. The early isolation of the Australian region by plate tectonics and the strong climatic delimitation of the Capensis from the Western Palaeotopis can explain the

666

U. Deil

situation for SW Australia and South Africa. For the difference between California and Chile, Keeley & Zedler (1998) formulate the amphitropical origin hypothesis: The Chilean vernal pool plants are deviated from ancestors, which evolved into the EWH in California and spread to Chile by long-distance dispersal. An answer to this hypothesis needs a better data set from Chile. 8. Seasonality amd interannual fluctuations are characteristic features of ephemeral wetland vegetation. It is therefore astonishing that permanent plot studies in EWV are scanty. Some permanent plot observations exist, but we did not come across monitoring programmes, which are individually based (but see Rudner 2005a for a very fine spatial resolution and Rudner 2001 for the search for within-community pattern). This is however the only way to verify whether the within-stand changes from yearto-year are just a fluctuation in the dominance of some species or whether spatial fluctuations support the ideas of the shuttle respectively carousel model. Such observations are available for the permanently submerged environment and species like Isoetes lacustris, Littorella uniflora and Lobelia dortmanna (Szmeja 1994), but not for the semiterrestrial environment. Observations about the inter-annual shifting of the zonation complexes are available only for a few regions (see for example Schneider 1994, Bliss & Zedler 1998, and Casanova & Brock 2000). 9. The role of the seed bank and the flooding regime for the establishment of plant communities as well as the year-to-year variations in floristic composition have been analysed in permanent plot studies for different parts of the world, like for example Spain and Portugal (Ballesteros 1984, Rudner 2005a), Morocco (Rhazi et al. 2001), California (Holland & Jain 1981/84), and the Appalachian Piedmont (HouleĚ & Philipps 1989a, 1989b). For many other regions and for most of the tropical species, data about seed bank, germination ecology, and inter-annual variability are not available. Such studies are however necessary for an evaluation of the extinction risk of rare species and the invadability of the communities for newly introduced species. 10. The setup of permanent plots is also required in order to monitor the persistence respectively the vulnerability of the habitats vis-a-vis human impact in the landscape dimension, and to understand better the role of physical and biogenic disturbance for the long-term survival of the EWH and their flora. 11. This review concerns to the plants of EWH and the producer level in these ecosystems. In the future, the fauna and the consumerâ&#x20AC;&#x2122;s viewpoint should be included to get a holistic view of the biocoenosis. Branchiopoda, Anostraca, Cladocerata, Odonata and amphibians are some groups studied so far (see for example Metge 1986, ThieĚ ry 1991, Belk 1998 and several contributions in Grillas et al. 2004a, 2004b, and Witham et al. 1998). Such an analysis should look for common traits in the life histories of plants and animals, for example in the survival forms of annual plants and short-living crustaceans. It should be investigated, which environmental factors stimulate the performance of survival organs such as seeds, corms, eggs and cysts.

Habitats, plant traits and vegetation of ephemeral wetlands

667

Other aspects might be a comparison of the ephemeral wetland flora and fauna in respect to diversity and endemism rate (Williams 1987, 2000), life cycles and dispersal strategies (Wiggins et al. 1980), distribution patterns, sensitivity to human impact (Beja & Alcázar 2003, Mawson 2000) and seasonality. The available data show that the animals in VP have a stronger seasonality than the macrophytes (see for example Barbéro et al. (1982) and Guidicelli & Thiéry (1998) for the Mediterranean area, Lake et al. (1989) for Australia). Convergent traits and extreme adaptations occur in animals and plants colonizing seasonal tropical rain pools: Polypedilum vanderplanki (Chironomidae) is unique amongst insect larvae in its ability to tolerate virtually complete loss of body water (McLachlan & Cantrell 1980). It can survive dry periods in situ and is able to recover within minutes after reflooding. The botanical equivalent is Chamaegigas intrepidus (Heilmeier et al. 2005). Acknowledgements. I would like to thank my colleagues from all over the world for their contributions about EWV (by publishing and by sending me reprints from remote areas and inaccessible journals). The support by Eva-Maria Bauer and Julia Schwarz in literature searches is gratefully acknowledged. I am indebted to Eva-Maria Bauer, Hiltrud Brose, Dr. Heike Culmsee, Markus Hall, Dr. Jonas Müller, Arne Saatkamp, Thomas Stalling and Anne Weyand for establishing the database and checking the floristic nomenclature, to E.-M. Bauer and Dr. Heike Culmsee for running classification programs, to Alexandra Böminghaus for finishing the drawings, and to Dr. Randy Cassada for the linguistic revision of the text. Prof. Dr. Erwin Bergmeier (Göttingen), Prof. Dr. Georg Philippi (Karlsruhe), Prof. Dr. Antonio Galán de Mera (Madrid) and Dr. Jonas Müller (Freiburg) were so kind as to read and criticize the manuscript or parts of it.

References Abbott, P. L. (1984): On the origin of vernal pool topography San Diego County, California. Ð In: Jain, S. K. & Moyle, P. (eds.): Vernal pools and intermittent streams: 18Ð29. Davis. Aberlin, J. P. (1986a): Les abris humides sous roches au Mali central. Ð Feddes Rep. 97: 697Ð704. Ð (1986b): Les grandes unités phytosociologiques au Mali central. Première partie: Les milieux humides. Ð Feddes Rep. 97: 185Ð196. Acres, B. D., Blair Rains, A., King, R. B., Lawton, R. M., Mitchell, A. J. B. & Rackham, L. J. (1985): African Dambos: their distribution, characteristics, and use. Ð Z. Geomorph. N. F. , Suppl. 52: 63Ð86. Adjanohoun, E. (1964): Végétation des savannes et des rochers découverts en Côte d’Ivoire centrale. Ð Mém. ORSTOM 7: 250 p., Paris. Affolter, J. M. (1985): A monograph of the genus Lilaeopsis (Umbelliferae). Ð Syst. Bot. Monogr. 6: 1Ð140. Albrecht, H. (1999): Vergesellschaftung, Standorteigenschaften und Populationsökologie von Arten der Klasse Isoeto-Nanojuncetea auf Ackerflächen. Ð Mitt. Bad. Landesver. Naturkd. Naturschutz Freib. i. Br. 17(2): 403Ð417. Allorge, P. (1922): Les associations végétales du Vexin français (14de aflevering). Ð Rev. Gén. Bot. 34: 564Ð576.

668

U. Deil

Alpert, P. (2000): The discovery, scope, and puzzle of desiccation tolerance in plants. Ð Plant Ecology 151: 5Ð17. Alston, A. H. G. (1959): The ferns and fern-allies of West Tropical Africa. A supplement to the second edition of the Flora of West Tropical Africa. Ð 89 p., London. Alves, R. J. V. & Kolbek, J. (1993): Penumbral rock communities in campo rupestre sites in Brazil. Ð J. Veg. Sci. 4: 357Ð366. Amritphale, D., Lyengar, S. & Sharma, R. K. (1989): Effects of light and storage temperature on seed germination in Hygrophila auriculata (Schumach.) Heines. Ð J. Seed Technol. 13: 39Ð43. Anderson, R. C., Fralish, J. S. & Baskin, J. M. (1999): Savannas, Barrens, and Rock Outcrop Plant Communities of North America. Ð 480 p., Cambridge. Anonymous (1999): Manuel d’interprétation des habitats de l’Union européenne EUR 15/2, Natura 2000. Ð Commission européenne DG Environnement, Natura 2000, 132 p., Bruxelles. Ð (2002): La convention sur les zones humides. Résolution VIII.33 Ð La désignation de mares temporaires. Ð //www.ramsar.org/. Ant, H. & Diekjobst, H. (1967): Zum räumlichen und zeitlichen Gefüge der Vegetation trockengefallener Talsperrenböden. Ð Arch. Hydrobiol. 62: 439Ð452. Anzalone, B. & Caputo, G. (1975): Flora e vegetazione delle Isole Ponziane (Golfo di Gaeta). Ð Delpinoa, N. S. 16Ð17: 1Ð184. APG II (2003): An update of the Angiosperm Phylogeny group. Classification for the orders and families of flowering plants: APG II. Ð Bot. J. Linn. Soc. 141: 399Ð436. Arle, J. (2002): Physical and chemical dynamics of temporary ponds on a calcareous plateau in Thuringia, Germany. Ð Limnologica 32. 83Ð101. Arnaiz, C. & Molina, J. A. (1985): Vegetación acuática y helofı́tica de la cuenca alta del rı́o Guadarrama (Madrid, España). Ð Lazaroa 8: 221Ð240. Arrington, A. D., Toth, L. A. & Koebel, J. W. (1999): Effect of rooting by feral hogs Sus scrofa L. on the structure of floodplain vegetation assemblage. Ð Wetlands 19(3): 535Ð 544. Ash, S. & Pigg, K. B. (1991): A new Jurassic Isoetites (Isoetales) from the Wallowa Terrace in Hells Canyon, Oregon, and Idaho. Ð Am. J. Bot. 78: 1636Ð1642. Ataholo, M. (2001): Pflanzensoziologische Untersuchungen der Segetalvegetation in der Sudanzone Westafrikas. Ð Diss. Univ. Frankfurt, FB Biologie, Frankfurt. Aubert, G. & Loisel, R. (1971): Contribution à l’étude des groupements des Isoeto-Nanojuncetea et des Helianthemetea annuae dans le Sud-Est méditerranéen francais. Ð Ann. Univ. Provence 45: 203Ð241. Bagi, I. (1987): Studies on the vegetation dynamics of Nanocyperion communities. III. Zonation and succession. Ð Tiscia 22: 31Ð45. Ð (1991): Edaphic factors in the development of dwarf-plant communities of mud. Ð Folia Geobot. Phytotax. 26: 431Ð437. Balátová-Tulácková, E. & Capote, R. P. (1985): Contribution to the knowledge of some savanna and forb-rich communities on the Isla de la Juventud (Cuba). Ð Folia Geobot. Phytotax. 20: 17Ð39. Ballesteros, E. (1984): Sobre l’estructura i la dinamica de les comunitats terofitiques humides (classe Isoeto-Nanojuncetea) i els pradells amb Ophioglossum lusitanicum L. del massis de Cadiretes (La Selva). Ð Collect. Bot. 15: 39Ð57. Barale, G. (1999): Sur la présence d’une nouvelle espèce d’Isoetites dans la flore du Crétacé inférieur dans la région de Tataouine (Sud Tunisien): implicationes paléoclimatiques et phylogénétiques. Ð Can. J. Bot. 77: 189Ð196. Barbagallo, G., Brullo, S. & Furnari, F. (1990): La vegetazione alofila palustre della Tunisia. Ð Boll. Acc. Gioenia Sci. Nat. 23: 581Ð652.

Habitats, plant traits and vegetation of ephemeral wetlands

669

Barbéro, M. (1965): Groupements hygrophiles de l’Isoetion dans les Maures. Ð Bull. Soc. Bot. Fr. 112: 276Ð290. Ð (1967): L’Isoetion des Maures. Groupements mésophiles. Etude du milieu. Ð Ann. Fac. Sc. Marseille 39: 25Ð37. Barbéro, M., Loisel, R. & Poiron, L. (1969): Sur quelques aspects mal connus de la flore et de la végétation de l’Estérel. Ð Monde Pl. 364. Barbéro, M., Giudicelli, J., Loisel, R., Quézel, P. & Terzian, E. (1982): Étude des biocénoses des mares et ruisseaux temporaires à éphémérophytes dominants en région méditerranéenne française. Ð Bull. Ecol. 13: 387Ð400. Barbour, M., Solomeshch, A., Witham, C. W., Holland, R., Macdonald, R., Cilliers, S., Molina, J. A., Buck, J. & Hillman, J. (2003): Vernal pool vegetation of California: Variation within pools. Ð Madroño 50(3): 129Ð146. Barbour, M., Solomeshch, A., Holland, R., Witham, C. W., Macdonald, R., Cilliers, S., Molina, J. A., Buck, J. & Hillman, J. (2005): Vernal pool vegetation of California: communities of long inundated deep habitats. Ð Phytocoenologia 35: 177Ð200. Barkman, J. J. (1973): Synusial approaches to classification. Ð In: Whittaker, R. H. (ed.): Classification and ordination of plant communities = Handbook of Vegetation Science 5: 435Ð491. Den Haag Ð (1988): New system of plant growth forms and phenological plant types. Ð In: Werger, M. J. A., van der Aart, P. J. M., During, H. J. & Verhoeven, J. T. A. (eds.): Plant form and vegetation structure: 9Ð44. The Hague. Barry, J. P. & Faurel, L. (1973): Notice de la Feuille de Ghardaia. Carte de la végétation de l’Algérie, 1:500000. Ð Mém. Soc. Hist. Nat. Afr. Nord 11: 125p., Marseille. Barry, S. J. (1998): Managing the Sacramento Vernal Pool Landscape to Sustain Native Flora. Ð In: Witham, C. W., Belk, D., Ferren, W. R. & Ornduff, R. (eds.): Ecology, Conservation, and Management of Vernal Pool Ecosystems: 236Ð240. Sacramento. Barthlott, W. & Porembski, S. (1998): Diversity and phytogeographical affinities of Inselberg vegetation in tropical Africa and Madagascar. Ð In: Huxley, C. R., Lock, J. M. & Cutler, D. F. (eds.): Chorology, Taxonomy, and Ecology of the Floras of Africa and Madagascar: 119Ð129. Kew. Ð Ð (2000): Vascular Plants on Inselbergs: Systematic overview. Ð In: Porembski, S. & Barthlott, W. (eds.): Inselbergs: 103Ð116. Berlin, Heidelberg. Bartolo, G., Brullo, P., Minissale, P. & Spampinato, G. (1990): Flora e vegetazione dell’ Isola di Lampedusa. Ð Boll. Acc. Gioenia Sci. Nat. 21(334): 119Ð255. Baskin, C. C. & Baskin, J. M. (1998): Seeds. Ecology, Biogeography and Evolution of Dormancy and Germination. Ð 666 p., San Diego. Baskin, C. C., Baskin, J. M. & Chester, E. W. (2003): Ecological aspects of seed dormancybreak and germination in Heteranthera limosa (Pontederiaceae), a summer annual weed of rice fields. Ð Weed Res. 43: 103Ð107. Baskin, J. M. & Baskin, C. C. (1972): Germination characteristics of Diamorpha cymosa seeds and an ecological interpretation. Ð Oecologia 10: 17Ð28. Ð Ð (1979): Role of temperature in the vegetative life cycle of Isoetes butleri. Ð Amer. Fern J. 69: 103Ð110. Ð Ð (1988): Endemism in rock outcrop plant communities of unglaciated eastern United States: An evaluation of the role of edaphic, genetic, and light factors. Ð J. Biogeogr. 15: 829Ð840. Ð Ð (1999): Cedar Glades of the southeastern United States. Ð In: Anderson, R. C., Fralish, J. S. & Baskin, J. M. (eds.): Savannas, barrens, and rock outcrop plant communities of North America: 206Ð219. Cambridge. Ð Ð (2000): Vegetation of limestone and dolomite glades in the Ozarks and Midwest regions of the United States. Ð Ann. Missouri Bot. Gard. 87: 286Ð294.

670

U. Deil

Bauder, E. T. (1989): Drought stress and competition effects on the local distribution of Pogogyne abramsii. Ð Ecology 70: 1083Ð1089. Ð (2000): Inundation effects on small-scale plant distributions in San Diego, California vernal pools. Ð Aquatic Ecol. 34: 43Ð61. Bauder, E. T. & McMillan, S. (1998): Current Distribution and Historical Extent of Vernal Pools in Southern California and Northern Baja California, Mexico. Ð In: Witham, C. W., Belk, D., Ferren, W. R. & Ornduff, R. (eds.): Ecology, Conservation, and Management of Vernal Pool Ecosystems: 56Ð70. Sacramento. Bauer, U. & Poschlod, P. (1994): Ökologie und Management periodisch abgelassener und trockenfallender kleinerer Stehgewässer im oberschwäbischen Voralpen-Gebiet. Veränderung der Phytozönose durch Sömmerung am Beispiel von Gloggere- und Tiefweiher. Ð Veröff. PAÖ 8: 337Ð351. Baumann, H. & Wahrenburg, W. (1995): Rare plants of the Böblingen military training area with special regard to dwarf reed communities. Ð Jahresh. Ges. Nat. Württ. 151: 185Ð215. Bazos, I. & Yannitsaros A. (1999): Pteridophyte flora of Lesvos (East Aegean Islands, Greece). Ð Edinburgh J. Bot. 56: 421Ð448. Beck, S. G. (1983): Vegetationsökologische Grundlagen der Viehwirtschaft in den Überschwemmungssavannen des Rio Yacuma (Departamento Beni, Bolivien). Ð Diss. Botan. 80: 186 p., Vaduz. Ð (1984): Comunidades vegetales de las sabanas inundizadas en el NE de Bolivia. Ð Phytocoenologia 12: 321Ð350. Beinlich, B., Hill, B., Köstermeyer, H., Beck, L. & van Rhemen, K. (2001): Schweinefreilandhaltung in der Landschaftspflege Ð ein Überblick zum aktuellen Kenntnisstand. Ð Veröff. Naturkundl. Verein Egge-Weser 14: 15Ð30. Beja, P. & Alcázar, R. (2003): Conservation of Mediterranean temporary ponds under agricultural intensification: an evaluation using amphibians. Ð Biol. Conserv. 114: 317Ð326. Bekker, R. M., Lammerts, E. J., Schutter, A. & Grootjans, A. P. (1999): Vegetation development in dune slacks: the role of persistent seed banks. Ð J. Veg. Sci. 10: 745Ð754. Belk, D. (1998): Global Status and Trends in Ephemeral Pool Invertebrate Conservation: Implications for Californian Fairy Shrimp. Ð In: Witham, C. W., Belk, D., Ferren, W. R. & Ornduff, R. (eds.): Ecology, Conservation, and Management of Vernal Pool Ecosystems: 147Ð150. Sacramento. Berg, A. L. (1998): Pflanzengesellschaften und Lebensformen des Superpáramo des Parque Nacional Sierra Nevada de Mérida in Venezuela. Ð Phytocoenologia 28: 157Ð 203. Berg, C. & Bolbrinker, P. (2004): 7. Klasse: Isoeto-Nano-Juncetea Br.-Bl. & Tx. ex Br.Bl. & al. 1952 Ð Eurasische Zwergbinsen-Pionierfluren. Ð In: Berg, C., Dengler, J., Abdank, A. & Isermann, M. (eds.): Die Pflanzengesellschaften Mecklenburg-Vorpommerns und ihre Gefährdung: 118Ð124 and Annex. Bergmeier, E. (2001): Seasonal pools in the vegetation of Gavdos (Greece) Ð in situ conservation required. Ð Bocconea 13: 511Ð516. Bergmeier, E. & Raus, T. (1999): Verbreitung und Einnischung von Arten der IsoetoNanojuncetea in Griechenland und in der Ägäis. Ð Mitt. Bad. Landesver. Naturkd. Naturschutz Freib. i. Br. 17(2): 463Ð479. Bernhardt, K. G. (1993): Untersuchungen zur Besiedlung und Dynamik der Vegetation von Sand- und Schlickpionierstandorten. Ð Diss. Botan. 203, 223 p., Berlin, Stuttgart. Ð (1999): Die Bedeutung der Diasporenbank für die langfristige Erhaltung von IsoetoNanojuncetea-Gesellschaften. Ð Mitt. bad. Landesver. Naturkunde u. Naturschutz 17 (2): 275Ð280.

Habitats, plant traits and vegetation of ephemeral wetlands

671

Biedinger, N., Porembski, S. & Barthlott, W. (2000): Vascular Plants on Inselbergs: Vegetative and Reproductive Strategies. Ð In: Porembski, S. & Barthlott, W. (eds.): Inselbergs: 117Ð142. Berlin, Heidelberg. Biondi, E., Casavecchia, S. & Radetic, Z. (2002): La vegetazione dei “guazzi” e il paesaggio vegetale della pianura alluvionale del tratto terminale del Fiume Musone (Italia centrale). Ð Fitosociologia 39(1): 45Ð70. Bissels, S., Donath, T., Hölzel, N. & Otte, A. (2005): Ephemeral wetland vegetation of irregularly flooded arable fields: the importance of persistent soil seed banks. Ð Phytocoenologia 35: 469Ð488. Biurrun, I. (1999): Flora y vegetación de los rı́os y humedales de Navarra. Ð Guineana 5: 338 p., Bilbao. Black, C. & Zedler, P. H. (1998): An Overview of 15 Years of Vernal Pool Restoration and Conservation Activities in San Diego County, California. Ð In: Witham, C. W., Belk, D., Ferren, W. R. & Ornduff, R. (eds.): Ecology, Conservation, and Management of Vernal Pool Ecosystems: 195Ð205. Sacramento. Blackman, J. G. & Locke, D. K. (1985): Quantitative analysis of seasonal wetlands in the Burdekin-Townsville region with special reference to water bird habitat. Ð Proc. Ecol. Soc. Aust. 13: 139Ð152. Blackstock, T. H., Duigan, C. A., Stevens, D. P. & Yeo, M. J. M. (1993): Vegetation zonation and invertebrate fauna in Pant-y-Ilyn, an unusual seasonal lake in South Wales, UK. Ð Aquatic Conserv. Marine Freshwater Ecosyst. 3: 253Ð268. Blanca, G., Hernández Bermejo, J. E., Herrera, C. M., Molero, J., Muñoz, J. & Valdés, B. (eds.)(1999): Libro rojo de la flora silvestre amenzada de Andalucia. I. Especies en peligro de extinción. Ð 302 p., Sevilla. Blasi, C., Stanisci, A., Filesi, L., Milanese, A., Perinelli, E. & Riggio, L. (2002): Syndynamics of lowland Quercus frainetto & Q. cerris forests in Lazio (central Italy). Ð Fitosociologia 39(1): 23Ð43. Bliss, S. A. & Zedler, P. A. (1998): The germination process in vernal pools: sensitivity to environmental conditions and effects on community structure. Ð Oecologia 113: 67Ð 73. Bliss, S. A., Zedler, P. A., Keeley, J. E. & Arroyo, M. T. K. (1998): A floristic survey of the temporary wetlands in the Mediterranean-climate region of Chile. Ð In: McComb, A. J. & Davis, J. A. (eds.): Wetlands for the Future: 219Ð228. Adelaide. Bolen, E. G., Smith, L. M. & Schramm, J. H. L. (1989): Playa lakes: prairie wetlands of the southern high plains. Ð BioScience 39: 615Ð623. Bolòs, O. de (1979): Sur quelques groupements herbaceés hygrophiles du Montseny (Catalogne). Ð Phytocoenologia 6: 202Ð208. Ð (1996): La vegetatión de les Illes Baleares. Comunitats de plantes. Ð Inst. Est. Catal. Arx. Secc. Ci. 114: 167 p., Barcelona. Bolòs, O. de & Masclans, F. (1955): La vegetación de los arrozales en la región mediterránea. Ð Collect. Bot. 4: 415Ð434. Bolòs, O. de, Molinier, R. & Montserrat, P. (1970): Observations phytosociologiques dans l’Ile de Minorque. Ð Acta Geobot. Barcinon. 5: 1Ð150. Bolòs, O. de, Masalles, R. M., Ninot, J. M. & Vigo, J. (1996): A survey on the vegetation of Cephalonia (Ionian islands). Ð Phytocoenologia 26: 81Ð123. Bonis, A., Lepart, J. & Laloé, F. (1996): Effet de la température sur l’installation et la croissance des plantes annuelles de marais temporaires méditerranéens. Ð Can. J. Bot. 74: 1086Ð1094. Borhidi, A. (1996a): Phytogeography and Vegetation Ecology of Cuba. Ð 923 p., Budapest.

