The páramo vegetation of Ramal de Guaramacal, Venezuela. 1. Zonal communities - Cuello & Cleef 2009 by JPZ.

Phytocoenologia, 39 (3), 295–329 Berlin – Stuttgart, October 21, 2009

The páramo vegetation of Ramal de Guaramacal, Trujillo State, Venezuela. 1. Zonal communities by Nidia L. CUELLO A., Guanare, Venezuela and Antoine M. CLEEF, Amsterdam, The Netherlands with 10 figures, 4 photographs and 7 tables Abstract. Zonal páramo vegetation communities present on top of Ramal de Guaramacal, Trujillo state, Venezuela, have been studied with the aim to provide a syntaxonomic scheme or classification, based on analysis of the physiognomy, floristic composition, ecological relations and spatial distribution of the different vegetation communities. A total of 91 vascular species, 33 species of bryophytes and 11 species of lichens have been documented from fifty 10 mline intercept transects, each surveying 10 m of altitudinal interval on zonal páramo vegetation present between 2800 and 3100 m altitude. The interpretation of the TWINSPAN clustering allowed the recognition of five vegetation communities at association level grouped into two alliances and one order. Three associations of lower subpáramo or shrubby páramo and two of upper subpáramo or bunchgrass páramo dominated by rosettes and tussock plants have been documented. The alliance Hyperico par a m i t a n u m -H e sp e ro m e l e t i o n o b t u si f o l i a e groups the shrubby páramo associations: Ruilopezio paltonioi d e s-Ne u ro l e p i d e t u m g l o m e ra t a e and D i st e ri g m o a c u m i n a tum-Arcytophylletum nitidum, present on wind protected slopes, dwarf forests edges or along streams. The alliance Hyperico cardonae–Xyridion ac u t i f o l i a e groups one widely distributed shrubby páramo association Co rtaderio hapalotrichae-Hyperice t u m j u n i p e ri n u m and two open grass páramo associations: P u y o aristeguietae-Ruilopezietum lopez-pal a c i i and R h y n c h o sp o ro g o l l m e ri -R u i l o p e z i e t u m j a b o n e n sis, present on wind exposed slopes. Asteraceae and Ericaceae are the most speciose of families, followed by Poaceae and Cyperaceae. The most diverse genera are Ruilopezia (Asteraceae), Rhynchospora (Cyperaceae) and Hypericum (Clusiaceae). Diversity of species and growth forms is greater among the shrubby communities, decreasing in the bunch grass-rosette communities. Canonical correspondence analysis (CCA) indicates that floristic composition of zonal vegetation communities is mostly related to slope angle and altitude than to other observed variables such as pH, soil depth and humus depth. The generic and species composition is that of a rain bamboo páramo. eschweizerbartxxx ingenta

Keywords: ﬂoristic composition, phytosociology, zonal bamboo páramo, Chusquea, Espeletiinae, Andes, Venezuela. Abbreviations: UFL = Upper Forest Line; SARF = Subalpine Rain Forest or high Andean forest; UMRF = Upper Montane Rain Forest or Andean forest.

Introduction Andean páramos play an essential role in the evolution and the ecology of the Andes (Vuilleumier & Monasterio 1986, Luteyn 1999, Hofstede et al. 2003, Hooghiemstra et al. 2006) and represent strategic ecosystems due to the environmental services they offer in the regional hydrological balance and agricultural production (Molinillo & Monasterio 1997, 2002; Monasterio & Molinillo 2003; Hofstede et al. 2003). Andean páramos are also, however, highly fragile ecosystems as a function of mounting demographic pressures, the expansion of agricultural and mining activities and of global warming, all of which represent major threats to the maintenance of environmental services and for the conservation of Andean biodiversity (Hofstede 2002, Van der Hammen 2002, Llambi et al. 2005). Since the publication of the ‘Flora de los Páramos de Venezuela’ by Vareschi (1970), a substantial number amount of studies in but a few Venezuelan páramos has been published. The ecological studies by M. DOI: 10.1127/0340 – 269X/2009/0039– 0295