672

U. Deil

Ð (1996b): An annotated checklist of the Hungarian plant communities. I. The nonforest vegetation. Ð In: Borhidi, A. (ed.): Critical revision of the Hungarian Plant Communities: 43Ð94. Pécs. Ð (2003): Magyarország növénytársulásai. (= Plant communities of Hungary). Ð 610 p., Budapest. Borhidi, A., Muñiz, O. & Del Risco, E. (1979): Clasificación fitocenológica de la vegetación de Cuba. Ð Acta Bot. Hung. 25: 263Ð301. Ð Ð Ð (1983): Plant communities of Cuba. I. Fresh and saltwater, swamp and coastal vegetation. Ð Acta Bot. Hung. 29: 337Ð376. Borysiak, J. & Stachnowicz, W. (2000): Vegetation in relation to fluvial mesoforms: The River Warta case study. Ð Perspectives Environ. Sci. 1: 7Ð13. Brackel, W. von, Franke, T., Messlinger, U. & Subal, W. (1990): Seltene Zwergbinsen in Franken. Ð Ber. Bayer. Bot. Ges. 61: 217Ð227. Braun-Blanquet, J. (1935): Un joyau floristique et phytosociologique Ð “L’Isoetion” méditerranéen. Ð Bull. Soc. Etude Sci. Nat. Nı̂mes 47: 1Ð23. Ð (1964): Pflanzensoziologie, Grundzüge der Vegetationskunde. Ð 3. ed., 865 p., Berlin, Wien, New York. Ð (1967): Vegetationsskizzen aus dem Baskenland, mit Ausblicken auf das weitere IberoAtlantikum. II. Ð Vegetatio 14: 1Ð126. Braun-Blanquet, J. & Moor, M. (1935): Über das Nanocyperion in Graubünden und Oberitalien. Ð Jahrb. Naturforsch. Ges. Graubünden 73: 25Ð35. Braun-Blanquet, J. & Tüxen, R. (1952): Irische Pflanzengesellschaften. Ð In: Lüdi, W. (ed.): Die Pflanzenwelt Irlands = Veröff. Geobot. Inst. Eidg. Tech. Hochsch. Stift. Rübel 25: 224Ð415. Braun-Blanquet, J., Roussine, N. & Nègre, R. (1952): Les groupements végétaux de la France méditerranéenne. Ð 298 p., Montpellier. Breen, C. M. (1991): Are intermittently flooded wetlands in arid environments important conservation sites? Ð Madoqua 17: 61Ð65. Breen, C. M., Heeg, J. & Seaman, M. (1993): Wetlands of Africa Ð South Africa. Ð In: Whigham, D. F., Dykyjová, D. & Hejný, S. (eds): Wetlands of the world. I. Inventory, ecology, and management: 79Ð110. Dordrecht. Bremer, K. (2002): Gondwanan evolution of the grass alliance of families (Poales). Ð Evolution 56: 1374Ð1387. Brendonck, L. & Riddoch, B. (1999): Wind-borne short-range egg dispersal in anostracans (Crustacea: Branchipoda). Ð Biol. J. Linn. Soc. 67: 87Ð95. Brock, M. A. (1998): Are temporary wetlands resilient? Evidence from seed banks of Australian and South African wetlands. Ð In: McComb, A. J. & Davis, J. A. (eds.): Wetlands for the Future: 193Ð206. Adelaide. Brock, M. A. & Casanova, M. T. (1997): Plant life at the edges of wetlands: ecological response to wetting and drying patterns. Ð In: Klomp, N. & Lunt, I. (eds.): Frontiers in Ecology: Building the Links: 181Ð192. Oxford. Brock, M. A. & Rogers, K. A. (1998): The regeneration potential of the seed bank of an ephemeral floodplain in South Africa. Ð Aquatic Bot. 61: 123Ð135. Brose, U. (2001): Relative importance of isolation, area, and habitat heterogeneity for vascular plant species richness of temporary wetlands in East-German farmland. Ð Ecography 24: 722Ð730. Brower, E., Backx, H. & Roelofs, J. G. M. (2001): Nutrient requirements of ephemeral plant species from wet, mesotrophic soils. Ð J. Veg. Sci. 12: 319Ð326. Bruggen, H. W. E. van (1985): Monograph of the genus Aponogeton. Ð 76 p., Stuttgart. Brullo, S. & Di Martino, A. (1974): Vegetazione dell’ Isola Grande dello Stagnone (Marsala). Ð Boll. Ist. Bot. Giard. Col. Palermo 26: 15Ð62.

Habitats, plant traits and vegetation of ephemeral wetlands

673

Brullo, S. & Furnari, F. (1994): La vegetazione del Gebel el-Akhdar (Cirenaica settentrionale). Ð Boll. Acc. Gioenia Sci. Nat. 27: 197Ð412. Brullo, S. & Grillo, M. (1978): Ricerche fitosociologiche sui pascoli dei Monti Nebrodi (Sicilia settentrionale). Ð Not. Fitosoc. 13: 23Ð61. Brullo, S. & Marcenò, C. (1974): La vegetazione estiva dei baccini artificiali siciliani. Ð Lavori Istituto Bot. Giardino Palermo 25: 184Ð194. Brullo, S. & Minissale, P. (1998): Considerazioni sintassonomiche sulla classe Isoeto-Nanojuncetea. Ð Itinera Geobotanica 11: 263Ð290. Brullo, S., Grillo, M. & Terrasi, M. C. (1976): Ricerche fitosociologiche sui pascoli di Monte Lauro (Sicilia meridionale). Ð Boll. Acc. Gioenia Sci. Nat. 12: 84Ð104. Brullo, S., Di Martino, A. & Marcenò, C. (1977): La vegetazione di Pantelleria. Studio fitosociologico. Ð 110 p., Catania. Brullo, S., Scelsi, F. & Siracusa, G. (1994): Contributo alla conoscenza della vegetazione terofitica della Sicilia occidentale. Ð Boll. Acc. Gioenia Sci. Nat. 27: 341Ð365. Büdel, B., Lüttge, U., Stelzer, R., Huber, O. & Medina, E. (1994): Cyanobacteria of rocks and soils of the Orinoco lowlands and the Guyana Uplands, Venezuela. Ð Bot. Acta 107: 422Ð431. Burbanck, M. P. & Phillips, D. L. (1983): Evidence of Plant Succession on Granite Outcrops of the Georgia Piedmont. Ð Am. Mid. Nat. 109(1): 94Ð104. Burbanck, M. P. & Platt, R. B. (1964): Granite outcrops communities of the piedmont plateau in Georgia. Ð Ecology 45: 292Ð306. Bussell, J. D. & James, S. H. (1997): Rocks as museums of evolutionary processes. Ð J. Roy. Soc. W. Austr. 80: 221Ð229. Bywater, M. & Wickens, G. E. (1984): New World Species of the Genus Crassula. Ð Kew Bull. 39: 699Ð728. Cabido, M. & Acosta, A. (1986): Variabilidad florı́stica a lo largo de un gradiente de degradación en céspedes de la Pampa de Achala, Sierras de Córdoba, Argentina. Ð Doc. Phytosociol. N. S. 10(2): 289Ð304. Cabido, M., Acosta, A. & Dı́az, S. (1990): The vascular flora and vegetation of granitic outcrops in the upper Cordoba mountains, Argentina. Ð Phytocoenologia 19: 267Ð 281. Callaghan, D. A. (1998): Lythrum hyssopifolium L. Ð J. Ecol. 86: 1065Ð1072. Camarda, I., Lucchese, F., Pignatti, E. & Pignatti, S. (1995): La vegetazione dell’area Pantaleo-Gutturu Mannu-Punta Maxia-Monte Arcosu nel Sulcis-Iglesiente (Sardegna sudoccidentale). Ð Webbia 49: 141Ð177. Campbell, B., Gubb, A. & Moll, É. (1980): The vegetation of the Edith Stephens Cape Flats Flora Reserve. Ð J. S. Afr. Bot 46: 435Ð444. Casanova, M. T. & Brock, M. A. (2000): How do depth, duration, and frequency of flooding influence the establishment of wetland plant communities? Ð Plant Ecol. 147: 237Ð 250. Casper, S. J. & Krausch, H. D. (1980): Pteridophyta und Anthophyta. I. Lycopodiaceae bis Orchidaceae. Ð In: Ettl, H., Gerloff, J. & Heynig, H. (eds.): Süsswasserflora von Mitteleuropa 23: 403 p., Jena. Ð Ð (1981): Pteridophyta und Anthophyta. II. Saururaceae bis Asteraceae. Ð In: Ettl, H., Gerloff, J. & Heynig, H. (eds.): Süsswasserflora von Mitteleuropa 24: 942 p., Jena. Castroviejo, S. & López, G. (1985): Estudio y descripción de la comunidades vegetales del “Hato El Frio”. Los Llanos de Venezuela. Ð Mem. Soc. Ci. Nat. La Salle 45(124): 79Ð151. Catarino, L., Duarte, M. C. & Moreira, I. (2002a): Vegetação da lagoa de Cufada (GuinéBissau): uma aproximação fitossociológica. Ð Quercetea 3: 127Ð140.

674

U. Deil

Catarino, L., Martius, E. S. & Diniz, M. A. (2002b): Vegetation structure and ecology of the Cufada Lagoon (Guinea-Bissau). Ð Afr. J. Ecol. 40: 252Ð259. Cesca, G. & Peruzzi, L. (2001): Isoetes (Lycophytina, Isoetaceae) with terrestrial habitat in Calabria (Italy). New karyological and taxonomical data. Ð Flora Medit. 11: 303Ð 309. Champeau, A. & Thiéry, A. (1990): Les Crustacés Entomostracés des eaux stagnantes de Corse. Ð Bull. Soc. Zool. Fr. 115: 55Ð75. Chang, H. J. & Hsu, K. S. (1977): Isoetes taiwanensis DeVol and its associates. Ð Q. J. J. Chinese For. 10(2): 138Ð142. Chevassut, G. & Quézel, P. (1956): Contribution à l’ étude des groupements végétaux de mares temporaires à Isoetes velata et de dépressions humides à Isoetes histrix en Afrique du Nord. Ð Bull. Soc. Hist. Nat. Afr. Nord 47: 59Ð73. Ð Ð (1958): L’ association à Damasonium polyspermum et Ranunculus batrachioides. Ð Bull. Soc. Hist. Nat. Afr. Nord 49: 204Ð210. Chytry, M. & Tichy, L. (2003): Diagnostic, constant, and dominant species of vegetation classes and alliances of the Czech Republic: a statistical revision. Ð Folia Fac. Sci. Nat. Univ. Masaryk. Brun., Biol. 108: 1Ð231. Cilliers, S. S. & Bredenkamp, G. J. (2003): Vegetation of inland endorheic pans in the North-West Province, South Africa. Ð Phytocoenologia. 33: 289Ð308. Cirujano, S. (1981): Las lagunas manchegas y su vegetación. II. Ð An. Jardı́n Bot. Madrid 38: 187Ð232. Clausnitzer, D. & Huddleston, J. H. (2002): Wetland determination of a southeast Oregon vernal pool and management implications. Ð Wetlands 22: 677Ð685. Cleef, A. M. (1981): The Vegetation of the Páramos of the Colombian Cordillera Oriental. Ð Diss. Botan. 61: 321 p., Vaduz. Cleef, A. M. & da Silva, M. F. F. (1994): Plant communities of the Serra dos Carajás (Pará), Brazil. Ð Bol. Mus. Para. Emilio Goeldi, sér. Bot. 10(2): 269Ð281. Clément, B. & Bouzille, J. B. (1996): La végétation des bords du lac de Grand-Lieu. Ð Bull. Soc. Bot. Centre-Ouest, N. S. 27: 503Ð512. Coan, A. I. & Scatena, V. L. (2004): Embryology and seed development of Blastocaulon scirpeum and Paepalanthus scleranthus (Eriocaulaceae). Ð Flora 199: 47Ð57. Coates, F., Walsh, N. G. & James, E. A. (2002): Threats to the survival of the Grampians pincushion lily (Borya mirabilis, Liliaceae): A short-range endemic from western Victoria. Ð Austr. Syst. Bot. 15: 477Ð483. Cockayne, L. (1958): The vegetation of New Zealand. Ð 456 p., London, Weinheim. Coldea, C. (ed.)(1997): Les associations végétales de Roumanie. I. Les associations herbacées naturelles. Ð 261 p., Cluj. Collinson, N. H., Biggs, J., Corfield, A., Hodson, M. J., Walker, D., Withfield, M. & Williams, P. J. (1995): Temporary and permanent ponds: an assessment of the effects of drying out on the conservation value of aquatic macroinvertebrate communities. Ð Biol. Conserv. 74: 125Ð133. Conn, B. I. (1983): Aquatic and semi-aquatic flora of the Purari River system. Ð In: Petr, T. (ed.): The Purari Ð tropical environment of a high rainfall river basin: 283Ð293. The Hague. Contreras, D., Verdugo, M., San Martı́n, J. & Ramı́rez, C. (1991): Flora y vegetación de las praderas húmedas de Chivilcán (Cautı́n, Chile). Ð Actas II Congreso Intern. Gestión en Recursos Naturales Valdivia 2: 438Ð455. Cook, C. D. K. (1990): Aquatic Plant Book. Ð 228 p., Den Haag. Ð (1999): The number and kinds of embryo-bearing plants which have become aquatic: a survey. Ð Perspectives Plant Ecol. Evol. Syst. 2(1): 79Ð102.

Habitats, plant traits and vegetation of ephemeral wetlands

675

Ð (2004): Aquatic and wetland plants of Southern Africa. Ð 282 p., Leiden. Corley, M. F. V. & Crundwell, A. C. (1991): Additions and amendments to the mosses of Europe and the Azores. Ð J. Bryol. 16: 337Ð356. Corley, M. F. V., Crundwell, A. C., Düll, R., Hill, M. O. & Smith, A. J. E. (1981): Mosses of Europe and the Azores: an annotated list of species, with synonyms from the recent literature. Ð J. Bryol. 11: 609Ð689. Cortini Pedrotti, C. (1992): Le briofite quale componente strutturale e funzionale degli ecosistemi forestali. Ð Ann. Accad. Ital. Sci. For. 41: 163Ð190. Cortini Pedrotti, C. & Aleffi, M. (1990): Associazioni di briofite e di alghi dei Laghi di Idro e Terlago (Italia settentrionale). Ð Doc. Phytosociol. N. S. 12: 265Ð272. Costa, J. C., Capelo, J., Jardim, R., Sequeira, M., Lousã, M., Espı́rito-Santo, M. D. & Rivas-Martı́nez, S. (2003): A vegetacão da Madeira. VII. A classe Molinio-Arrhenatheretea Tüxen 1937 e Isoeto-Nanojuncetea Br.-Bl. & Tüxen 1937 ex Westhoff, Dijk & Passchier. Ð Silva Lusitana 11: 251Ð256. Cowardin, L. M., Carter, V., Golet, F. C. & LaRoe, E. T. (1979): Classification of wetlands and deepwater habitats of the United States. Ð US Fish Wildl. Serv. FWS/OBS 79/31, 131 p., Washington, D. C. Cox, G. W. (1984): Soil transport by pocket gophers in mima mounds and vernal pools microterrain. Ð In: Jain, S. K. & Moyle, P. (eds.): Vernal pools and intermittent streams: 37Ð45. Davis. Crampton, B. (1954): Morphological and ecological considerations in the classification of Navarretia. Ð Madroño 12: 225Ð239. Ð (1959): The grass genera Orcuttia and Neostapfia: A study in habitat and morphological specialization. Ð Madroño 15: 97Ð110. Croft, J. R. (1980): A taxonomic revision of Isoetes L. (Isoetaceae) in Papuasia. Ð Blumea 26: 177Ð190. Crowe, E. A., Busaca, A. J., Reganold, J. P. & Zamora, B. A. (1994): Vegetation zones and soil characteristics in vernal pools in the channelled scabland of Eastern Washington. Ð Great Basin Nat. 54: 234Ð247. Cruden, R. W. (1966): Birds as agents of long-distance dispersal, for disjunct plant groups of the temperate western hemisphere. Ð Evolution 20: 517Ð532. Darwin, C. (1859): On the origin of species by means of natural selection. Ð London. Daumas, P., Quézel, P. & Santa, S. (1952): Deux nouvelles stations algériennes de Pilularia minuta DR. Ð Bull. Soc. Hist. Nat. Afr. Nord 43: 65Ð68. Debazac, E. F. (1959): La végétation forestiere de la Kroumerie. Ð Ann. Ecol. Nat. Eaux Forêts 16(2): 1Ð133. Deil, U. (1997): Zur geobotanischen Kennzeichnung von Kulturlandschaften. Vergleichende Untersuchungen in Südspanien und Nordmarokko. Ð Erdwissen. Forschung 36: 189p., Stuttgart. Ð (1999): Synvikarianz und Symphylogenie Ð Zur Evolution von Pflanzengesellschaften. Ð Ber. d. Reinh.-Tüxen-Ges. 11: 223Ð244. Hannover. Deil, U. & Müller-Hohenstein, K. (1985): Beiträge zur Vegetation des Jemen. I. Pflanzengesellschaften und Ökotopgefüge der Gebirgstihamah am Beispiel des Beckens von At Tur (J. A. R.). Ð Phytocoenologia 13: 1Ð102. Deil, U., Bogenrieder, A., & Bergmeier, E. (eds.)(1999): Im Zwergengarten der Botanik. Ökologische und populationsbiologische Forschungen zu Isoeto-Nanojuncetea- und Isoeto-Littorelletea-Arten und -Gesellschaften. Ergebnisse des 1. Freiburger Geobotanischen Kolloquiums. Ð Mitt. Bad. Landesver. Naturkd. Naturschutz Freib. i. Br. N. F. 17(2): 219Ð507. Del Monte, J. P. & Aguado, P. L. (2003): Survey of the non-native plant species in the Spanish Iberia in the period 1975Ð2002. Ð Flora Medit. 13: 241Ð259.

676

U. Deil

Den Hartog, D. & Segal, S. (1964): A new classification of the water-plant communities. Ð Acta Bot. Neerl. 13: 367Ð393. Desfayes, M. (2004): List of Isoetes species. http://web.odu.edu/webroot/instr/sci/ plant.nsf/pages/bibliography. Accessed 23 March 2005. Destombes, J. & Jeannette, A. (1966): Mémoire explicatif de la carte géologique de la méséta côtière à l’est de Casablanca au 1/50000, région de Mohammedia, Bouznika et Benslimane. Ð Notes Mém. Serv. géol. Maroc: 180(2): 1Ð104. Devillers-Terschuren, J. & Devillers, P. (2001): Application and development of the Palaearctic habitat classification in the course of the setting up of the Emerald Project Ð Iceland. Ð T-PVS/Emerald 8: 82 p., Strassburg. De Vol, C. E. (1972): Isoetes found in Taiwan. Ð Taiwania 17: 1Ð7. Dı́az, T. E. (1976): La vegetación del litoral occidental Asturiano. Ð Rev. Fac. Ciens. Univ. Oviedo 16: 369Ð545. Diels, L. (1906): Die Pflanzenwelt von West-Australien südlich des Wendekreises mit einer Einleitung über die Pflanzenwelt Gesamt-Australiens in Grundzügen. Ð Die Vegetation der Erde 7: 413 p., Leipzig. Dienst, M., Strang, I. & Peintinger, M. (2004): Entdeckung und Verlust botanischer Raritäten am Bodenseeufer Ð das Leiner-Herbar und die Strandrasen. Ð Ber. Bot. Arbeitsgem. Südwestdeutschland, Beiheft 1: 209Ð230. Dierssen, K. (1996): Vegetation Nordeuropas. Ð 840 p., Stuttgart. Ð (2001): Distribution, ecological amplitude, and phytosociological characterization of European bryophytes. Ð Bryo. Bibl. 56: 289 p., Berlin, Stuttgart. Dörrstock, S., Porembski, S. & Barthlott, W. (1996): Ephemeral flush vegetation on inselbergs in the Ivory Coast (West Africa). Ð Candollea 51: 407Ð419. Doing, H. (1994): Nanocyperion in Australie? Ð Stratiotes 9: 108Ð112. Duivenvoorden, J. F. & Cleef, A. M. (1994): Amazonian savanna vegetation on the sandstone plateau near Araracuara, Colombia. Ð Phytocoenologia 24: 197Ð232. During, H. J. (1980): Life forms and life strategies in Nanocyperion communities from the Netherlands Frisian islands. Ð Acta Bot. Neerl. 29: 483Ð496. Ð (1994): Oecologische indicatiewaarde van mossen in Nanocyperion-gemeenschappen. Ð Stratiotes 9: 39Ð51. Duvigneaud, P. & Symoens, J. J. (1951): Contribution à l’étude des associations tourbeuses du Bas-Congo. Le Rhynchosporetum candidae de l’étang de Kibambi. Ð Trav. Ass. Int. Limnol. théor. et appl. 11: 100Ð104. Eckhardt, H. C., van Rooyen, N. & Bredenkamp, G. J. (1996): Plant communities and species richness of the Agrostis lachnantha-Eragrostis plana wetlands of northern Kwa Zulu Ð Natal. Ð S. Afr. J. Bot. 62: 306Ð315. Eggeling, W. J. (1935): The vegetation of Namanve swamp, Uganda. Ð J. Ecol. 23: 422Ð435. Eig, A. (1946): Synopsis of the Phytosociological Units of Palestine. Ð Palest. J. Bot., Jerusalem Ser. 3: 183Ð246. Elam, D. R. (1998): Population Genetics of Vernal Pool Plants: Theory, Data and Conservation Implications. Ð In: Witham, C. W., Belk, D., Ferren, W. R. & Ornduff, R. (eds.): Ecology, Conservation, and Management of Vernal Pool Ecosystems: 180Ð189. Sacramento. Ellenbroek, G. A. (1987): Ecology and productivity of an African wetland system. The Kafue Flats, Zambia. Ð Geobotany 9: 276p., Dordrecht. Eskuche, K. (1975): Análisis corológico y sistemático del Lindernio-Mecardonietum herniarioidis. Ð Phytocoenologia 2: 261Ð269. Eskuche, U. (1986): Bericht über die 17. Internationale Pflanzengeographische Exkursion durch Nordargentinien. Ð Contribuciones al conocimiento da flora y vegetación del norte de la Argentina = Veröff. Geobot. Inst. Eidg. Tech. Hochsch. Stift. Rü. 91: 12Ð177.

Habitats, plant traits and vegetation of ephemeral wetlands

677

Espı́rito-Santo, D. & Arsénio, P. (2005): Influence of landuse on the composition of plant communities from seasonal pond ecosystems in the Guadiana Valley National Park (Portugal). Ð Phytocoenologia 35: 267Ð281. EUR-OP, Office des publications officielles des Communautés européennes (ed.)(1992): Directive 92/43/CEE du Conseil du 21 mai 1992 concernant la conservation des habitats naturels ainsi que de la faune et de la flore sauvages. Ð JOCE L 206,7: 44 p., Bruxelles. Ferren Jr., W. R., Hubbard, D. M., Wiseman, S., Parikh, A. K. & Gale, N. (1998): Review of Ten Years of Vernal Pool Restoration and Creation in Santa Barbara, California. Ð In: Witham, C. W., Belk, D., Ferren, W. R. & Ornduff, R. (eds.): Ecology, Conservation, and Management of Vernal Pool Ecosystems: 206Ð216. Sacramento. Fiedler, P. L. (ed.)(2001): Vernal pools and related wetland ecosystems of California, Southwestern Oregon, and Northern Baja California, Mexico. Bibliography. Ð 105 p., San Francisco. Figuerola, J. & Green, A. J. (2002): How frequent is external transport of seeds and invertebrate eggs by waterbirds? A study in Doñana, SW Spain. Ð Archiv Hydrobiol. 155: 557Ð565. Figuerola, J., Green, A. J. & Santamaria, L. (2003): Passive internal transport of aquatic organisms by waterfowl in Doñana, South-west Spain. Ð Global Ecology and Biogeography Letters 12: 427Ð436. Filipello, S. & Sartori, F. (1981): La vegetazione dell’Isola di Montecristo (Archipelago Tuscano). Ð Atti Ist. Bot. Univ. Pavia, Ser. 6 14: 113Ð202. Finlayson, M. C. & Van der Valk, A. G. (eds.) (1995): Classification and inventory of the world’s wetlands. Ð Proceedings of a symposium held in Columbia, Ohio, in Sept. 1992, during the IV International Wetlands Conference. Vegetatio 118 = Reprint from Adv. Veg. Sci. 16: 192p., Dordrecht. Fischer, E. (1992): Systematik der afrikanischen Lindernieae (Scrophulariaceae). Ð Trop. Subtrop. Pflanzenwelt 81: 1Ð365. Ð (1996): Die Vegetation des Parc National de Kahnzi-Biéga, Süd-Kivu, Zaire. Ð Erdwissen. Forschung 35: 99p., Stuttgart. Ð (1997): A revision of the genus Dopatrium (Scrophulariaceae-Gratiolioideae). Ð Nordic J. Bot. 17: 527Ð555. Fischer, E. & Theisen, I. (2000): Vegetation of Malagasy Inselbergs. Ð In: Porembski, S. & Barthlott, W. (eds.): Inselbergs: 259Ð276. Berlin, Heidelberg. Foggi, B. & Grigioni, A. (1999): Contributo alla conoscenza della vegetazione dell l’Isola di Capraia (Arcipelago Toscano). Ð Parlatorea 3: 5Ð33. Fontana, J. L. (1991): Las comunidades vegetales de una laguna chaqueña del valle del rı́o Parana. Ð Fol. Bot. Geobot. Correntesiana 6: 1Ð17. Foucault de, B. (1978): Premieres observations phytosociologiques sur le marais de SaintLouis-Marie-Galante (Guadeloupe). Ð Doc. Phytosociol. N. S. 2: 181Ð189. Ð (1983): Nouvelles observations phytosociologiques sur la végétation aquatique et subaquatique à la Guadeloupe (Antilles françaises): De la végétation phanérogamique marine aux bombement à sphaignes culminaux. Ð In: Gehu, J. M. (ed.): Les végétations aquatiques et amphibies = Coll. Phytosoc. 10: 255Ð278. Vaduz. Ð (1988): Les végétations herbacées basses amphibies: systématique, structuralisme, synsystematique. Ð Diss. Botan. 121: 150 p., Berlin, Stuttgart. Franceschi, E. A. & Lewis, J. P. (1991): Early stages in the Paraná river tall grasland recovery after an extraordinary flood. Ð Coenoses 6: 47Ð52. Franceschi, E. A., Torres, D. S., Prado, D. E. & Lewis, J. P. (2000): Disturbance, succession and stability: a ten year study of temporal variation of species composition after a catastrophic flood in the river Paraná, Argentina. Ð Community Ecology 1: 205Ð214.

678

U. Deil

Franke, T. (1987): Pflanzengesellschaften der fränkischen Teichlandschaft. Ð Ber. Naturforsch. Ges. Bamberg 61(2): 1Ð192. Fredskild, B. (1998): The vegetation types of Northeast Greenland. A phytosociological study based mainly on material left by Th. Sørensen from the 1931Ð35 expeditions. Ð Meddr. Grønland, Biosci. 49: 1Ð84. Copenhagen. Friedrich, H. C. (1979): Vorarbeiten zu einer Monographie der Gattung Crassula. III. Die hydrophilen Sippen in Süd- und Ostafrika. Ð Mitt. Bot. Staatssammlung München 15: 577Ð598. Fuchs, G., Grauvogel-Stamm, L. & Mader, D. (1991): Une remarquable flore à Pleuromeia et Anomopteris in situ du Buntsandstein Moyen (Trias inférior) de l’Eifel (R. F. D. Allemagne), morphologie, paléoécologie et paléogéographie. Ð Palaeontographica B 222: 89Ð120. Furness, H. D. & Breen, C. M. (1980): The vegetation of seasonally flooded areas of the Pongolo river floodplain. Ð Bothalia 13: 217Ð231. Gacia, E. & Ballesteros E. (1993): Diel acid fluctuations in pyrenean Isoetes species: The effects of seasonality and emersion. Ð Archiv Hydrobiol. 128: 187Ð196. Gaff, D. F. (1977): Desiccation tolerant vascular plants of southern Africa. Ð Oecologia 31: 95Ð109. Gaff, D. F. & Giess, W. (1986): Drought resistance in water plants in rock pools of Southern Africa. Ð Dinteria 18: 17Ð36. Galán de Mera, A. (1995): Ensayo sintaxonómico sobre las comunidades vegetales acuáticas de Perú. Ð Arnaldoa 3(1): 51Ð58. Galán de Mera, A., Rosa, V. M. & Cáceres, C. (2002): Una aproximación sintaxonómica sobre la vegetación del Perú. Clases, órdenes y alianzas. Ð Acta Bot. Malacitana 27: 75Ð103. Galán de Mera, A., Cáceres, C. & González, A. (2003): La vegetación de la alta montaña andina del Sur del Perú. Ð Acta Bot. Malacitana 28: 121Ð147. Galiano, E. F. (1957): Quelques associations de la classe des Littorelletea dans la province de Québec. Ð Contrib. Inst. Bot. Univ. Montréal 70: 107Ð118. Gamisans, J. (1976): La végétation des montagnes corses. I. Ð Phytocoenologia 3: 425Ð498. Gamisans, J., Moret, J., Fridlender, A., Deschatres, R. & Dutartre, G. (1996): Le Naufraga balearica est-il eteint en Corse? Etude du site originel, recherche de stations comparables, possibilités de reintroduction. Ð Candollea 51: 552Ð557. Garcı́a Rı́o, R. & Navarro, F. (1994): Flora y vegetación cormofı́ticas de las comarcas zamoranas del Pan, Tera y Carballeda. Ð Stud. Bot. 12: 23Ð202. Gasc, J. P., Sarthou, C., Garrouste, R., Villiers, J. F., Cremers, G. & Thiollay, J. M. (1998): Inselbergs et savannes-roches en Guyane: biodiversité et conservation des milieux associés aux affleurements granitique. Ð JATBA, Revue d’Ethnobiologie 40: 311Ð327. Géhu, J. M. (1975): Synécologie de Lilaeopsis attenuata (Hooker et Arnott.) Fernald dans l’extreme nord-ouest de l’Espagne. Ð Anal. Inst. Bot. Cavanilles 32: 993Ð1004. Ð (1992): Réflexions sur les fondements syntaxonomiques, néçessaires à une synthèse des végétations à l’échelle du continent européen et esquisse d’une synsystème dans l’optique de la phytosociologie Braun-Blanqueto-Tuxennienne ébauche de synsystème pour la France. Ð Ann. Bot. (Roma) 50: 131Ð151. Géhu, J. M. & Géhu-Franck, J. (1985): La mégaphorbiaie à Sanguisorba canadensis, élément remarquable de la zonation végétale soumise aux marées d’eau douce des berges du fleuve St.-Laurent (Québec, Canada). Ð Coll. Phytosociol. 12: 161Ð173. Géhu, J. M., Kaabeche, M. & Gharzouli, R. (1994): Phytosociologie et typologie des habitats des rives des lacs de la région de El Kala (Algérie). Ð Coll. Phytosoc. 22: 297Ð329. Gerhardt, F. & Collinge, S. K. (2003): Exotic plant invasions of vernal pools in the central valley of California, USA. Ð J. Biogeogr. 30: 1043Ð1052.

Habitats, plant traits and vegetation of ephemeral wetlands

679

Germain, R. (1952): Les associations végétales de la plaine de la Ruzizi (Congo Belge) en relation avec le milieu. Ð Pub. I. N. É. A. C., Sér. Sci. 52: 321 p., Bruxelles. Gill, D. (1974): Influence of water fowl on the distribution of Beckmania syzigachne in the Mackenzie River Delta, Northwest Territories. Ð J. Biogeogr. 1: 63Ð69. Gledhill, D. (1970): The vegetation of superficial ironstone hardpans in Sierra Leone. Ð J. Ecol. 58: 265Ð274. Gómez-Mercado, F. & Valle, F. (1992): Pastizales higrófilos en el sector Subbético. Ð Stud. Bot. 10: 39Ð52. Granville, J. J. de (2002): Milieux et formations vegetales de Guyane. Ð Acta Bot. Gallica 149: 319Ð337. Grauvogel-Stamm, L. (1993): Pleuromeia sternbergii (Münster) Corda from the Lower Triassic of Germany: Further observations and comparative morphology of its rooting organ. Ð Rev. Palaeobot. Palynol. 77: 185Ð212. Grauvogel-Stamm, L. & Lugardon, B. (2001): The Triassic lycopsids Pleuromeia and Annalepis: Relationships, evolution, and origin. Ð Amer. Fern J. 91(3): 115Ð149. Green, A. J., Figuerola, J. & Sánchez, M. I. (2002): Implications of waterbird ecology for dispersal of aquatic organisms. Ð Acta Oecol., Oecol. Gen. 23: 177Ð189. Gremmen, N. J. M. (1981): The vegetation of the subantarctic islands Marion and Prince Edward. Ð Geobotany 3: 149 p., Den Haag. Griggs, F. T. (1984): A strategy for the conservation of the genus Orcuttia. Ð In: Jain, S. K. & Moyle, P. (eds.): Vernal pools and intermittent streams: 255Ð262. Davis. Griggs, F. T. & Jain, S. K. (1983): Conservation of vernal pool plants in California. II. Population biology of a rare and unique grass genus (Orcuttia). Ð Biol. Conserv. 27: 171Ð193. Grillas, P. & Tan Ham, L. (1998): Dynamique intra- et inter-annuelle de la végétation dans les mares de la Réserve Naturelle de Roque-Haute: programme d’étude et résultats préliminaires. Ð Ecol. Medit. 24: 215Ð222. Grillas, P., Gauthier, P., Yavercovski, N. & Perennou, C. (eds.)(2004a): Mediterranean temporary pools. I. Issues relating to conservation, functioning, and management. Ð 119 p., Arles. Ð Ð Ð Ð (eds.)(2004b): Mediterranean temporary pools. II. Species information sheets. Ð 128 p., Arles. Gröger, A. (2000): Flora and Vegetation of Inselbergs of Venezuelan Guayana. Ð In: Porembski, S. & Barthlott, W. (eds.): Inselbergs: 291Ð314. Berlin, Heidelberg. Grolle, R. & Long, D. G. (2000): An annotated check-list of the Hepaticae and Anthocerotae of Europe and Macaronesia. Ð J. Bryol. 22: 103Ð140. Guidicelli, J. & Thiéry, A. (1998): La faune des mares temporaires, son originalité et son intérêt pour la biodiversité des eaux continentales méditerranéennes. Ð Ecol. Medit. 24: 135Ð143. Guinko, S. (1984): La Végétation de la Haute-Volta. Ð Thèse Doct., Univ. Bordeaux III, 394 p., Bordeaux. Gutte, P. (1980): Beitrag zur Kenntnis zentralperuanischer Pflanzengesellschaften. II. Die hochandinen Moore und ihre Kontaktgesellschaften. Ð Feddes Rep. 91: 327Ð336. Ð (1986): Beitrag zur Kenntnis zentralperuanischer Pflanzengesellschaften. III. Pflanzengesellschaften der subalpinen Stufe. Ð Feddes Rep. 97: 319Ð371. Ð (1988): Zu einigen Wasserpflanzen- und Röhrichtgesellschaften in den Hochanden Zentralperus. Ð Catalogus herbarii Lipsiensis, Plant. Neotrop. 1: 48 p., Leipzig. Guyot, M., Roussel, B., Akpagana, K. & Edorh, T. (1994): La végétation des zones inondées du sud du Togo et son état actuel sous l’emprise humaine. Ð Biogeographica 70(4): 161Ð182.

680

U. Deil

Haacks, M. (2003): Die Küstenvegetation von Neuseeland. Ð Mitt. Geogr. Hamburg 95: 269 p., Hamburg. Haacks, M. & Thannheiser, D. (2000): Studien zur Küstenvegetation Tasmaniens. Ð 17. Jahrestagung des AK Geographie der Meere und Küsten, Bremer Beitr. Geogr. Raumplan. 36: 45Ð56. Ð Ð (2003): Vergleich der Pflanzengesellschaften der Salzmarschen Neuseelands und Tasmaniens. Ð Essener Geogr. Arbeiten 35: 65Ð75. Haase, R. (1989): Plant communities of a savanna in northern Bolivia. I. Seasonally flooded grassland and gallery forest. Ð Phytocoenologia 18: 55Ð81. Ð (1990): Plant communities of a savanna in northern Bolivia. II. Palm swamps, dry grassland, and shrubland. Ð Phytocoenologia 18: 343Ð370. Hadač, E. (1971): The vegetation of springs, lakes, and “flags” of Reykjanes Peninsula, SW Iceland (Plant communities of Reykjanes Peninsula, Part 3). Ð Folia Geobot. Phytotax. 6: 29Ð41. Ð (1985): Plant communities of the Kaldidalur area, WSW Iceland. I. Syntaxonomy. Ð Folia Geobot. Phytotax. 20: 113Ð175. Hall, J. B. (1971): Observations on Isoetes in Ghana. Ð Bot. J. Linn. Soc. 64: 117Ð139. Halliday, G. & Beadle, M. (1983): Consolidated Index to Flora Europaea. Ð 210 p., Cambridge. Hambler, D. J. (1964): The vegetation of granitic outcrops in western Nigeria. Ð J. Ecol. 52: 573Ð594. Hanes, T. & Stromberg, L. (1998): Hydrology of vernal pools on non-volcanic soils in the Sacramento valley. Ð In: Witham, C. W., Belk, D., Ferren, W. R. & Ornduff, R. (eds.): Ecology, Conservation, and Management of Vernal Pool Ecosystems: 38Ð49. Sacramento. Hansen, O. I. (1975): The genus Rhamphicarpa Benth. emend. Engl. (Scrophulariaceae). A taxonomic revision. Ð Bot. Tidsskrift 70: 103Ð125. Hanski, I. (1982): Dynamics of regional distribution: the core and satellite species hypothesis. Ð Oikos 31: 210Ð221. Ð (1991): Single-species metapopulation dynamics: concepts, models and observations. Ð Biol. J. Linn. Soc. 42: 17Ð38. Haukos, D. A. & Smith, L. M. (1993): Seed-bank composition and predictive ability of field vegetation in playa lakes. Ð Wetlands 13: 32Ð40. Ð Ð (1994a): The importance of playa wetlands to biodiversity of the Southern High Plains. Ð Landscape and Urban Planning 28: 83Ð98. Ð Ð (1994b): Composition of seed banks along an elevation gradient in playa wetlands. Ð Wetlands 14: 301Ð307. Heckmann, C. W. (1998): The Pantanal of Poconé: biota and ecology in the northern section of the world’s largest pristine wetland. Ð Monogr. Biol. 77: 622 p., Dordrecht. Hedberg, O. (1964): Features of Afroalpine Plant Ecology. Ð Acta Phytogeogr. Suecica 49: 1Ð144. Heenan, P. B. (1997): Selliera rotundifolia (Goodeniaceae), a new, round-leaved species from New Zealand. Ð New Zealand J. Bot. 35: 133Ð138. Heilmeier, H., Durka, W., Woitke, M. & Hartung, W. (2005): Ephemeral pools as stressful and isolated habitats for the endemic aquatic ressurrection plant Chamaegigas intrepidus. Ð Phytocoenologia 35: 449Ð468. Heise, K. L. & Merenlender A. M. (1999): Flora of a vernal pool complex in the Mayacmas Mountains of southeastern Mendocino County, California. Ð Madroño 46: 38Ð45. Hejný, S. (1957): Ein Beitrag zur ökologischen Gliederung der Makrophyten der tschechoslowakischen Niederungs-Gewässer. Ð Preslia 29: 349Ð368.