Monasterio and (own staff/foreign) collaborators (Monasterio 1980a, Sarmiento et al. 2003) were developed primarily in the central core of dry páramos in the state of Mérida. They remain ongoing in these páramos with highest altitude and most extension of the Cordillera of Mérida. At present, a great number of studies by researchers from the ICAE-ULA-Mérida, are available (see Sarmiento 2006 CD-ROM). These studies are mostly concerned with ecophysiology and functional processes in both natural and agro-ecosystems of the páramo and as such, remain unique in that there are not similar groups of this magnitude and focus elsewhere in the tropical Andes and high mountains of Central America and Mexico. Despite a great environmental variability throughout a number of páramo areas and their associated vegetation communities along of the Cordillera de Mérida (Monasterio & Reyes 1980, Monasterio 1980, Luteyn, 1999), little is currently known about páramo vegetation communities and their ﬂora in other sectors of the Venezuelan Andes beyond the borders of Mérida state. To date, local ﬂoristic list0340 – 269X/09/0039 – 0295 $ 15.75 © 2009 Gebrüder Borntraeger, D-14129 Berlin · D-70176 Stuttgart

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ings have appeared that include páramo areas such as those from Táchira and Trujillo states (Bono 1996, Dorr et al. 2000), there is a list of flowering plants of Venezuelan páramos (Briceño & Morillo 2002, 2006) and phytogeographical analyses of the páramo flora (Ricardi et al. 1997, 2000). Studies of classification and characterization of the vegetation communities in páramos of the Venezuelan Andes are limited to the descriptions of different sectors of Sierra Nevada de Mérida (Vareschi 1953, 1956, Baruch 1984, Berg 1998, Berg & Suchi 2000, Yánez 1998) and, as outlined above, to a general descriptive account for the whole region (Monasterio 1980b), floristic lists with comments on vegetation communities of páramos of Táchira state (Bono 1996) and a brief description of a selected area of Páramo Cendé in Trujillo state (Niño et al. 1997). In comparison, a much larger body of literature on plant diversity and vegetation exists for Colombian páramos (Cuatrecasas 1934, 1958, Cleef 1981, Sturm & Rangel 1985, Van der Hammen et al. 1983, 1984, 2003, 2005, 2008, Rangel 2000a, among others). Luteyn (1999) and Rangel (2000a) provide a summary of the flora and vegetation studies conducted throughout the last century in Colombian páramos. Previous studies divided the north Andean páramo vegetation into several zones related to altitude (for a complete review we refer to Luteyn 1999). The Cuatrecasas (1934, 1958) altitudinal classification of superpáramo, páramo and subpáramo has since been widely adopted (Cleef 1981, Acosta-Solís 1984, Ramsay 1992, Jørgensen & Ulloa 1994, Hooghiemstra et al. 2006). For Venezuelan páramos, Monasterio (1980b) recognises two altitudinal zones called ‘pisos altitudinales’: a High Andean zone or ‘Piso Altiandino’ (4000–4800 m) and the Upper Andean zone or ‘Piso Andino Superior’ (2800–4000 m) with a total of seven vegetation formation types and thirty four vegetation communities or “associations”. There are three vegetation types from the ‘Piso Altiandino’, called 1) the High Andean Desert Páramo or ‘Páramo Desértico Altiandino’, 2) the High Andean Periglacial Desert or ‘Desierto Periglacial Altiandino’ and 3) the High Andean Forest of Polylepis sericea. Many authors agreed that the ‘Piso Altiandino’ and the Superpáramo represent equivalent vegetation zones (Berg 1998, Luteyn 1999, Berg & Suchi 2000). In the ‘Piso Andino’ zone, the four vegetation types recognized are 4) the Andean Páramo or ‘Páramo Andino’, which includes heterogeneous páramo vegetation associations dominated either by rosettes or shrubs; 5) the Andean Grass Páramo or ‘Pajonal Paramero Andino’, including páramo vegetation associations with high cover of tussock grasses; 6) the Andean Pasture Páramo or ‘Pastizal Paramero Andino’, which is represented by vegetation associations with high cover of other non-tussock grasses; and 7) the Andean Páramo Forest or ‘Bosque Paramero Andino’ (Monasterio 1980b). The wet páramo of Guaramacal found on the high summits of Ramal de Guaramacal (Fig. 1), has