Habitats, plant traits and vegetation of ephemeral wetlands

681

Ð (1962): Über die Bedeutung der Schwankungen des Wasserspiegels für die Charakteristik der Makrophytengesellschaften in den mitteleuropäischen Gewässern. Ð Preslia 34: 359Ð367. Ð (1971): The dynamic characteristics of littoral vegetation with respect to changes of water level. Ð Hidrobiologia 12: 71Ð86. Ð (1995): Isoeto-Nanojuncetea. Ð In: Moravec, J. et al. (eds.): Rostlinna spolenast na Ceske repulbliky a jejich ohrozeni, 2. ed. Supl. 1: 37Ð39. Hejný, S. & Husák, S. (1978): Higher plant communities. Ð Ecol. Studies 28: 23Ð64 and 93Ð95. Berlin. Heyligers, P. C. (1963): Vegetation and soil of a white-sand savanna in Suriname. Ð The vegetation of Suriname 3: 148 p., Amsterdam. = Verh. Kon. Ned. Akad. Wet., Ser.2, 54(3) = Meded. Bot. Mus. Herb. Utrecht 191. Hickey, R. J. (1986): The early evolutionary and morphological diversity of Isoetes, with description of two new Neotropical species. Ð Syst. Bot. 11: 309Ð321. Ð (1997): The genus Isoetes in the New World: An overview. Ð Am. J. Bot. 84(6, suppl.): 1Ð162. Hilbig, W. (1987): Pflanzengesellschaften der Mongolischen Volksrepublik. Ð Univ. Halle, Dissert. B 239 p. text + 202 p. tab., Halle. Ð (1995): The vegetation of Mongolia. Ð 258 p., Amsterdam. Ð (2000): Kommentierte Übersicht über die Pflanzengesellschaften und ihre höheren Syntaxa in der Mongolei. Ð Feddes Rep. 111: 75Ð120. Hilbig, W. & Schamsran, Z. (1981): Zwergbinsengesellschaften in der Mongolei. Ð Feddes Rep. 92: 557Ð561. Hilton, J. L. & Boyd, R. S. (1996): Microhabitat requirements and seed/microsite limitation of the rare granite outcrop endemic Amphianthus pusillus (Scrophulariaceae). Ð Bull. Torrey Bot. Club 123: 189Ð196. Hines, C. J. H. (1990/93): Temporary wetlands in Bushmanland and Kavango, northeast Namibia. Ð Madoqua 18(2): 57Ð69. Hoagland, B. W. & Collins, S. L. (1997): Heterogeneity of shortgrass prairie vegetation: the role of playa lakes. Ð J. Veg. Sci. 8: 277Ð286. Hobohm, C. & Petersen, J. (1999): Zur Artenvielfalt von Zwergbinsengesellschaften. Ð Mitt. Bad. Landesver. Naturkd. Naturschutz Freib. i. Br. 17(2): 303Ð308. Hobohm, C., Hennekens, S. M. & Schaminée, J. H. J. (2003): Zur Artenvielfalt der Pflanzengesellschaften in den Niederlanden. Ð Tuexenia 23: 51Ð56. Hobson, W. A. & Dahlgren, R. A. (1998): Soil forming processes in vernal pools of Northern California, Chico area. Ð In: Witham, C. W., Belk, D., Ferren, W. R. & Ornduff, R. (eds.): Ecology, Conservation, and Management of Vernal Pool Ecosystems: 24Ð37. Sacramento. Hoff, M. & Brisse, H. (1983): Proposition d’un schema synthétique des végétations secondaires intertropicales. Ð Coll. Phytosociol. 12: 249Ð267. Ð Ð (1990): Contribution à l’étude des groupements végétaux des Iles Wallis et Futuna. Ð Doc. Phytosociol. N. S. 12: 19Ð76. Hogeweg, P. & Brenkert, A. L. (1969): Structure of aquatic vegetation: comparison of aquatic vegetation in India, the Netherlands and Czechoslovakia. Ð Tropical Ecology 10: 139Ð162. Hohensee, C. D. & Frey, W. (2001): Experiments on the epizoochoral dispersal by mallards (Anas platyrhinchos). Ð Bot. Jahrb. Syst. 123: 209Ð216. Holland, R. F. (1986): Preliminary description of the terrestrial natural communities of California. State of California. Ð 186 p., Sacramento, CA. Ð (1998): Great Valley Vernal Pool Distribution, Photorevised 1996. Ð In: Witham,

682

U. Deil

C. W., Belk, D., Ferren, W. R. & Ornduff, R. (eds.): Ecology, Conservation, and Management of Vernal Pool Ecosystems: 71Ð75. Sacramento. Holland, R. F. & Jain, S. K. (1977/88): Vernal pools. Ð In: Barbour, M. G. & Major, J. (eds.): Terrestrial Vegetation of California: 515Ð533. Sacramento. Ð Ð (1981/84): Spatial and temporal variation in plant species diversity of vernal pools. Ð In: Jain, S. K. & Moyle, P. (eds.): Vernal pools and intermittent streams: 198Ð209. Davis. Hoock, J. (1971): Les savannes guyanaises: Kourou. Essai de phytoécologie numérique. Ð Mém. ORSTOM 44: 251 p., Paris. Hopper, S. D. (2000a): Creation of conservation reserves and managing fire on granite outcrops Ð a case study of Chiddar cooping Nature Reserve in the western Autralian wheatbelt. Ð J. Roy. Soc. W. Austr. 83: 173Ð186. Ð (2000b): Floristics of Australian Granitoid Inselberg Vegetation. Ð In: Porembski, S. & Barthlott, W. (eds.): Inselbergs: 391Ð407. Berlin, Heidelberg. Hopper, S. D., Brown, A. P. & Marchant, N. G. (1997): Plants of Western Australian granite outcrops. Ð J. Roy. Soc. W. Austr. 80(3): 141Ð158. Horvatic, S. (1954): Fimbristylion dichotomae Ð ein neuer Verband der Isoetetalia. Ð Vegetatio 5Ð6: 448Ð453. Houle, G. & Phillips, D. L. (1988): The soil seed bank of granite outcrop plant communities. Ð Oikos 52: 87Ð93. Ð Ð (1989a): Seed availability and biotic interactions in Granite outcrop plant communities. Ð Ecology 70: 1307Ð1316. Ð Ð (1989b): Seasonal variation and annual fluctuation in granite outcrop plant communities. Ð Vegetatio 80: 25Ð35. Howard, G. W. (1985): The Kafue Flats of Zambia Ð a wetland ecosystem comparable with floodplain areas of northern Australia. Ð Proc. Ecol. Soc. Aust. 13: 293Ð306. Hübschmann, A. v. (1986): Prodromus der Moosgesellschaften Zentraleuropas. Ð Bryo. Bibl. 32: 414 p., Berlin, Stuttgart. Hultén, E. (1958): The amphiatlantic plants and their phytogeographical connections. Ð 340 p., Stockholm. Ð (1971): The circumpolar plants. II. Dicotyledons. Ð 463 p., Stockholm. Hunter, J. T. & Clarke, P. J. (1998): The vegetation of granitic outcrop communities on the New England Bartholith of eastern Australia. Ð Cunninghamia 5: 547Ð618. Ibisch, P. L., Rauer, G., Rudolph, D. & Barthlott, W. (1995): Floristic, biogeographical, and vegetational aspects of Pre-Cambrian rock outcrops (inselbergs) in eastern Bolivia. Ð Flora 190: 299Ð314. Ikeda, D. H. & Schlising, R. A. (eds.)(1990): Vernal pool plants: their habitat and biology. Ð Studies Herbarium 8: 179 p., Chico. Iltis, A. & Lemoalle, J. (1983): The aquatic vegetation of Lake Chad. Ð In: Carmouze, J.-P., Durand, J.-R. & Lévêque, C. (eds.): Lake Chad: Ecology and productivity of a shallow tropical ecosystem = Monogr. Biol. 53: 125Ð143. The Hague. Isichei, A. O. & Longe, P. A. (1984): Seasonal succession in a small isolated rock dome plant community in western Nigeria. Ð Oikos 43: 17Ð22. Ivimey-Cook, R. B. & Proctor, M. C. F. (1966): The plant communities of the Burren, Co. Clare. Ð Proc. Royal Irish Acad., Sect. B 64: 211Ð301. Jacobs, S. W. L. & Brock, M. A. (1993): Wetlands of Australia: Southern (Temperate) Australia. Ð In: Whigham, D. F., Dykyjová, D. & Hejný, S. (eds.): Wetlands of the World. I. Inventory, Ecology, and Management: 244Ð305. Dordrecht. Jacobs, S. W. L. & Lapinpuro, L. (1986): The Australasian species of Amphibromus (Poaceae). Ð Telopea 2(6): 715Ð729.

Habitats, plant traits and vegetation of ephemeral wetlands

683

Jäger-Zürn, I. (1998): Anatomy of the Hydrostachyaceae. Ð In: Landolt, E., Jäger-Zürn, I. & Schnell, R. A.: Extreme adaptations in angiospermous hydrophytes = Handbuch der Pflanzenanatomie 13(4): 129Ð196. Berlin. Jain, S. K. (ed.)(1976): Vernal pools, their ecology and conservation. Ð Inst. Ecol. Pub. 9: 93 p., Davis. Jain, S. K. & Moyle, P. (eds.)(1981/84): Vernal pools and intermittent streams. Ð A symposium sponsored by the Institute of Ecology, Univ. of California, May-1981, Inst. Ecol.Pub. 28: 280 p., Davis. Jansen, A. J. M., Fresco, L. F. M., Grootjans, A. P. & Jalink, M. H. (2004): Effects of restoration measures on plant communities of wet heathland ecosystems. Ð Appl. Veg. Sci. 7: 243Ð252. Jansen, J. & Sequeira, M. (1999): The vegetation of shallow waters and seasonally inundated habitats (Littorelletea and Isoeto-Nanojuncetea) in the higher parts of the Serra da Estrela, Portugal. Ð Mitt. Bad. Landesver. Naturkd. Naturschutz Freib. i. Br. 17(2): 449Ð462. Janssen, A. (1986): Flora und Vegetation der Savannen von Humaitá und ihre Standortbedingungen. Ð Diss. Botan. 93: 321 p., Berlin. Jasprica, N. & Caric, M. (2002): Vegetation of the natural park of Hutovo, Blato (Neretva river delta, Bosnia and Herzegovina). Ð Biologia 57: 505Ð516. Jermy, A. C. (1990): Isoetaceae. Ð In: Kubitzki, K. (ed.): The families and genera of vascular plants 1: 26Ð31. Berlin. Johnson, E. R. I. (1984): Taxonomic revision of Isoetes L. in western Australia. Ð J. Roy. Soc. W. Austr. 67: 28Ð43. Johnson, P. N. & Brooke, P. A. (1989): Wetland plants in New Zealand. Ð 319 p.,Wellington. Johnson, P. N. & Rogers, G. M. (2003): Ephemeral wetlands and their turfs in New Zealand. Ð Sci. Conserv. 230: 109 p., Wellington. Julve, P. (1993): Synopsis phytosociologique de la France (Communautés de plantes vasculaires). Ð Lejeunia, N. S. 140: 160 p., Liège. Junk, W. J. & Piedade, M. T. F. (1993): Herbaceous plants of the Amazon floodplain near Manaus: Species diversity and adaptations to the flood pulse. Ð Amazoniana 7: 467Ð484. Ð Ð (1997): Plant life in the floodplain with special reference to herbaceous plants. Ð In: Junk, W. J. (ed.): The Central Amazon Floodplain: Ecology of a pulsing system: 147Ð 185. Berlin. Jurik, T. N., Wang, S. C. & van der Valk A. G. (1994): Effects of sediment load on seedling emergence from wetland seed banks. Ð Wetlands 14: 159Ð165. Kammer, P. M. (1997): Räumliche, zeitliche und witterungsbedingte Variabilität eines Trespen-Halbtrockenrasens (Mesobromion) im Schweizer Mittelland. Ein Beitrag zur Methodik der Dauerflächenbeobachtung. Ð Diss. Botan. 272: 255 p., Berlin, Stuttgart. Karrfalt, E. E. (1984): The origin and early development of the root-producing meristem of Isoetes andicola L. D. Gómez. Ð Bot. Gazette 145: 372Ð377. Ð (1999): Some observations on the reproductive anatomy of Isoetes andicola. Ð Am. Fern J. 89(3): 198Ð203. Käsermann, C. (1999): Anagallis minima. Ð Merkblätter Artenschutz: 44Ð45. Birmensdorf. Kautsky, L. (1988): Life strategies of aquatic soft-bottom macrophytes. Ð Oikos 53: 126Ð 135. Keeley, J. E. (1988): Anaerobiosis as a stimulus to germination in two vernal pool grasses. Ð Am. J. Bot. 75: 1086Ð1089. Ð (1996): Aquatic CAM photosynthesis. Ð In: Winter, K. & Smith, J. A. C. (eds.): Crassulacean Acid Metabolism: biochemistry, ecophysiology and evolution. = Ecological Studies 114: 281Ð295. Berlin.

684

U. Deil

Ð (1998a): CAM photosynthesis in submerged aquatic plants. Ð Bot. Rev. 64: 121Ð175. Ð (1998b): C4 photosnthetic modifications in the evolutionary transition from land to water in aquatic grasses. Ð Oecologia 116: 85Ð97. Ð (1999): Photosynthetic pathway diversity in a seasonal pool community. Ð Funct. Ecol. 13(1): 106Ð118. Keeley, J. E. & Rundel, P. W. (2003): Evolution of CAM and C4 carbon concentrating mechanisms. Ð Int. J. Plant Sci. 164 (3 suppl.): 555Ð577. Keeley, J. E. & Zedler, P. H. (1998): Characterization and Global Distribution of Vernal Pools. Ð In: Witham, C. W., Belk, D., Ferren, W. R. & Ornduff, R. (eds.): Ecology, Conservation, and Management of Vernal Pool Ecosystems: 1Ð14. Sacramento. Keeley, J. E., De Mason, D. A., González, R. & Markham, K. R. (1994): Sediment-based carbon nutrition in tropical alpine Isoetes. Ð In: Rundel, P. N., Smith, A. P. & Meinzer, F. C. (eds.): Tropical Alpine Environments. Plant Form and Function: 167Ð194. Cambridge. Kellogg, E. A. & Linder, H. P. (1995): Phylogeny of Poales. Ð In: Rudall, P. J., Cribb, P. J., Cutler, D. F. & Humphries, C. J. (eds.): Monocotyledons: systematics and evolution 2: 511Ð542. Kiesslich, M., Dengler, J. & Berg, C. (2003): Die Gesellschaften der Bidentetea tripartitae Tx. et al. ex von Rochow 1951 in Mecklenburg-Vorpommern mit Anmerkungen zur Synsystematik und Nomenklatur der Klasse. Ð Feddes Rep. 114: 91Ð139. King, J. L. (1998): Loss of Diversity as a Consequence of Habitat Destruction in California Vernal Pools. Ð In: Witham, C. W., Belk, D., Ferren, W. R. & Ornduff, R. (eds.): Ecology, Conservation, and Management of Vernal Pool Ecosystems: 119Ð123. Sacramento. Kirkman, L. K., Goebel, P. C., West, L.T, Drew, M. B., & Palik, B. J. (1998): Depressional wetland vegetation types: a question of plant community development. Ð Wetlands 20(2): 373Ð385. Kirkpatrick, J. B. (1975): Phytosociological analysis of the vegetation at Lagoon Beach, Tasmania. Ð Pap. Proc. R. Soc. Tasm. 109: 53Ð63. Kirkpatrick, J. B. & Harwood, C. E. (1983): Plant communities of Tasmanian wetlands. Ð Australian J. Bot. 31: 437Ð451. Kirschner, J. & Orchard, A. E. (eds.)(2002a): Juncaceae. I. Rostkovia to Luzula. Ð Species Plantarum, Flora of the World 6: 237 p., Canberra. Ð Ð (eds.)(2002b): Juncaceae. II. Juncus subgen. Juncus. Ð Species Plantarum, Flora of the World 7: 336 p., Canberra. Kirschner, J., Novara, L. J., Novikov, V. S., Snogerup, S. & Kaplan, Z. (1999): Supraspecific division of the genus Juncus (Juncaceae). Ð Folia Geobot. Phytotax. 34: 377Ð390. Kirschner, J., Orchard, A. E. & Wilson, A. J. G. (eds.)(2002): Juncaceae. III. Juncus subgen. Agathyron. Ð Species Plantarum, Flora of the World 8: 192 p., Canberra. Klika, J. (1935): Die Pflanzengesellschaften des entblössten Teichbodens in Mitteleuropa. Ð Beih. Bot. Centralbl. 53: 283Ð310. Klotz, S. & Köck, U. V. (1984): Vergleichende geobotanische Untersuchungen in der Baschkirischen ASSR. III. Wasserpflanzen-, Flussufer- und Halophytenvegetation. Ð Feddes Rep. 95(5Ð6): 381Ð408. Knapp, R. (1957): Über die Gliederung der Vegetation in Nord-Amerika. Höhere Vegetationseinheiten. Ð Geobot. Mitt. 4(3): 63 p., Giessen. Ð (1965): Die Vegetation von Nord- und Mittelamerika und der Hawaii-Inseln. Ð 373 p., Stuttgart. Ð (1966): Höhere Vegetations-Einheiten von West-Afrika unter besonderer Berücksichtigung von Nigeria und Kamerun. Ð Geobot. Mitt. 34: 15 p., Giessen.

Habitats, plant traits and vegetation of ephemeral wetlands

685

Ð (1968): Höhere Vegetationseinheiten von Äthiopien, Somalia, Natal, Transvaal, Kapland und einigen Nachbargebieten. Ð Geobot. Mitt. 56: 36 p., Giessen. Koch, W. (1926): Die Vegetationseinheiten der Linthebene unter Berücksichtigung der Verhältnisse in der Nordostschweiz. Systematisch-kritische Studie. Ð Jahrb. St.-Gall. Nat. Ges. 61: 1Ð144. Ð (1934): Cyperus michelianus (L.) Link und Lindernia pyxidaria L. am Luganer See bei Agno als Charakterarten der Eleocharis ovata-Assoziation. Ð Ber. Schweiz. Bot. Ges. 43(2): 182Ð190. Ð (1954): Pflanzensoziologische Skizzen aus den Reisfeldgebieten des Piemont (PoEbene). Ð Vegetatio 5Ð6: 487Ð493. König, P. & Rilke, S. (2004): Vegetation pattern within a thermokarst landscape in the central Altay Mountains (West Siberia). Ð Feddes Rep. 115: 574Ð584. Kooij, M. S., Scheepers, J. C., Bredenkamp, G. J. & Theron, G. K. (1991): The vegetation of the Kroonstad area, Orange Free State. I. Vlei and bottomland communities. Ð S. Afr. J. Bot. 57: 213Ð219. Kopecko, K. J. P. & Lathrop, E. W. (1975): Vegetation zonation in a vernal marsh on the Santa Rosa Plateau of Riverside County, California. Ð Aliso 8: 281Ð288. Kornas, J. (1988): Adaptive strategies of Marsilea (Marsileaceae: Pteridophyta) in the lake Chad basin of N. E.Nigeria. Ð Fern Gazette 13(4): 231Ð243. Korotkov, K. O., Morozova, O. V. & Belonovskaja, E. A. (1991): The USSR vegetation syntaxa prodromus. Ð 346 p., Moscow. Kramer, K. U. & Van Donselaar, J. (1968): A sketch of the vegetation and flora of the Kappel savanna near Tafelberg, Suriname. I. Ð Proc. Kon. Ned. Akad. Wet. Amsterdam, Ser. C 71: 495Ð524. Krause, W., Ludwig, W. & Seidel, F. (1963): Zur Kenntnis der Flora und Vegetation auf Serpentinstandorten des Balkans. VI. Vegetationsstudien in der Umgebung von Mantoudi (Euböa). Ð Bot. Jahrb. Syst. 82: 337Ð403. Krieger, A., Porembski, S. & Barthlott, W. (2000): Vegetation of seasonal rock pools on inselbergs situated in the savanna zone of the Ivory Coast (West Africa). Ð Flora 195: 257Ð266. Ð Ð Ð (2003): Temporal dynamics of an ephemeral plant community: species turnover in seasonal rock pools on Ivorian inselbergs. Ð Plant Ecol. 167: 283Ð292. Kürschner, H. (2003): The Riccietum jovet-astii-argenteolimbatae ass. nov. of the Jabal Arays area, Yemen Ð life strategies of a remarkable xerotropical African bryophyte community. Ð Nova Hedwigia 76: 399Ð413. Ð (2004): Phytosociological studies in the Alashan Gobi. Ð A contribution to the flora and vegetation of Inner Mongolia (NW-China). Ð Phytocoenologia 34: 169Ð224. Kürschner, H. & Parolly, G. (1999): On the occurrence of Isoetes histrix in the Menderes Massif of western Turkey Ð a synecological study and the first record of an Isoetion community for Turkey. Ð Bot. Jahrb. Syst. 121: 423Ð451. Lake, P. S., Bayly, I. A. E. & Morton, D. W. (1989): The phenology of a temporary pond in Western Victoria, Australia, with special reference to invertebrate succession. Ð Arch. Hydrobiol. 115(2): 171Ð202. Lampe von, M. (1996): Wuchsform, Wuchsrhythmus und Verbreitung der Arten der Zwergbinsengesellschaften. Ð Diss. Botan. 266: 353 p., Berlin, Stuttgart. Landolt, E., Jäger-Zürn, I., Schnell, R. A. (1998): Extreme Adaptations in Angiospermous Hydrophytes. Ð Handbuch der Pflanzenanatomie 13(4): 290 p., Berlin, Stuttgart. Lathrop, E. W. & Thorne, R. F. (1983): A flora of the vernal pools on the Santa Rosa Plateau, Riverside County, California. Ð Aliso 10: 449Ð469. Lavania, G. S., Paliwal, S. C. & Gopal, B. (1990): Aquatic vegetation of the Indian subcontinent. Ð In: Gopal, B. (ed.): Ecology and management of aquatic vegetation of the Indian subcontinent: 29Ð76. Dordrecht.

686

U. Deil

Lawalrée, A. (1969): La dissémination des plantes par les oiseau (Ornithochorie). Ð Natura Mosana 22(4): 153Ð164. Le Dantec, C., Suc, J. P., Suballyova, D. & Vernet, J. L. (1998): Évolution floristique des abords de la mare de Grammont (Montpellier, sud de la France) depuis un siècle: disparition d’Isoetes setacea Lam. Ð Ecol. Medit. 24: 159Ð170. Le Page, C. & Keddy, P.A (1998): Reserves of buried seeds in beaver ponds. Ð Wetlands 18: 242Ð248. Lebrun, J. P. (1947): La végétation de la plaine alluviale au sud du lac Édouard. Ð Expl. Parc. Nat. Albert 1: 1Ð367. Lebrun, J. P. & Stork, A. L. (1991Ð1997): Énumération des plantes à fleurs d’ Afrique tropicale. Ð IÐIV. Genève. Leistner, O. A. (1967): The plant ecology of the southern Kalahari. Ð Mem. Bot. Surv. S. Afr. 38: 1Ð172. Lejoly, J. & Lisowski, S. (1999): Novitates Guineae Aequinoctialis. V. Premier aperçu sur la végétation des Inselbergs au Rio Muni. Ð Bull. Jard. Bot. Nat. Belg. 67: 114Ð121. Ð Ð (2000): La végétation des clairières sur sol hydromorphe dans le Parc National d’Odzala (Congo-Brazzaville). Ð Coll. Phytosoc. 27: 371Ð382. Lemaire, A. J. J., Schaminée, J. H. J. & Weeda, E. J. (1998): Isoeto-Nanojuncetea. Ð In: Schaminée, J. H. J., Weeda, E. J. & Westhoff, V. (eds.): De vegetatie van Nederland 4: 147Ð172. Uppsala. Léonard, J. (1950): Botanique du Congo belge. I. Les Groupements végétaux. Ð Encyclopédie du Congo belge 1: 345Ð389. Bruxelles. Ð (1951): Aperçu préliminaire des groupements végétaux pionniers dans la région de Yangambi (Congo Belge). Ð Vegetatio 3: 279Ð297. Ð (1996): Marsilea nubica A. Braun au Cameroun. Ð Bull. Jard. Bot. Nat. Belg. 65: 421Ð 422. Ð (2001): Flore et végétation du Jebel Uweinat (Désert de Libye: Libye, Egypte, Sudan). VI. Étude de la végétation. Analyse phytosociologique et phytochorologique des groupements végétaux. Ð Scripta Botanica Belgica 21: 139 p., Meise. Leredde, C. (1954): Note préliminaire sur les formations hygrophiles au Tassili-N’Ajjer. Ð Bull. Soc. Hist. Nat. Toulouse 89: 19Ð26. Lewis, J. P., Franceschi, E. A. & Prado, D. E. (1987): Effects of extraordinary floods on the dynamics of tall grasland of the river Paraná valley. Ð Phytocoenologia 15: 235Ð251. Lewis, J. P., Collantes, M. B., Pire, E. F., Carnevale, N. J., Boccanelli, S. I., Stofella, S. L. & Prado, D. E. (1995): Floristic groups and plant communities of southeastern Santa Fe, Argentina. Ð Vegetatio 60: 67Ð90. Lindeque, M. & Archibald, T. J. (1990/91): Seasonal wetlands in Owambo and Etosha National Park. Ð Madoqua 17: 129Ð133. Linhart, Y. B. (1988): Intrapopulation differentiation in annual plants. III. The contrasting effects of intra- and interspecific competition. Ð Evolution 42: 1047Ð1064. Llorens, L. (1979): Notes sobre l’Isoetion en Mallorca. Ð Collect. Bot. 11: 241Ð249. Loidi, J., Biurrun, I. & Herrera, M. (1997): La vegetación del centro-septentrional de España. Ð Itinera Geobotanica 9: 161Ð618. Loisel, R., Médail, F. & Quézel, P. (1994): Syntaxonomie, habitats et intérêt patrimoniale de la plaine des Maures (sud-est continental français). Ð Coll. Phytosoc. 22: 555Ð564. Looman, J. (1982): The vegetation of the Canadian Prairie Provinces. III. Aquatic and semi-aquatic vegetation Part 2. Freshwater marshes and bogs. Ð Phytocoenologia 10: 401Ð423. Lorenzoni, C. & Paradis, G. (1997): Description phytosociologique d’une mare temporaire à Elatine brochonii dans le sud de la Corse. Ð Bull. Soc. Bot. Centre-Ouest, N. S. 28: 21Ð46.

Habitats, plant traits and vegetation of ephemeral wetlands

687

Ð Ð (1998): Description phytosociologique de la station corse d’Eryngium pusillum. Ð Bull. Soc. Bot. Centre-Ouest, N. S. 29: 7Ð32. Ð Ð (2000): Phytosociologie de mares temporaires méditerranéennes: les Tre Padule et la Padule Maggiore (Suartone, commune de Bonifacio, Corse). Ð Coll. Phytosoc. 27: 571Ð593. Lucchese, F. & Pignatti, S. (1990): Squardo sulla vegetazione del Lazio marittimo. Ð Acc. Naz. Lincei Quad. 264: 5Ð48. Luebert, F. & Gajardo, R. (2005): Vegetación alto andina del Parinacota, norte de Chile y una sinopsis de la vegetación de la Puna meridional. Ð Phytocoenologia 35: 79Ð128. Lüpnitz, D. (1975): Geobotanische Studien zur natürlichen Vegetation der Azoren unter Berücksichtigung der Chorologie innerhalb Makaronesiens. Ð Beitr. Biol. Pflanzen 51: 149Ð319. Maarel, E. van der (1988): Vegetation dynamics: patterns in time and space. Ð Vegetatio 77: 7Ð19. Madsen, T. V., Olesen, B. & Bagger, J. (2002): Carbon acquisition and carbon dynamics by aquatic isoetids. Ð Aquatic Botany 73: 351Ð371. Mäckel, R. (1974): Dambos: A study in morphodynamic activity on the plateau regions of Zambia. Ð Catena 1: 327Ð365. Malcuit, G. (1962): L’ Isoetion en Corse. Ð Ann. Fac. Sci. Marseille 33: 87Ð102. Mandango, A. & Ndjele, M. (1986): Végétation aquatique et semi-aquatique de l’Ile Kongolo à Kisangani (Zaire). Ð Bull. Soc. Roy. Bot. Belg. 119: 63Ð73. Mandango, M. A. (1988): Associations nouvelles des iles du fleuve, dans le Haut-Zaire. Ð Am. Mus. Roy. Afr. Centrale Tervuren Sér. In 8 Ð Sci. Econ. 17: 279Ð291. Manz, E. (1997): Vegetation ehemals militärisch genutzter Übungsplätze und Flugplätze und deren Bedeutung für den Naturschutz. Ð Tuexenia 17: 173Ð192. Marcenò, C. & Raimondo, F. M. (1977): Osservazioni su alcuni aspetti di vegetazione lacustre nella Sicilia centrale. Ð Giorn. Bot. Italiano 111: 13Ð26. Marcenò, C. & Trapani, S. (1978): L’ Isoetetum duriei Bory nell ’Piana dei Greci’ (Sicilia Occidentale). Ð Atti Accad. Sci. Lettr. Arti Palermo Ser. 4 (1975/76) 35(1): 395Ð399. Martin, B. D. & Lathrop, E. W. (1986): Niche partitioning in Downingia bella and D. cuspidata (Campanulaceae) in the vernal pools of the Santa Rosa Plateau Preserve, California. Ð Madroño 4: 284Ð299. Martı́nez, M. L., Moreno-Casasola, P. & Vásquez, G. (1997): Effects of disturbance by sand movement and inundation by water on tropical dune vegetation dynamics. Ð Can. J. Bot. 75: 2005Ð2014. Martı́nez Parras, J. M., Peinado, M., Bartolomé, C. & Molero, J. (1988): Algunas comunidades vegetales higrófilas e higronitrófilas estivo-autumnales de la provincia de Granada. Ð Acta Bot. Barc. 37: 271Ð279. Masens, D. M. (2000): La prairie aquatique à Salvinia nymphellula et Limnophila ceratophylloides dans la région de Kikwit (Bandundu, Rép. Dém. Congo). Ð Coll. Phytosoc. 27: 429Ð442. Matthews, J. F. & Murdy, W. H. (1969): A study of Isoetes common to the granite outcrops of the southeastern Piedmont, United States. Ð Bot. Gazette 130: 53Ð61. Matus, G., Verhagen, R., Bekker, R. M. & Grootjans, A. P. (2003): Restoration of the Cirsio dissecti-Molinietum in The Netherlands: Can we rely on soil seed banks? Ð Appl. Veg. Sci. 6: 73Ð84. Mawson, P. R. (2000): Conservation of native fauna inhabiting granite outcrops: How do you manage it? Ð J. Roy. Soc. W. Austr. 83: 163Ð167. McLachlan, A. J. & Cantrell, M. A. (1980): Survival strategies in tropical rain pools. Ð Oecologia 47: 344Ð351.

688

U. Deil

McVaugh, R. (1943): The vegetation of the granite flatrocks of the southeastern United States. Ð Ecol. Monograph 13: 119Ð166. Médail, F. (2004): Plant species. Ð In: Grillas, P., Gauthier, P., Yavercovski, N. & Perennou, C. (eds.): Mediterranean Temporary Pools. I. Issues relating to conservation, functioning and management: 18Ð24. Arles. Médail, F., Michaud, H., Molina, J. & Loisel, R. (1996): Biodiversité et conservation des phytocénoses des mares temporaires dulçaquicoles et oligotrophes de France méditerranéenne. Ð 7ème Rencontres de l’ARPE, Digne-les-Bains, Coll.Bio’Mes: 47Ð57. Médail, F., Michaud, H., Molina, J., Paradis, G. & Loisel, R. (1998): Conservation de la flore et de la végétation des mares temporaires dulçaquicoles et oligotrophes de France méditerranéenne. Ð Ecol. Medit. 24: 119Ð134. Meirelles, S. T., Pivello, V. R. & Joly, C. A. (1999): The vegetation of granite rock outcrops in Rio de Janeiro, Brazil, and the need for its protection. Ð Environ. Conserv. 26: 10Ð20. Melendo, M. & Cano, E. (1997): La clase Isoeto-Nanojuncetea en el noreste de la provincia de Córdoba (Sierra Morena, España). Ð Monogr. Fl. Veg. Béticas 10: 127Ð142. Melendo, M., Cano, E. & Valle, F. (1996): Aportaciones al conocimiento de los pastizales mediterraneo-iberoatlánticos (Sierra Morena, España). Ð Ecol. Medit. 22: 25Ð37. Meng, F. S. (1998): Studies on Annalepis from Middle Triassic along the Yangtze River and its bearing on the origin of Isoetes. Ð Acta Bot. Sinica 40: 768Ð774. Metge, G. (1986): Étude des écosystèmes hydromorphes (daja et merdja) de la Meseta occidentale marocaine. Ð Thèse Doct. Fac. Sci., 280 p., Marseille. Meusel, H. & Jäger, E. J. (1992): Vergleichende Chorologie der zentraleuropäischen Flora. III. Ð 333 p., Jena. Meusel, H., Jäger, E. J. & Weinert, E. (1965): Vergleichende Chorologie der zentraleuropäischen Flora. I. Ð 583 p., Jena. Meusel, H., Jäger, E. J., Rauschert, S. & Weinert, E. (1978): Vergleichende Chorologie der zentraleuropäischen Flora. II. Ð 418 p., Jena. Milberg, P. & Stridh, B. (1994): Seed bank of annual mudflat species at lake Vikarsjön, central Sweden. Ð Svensk Bot. Tidskr. 88: 237Ð240. Minissale, P. & Spampinato, G. (1987): Osservazioni fitosociologiche sul “Lago Gurrida” (Sicilia nord-orientale). Ð Giorn. Bot. Italiano 119: 197Ð225. Miyawaki, A. (1960): Pflanzensoziologische Untersuchungen über Reisfeld-Vegetation auf den japanischen Inseln mit vergleichender Betrachtung Mitteleuropas. Ð Vegetatio 9: 345Ð402. Miyawaki, A. & Okuda, S. (1972): Pflanzensoziologische Untersuchungen über die Auenvegetation des Flusses Tama bei Tokyo, mit einer vergleichenden Betrachtung über die Vegetation des Flusses Tone. Ð Vegetatio 24: 229Ð311. Mörsdorf, S. W. (1989): Vegetationskundliche Untersuchungen in Breidafjördur. Ð Ber. Forschst. Nedr. As. 51: 1Ð78. Molero, J. (1984): Contribució al coneixement fitocenològic dels Catalànids Centrals (Serra de Prades i Montsant): comunitats noves e poc conegudes. Ð Bull. Inst. Cat. Hist. Nat. 51: 139Ð160. Molero, J. & Romo, M. (1988): Vegetación higronitrófila de los embalses del curso superior del Segre y de la Noguera Pallaresa (Prepirineos centrales). Ð Acta Bot. Barc. 37: 289Ð296. Molesworth, A. B. (1975): A note on the distribution of Isoetes in the Cadiz province, Spain. Ð Brit. Fern Gaz. 11: 163Ð164. Molina, J. A. (2005): The vegetation of temporary ponds with Isoetes on the Iberian Peninsula. Ð Phytocoenologia 35: 219Ð230. Molina, J. A. & Casado Álvaro, R. (1997): Datos sobre la vegetación anfibia de la Penı́nsula Ibérica. II. Ð Boll. Soc. Brot., sér 2 68: 89Ð100.

Habitats, plant traits and vegetation of ephemeral wetlands

689

Molina, J. A. & Pertiñez, C. (2000): Variabilidad de las comunidades de Eryngium corniculatum en la Penı́nsula Ibérica. Ð Anales Biol. 22 (Biol. vegetal 11)(1997): 117Ð124. Molinier, R. (1937): Les Iles d’Hyères. Etude phytosociologique. Ð Ann. Soc. Hist. Nat. Toulon 21: 91Ð129. Molinier, R. & Tallon, G. (1948): L’ Isoetion en Costière nimoise. Ð Bull. Soc. Bot. Fr. 95: 343Ð353. Ð Ð (1949/50): La végétation de la Crau (Basse Provence). Ð Rev. Gén. Bot. 56: 525Ð540. Molnár, Z. & Borhidi, A. (2003): Hungarian alkali vegetation: origins, landscape history, syntaxonomy, conservation. Ð Phytocoenologia 33: 377Ð408. Moor, M. (1936): Zur Soziologie der Isoetetalia. Ð Beitr. Geobot. Landesaufn. Schweiz 20: 148 p., Bern Ð (1937): Ordnung der Isoetetalia (Zwergbinsengesellschaften). Ð Prodromus der Pflanzengesellschaften 4: 24 p., Leiden Ð (1958): Pflanzengesellschaften schweizerischer Flussauen. Ð Mitt. Schweiz. Anst. Forstl. Versuchswes. 34: 221Ð360. Moore, D. R. J. & Keddy, P. A. (1988): Effects of a water-depth gradient on the germination of lake shore plants. Ð Can. J. Bot. 66: 548Ð552. Moran, R. (1984): Vernal pools in Northwest Baja California, Mexico. Ð In: Jain, S. K. & Moyle, P. (eds.): Vernal pools and intermittent streams: 173Ð184. Davis. Morat, P. (1973): Les savanes du sud-ouest de Madagascar. Ð Mém. ORSTOM 68: 1Ð 235. Muasya, A. M. & Simpson, D. A. (2002): A monograph of the genus Isolepis R.Br. (Cyperaceae). Ð Kew Bull. 57: 257Ð362. Mucina, L. (1993): Puccinellio-Salicornietea. Ð In: Mucina, L., Grabherr, G. & Ellmauer, T. (eds.): Die Pflanzengesellschaften Österreichs. I. Anthropogene Vegetation: 522Ð 549. Jena. Ð (1997): Conspectus of classes of European vegetation. Ð Folia Geobot. Phytotax. 32: 117Ð172. Mucina, L., Janssen, J. A. M. & O’Callaghan, M. (2003): Syntaxonomy and zonation patterns in coastal salt marshes of the Uikraals Estuary, Western Cape (South Africa). Ð Phytocoenologia 33: 309Ð334. Müller, G. K. & Gutte, P. (1985): Beiträge zur Kenntnis der Vegetation der Flussauen, Sümpfe und Gewässer der zentralperuanischen Küstenregion. Ð Wiss. Z. Univ. Leipzig, Math.-Nat. Reihe 34(4): 410Ð429. Müller, J. (1996): Experimentelle Sukzessionsforschung zum Schutz seltener Zwergbinsengesellschaften in Norddeutschland. Ð Abh. Naturwiss. Verein Bremen 43(2): 289Ð 308. Müller, J. & Rosenthal, G. (1998): Brachesukzessionen Ð Prozesse und Mechanismen. Ð Ber. Inst. Landschafts- und Pflanzenökol. Univ. Hohenheim, Beih. 5: 103Ð132. Müller, J. V. (2003): Zur Vegetationsökologie der Savannenlandschaften im Sahel Burkina Fasos. Ð Diss. Univ. Frankfurt, FB Biologie und Informatik, 218 p. + Annex. Frankfurt. Ð (submitted): Herbaceous vegetation of seasonally wet rock habitats on inselbergs and lateritic crusts in tropical West Africa. Müller, J. V. & Deil, U. (2005): The ephemeral vegetation of seasonal and semi-permanent ponds in tropical West Africa. Ð Phytocoenologia 35: 327Ð388. Mulligan, G. A. & Calder, J. A. (1964): The genus Subularia (Cruciferae). Ð Rhodora 66: 127Ð135. Murdy, W. H. (1966): Plant speciation associated with granite outcrop communities of the south eastern Piedmont. Ð Rhodora 70: 394Ð407.

690

U. Deil

Musselman, L.J, Bray, R. D., Heafner, K. D. & Knepper, D. A. (1997): The genus Isoetes (Quillworts) in the Southern United States. Ð Am. J. Bot. 84(Suppl.6): 162. Nagler, A. (1999): Bemerkenswerte Vegetationsentwicklung nach Abtrag des Oberbodens in verschiedenen bremischen Schutzgebieten. Ð Abh. Naturwiss. Verein Bremen 44: 579Ð591. Nakamura, Y. (1994): Short life short grass community in Anhui Province, China. Ð EcoHabitat: JISE Research 1/1: 65Ð69. Navarro, F. & Valle, C. (1984): Vegetación herbácea del centro-occidente zamorano. Ð Stud. Bot. 3: 63Ð177. Nebel, M., Philippi, G., Quinger, B., Rösch, M., Schiefer, J., Sebald, O. & Seybold, S. (eds.)(1990): Die Farn- und Blütenpflanzen Baden-Württembergs. I. Allgemeiner Teil. Spezieller Teil (Pteridophyta, Spermatophyta). Ð 613 p., Stuttgart. Nègre, R. (1952): Note phytosociologique sur quelques mares et tourbières de Kroumerie. Ð Bull. Soc. Bot. Fr. 99: 16Ð22. Ð (1956): Note sur la végétation de quelques daya des Jbilete orientaux et occidentaux. Ð Bull. Soc. Sci. Nat. Phys. Maroc 36: 229Ð241. Neugebauer, K. R. (2003): Auswirkungen der extensiven Freilandhaltung von Schweinen auf Gefässpflanzen in Grünlandökosystemen. Ð Diss. Univ. Regensburg, 265 p., Regensburg. Newman, J. R. & Raven, J. A. (1995): Photosynthetic carbon assimilation by Crassula helmsii. Ð Oecologia 101: 494Ð499. Nezadal, W. (1999): Isoeto-Nanojuncetea-Arten als Bestandteil von Ackerunkrautgesellschaften in Nordbayern und auf der Iberischen Halbinsel. Ð Mitt. Bad. Landesver. Naturkd. Naturschutz Freib. i. Br. N. F. 17(2): 419Ð425. Nicol, J. M., Ganf, G. G. & Pelton, G. A. (2003): Seed banks of a southern Australian wetland: the influence of water regime on the final floristic composition. Ð Plant Ecol. 168: 191Ð205. Nicolet, P. (2001): Temporary ponds in the UK: a critical biodiversity resource for freshwater plants and animals. Ð Freshwater Forum 17: 16Ð25. Norwick, S. A. (1991): Vernal pools and other seasonal bodies of standing water. Ð Fremontia 19(3): 8Ð19. Nozeran, R. & Roux, J. (1958): A propos d’un Isoetion dans les Pyrénées orientales. Ð Nat. Monsp. Sér. Bot. 10: 81Ð90. Nyakabwa, M. (1988): Associations nouvelles de l’écosysteme urbain de Kisangani (HautZaire). Ð Am. Mus. Roy. Afr. Centrale Tervuren Sér. In 8, Sci. Econ. 17: 293Ð310. Oberdorfer, E. (1952): Beitrag zur Kenntnis der nordägäischen Küstenvegetation. Ð Vegetatio 3: 329Ð349. Ð (1960): Pflanzensoziologische Studien in Chile Ð ein Vergleich mit Europa. Ð Flora et Vegetatio Mundi 2: 208p., Stuttgart. Oesau, A. (1972): Zur Soziologie von Limosella aquatica L. Ð Beitr. Biol. Pflanzen 48: 377Ð397. Ohlemüller, R. (1997): Biodiversity patterns of plant communities in shallow depressions of Western Australian granite outcrops (inselbergs). Ð MSc Thesis, Univ. Bonn, 147p. + Annex, Bonn. Ohnstead, R. G., De Pamphilis, C. W., Wolfe, A. D., Young, N. D., Elison, W. J. & Reeves, P. A. (2001): Disintegration of the Scrophulariaceae. Ð Am. J. Bot. 88: 348Ð361. Oliver, L., Galand, J. P. & Mauvin, H. (eds.)(1995): Livre Rouge de la flore menacée de France. I. Espèces prioritaires. Ð 486 p., Paris. Olmsted, I. (1993): Wetlands of Mexico. Ð In: Whigham, D. F., Dykyjová, D. & Hejný, S. (eds): Wetlands of the world. I. Inventory, ecology, and management: 637Ð677. Dordrecht.