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previously been reported as an important center of diversification of the genus Ruilopezia of the Espeletiinae (Cuatrecasas 1986). Moreover, due to its relative isolation, Ramal de Guaramacal is also an area with an endemic flora (Steyermark 1979, Ortega et al. 1987, Dorr et al. 2000). An important number of new and endemic species have been described from the forests and páramos of Guaramacal (Morillo 1988, Axelius & D’Arcy 1993, Carnevali & Ramírez 1998, Aymard et al. 1999, Benítez & Sawyer 1999, Taylor 2002, Stančik 2004, Stergios & Dorr 2003, Niño et al. 2005, Cuello & Aymard 2008). Endemic species of the Guaramacal subpáramo-páramo flora include: Elaphoglossum appressum Mickel, Epidendrum guaramacalense Hágsater, Festuca guaramacalana Stančik, Ilex guaramacalensis Cuello & Aymard, Libanothamnus griffinii (Ruiz-Terán & López-Fig.) Cuatrec., Miconia aymardii Wurdack, M. elvirae Wurdack, Rhynchospora guaramacalensis Strong and Ruilopezia lopez-palacii (Ruiz-Terán & López-Fig.) Cuatrec., among others. The zonal vegetation of the Páramo of Guaramacal is generally characterized by a mosaic of subpáramo formations (shrub páramo, bunchgrass páramo, most common bamboo páramo), intermingled with patches of dwarf forests. The páramo vegetation is distributed between 2800 and 3130 m. Due to its low altitude, the Páramo of Guaramacal has been catalogued by some authors as a subpáramo (Cuatrecasas 1986, Luteyn 1999). For the purpose of this paper, subdivison of subpáramo and grass páramo, each in a lower and higher subzone, we refer to Cleef (1980, 1981). Zonal and azonal vegetation is defined sensu Walter (1979). Zonal vegetation corresponds to the present vegetation as a function of the actual regional macroclimate. Zonal vegetation occurs on zonal soils and represents the majority of vegetation within the study area. Azonal vegetation is dependent on the special substrate conditions, such as where stress by water or dryness is experienced. Azonal vegetation communities in concave terrain is represented by peat bogs, mires or aquatic vegetation in the Guaramacal bamboo páramo, were treated separately (Cuello & Cleef, 2009b). The primary goal of the present study is to identify, define and characterize the zonal vegetation of Páramo de Guaramacal, and to establish a syntaxonomic scheme based on analysis of physiognomy, floristic composition, ecological relations and the altitudinal distribution of the different vegetation communities also in comparison to bamboo páramos elsewhere. This work was carried out within the wider framework of a project aiming to study the diversity of flora and vegetation of the Guaramacal National Park (Cuello 1999, 2000, 2002, 2004, Dorr et al. 2000). Classification of forest vegetation and azonal páramo communities in Ramal de Guaramacal are described separately elsewhere (Cuello & Cleef 2009a, 2009b).

The pรกramo vegetation of Ramal de Guaramacal, Trujillo State, Venezuela. 1. Zonal communities

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Fig. 1. Location of study area in the Venezuelan Andes.

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Study area Zonal páramo communities of the summit of Ramal de Guaramacal have been studied between 2800– 3100 m, in the surroundings of ‘Las Antenas’ area (9° 14’ 1.02” N; 70° 11’ 6.47” W) and Páramo El Pumar (9° 12’ 45.6” N; 70° 12’ 5.55” W), 2.5 km Southwest of ‘Las Antenas’. Ramal de Guaramacal is an outlier of the Venezuelan Andes, located South from the town of Boconó, Trujillo state, approximately 120 km Northeast of Mérida, in the centre of the Sierra Nevada de Mérida (Fig. 1). The climatic characteristics of high humidity with permanent fog favour the development of abundant ground cover of Sphagnum spp. characteristic of the zonal shrub páramo vegetation associations and border of forests. This condition is very common all over the páramo areas of Ramal de Guaramacal and is not considered here as an azonality. First climatic records from a Davis Pro 2 climate station installed near the summit of Guaramacal (3100 m) by the ﬁrst author since December 2006 to December 2007 (monthly precipitation in mm and monthly temperature in Celsius), registered a total amount of yearly rainfall of at least 2995.4 mm (some data were lost during some days in the most rainy months of june and july 2007). Relative humidity is extraordinary high, with a mean humidity of 96.88 % throughout the year. The lowest mean relative humidity was observed in the month of February with a value of 92.35 %. Mean temperature is 8.6°C, the lowest temperatures of 1.3 °C are recorded in December and January and the highest temperature of 18.6 °C in March. Detailed data of the Davis Pro 2 climate station are intended to be published in a forthcoming paper on the upper forest line (Cuello et al. in prep.). For a more complete description of the study area the reader is referred to Cuello (1999) and Cuello & Cleef (2009a).