Habitats, plant traits and vegetation of ephemeral wetlands

691

O’Shea, B. J. (2003): Checklist of the mosses of sub-Saharan Africa (version 4,12/03). Ð Trop. Bryol. Res. Rep. 4: 1Ð182. Oumorou, M. & Lejoly, J. (2003a): Écologie, flore et végétation de l’inselberg Sobakpérou (nord-Bénin). Ð Acta Bot. Gallica 150(1): 65Ð84. Ð Ð (2003b): Aperçu de la végétation de quelques inselberg du Bénin. Ð Syst.. Geogr. Pl. 73: 215Ð236. Paradis, G. (1992): Observations synécologiques sur des stations corses de trois thérophytes fini-estivalesi Crypsis aculeata, Crypsis schoenoides et Chenopodium chenopodioides. Ð Monde Pl. 444: 11Ð21. Paradis, G. & Lorenzoni, C. (1994): Etude phytosociologique de communautés thérophytiques hygro-nitrophiles estivo-automnales de la Corse (groupements à Crypsis aculeata, Crypsis schoenoides, Glinus lotoides et Chenopodium chenopodioides). Nouvelles propositions syntaxonomiques (deuxième contribution). Ð Monde Pl. 449: 19Ð26. Paradis, G., Pozzo di Borgo, M. L. & Lorenzoni, C. (2002): Contribution à l’étude de la végétation des mares temporaires de la Corse. IV. Dépression de Padulu (Bonifacio, Corse). Ð Bull. Soc. Bot. Centre-Ouest, N. S. 33: 133Ð184. Parmentier, I. (2002): Premières études sur la diversité végétale des inselbergs de Guinée Équatoriale continentale. Ð Syst. Geogr. Pl. 71(2): 911Ð922. Ð (2003): Study of the vegetation composition in three inselbergs from continental Equatorial Guinea (Western Central Africa): Effects of site, soil factors, and position relative to forest fringe. Ð Belgian J. Bot. 136: 63Ð72. Parmentier, I., Lejoly, J. & Nguema, N. (2001): La végétation des inselbergs du monument naturel de Piedra Nzas (Guinée Équatoriale Continentale). Ð Acta Bot. Gallica 148(4): 341Ð365. Parmentier, I., Stévart, T. & Hardy, O. J. (2005): The inselberg flora of Atlantic Central Africa I. Determinants of species assemblages. Ð J. Biogeogr. 32: 685Ð696. Partridge, T. R. & Wilson, J. B. (1987): Salt tolerance of salt marsh plants of Otago, New Zealand. Ð New Zealand J. Bot. 25: 559Ð566. Pedrotti, F. (1982): La végétation des collines entre le Trasimène et le Val de Chiana. Ð Excurs. Intern. Phytosoc. Italie Central: 482Ð493. Camerino. Pedrotti, F., Ballelli, S. & Biondi, E. (1982): La végétation de l’ancien bassin lacustre de Gubbio (Italie centrale). Ð Doc. Phytosociol. N. S. 6: 221Ð243. Philcox, D. (1970): A taxonomic revision of the genus Limnophila R. Br. (Scrophulariaceae). Ð Kew Bull. 24: 101Ð170. Philippi, G. (1969): Zur Verbreitung und Soziologie einiger Arten von Zwergbinsen- und Strandlingsgesellschaften im badischen Oberrheingebiet. Ð Mitt. Bad. Landesver. Naturkd. Naturschutz Freib. i. Br. 10: 139Ð172. Ð (1985): Das Eleocharitetum acicularis im südlichen und mittleren Oberrheingebiet. Ð Tuexenia 5: 59Ð72. Phillips, D. L. (1981): Succession in granite outcrop shrub-tree communities. Ð Am. Mid. Nat. 106: 313Ð317. Phillips, D. L. (1982): Life forms of granite outcrop plants. Ð Am. Mid. Nat. 107: 206Ð208. Piccoli, F. & Merloni, N. (1989): Vegetation dynamics in coastal wetlands. An example in Northern Italy: The Bardello. Ð Ecol. Medit. 15: 81Ð95. Pietsch, W. (1973a): Beitrag zur Gliederung der europäischen Zwergbinsengesellschaften (Isoeto-Nanojuncetea Br.-Bl. & Tx. 1943). Ð Vegetatio 28: 401Ð438. Ð (1973b): Zur Soziologie und Ökologie der Zwergbinsen-Gesellschaften Ungarns (Klasse Isoeto-Nanojuncetea Br.-Bl. & Tx. 1943). Ð Acta Bot. Hung. 19: 269Ð288. Ð (1999): Zum Keimverhalten ausgewählter Arten mitteleuropäischer Zwergbinsengesellschaften. Ð Mitt. Bad. Landesver. Naturkd. Naturschutz Freib. i. Br. 17(2): 261Ð274.

692

U. Deil

Pigg, K. B. (1992): Evolution of Isoetalean lycopsids. Ð Ann. Missouri Bot. Gard. 79: 589Ð612 Ð (2001): Isoetalean lycopsid evolution: From the Devonian to the present. Ð Am. Fern J. 91(3): 99Ð114. Pignatti, E. & Pignatti, S. (1994): Centrolepidi-Hydrocotyletea alatae, a new class of ephemeral communities in Western Australia. Ð J. Veg. Sci. 5: 55Ð62. Ð Ð (2005): Ephemeral wetland vegetation of W Australia. Ð Phytocoenologia 35: 201Ð 218. Pignatti, S. (1957a): Associazioni vegetali dei dintorni di Pavia. Ð Guida Escurs. Fitosoc. Inter. Pavia. Ð (1957b): La vegetazione delle risaie pavesi (Studio fitosociologico). Ð Atti Ist. Bot. Univ. Pavia, Ser. 5 12: 360Ð424 Ð (1984): Flora d’Italia. Vol. 3. Ð 780p., Bologna. Pinder, L. & Rosso, S. (1998): Classification and ordination of plant formations in the Pantanal of Brazil. Ð Plant Ecol. 136: 151Ð165. Pinto-Gomes, C., Garcı́a-Fuentes, A., Almeida Leite, A. M. de & Cardoso Gonçalves, P. C. (1999): Charcos temporários mediterrânicos do Barrocal Algarvio: diversidade e conservação. Ð Quercetea 1: 53Ð64. Pires-O’Brien, M. J. (1992): Report on a remote swampy rock savanna at the mid-Javi river basin. Ð Bot. J. Linn. Soc. 108: 21Ð33. Poiron, L. & Barbéro, M. (1965): Groupements à Isoetes velata A. Braun (Isoetes variabilis Le Grand). Ð Bull. Soc. Bot. Fr. 112: 436Ð442. Ð Ð (1966): L’Isoetion du massif de Biot (Alpes-Maritimes). Ð Bull. Soc. Bot. Fr. 113: 410Ð415. Pollak, O. & Kan, T. (1998): The Use of Prescribed Fire to Control Invasive Exotic Weeds at Jepson Prairie Preserve. Ð In: Witham, C. W., Belk, D., Ferren, W. R. & Ornduff, R. (eds.): Ecology, Conservation, and Management of Vernal Pool Ecosystems: 241Ð 249. Sacramento. Polley, H. W. & Collins, S. L. (1984): Relationships of vegetation and environment in buffalo wallows. Ð Am. Mid. Nat. 112: 178Ð186. Polley, H. W. & Wallace, L. L. (1986): The relationships of plant species heterogeneity to soil variation in buffalo wallows. Ð SW Nat. 31: 493Ð501. Popiela, A. (1997): Zbiorowiska namulkowe z klasy ’Isoëto-Nanojuncetea’ Br.-Bl. et Tx. 1943 w Polsce. (= Occurrence of the Isoeto-Nanojuncetea-class communities in Poland). Ð Monogr. Bot. / Polskie Towarzystwo Botaniczne 80: 58 p., Warschau Ð (1999): Communities and species of Isoeto-Nanojuncetea in Poland Ð syntaxonomic classification, distribution, and state of research. Ð Mitt. Bad. Landesver. Naturkd. Naturschutz Freib. i. Br. 17(2): 369Ð380. Ð (2005): Isoeto-Nanojuncetea species and plant communities occuring on their eastern distribution range (Poland). Ð Phytocoenologia 35: 283Ð303. Por, F. D. (1995): The Pantanal of Mato Grosso (Brazil): world’s largest wetlands. Ð Monogr. Biol. 73: 122 p., Dordrecht. Porembski, S. (1996): Notes on the vegetation of inselbergs in Malawi. Ð Flora 191: 1Ð8. Ð (1999): Dynamik und Diversität von Sickerfluren auf tropischen Inselbergen. Ð Mitt. Bad. Landesver. Naturkd. Naturschutz Freib. i. Br. 17(2): 497Ð507. Ð (2000a): West African Inselberg Vegetation. Ð In: Porembski, S. & Barthlott, W. (eds.): Inselbergs: 177Ð211. Berlin, Heidelberg. Ð (2000b): The invasability of tropical granite outcrops (“inselbergs”) by exotic weeds. Ð J. Roy. Soc. W. Austr. 83: 131Ð137. Ð (2000c): Biodiversity of Terrestrial Habitat Islands, the Inselberg Evidence. Ð In: Porembski, S. & Barthlott, W. (eds.): Inselbergs: 507Ð514. Heidelberg.

Habitats, plant traits and vegetation of ephemeral wetlands

693

Porembski, S. & Barthlott, W. (1997): Seasonal dynamics of plant diversity on inselbergs in the Ivory Coast (West Africa). Ð Bot. Acta 110: 466Ð472. Ð Ð (eds.)(2000a): Inselbergs: Biotic Diversity of Isolated Rock Outcrops in Tropical and Temperate Regions. Ð Ecol. Studies 146: 524p., Berlin, Heidelberg. Ð Ð (2000b): Granitic and gneissic outcrops (inselbergs) as centers of diversity for desiccation-tolerant vascular plants. Ð Plant Ecol. 151: 19Ð28. Porembski, S. & Brown, G. (1995): The vegetation of inselbergs in the Comoé National Park (Ivory Coast). Ð Candollea 50: 351Ð363. Porembski, S. & Watve, A. (2005): Remarks on the species composition of ephemeral flush communities on palaeotropical rock outcrops. Ð Phytocoenologia 35: 389Ð401. Porembski, S., Barthlott, W., Dörrstock, S. & Biedinger, N. (1994): Vegetation of rock outcrops in Guinea: granite inselbergs, sandstone table mountains, and ferricretes Ð remarks on species numbers and endemism. Ð Flora 189: 315Ð326. Porembski, S., Brown, G. & Barthlott, W. (1995): An inverted latitudinal gradient of plant diversity in shallow depressions on Ivorian inselbergs. Ð Vegetatio 117: 151Ð163. Ð Ð Ð (1996a): A species-poor tropical sedge community: Afrotrilepis pilosa mats on inselbergs in West Africa. Ð Nordic J. Bot. 16: 239Ð245. Porembski, S., Fischer, E. & Gemmel, B. (1996b): Genlisea barthlottii (Lentibulariaceae), a new species from Guinean inselbergs. Ð Bull. Mus. natl. Hist. nat. Paris, 4e sér. section B, Adansonia 18: 151Ð154. Porembski, S., Fischer, E. & Biedinger, N. (1997): Vegetation of inselbergs, quarzitic outcrops, and ferricretes in Rwanda and eastern Zaire. Ð Bull. Jard. Bot. Nat. Belg. 66: 81Ð99. Porembski, S., Martinelli, G., Ohlemüller, R. & Barthlott, W. (1998): Diversity and ecology of saxicolous vegetation mats on inselbergs in the Brazilian Atlantic rainforest. Ð Div. Distribut. 4: 107Ð119. Porembski, S., Becker, U. & Seine, R. (2000): Islands on Islands: Habitats on Inselbergs. Ð In: Porembski, S. & Barthlott, W. (eds.): Inselbergs: 49Ð68. Berlin, Heidelberg. Poschlod, P. (1993): “Underground floristics” Ð keimfähige Diasporen im Boden als Beitrag zum floristischen Inventar einer Landschaft am Beispiel der Teichbodenflora. Ð Natur & Landschaft 68: 155Ð159. Ð (1996): Population biology and dynamics of a rare short-lived pond mud plant, Carex bohemica Schreber. Ð Verh. GfÖ 25: 321Ð337. Poschlod, P., Bauer, U., Grunicke, U., Heimann, B. & Kohler, A. (1993): Ökologie und Management periodisch abgelassener und trockenfallender kleinerer Stehgewässer im oberschwäbischen und schwäbischen Voralpengebiet. Die Bedeutung der Diasporenbank für das Überleben der Schlammbodenvegetation. Ð Veröff. PAÖ 7: 81Ð107. Poschlod, P., Böhringer, J., Fennel, S., Prume, C. & Tiekötter, A. (1999): Aspekte der Biologie und Ökologie von Arten der Zwergbinsenfluren. Ð Mitt. Bad. Landesver. Naturkd. Naturschutz Freib. i. Br. 17(2): 219Ð260. Pottier-Alapetite, G. (1952): Note préliminaire sur l’ Isoetion tunisien. Ð Bull. Soc. Bot. Fr. 99: 4Ð6. Ð (1954): L’ile de Zembra. Excursion phytosociologique. Ð Mém. Soc. Sci. Nat. Tunisie 2: 35Ð44. Prach, K., Květ, J. & Ostrý, I. (1987): Ecological analysis of the vegetation in a summerdrained fishpond. Ð Folia Geobot. Phytotax. 22: 43Ð70. Prada, C. (1983): El género Isoetes en la Penı́nsula Ibérica. Ð Acta Bot. Malacitana 8: 73Ð 101. Prado, A. L. do, Heckman, C. W. & Martins, F. R. (1994): The seasonal succession of biotic communities in wetlands of the tropical wet-and-dry climatic zone. II. The

694

U. Deil

aquatic macrophyte vegetation in the Pantanal of Mato Grosso. Ð Int. Revue ges. Hydrobiol. 79: 569Ð589. Pressey, R. L. & Adam, P. (1995): A review of wetland inventory and classification in Australia. Ð Vegetatio 118: 81Ð101. Preston, C. D. & Whitehouse, H. L. K. (1986): The habitat of Lythrum hyssopifolia L. in Cambridgeshire, its only surviving English locality. Ð Biol. Conserv. 35: 41Ð62. Purer, E. (1939): Ecological study of vernal pools, San Diego County. Ð Ecology 20: 217Ð229. Pyke, C. R. (2004a): Habitat loss confounds climate change impacts. Ð Front. Ecol. Environ. 2: 178Ð182. Ð (2004b): Simulating vernal pool hydrologic regimes for two locations in California, USA. Ð Ecol. Modelling 173: 109Ð127. Quarterman, E. (1950): Major plant communities of the Tennessee cedar glades. Ð Ecology 31: 234Ð254. Quarterman, E., Burbanck, M. P. & Shure, D. J. (1993): Rock outcrop communities: limestone, sandstone, and granite. Ð In: Martin, W. H., Boyce, S. G. & Echternacht, A. E. (eds.): Biodiversity of the southeastern United States: Upland Terrestrial communities: 35Ð86. New York. Quézel, P. (1957): Peuplement végétal des hautes montagnes de l’Afrique du Nord. Essai de synthèse biogéographique et phytosociologique. Ð Encyclopédie biogéographique et écologique 10: 463 p., Paris. Ð (1958): Mission botanique au Tibesti. Ð Mémoire Inst. Recher. Sahar. 4: 357 p., Alger. Ð (1975): Contribution à l’étude phytosociologique du massif du Taurus. Ð Phytocoenologia 1: 131Ð222. Ð (1998): La végétation des mares transitoires à Isoetes en région méditerranéenne, interêt patrimonial et conservation. Ð Ecol. Medit. 24: 111Ð117. Quézel, P., Barbéro, M. & Loisel, R. (1966): Artemisia molinieri, espèce nouvelle de la flore française. Ð Bull. Soc. Bot. Fr. 113: 524Ð530. Raabe, U. & Raus, T. (2001): Heteranthera limosa (Sw.) Willd. Ð In: Greuter, W. & Raus, T. (eds.): Med-Checklist Notulae 20. Willdenowia 31: 327. Raghoenandan, U. P. D. (2000): The Guianas (Guyana, Suriname, French Guiana). Ð In: Porembski, S. & Barthlott, W. (eds.): Inselbergs: 315Ð338. Berlin, Heidelberg. Ramı́rez, C., San Martı́n, C., Contreras, D. & San Martı́n, J. (1994): Estudio fitosociológico de la vegetación pratense del Valle del rı́o Chol-Chol (Cautı́n, Chile). Ð Agro Sur 22: 41Ð56. Ramı́rez, C., San Martı́n, C. & Keim, M. L. (1996): La vegetación espontánea del antiguo basural de Ovejerı́a (Osorno, Chile). Ð Medio Ambiente 13: 42Ð57. Ramı́rez, C., San Martı́n, C. & Ojeda, P. (2000): Estudio de la flora de comunidades ruderales antropogénicas en la IX Región de la Araucanı́a, Chile. Ð Stud. Bot. 1999; 18: 47Ð68. Rasomavicius, V. & Biveinis, A. (1996): The communities of the Isoeto-Nanojuncetea bufonii Br.-Bl. et Tx. 1943 class in Lithuania. Ð Bot. Lithuanica 2(1): 3Ð25. Rastetter, V. (1963): Contribution à l’étude de la végétation du Haut-Rhin. Les étangs du Sundgau. Ð Bull. Soc. Bot. France 110: 142Ð146. Rauh, W. (1973): Über die Zonierung und Differenzierung der Vegetation Madagaskars. Ð Trop. Subtrop. Pflanzenwelt 1: 146 p., Stuttgart. Rauh, W. & Falk, H. (1959a): Stylites E. Amstutz, eine neue Isoetacee aus den Hochanden Perus. I. Morphologie, Anatomie und Entwicklungsgeschichte der Vegetationsorgane. Ð Sitzungsber. Heidelberger Akad. Wiss., Math.-nat. Klasse: 83 p., Heidelberg. Ð Ð (1959b): Stylites E. Amstutz, eine neue Isoetacee aus den Hochanden Perus. II. Zur

Habitats, plant traits and vegetation of ephemeral wetlands

695

Anatomie des Stammes mit besonderer Berücksichtigung der Verdickungsprozesse. Ð Sitzungsber. Heidelberger Akad. Wiss., Math.-nat. Klasse: 76 p., Heidelberg. Raven, J. A., Handley, L. L., MacFarlane, J. J., McInroy, S., McKenzie, L., Richards, J. H. & Samuelsson, G. (1988): The role of CO2 uptake by roots and CAM in acquisition of inorganic C by plants of the isoetid life-forms: a review with new data on Eriocaulon decangulare L. Ð New Phytologist 108: 125Ð148. Raven, P. H. (1963): Amphitropical relationships in the floras of North and South America. Ð Quart. Rev. Biol. 38: 151Ð177. Raven, P. H. & Moore, D. M. (1965): A revision of Boisduvalia (Onagraceae). Ð Brittonia 17: 238Ð254. Raynal, A. & Raynal, J. (1961): Observations botaniques dans la région de Bamako. Ð Bull. I. F. A. N., Sér. A. 23(4): 994Ð1027. Dakar. Raynal-Roques, A. & Jérémie, J. (1980): Un marécage saxicole à Isoetes et Ophioglossum en Guyane française. Ð Adansonia, sér. 2 19(4): 403Ð412. Reed, E. L. (1930): Vegetation of the Playa lakes in the Staked Plains of Western Texas. Ð Ecology 11: 597Ð600. Reeder, J. R. (1982): Systematics of the tribe Orcuttieae (Gramineae) and the description of a new segregate genus, Tuctoria. Ð Am. J. Bot. 69: 1082Ð1095. Reekmans, M. (1982): Les rythmes phénologiques dans les principales associations végétales de la plaine de la basse Rusizi (Burundi). Ð Bull. Jard. Bot. Nat. Belg. 52: 3Ð93. Ð (1980): La végétation de la plaine de la basse Rusizi (Burundi). Ð Bull. Jard. Bot. Nat. Belg. 40: 401Ð444. Reitsma, J. M., Louis, A. M. & Floret, J. J. (1992): Flore et végétation des inselbergs et dalles rocheuses: première étude au Gabon. Ð Adansonia 1: 73Ð97. Rennwald, E. (ed.)(2000): Verzeichnis und Rote Liste der Pflanzengesellschaften Deutschlands. Ð Schriftenreihe für Vegetationskunde 35: 800p., Bonn. Retallack, G. J. (1997): Earliest Triassic origin of Isoetes and quillwort evolutionary radiation. Ð J. Paleont. 71: 500Ð521. Reyes-Betancort, J. A., Wildpret de la Torre, W. & Léon Arencibia, M. C. (2001): The vegetation of Lanzarote (Canary Islands). Ð Phytocoenologia 31: 185Ð247. Rhazi, L. (2001): Étude de la végétation des mares temporaires et l’impact des activités humaines sur la richesse et la conservation des espèces rares au Maroc. Ð Thèse de l’Univ. Hassan II, Maroc. Rhazi, L., Grillas, P., Toure, A. M. & Tan Ham, L. (2001a): Impact of landuse in catchment and human activities on water, sediment, and vegetation of Mediterranean temporary pools. Ð C. R. Acad. Sci. Paris Sciences de la Vie 324: 165Ð177. Rhazi, L., Grillas, P., Tan Ham, L. & El Khyari, D. (2001b): The seed bank and the between years dynamics of the vegetation of a Mediterranean temporary pool (NW Morocco). Ð Ecol. Medit. 27: 69Ð88. Rhazi, M., Grillas, P., Charpentier, A. & Médail, F. (2004): Experimental management of Mediterranean temporary pools for conservation of the rare quillwort Isoetes setacea. Ð Biol. Conserv. 118: 675Ð684. Rhazi, M., Grillas, P., Médail, F. & Rhazi, L. (2005): Consequences of shrub clearing on the richness of aquatic vegetation in oligotrophic seasonal pools in Southern France. Ð Phytocoenologia 35: 489Ð510. Richards, P. W. (1957): Ecological notes on Westafrican vegetation. I. The plant communities of Idanane Hills, Nigeria. Ð J. Ecol. 45: 563Ð577. Richardson, K., Griffiths, H., Reed, M. L., Raven, J. A. & Griffiths, N. M. (1984): Inorganic carbon assimilation in the Isoetids, Isoetes lacustris L. and Lobelia dortmanna L. Ð Oecologia 61: 115Ð121.

696

U. Deil

Rivas Goday, S. (1955): Aportaciónes a la fitosociologı́a hispánica, not. I. (Proyectos de comunidades hispánicas). Ð Anal. Inst. Bot. Cavanilles 13: 335Ð422. Ð (1956): Comportamiento fitosociológico del Eryngium corniculatum Lam. y de otras especies de Phragmitetea e Isoeto-Nanojuncetea. Ð Anal. Inst. Bot. Cavanilles 14: 1Ð 528. Ð (1964): Vegetación y flórula de la cuenca extremeña del Guadiana. Ð Publ. Exma. Dip. Prov. Badajos, 777 p., Madrid. Ð (1968): Algunas novedades fitosociológicas de España meridional. Ð Collect. Bot. 7: 998Ð1031. Ð (1970): Revisión de las comunidades hispánicas de la clase Isoeto-Nanojuncetea Br.Bl. & Tx. 1943. Ð Anal. Inst. Bot. Cav. 27: 225Ð276. Rivas Goday, S. & Rivas-Martı́nez, S. (1963): Estudio y clasificación de los pastizales españoles. Ð Pub. Ministerio de Agricultura 277: 269p., Madrid. Rivas-Martı́nez, S. (1963): Estudio de la vegetación y flora de las Sierras de Guadarrama y de Gredos. Ð Anal. Inst. Bot. Cavanilles 21: 1Ð325. Rivas-Martı́nez, S. & Tovar, O. (1982): Vegetatio Andinae I. Datos sobre las comunidades vegetales altoandinas de los Andes Centrales del Perú. Ð Lazaroa 4: 161Ð187. Rivas-Martı́nez, S., Costa, M., Castroviejo, S. & Valdés, E. (1980): La vegetación de Donaña (Huelva, España). Ð Lazaroa 2: 5Ð190. Rivas-Martı́nez, S., Wildpret de la Torre, W., del Arco, M., Rodrı́guez, O., Pérez de Paz, P. L., Garcı́a Gallo, A., Acebes, J. R., Dı́az, T. E. & Fernández-Gonzáles, F. (1993): Las comunidades vegetales de la Isla de Tenerife (Islas Canarias). Ð Itinera Geobotanica 7: 169Ð375. Rivas-Martı́nez, S., Fernández-González, F., Loidi, J., Lousã, M. & Penas, A. (eds.)(2001): Syntaxonomical checklist of vascular plant communities of Spain and Portugal to association level. Ð Itinera Geobotanica 14: 5Ð341. Rivas-Martı́nez, S., Dı́az, T. E., Fernández-González, F., Izco, J., Loidi, J., Lousã, M. & Penas, A. (eds.)(2002): Addenda to the syntaxonomical checklist of vascular plant communities of Spain and Portugal. Ð Itinera Geobotanica 15(1+2): 1Ð922. Roberty, G. (1946): Les associations végétales de la vallée moyenne du Niger. Ð Veröff. Geobot. Inst. Eidg. Tech. Hochsch. Stift. Rübel 22: 1Ð160. Rodrı́guez, B. J. A., Montera, I. & Tormo, R. (1995): Heteranthera limosa (Sw.) Willd. (Pontederiaceae), allochthonous species infesting the rice fields of Badajoz Province: new record for Spain. Ð An. Jardı́n Bot. Madrid 53: 138. Rodrı́guez, J., Romero, M. I. & Ortiz, S. (1997). Communities of the class Littorelletea uniflorae in the northwest Iberian Peninsula. Ð Acta Bot. Gallica 144: 155Ð169. Rodrı́guez-Oubiña, J., Reinoso Franco, J. & Gómez Valverde, M. (2001): Pleuridio acuminati-Ophioglossetum lusitanici, una nueva asociación del afloramiento de rocas ultrabásicas del centro de Galicia (N. O. de España). Ð Nova Acta Cient. Compostelana (Bioloxia) 11: 167Ð175. Rodwell, J. S. (ed.)(2000): British plant communities. V. Maritime communities and vegetation of open habitats. Ð 512 p., Cambridge. Rodwell, J. S., Schaminée, J. H. J., Mucina, L., Pignatti, S., Dring, J. & Moss, D. (2002): The Diversity of European Vegetation. An overview of phytosociological alliances and their relationships to EUNIS habitats. Ð Report ECÐLNV nr. 2002/054, 168 p., Wageningen. Rogers, G., Walker, S., Tubbs, M. & Henderson, J. (2002): Ecology and conservation status of three “spring annual” herbs in dryland ecosystems of New Zealand. Ð New Zealand J. Bot. 40: 649Ð669. Rosario, J. A. & Lathrop, E. W. (1984): Distributional ecology of vegetation in the vernal pools of the Santa Rosa Plateau, Riverside County, California. Ð In: Jain, S. K. & Moyle, P. (eds.): Vernal pools and intermittent streams: 210Ð217. Davis.

Habitats, plant traits and vegetation of ephemeral wetlands

697

Rudner, M. (2001): Zum Maßstab kleinräumiger Muster innerhalb westmediterraner Zwergbinsenrasen (Isoeto-Nanojuncetea) Ð ein Beispiel aus der Serra de Monchique (Portugal). Ð Ber. d. Reinh.-Tüxen-Ges. 13: 279Ð283. Hannover. Ð (2005a): Seasonal and interannual dynamics in dwarf rush vegetation in the Southwestern Iberian Peninsula. Ð Phytocoenologia 35: 403Ð420. Ð (2005b): Environmental patterns and plant communities of the ephemeral wetland vegetation in two areas of the Southwestern Iberian Peninsula. Ð Phytocoenologia 35: 231Ð265. Rudner, M., Deil, U. & Galán de Mera, A. (1999): Zwergbinsengesellschaften im Südwesten der Iberischen Halbinsel. Standörtliche Einnischung und floristische Differenzierung. Ð Mitt. Bad. Landesver. Naturkd. Naturschutz Freib. i. Br. 17(2): 427Ð448. Ruiz, T. & Valdés, A. (1987): Novedades y comentarios fitosociológicos sobre vegetación luso-extremadurense. Ð Studia Bot. 6: 25Ð38. Ruthsatz, B. (1977): Pflanzengesellschaften und ihre Lebensbedingungen in den andinen Halbwüsten Nordwest-Argentiniens. Ð Diss. Botan. 39: 168 p., Vaduz. Ð (1995): Vegetation und Ökologie tropischer Hochgebirgsmoore in den Anden NordChiles. Ð Phytocoenologia 25: 185Ð234. Rydin, C. & Wikström, N. (2002): Phylogeny of Isoetes (Lycopsida): Resolving basal relationships using rbcL sequences. Ð Taxon 51: 83Ð89. Safford, H. D. & Martinelli, G. (2000): Southeast Brazil. Ð In: Porembski, S. & Barthlott, W. (eds.): Inselbergs: 339Ð389. Berlin, Heidelberg. Salazar, C., Garcı́a-Fuentes, A. & Valle, F. (2001): Datos sobre la vegetación edaphohigrófila del sector Malacitano-Almijarense (Málaga-Granada, sur de España). Ð Acta Bot. Malacitana 26: 111Ð141. Salisbury, E. J. (1968): The reproductive biology and occasional seasonal dimorphism of Anagallis minima and Lythrum hyssopifolia. Ð Watsonia 7: 25Ð39. Ð (1970): The pioneer vegetation of exposed muds and its biological features. Ð Philos. Trans. Roy. Soc. London, Series B, Biol Sci. 259: 207Ð255. Sánchez-Mata, D. (1989): Flora y vegetación del macizo oriental de la Sierra de Gredos (Avila). Ð Ed. Excma. Dip. Prov. Ávila. Inst. Gran Duque de Alba, 440 p., Avila. Sánchez Rodrı́guez, J. A. & Elı́as Rivas, J. (1998): Centipeda cunninghamii (DC.) A. Braun & Ascherson (Asteraceae), una planta adventicia nueva para Europa. Ð An. Jardı́n Bot. Madrid 56: 167. Sánchez Rodrı́guez, J. A. & Fernández Dı́ez, F. J. (1987): Comentarios fitosociológicos sobre Ranunculus batrachioides Pomel. ssp. brachypodus G. Lopez. Ð Lazaroa 10: 101Ð104. San Martı́n, C., Ramı́rez, C. & Ojeda, P. (1998): La vegetación de lagunas primaverales en la cercanı́as de Temuco (Cautı́n, Chile). Ð Acta Bot. Malacitana 23: 99Ð120. San Martı́n, C., Ramı́rez, C. & Alvarez, M. (2003): Macrófitos como bioindicadores: une propuesta metodológico para caracterizar ambientes dulciacuı́colas. Ð Revista Geogr. Valparaiso 34: 243Ð253. Sardinero, S. (2004): Flora y vegetación del Macizo occidental de la Sierra de Gredos (Sistema Central, España). Ð Guineana 10: 1Ð474. Sarika-Hatzinikolaou, M., Yannitsaros, A. & Babalonas, D. (2003): The macrophytic vegetation of seven aquatic ecosystems of Epirus (NW Greece). Ð Phytocoenologia 33: 93Ð151. Sarthou, C. (2001): Plant communities on a granitic outcrop. Ð In: Bongers, F., CharlesDominique, P., Forget, P. M. & Théry, M. (eds.): Nouragues: dynamics and plantanimal interactions in a neotropical rainforest: 65Ð78. Dordrecht. Sarthou, C. & Grimaldi, C. (1992): Mécanismes de colonisation pour la végétation d’un inselberg granitique en Guyane française. Ð Rev. Ecol. (Terre Vie) 47: 329Ð349.

698

U. Deil

Sarthou, C. & Villiers, J. F. (1998): Epilithic plant communities on inselbergs in French Guiana. Ð J. Veg. Sci. 9: 847Ð860. Scarpa, G. F. & Arenas, P. (2004): Vegetation units of the Argentine Semiarid Chaco: The Toba-Pilagá perception. Ð Phytocoenologia 34: 133Ð161. Schessl, M. (1997): Flora und Vegetation des nördlichen Pantanal von Mato Grosso, Brasilien. Floristische Zusammensetzung, Pflanzengesellschaften und Vegetationsdynamik saisonal und permanent überfluteter Standorte eines tropischen Sedimentationsbeckens. Ð Archiv Nat. Diss. 4: 276 p., Wiehl. Ð (1999): Floristic composition and structure of floodplain vegetation in the northern Pantanal of Mato Grosso, Brazil. Ð Phyton (Austria) 39: 303Ð336. Schiller, J. R., Zedler, P. H. & Black, C. H. (2000): The effect of density-dependent insect visits, flowering phenology, and plant size on seed set of the endangered vernal pool plant Pogogyne ambrasii (Lamiaceae) in natural compared to created vernal pools. Ð Wetlands 20: 386Ð396. Schlising, R. A. (1989): Yearly fluctuations in a vernal pool annual, Sidalcea hirsuta. Ð In: Bock, J. H. & Linhard, Y. B. (eds.): The evolutionary ecology of plants: 285Ð301. Boulder. Schlising, R. A. & Sanders, E. L. (1982): Quantitative analysis of vegetation at the Richvale vernal pools, California. Ð Am. J. Bot. 69: 734Ð742. Schmitz, A. (1963): Aperçu sur les groupements végétaux du Katanga. Ð Bull. Soc. Roy. Bot. Belg. 96: 233Ð447. Ð (1988): Revision des groupements végétaux décrits du Zaire, du Rwanda et du Burundi. Ð Am. Mus. Roy. Afr. Centrale Tervuren Sér. In 8 Ð Sci. Econ. 17: 1Ð277. Schneider, R. (1994): The role of hydrologic regime in maintaining rare plant communities of New York’s coastal plain pond shores. Ð Biol. Conserv. 68: 253Ð260. Schnell, R. (1951Ð52): Végétation et flore des Monts Nimba (Afrique occidentale française). Ð Vegetatio 3: 350Ð406. Schnell, R. A. A. (1998): Anatomie des Podostémacées. Ð Extreme adaptations in angiosperm hydrophytes, Handbuch der Pflanzenanatomie 13: 197Ð283. Berlin. Scholnick, D. A. (1994): Seasonal variation and diurnal fluctuations in ephemeral desert pools. Ð Hydrobiologia 294: 111Ð116. Schweigert, G. (1993): The Middle Miocene flora (MN 7) of Steinheim am Albuch (Swabian Jura, Baden-Württemberg). Ð Jahresh. Ges. Nat. Württ. 148: 61Ð96. Sculthorpe, C. D. (1967): The biology of aquatic vascular plants. Ð610p., London. Seabloom, E. W., Van der Valk, A. G. & Moloney, K. A. (1998): The role of water depth and soil temperature in determining initial composition of prairie wetland coenoclines. Ð Plant Ecol. 138: 203Ð216. Seibert, P. & Menhofer, X. (1991): Die Vegetation des Wohngebietes der Kallawaya und des Hochlandes von Ulla-Ulla in den bolivianischen Anden. I. Ð Phytocoenologia 20: 145Ð276. Ð Ð (1992): Die Vegetation des Wohngebietes der Kallawaya und des Hochlandes von Ulla-Ulla in den bolivianischen Anden. II. Ð Phytocoenologia 20: 289Ð438. Seidenschwarz, F. (1986): Pioniervegetation im Amazonasgebiet Perus. Ein pflanzensoziologischer Vergleich von vorandinem Flussufer und Kulturland. Ð Monographs on agriculture and ecology of warmer climates 3: 226 p., Langen. Seine, R. (1996): Vegetation von Inselbergen in Zimbabwe. Ð Archiv Nat. Diss. 2: 1Ð370. Wiehl. Seine, R. & Becker, U. (2000): East and Southeast Africa. Ð In: Porembski, S. & Barthlott, W. (eds.): Inselbergs: 213Ð235. Berlin, Heidelberg. Seine, R., Becker, U., Porembski, S., Follmann, G. & Barthlott, W. (1998): Vegetation of inselbergs in Zimbabwe. Ð Edinburgh J. Bot. 55: 267Ð293.

Habitats, plant traits and vegetation of ephemeral wetlands

699

Semeniuk, C. A. & Semeniuk, V. (1995): A geomorphic approach to global classification for inland wetlands. Ð Vegetatio 118: 103Ð124. Sérgio, C., Cros, R. M., Brugués, M. & Casas, C. (1997/98): Datos sobre a brioflora de charcos e de cursos de agua temporarios com Isoetes, na Peninsula Iberica. Ð Agronomia Lusitana 46: 21Ð28. Sharma, K. P., Khan, T. I. & Bhardwaj, N. (1984): Temperature regulated seed germination in Neptunia oleracea Lour. and its ecological significance. Ð Aquatic Botany 20: 185Ð 188. Shepard, G. H. Jr., Yu, D. W., Lizerralde, M. & Italiano, M. (2001): Rain forest habitat classification among the Matsigenka of the Peruvian Amazon. Ð J. Ethnobiol. 21: 1Ð38. Shimoda, M. (1983): Deinostema-Eriocauletum hondoensis (nov.): Communities of emerged pond shores in Hiroshima Prefecture, Japan. Ð Japan. J. Ecol. 33: 121Ð134. Ð (1985): Phytosociological studies on the vegetation of irrigation ponds in the Saijo Basin, Hiroshima Prefecture, Japan. Ð J. Sci. Hiroshima Univ., Ser. B, Div. 2 19: 237Ð297. Ð (1986): The vegetation of irrigation ponds in the Ôasa basin, Hiroshima Prefecture, Western Japan. Ð Hikobia 9: 457Ð465. Ð (1987): The vegetation of ponds and marshes of Mt. Gokurakuji, Hiroshima Prefecture, Western Japan. Ð Hikobia 10: 31Ð37. Ð (1993): Effects of urbanization on pond vegetation in the Saijo Basin, Hiroshima Prefecture, Japan. Ð Hikobia 11: 305Ð312. Ð (2005): Emerged shore vegetation of irrigation ponds in western Japan. Ð Phytocoenologia 35: 305Ð325. Shukla, P. K., Srivastava, G. K. & Shukla, S. K. (2002): The quillworts (Isoetes) of India: Distribution, endemism, and species radiation. Ð Biodiv. Conserv. 11(6): 959Ð973. Shure, D. J. (1999): Granit Outcrops of the Southeastern United States. Ð In: Anderson, R. C., Fralish, J. S. & Baskin, J. M. (eds.): Savannas, Barrens, and Rock Outcrop Plant communities of North America: 99Ð118. Cambridge. Shure, D. J. & Ragsdale, H. G. (1977): Patterns of primary succession on granite outcrop surfaces. Ð Ecology 58: 993Ð1006. Sinelnikova, N. V. & Taran, G. S. (2003): A find of association Cypero-Limoselletum (Oberd. 1957) Korneck 1960 (Isoeto-Nanojuncetea) in Magadan Region, Russian Far East. Ð Vegetation of Russia 4: 92 p., St. Petersburg. Slavic, Z. (1951): Prodrome des groupements végétaux nitrophiles de la Volvodine (Yugoslavie). Ð Arch. Sci. Matica srpska, Ser. Sci. Nat. 1: 84Ð169. Small, R. L. & Hickey, R. J. (2001): Systematics of the Northern Andean Isoetes karstenii complex. Ð Am. Fern J. 91(2): 41Ð69. Smith, D. W. & Verrill, W. L. (1998): Vernal Pool-Soil-Landform Relationships in the Central Valley, California. Ð In: Witham, C. W., Belk, D., Ferren, W. R. & Ornduff, R. (eds.): Ecology, Conservation, and Management of Vernal Pool Ecosystems: 15Ð 23. Sacramento. Smolders, A. J. P., Lucassen, E. C. H. E. T. & Roelofs, J. G. M. (2002): The isoetid environment: Biogeochemistry and threats. Ð Aquatic Botany 73: 325Ð350. Sörensen, T. (1942): Untersuchungen über die Therophytengesellschaften auf den isländischen Lehmflächen (“Flags”). Ð Kongel. Danske Vid. Selsk., Biol. Skr. 2(2): 1Ð30. Species 2000 Project Team (2003): Species 2000. Annual Checklist. Ð Catalogue of Life 2003: http://www.sp2000.org/AnnualChecklist2003.html. Spencer, S. C. & Rieseberg, L. H. (1998): Evolution of Amphibious Vernal Pool Specialist Annuals: Putative Vernal Pool Adaptive Traits in Navarretia (Polemoniaceae). Ð In: Witham, C. W., Belk, D., Ferren, W. R. & Ornduff, R. (eds.): Ecology, Conservation, and Management of Vernal Pool Ecosystems: 76Ð85. Sacramento.

700

U. Deil

Stagg, C. M. & Lathrop, E. W. (1984): Distribution of Orcuttia californica (Poaceae) in vernal pools of the Santa Rosa Plateau, Riverside County, California. Ð In: Jain, S. K. & Moyle, P. (eds.): Vernal pools and intermittent streams: 250Ð254. Davis. Stalling, T. (2005): Arten und Gesellschaften der Isoeto-Nanojuncetea und Littorelletea der Äcker und Teiche des Sundgaus (F). Ð Unpubl. Diploma Thesis, Universität Freiburg, Fakultät für Biologie, 88 p + Annex, Freiburg. Stevenson, D. W. & Loconte, H. (1995): Cladistic analysis of monocot families. Ð In: Rudall, P. J., Cribb, P. J., Cutler, D. F. & Humphries, C. J. (eds.): Monocotyledons: systematics and evolution 2: 543Ð578. Kew. Stierstorfer, C. (2005): The Vascular Plant Vegetation in the Forest Belt of El Hierro (Canary Islands). Ð Diss. Botan. 393: 375 p., Berlin, Stuttgart. Stone, D. E. (1959): A unique balanced breeding system in vernal pool mouse-tail. Ð Evolution 13: 151Ð174. Stützel, T. (1984): Blüten- und infloreszenzmorphologische Untersuchungen zur Systematik der Eriocaulaceen. Ð Diss. Botan. 71: 108 p., Vaduz. Ð (1998): Eriocaulaceae. Ð In: Kubitzki, K. (ed.): Flowering Plants: The families and genera of vascular plants 4: 197Ð207. Berlin. Sumberová, K. (2003): Veränderungen in der Teichwirtschaft und ihr Einfluss auf die Vegetation in der Tschechischen Republik. Mit Beispielen von Isoeto-Nanojuncetea-, Littorelletea- und Bidentetea-Arten im Becken von Ťreboň (Wittingauer Becken). Ð Mitt. Bad. Landesver. Naturkd. Naturschutz Freib. i. Br. N. F. 18(2): 7Ð24. Sumberová, K., Horáková, V. & Lasosová, Z. (2005): Vegetation dynamics on exposed pond bottoms in the Cesko budejovická basin (South Bohemia). Ð Phytocoenologia 35: 421Ð448. Sunding, P. (1972): The vegetation of Gran Canaria. Ð Skr. Norske Vidensk. Akad. Oslo I. Matem.-Naturv. Kl. N. S. 29: 1Ð186. Susach, F. (1989): Caracterización y clasificación fitosociológica de la vegetación de sabanas del sector oriental de los Llanos Centrales Bajos Venezolanos. Ð Acta Biol. Venez. 12(3Ð4): 1Ð54. Sutter, G. & Francisco, R. (1998): Vernal Pool Creation in the Sacramento Valley: A Review of the Issues Surrounding Its Role as a Conservation Tool. Ð In: Witham, C. W., Belk, D., Ferren, W. R. & Ornduff, R. (eds.): Ecology, Conservation, and Management of Vernal Pool Ecosystems: 190Ð194. Sacramento. Sykes, M. T. & Wilson, J. B. (1987): The vegetation of a New Zealand dune slack. Ð Vegetatio 71: 133Ð139. Szafranski, F. & Apema, A. K. (1983): Contribution à la connaissance des groupements végétaux aquatique et semi-aquatique dans les environs de Kisangani (Haut-Zaire). I. Ð Bull. Soc. Roy. Bot. Belg. 116: 93Ð106. Szafranski, F., Apema, A. K. & Nyakabwa, M. (1986): Contribution à la connaissance des groupements végétaux aquatiques et semi-aquatiques dans les environs de Kisangani (Haute-Zaire). III + IV. Ð Bull. Soc. Roy. Bot. Belg. 119: 81Ð91. Szmeja, J. (1994): Dynamics of the abundance and spatial organisation of isoetid populations in an oligotrophic lake. Ð Aquatic Bot. 49: 19Ð32. Täuber, T. (1994): Vegetation studies on a tank training area in the Lueneburger Heide nature reserve. Ð Tuexenia 14: 197Ð228. Ð (1999a): Zwergbinsen-Gesellschaften (Isoeto-Nanojuncetea) in Niedersachsen. Verbreitung, Gliederung, Dynamik, Keimungsbedingungen der Arten und Schutzkonzepte. Ð267p., Göttingen. Ð (1999b): Vegetationsökologische und populationsbiologische Untersuchungen an niedersächsischen Zwergbinsengesellschaften Ð Mit einem Beitrag zur Gliederung der

Habitats, plant traits and vegetation of ephemeral wetlands

701

Isoeto-Nanojuncetea Deutschlands. Ð Mitt. bad. Landesver. Naturkunde u. Naturschutz 17(2): 337Ð354. Ð (2000): Phänologische Daten als Hilfsmittel zur syntaxonomischen Differenzierung von Pionierbeständen Ð dargestellt am Beispiel von Zwergbinsen-Gesellschaften. Ð Tuexenia 20: 365Ð375. Täuber, T. & Petersen, J. (2000): Isoeto-Nanojuncetea (D1) Zwergbinsen-Gesellschaften. Ð Synopsis Pflanzenges. Deutschlands 7: 87 p., Göttingen. Täuber, T., Wagner, A., Wagner, I., Schleier, V. & Scheuerer, M. (2002): Cyperus flavescens und Anagallis minima im südlichen Ammer-Loisach-Hügelland: Verbreitung, Vergesellschaftung und Schutzmöglichkeiten. Ð Hoppea, Denkschr. Regensburg. Bot. Ges. 63: 489Ð503. Tamajón Gómez, R. & Muñoz Alvarez, J. M. (2001): La vegetación de las marismas y lagunas de la Hoja cartográfica de Lebrija (suroeste de España). Ð Stud. Bot. 20: 93Ð114. Taran, G. S. (1993): On syntaxonomy of Black Irtysh flood-plain ephemerous vegetation. Ð Sib. J. Biol. 5: 79Ð84. Ð (1994): Floodplain Ephemeretum of Middle Ob Ð a new class for Siberia, Isoeto-Nanojuncetea Br.-Bl. et Tx. 1943 on the northern border of expansion. Ð Sib. J. Ecol. 1(6): 578Ð582. Ð (1995): A little known vegetation class of the former USSR Ð Flood-plain Ephemeretum (Isoeto-Nanojuncetea Br.-Bl. et Tx. 43). Ð Sib. J. Ecol. 2(4): 372Ð380. Ð (1998): Finds of Cypero-Limoselletum (Oberd. 1957) Korneck 1960 in the floodplains of the lower Ob and lower Irtysh. Ð Biol. Ressources Nat. Use 2: 72Ð78. Ð (2000): Essay of the vegetation of the east part of Elizarovsky Zakaznik (Lower Ob River). Ð Biol. Ressources Nat. Use 3: 3Ð23. Ð (2001): Association Cypero-Limoselletum (Oberd. 1957) Korneck 1960 (Isoeto-Nanojuncetea) in the middle Ob River floodplain. Ð Vegetation of Russia 1(1): 43Ð56. Taran, G. S., Sedelnikova, N. V., Pisarenko, O. Y. & Golomolzin, V. V. (2004): Flora and vegetation of Elizarovskiy state zakaznik (lower Ob river) (in Russian). Ð 212 p., Novosibirsk. Taton, A. (1948): La colonisation des rochers granitiques de la région de Kioka (HautIturi, Congo belge). Ð Vegetatio 1: 317Ð332. Taton, A. & Risopoulos, S. (1955): Contribution à l’étude des principales formations marécageuses de la région de Nioka (distr. du Kibali-Ituri). Ð Bull. Soc. Roy. Bot. Belg. 87(1): 5Ð19. Taylor, A. R. D., Howard, G. W. & Begg, G. W. (1995): Developing wetland inventories in Southern Africa: A review. Ð Vegetatio 118: 57Ð79. Taylor, H. C. (1972): Notes on the vegetation of the Cape Flats. Ð Bothalia 10: 637Ð646. Taylor, J. A. & Dunlop, C. R. (1985): Plant communities of the wet-dry tropics of Australia: the Alligator River Region. Ð Proc. Ecol. Soc. Aust. 13: 83Ð128. Taylor, P. (1989): The genus Utricularia Ð a taxonomic monograph. Ð Kew Bull., add. ser. 14: 1Ð724. Taylor, W. C. & Hickey, R. J. (1992): Habitat, Evolution, and Speciation in Isoetes. Ð Am. Missouri Bot. Gard. 79: 613Ð622. Thannheiser, D. (2001): Studien zur Küstenvegetation Viktorias (Südaustralien). Ð Bamberger Geogr. Schriften 20: 271Ð285. Bamberg. The International Plant Names Index (2005): http://www.ipni.org. Accessed September 2003-May 2005. Thiéry, A. (1991): Multispecies coexistence of branchiopods, Anostraca, Notostraca & Spinicaudata in temporary ponds of Chaouia plain (western Morocco): sympatry or syntopy between usually allopatric species. Ð Hydrobiologia 212: 117Ð136.

702

U. Deil

Thompson, K., Bakker, J. & Bekker, R. (1997): The soil seed banks of North West Europe: methodology, density and longevity. Ð Cambridge. Thorn, V. (2001): Vegetation communities of a high palaeolatitude, Middle Jurassic forest in New Zealand. Ð Palaeogeo. Palaeoclimat. Palaeoecol. 168: 273Ð289. Thorne, R. F. (1984): Are California’s Vernal Pools unique? Ð In: Jain, S. K. & Moyle, P. (eds.): Vernal pools and intermittent streams: 1Ð8. Davis. Thorp, R. W. & Leong, J. M. (1998): Specialist Bee Pollinators of Showy Vernal Pool Flowers. Ð In: Witham, C. W., Belk, D., Ferren, W. R. & Ornduff, R. (eds.): Ecology, Conservation, and Management of Vernal Pool Ecosystems: 169Ð179. Sacramento. Tiner, R. W. (1999): Wetland indicators: a guide to wetland identification, delineation, classification, and mapping. Ð 392 p., Boca Raton. Titolet, D. (1989): Première contribution à l’étude phytosociologique des groupements végétaux des mares temporaires de la Mamora sud occidentale. Ð Rapport ined., 4p., Rabat. Titolet, D. & Rhazi, L. (1998): Interêt patrimoniale des mares temporaires des rives gauche et droite de l’oued Cherrat. Ð 3ème Journée mondiale des zones humides, Mnsc. ined., 7 p., Rabat. Trabaud, L. (1998): Historique de la création de la Réserve Naturelle de Roque-Haute et sa végétation. Ð Ecol. Medit. 24: 173Ð177. Traxler, A. (1991): Gefährdung und Förderung von Isoeto-Nanojuncetea-Gesellschaften unter intensiver Teichbewirtschaftung im österreichischen Waldviertel. Ð Wissenschaftl. Beitr. Univ. Halle-Wittenberg 6(P46): 347Ð350. Ð (1993): Isoeto-Nanojuncetea. Ð In: Grabherr, G. & Mucina, L. (eds.): Die Pflanzengesellschaften Österreichs. II. Natürliche waldfreie Vegetation: 197Ð212. Stuttgart. Troia, A. (2001): The genus Isoetes L. (Lycophyta, Isoetaceae): Synthesis of karyological data. Ð Webbia 56: 201Ð218. Tüxen, R. & Zevaco, C. (1973): Isoeto-Nanojuncetea. Ð Bibliogr. Phytosoc. Syntax. 19: 1Ð90. Tutin, G. et al. (eds.)(1968/93): Flora Europaea. IÐV. Ð Cambridge. Ubriszy, G. (1961): Unkrautvegetation der Reiskulturen in Ungarn. Ð Acta Bot. Hung. 7: 175Ð220. Ünal, A. (1999): Zum Stand der Erforschung von Zwergbinsengesellschaften in Sibirien. Ð Mitt. Bad. Landesver. Naturkd. Naturschutz Freib. i. Br. 17(2): 481Ð496. Uno, G. E. (1989): Dynamics of plants in buffalo wallows: ephemeral pools in the Great Plains. Ð In: Bock, J. H. & Linhart, Y. B. (eds.): The evolutionary ecology of plants: 431Ð444. San Francisco. Urban, K. E. (2005a): Oscillating vegetation dynamics in a wet heathland. Ð J. Veget. Sci. 16: 111Ð120. Ð (2005b): Plant species dynamics during restoration of heath ponds in north-western Germany. Ð Phytocoenologia 35: 511Ð532. Valachovic, M., Otahelová, H. & Hrivnák, R. (2001): Isoeto-Nanojuncetea. Ð In: Valachovic, M. (ed.): Plant communities of Slovakia. III. Wetland vegetation: 345Ð373. Bratislava. Van Beers, P. W. M. & Dirkse, G. M. (2000): Koprus (Juncus capitatus Weigel) terug in Noord-Brabant door natuurontwikkeling. Ð Gorteria 26: 7Ð16. Vanden Berghen, C. (1969): La végétation amphibie des rives des étangs de la Gascogne. Ð Bull. Centr. Etude Rech. Sc. 7: 893Ð963. Ð (1979a): Observation sur la végétation de l’Ile de Djerba (Tunisie méridionale). III. Les dépressions dans les dunes littorales. Ð Bull. Soc. Roy. Bot. Belg. 112: 45Ð63. Ð (1979b): La végétation des sables maritimes de la Basse Casamance meridionale (Sénégal). Ð Bull. Jard. Bot. Nat. Belg. 49: 185Ð238.

Habitats, plant traits and vegetation of ephemeral wetlands

703

Ð (1982a): Premier aperçu sur la végétation aquatique de la basse Casamance (Sénégal méridional). Ð In: Symoens, J. J., Hooper, S. S. & Compère, P. (eds.): Studies in aquatic vascular plants: 266Ð271. Bruxelles. Ð (1982b): Observations sur la végétation littorale à Kafoutine (Basse Casamance, Sénégal). Ð Bull. Soc. Roy. Bot. Belg. 115: 107Ð120. Ð (1984): La végétation des sables de Djibonker, en Basse Casamance (Sénégal méridional). Ð Bull. Jard. Bot. Nat. Belg. 52: 211Ð224. Ð (1990a): La végétation des mares temporaires au Sénégal oriental. Ð Rev. Hydrobiol. Trop. 23: 95Ð113. Ð (1990b): La végétation des sables maritimes de la Casamance (Sénégal méridional). Ð Lejeunia, N. S. 133: 1Ð84. Ð (1997): La végétation des plaines alluviales et des terrasses sablonneuses de la Basse Casamance (Sénégal méridional). Ð Lejeunia, N. S. 154: 1Ð195. Van Donselaar, J. (1965): The Vegetation of Suriname. IV. An ecological and phytogeographic study of northern Suriname savannas. Ð Wentia, 14: 163p. = Meded. Bot. Mus. Herb. Utrecht 211. Ð (1968): Phytogeographic notes on the savanna flora of southern Suriname (South America). Ð Acta Bot. Neerl. 17: 393Ð404. Ð (1969): Observations on savanna vegetation-types in the Guianas. Ð Vegetatio 17: 271Ð312. Vasconcelos, T., Taveres, M. & Gaspar, N. (1999): Aquatic plants in rice fields of the Tagus Valley, Portugal. Ð Hydrobiologia 15: 59Ð65. Vega, E., Caudales, R. & Sánchez-Perez, A. (1997): New records of pteridophytes for Botswana. Ð Am. Fern J. 87: 127Ð130. Velayos, M., Carrasco, M. A. & Cirujano, S. (1989): Las lagunas del Campo de Calatrava (Ciudad Real). Ð Bot. Complutensis 14: 9Ð50. Vesey-Fitzgerald, D. F. (1963): Central african grasslands. Ð J. Ecol. 51: 243Ð274. Ð (1970): The origin and distribution of valley grassland in East Africa. Ð J. Ecol. 58: 51Ð75. Vevle, O. (1989): On dverg plante samfunn i Klassen Isoeto-Nanojuncetea i Norge. Ð Rapp. bot. ser. univ. Trondheim 1989(2): 57Ð86. Vicherek, J. (1968): Poznámky k cenologické afinité Myosurus minimus L. Ð Preslia 40: 387Ð396. Ð (1973): Die Pflanzengesellschaften der Halophyten- und Subhalophytenvegetation der Tschechoslowakei. Ð 200 p., Prag. Vitalis, R., Colas, B., Riba, M. & Olivieri, I. (1998): Marsilea strigosa Willd.: statut génétique et démographique d’une espèce menacée. Ð Ecol. Medit. 24: 145Ð157. Vives, J. (1964): Vegetación de la alta cuenca del Cardener. Estudio florı́stico y fitocenológico comarcal. Ð Acta Geobot. Barcinon. 1: 1Ð218. Vivian-Smith, G. (1997): Microtopographic heterogeneity and floristic diversity in experimental wetland communities. Ð J. Ecol. 85: 71Ð82. Vogel, A. (1999): Das Überleben von Corrigiola littoralis, Illecebrum verticillatum und Herniaria glabra (Illecebraceae) auf Industriebrachen und an Talsperrenufern in Nordrhein-Westfalen. Ð Mitt. Bad. Landesver. Naturkd. Naturschutz Freib. i. Br. 17(2): 323Ð335. Volk, O. H. (1984): Pflanzenvergesellschaftungen mit Riccia-Arten in Südwestafrika (Namibia). Ð Vegetatio 55: 57Ð64. Volk, O. H. & Leippert, H. (1971): Vegetationsverhältnisse im Windhoeker Bergland, Südwestafrika. Ð J. S. W. A. Wiss. Ges. Windhoek 25: 5Ð44. Wacker, M. & Kelly, N. M. (2004): Changes in vernal pool edaphic settings through mitigation at the project and landscape scale. Ð Wetlands Ecol. Manage. 12(3): 165Ð178.

704

U. Deil

Wang, Q. F., Xing, L., Taylor, W. C. & He, Z. R. (2002): Isoetes yungiensis (Isoetaceae) a new basic diploid quillwort from China. Ð Novon 12(4): 587Ð591. Wang, Z. Q. (1996): Recovery of vegetation from the terminal Permian mass extinction in North China. Ð Rev. Palaeobot. Palynol. 91: 121Ð142. Wardle, P. (1991): Vegetation of New Zealand. Ð 672 p., Cambridge. Ware, S. (2002): Rock outcrop plant communities (glades) in the Ozarks: A synthesis. Ð SW Nat. 47: 585Ð597. Watve, A. (2003): Vegetation on rock outcrops in Northern Western Ghats and Konkan region, Maharashtra. Ð Geobios (Jodhpur) 30: 41Ð46. Weber, H. E., Moravec, J. & Theurillat, J. P. (2000): International Code of Phytosociological Nomenclature. Ed. 3. Ð J. Veg. Sci. 11: 739Ð768. Wells, R. D. S., Clayton, J. S. & De Winton, M. D. (1998): Submerged vegetation of Lakes Te Anau, Manapouri, Monowai, Hauroko, and Poteriteri, Fiordland, New Zealand. Ð New Zealand J. Marine Freshwater Res. 32: 621Ð638. Wester, L. (1994): Weed management and the habitat protection of a rare species: a case study of the endemic Hawaiian fern Marsilea villosa. Ð Biol. Conserv. 68: 1Ð9. Western Australian Herbarium (1998Ð2005): FloraBase: The Western Australian Flora. Ð Department of Conservation and Land Management: http://florabase.calm.wa.gov.au. Accessed May 2005. Whitehead, P. J., Wilson, B. A. & Bowman, D. M. J. S. (1990): Conservation of coastal wetlands of the Northern Territory of Australia: the Mary River floodplain. Ð Biol. Conserv. 52: 85Ð111. Wichmann, M. & Burkart, M. (2000): Die Vegetationszonierung des Grünlandes am Südufer des Gülper See. Ð Verh. Bot. Verein. Berlin Brandenburg 133: 145Ð175. Wiegleb, G. (1991): Die Lebens- und Wuchsformen der makrophytischen Wasserpflanzen und deren Beziehungen zur Ökologie, Verbreitung und Vergesellschaftung der Arten. Ð Tuexenia 11: 135Ð148. Wienhold, C. E. & Van der Valk, A. G. (1989): The impact of duration of drainage on the seed banks of northern prairie wetlands. Ð Can. J. Bot. 67: 1878Ð1884. Wiggins, G. B., Mackay, R. J. & Smith, I. M. (1980): Evolutionary and ecological strategies of animals in annual temporary pools. Ð Arch. Hydrobiol. 58 (Suppl.): 97Ð206. Wigginton, M. J. (2004): Checklist and distribution of the liverworts and hornworts of sub-Saharan Africa, including the East African Islands (ed. 2, September 2004). Ð Trop. Bryol. Res. Rep. 5: 1Ð102. Willby, N. J., Abernethy, V. J. & Demars, B. O. L. (2000): Attribute-based classification of European hydrophytes and its relationship to habitat utilisation. Ð Freshwater Biology 43: 43Ð74. Willen, B. O. & Tiner, R.W (1993): Wetlands of the United States. Ð In: Whigham, D. F., Dykyjová, D. & Hejný, S. (eds): Wetlands of the world. I. Inventory, ecology, and management: 515Ð636. Dordrecht. Williams, D. D. (1987): The Ecology of Temporary Waters. Ð 205 p., London. Williams, W. D. (2000): Biodiversity in temporary wetlands of dryland regions. Ð Verh. Int. Verein Limn. 27: 141Ð144. Wilson, J. B., Watkins, A. J., Rapson, G. L. & Bannister, P. (1993): New Zealand machair vegetation. Ð J. Veg. Sci. 4: 655Ð660. Witham, C. W., Bauder, E. T., Belk, D., Ferren, W. R. & Ornduff, R. (eds.)(1998): Ecology, Conservation, and Management of Vernal Pool Ecosystems. Ð Proceedings from a 1996 Conference, California Native Plant Society, 284 p., Sacramento. Wittig, R. (2005): Echinochloetea colonae classis nova. Ð Etudes flor. vég. Burkina Faso 9: 11Ð18.

Habitats, plant traits and vegetation of ephemeral wetlands

705

Wolf, A. (1990): Vegetationskundliche Beobachtungen an Flachwasserseen nahe der Mündung des Rio Ypané, Paraguay. Ð Amazoniana 11: 167Ð184. Wyatt, R. (1981): Ant-pollination of the granite outcrop endemic Diamorpha smallii (Crassulacae). Ð Am. J. Bot. 68: 1212Ð1217. Ð (1983): Reproductive biology of the granite outcrop endemic Sedum pusillum (Crassulaceae). Ð Syst. Bot. 8: 24Ð28. Ð (1997): Reproductive ecology of granite outcrop plants from the south-eastern United States. Ð J. Roy. Soc. W. Austr. 80(3): 123Ð129. Wyatt, R. & Allison, J. R. (2000): Flora and Vegetation of Granite Outcrops in the Southeastern United States. Ð In: Porembski, S. & Barthlott, W. (eds.): Inselbergs: 409Ð433. Berlin, Heidelberg. Wyatt, R. & Fowler, N. (1977): The vascular flora and vegetation of the North Carolina granite outcrops. Ð Bull. Torrey Bot. Club 104: 245Ð253. Zammit, C. & Zedler, P. H. (1990): Seed yield, seed size, and germination behavior in the annual Pogogyne abramsii. Ð Oecologia 84: 24Ð28. Zedler, P. H. (1984): Micro-distribution of vernal pool plants of Kearny Mesa, San Diego County. Ð In: Jain, S. K. & Moyle, P. (eds.): Vernal pools and intermittent streams: 185Ð197. Davis. Ð (1987): The ecology of southern California vernal pools: a community profile. Ð U. S. Fish Wildl. Serv. Biol. Rep. 85(7.11): 136 p., Washington, D. C. Ð (1990): Life histories of vernal pool vascular plants. Ð In: Ikeda, D. H. & Schlising, R. A. (eds.): Vernal pool plants Ð their habitat and biology, Studies Herbarium 8: 123Ð 146. Chico. Zedler, P. H. & Black, C. (1992): Seed dispersal by a generalized herbivore: rabbits as dispersal vectors in a semiarid California vernal pool landscape. Ð Am. Mid. Nat. 128: 1Ð10. Zeilhofer, P. & Schessl, M. (1999): Relationship between vegetation and environmental conditions in the northern Pantanal of Mato Grosso, Brazil. Ð J. Biogeogr. 27: 159Ð 168. Zinderen Bakker, E. M. van (1965): Über Moorvegetation und den Aufbau der Moore in Süd- und Ostafrika. Ð Bot. Jahrb. Syst. 84: 215Ð231. Zinderen Bakker, E. M. van & Werger, M. J. A. (1974): Environment, vegetation, and phytogeography of the high-altitude bogs of Lesotho. Ð Vegetatio 29: 27Ð49. Zohary, M. & Orshansky, G. (1947): The Vegetation of the Huleh Plain. Ð Palest. J. Bot., Jerusalem Ser. 4: 90Ð104. Address of the author: Ulrich Deil, University of Freiburg, Institute of Biology, Dept. of Geobotany, Schänzlestrasse 1, D-79104 Freiburg i.Br., Germany. E-mail: ulrich.deil@biologie.uni-freiburg.de