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Methods Field Sampling Fieldwork on the zonal páramo vegetation of the Guaramacal range was conducted over a short altitudinal gradient between 2800 and 3100 m. Observations, general collections and quantitative sampling using line-intercept methods (Barbour et al. 1987), were conducted here. Lines of 10 m were laid down at ca. 10 m altitudinal intervals on patches of vegetation with an apparently homogenous structure and composition; however, on occasion, it happened that the line also crossed other vegetation type(s). To avoid this, each line was divided into two sections of 5 m, a perpendicular 5 m line was then situated close to the ﬁrst 5 m of the line to complete the 10 m. In few cases, some of those 5 m line segments on mixed vegetation were later excluded for the analysis. The horizontal measurement of interception of every plant species

(vascular plants and cryptogams) touching the line was performed. The measurement of height and location of the plant with respect to the line was also registered, and together with measurements of relief variation each 25 cm, were used for drawing of vegetation and land form profiles. For the delineation of relief a cord extended horizontally along the length of the line (tape measure) leveled with a bubble level, was used as a reference. Soil sampling with an auger from 15 cm depth were conducted at the centre of each 5 m line interval. Soil pH and conductivity were later determined in the laboratory. A total of fifty observations sites and a hundred 5 m line sections were surveyed. At each observation site, information on topography, exposition, slope, geographic position (UTM coordinates), altitude and floristic composition were recorded. Botanical vouchers of all recorded species, including those with doubt as to their identification, equally found beyond the lines of interception as within were collected. Photographs, where possible, were also taken. The collected botanical material was processed, identified and deposited at Herbario Universitario PORT of UNELLEZ. For vascular plants, the nomenclature follows that of Dorr et al. (2000). Duplicates of mosses and lichens were sent to Dr. D. Griffin III (FLAS) and Dr. H.J.M. Sipman (B), respectively, for their identification. Additional duplicates were also deposited in MER, VEN and US. The collection number referred to is that of the first author. Processing and data analysis Data for each survey were stored and processed using Microsoft Excel. For each species in each line section of zonal vegetation surveyed, the sum of the intersection and a percentage value of cover and relative cover were calculated. Percentage cover for each species is equal to the total sum of intersection for the species, multiplied by 100, then divided by the length of the line. Relative cover for each species is equal to the total sum of intersection for the species in the line, multiplied by 100, then divided by the total sum of intersections of all species. The number of individuals, relative abundance and the frequency of a species, based on the number of appearances of the species throughout 1 m sections of the line, were also computed. A data matrix containing the percentage of relative cover of 91 vascular species recorded for ninety one 5 m-line surveys was processed with TWINSPAN (Hill 1979) using program PC-Ord 4 (McCune & Mefford 1999). Vegetation data were then interpreted in terms of syntaxonomical classification, based on cover and floristic affinities, following the ZürichMontpellier approach (Braun-Blanquet 1979) and the International Code of Phytosociological Nomenclature (Weber et al. 2000).

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The diverse subunits, recognized in a progressive way by the TWINSPAN procedure, were hierarchized in associations, and higher (alliances, order) and lower syntaxa (subassociations and variants). In order to explore relationships between the species composition of vegetation types and some of the environmental variables measured in this study (altitude, slope angle, soil and humus depth), an ordination analysis, using canonical correspondence analysis (CCA), also available in the PC-Ord package, was performed.

p alto n ioides–Cy b ian th ion margin ati (Cuello & Cleef 2009a). They are growing in combination with high densities of tussock grasses dominated by Cortaderia hapalotricha, and the bamboo Chusquea angustifolia together with shrubs (up to 2 m) and proper woody páramo species, such as Hypericum juniperinum, Arcytophyllum nitidum, Chaetolepis lindeniana, among other species of Hypericum, Asteraceae and Ericaceae.

Results

The zonal upper subpáramo vegetation corresponds to open vegetation pertaining to the new Hyp erico card o n ae–Xyridion acu tifoliae alliance. This upper subpáramo vegetation extends in greater proportion on low inclined convex slopes, and is represented by grass páramo of the Puyo aristegu ietae–Ruilo p ezietu m lo p ez-p alacii; bordered by or combined, with the vegetation of the new association Co rtaderio hapalo trichae– Hyp ericetu m ju n iperin u m. There, the grasses Cortaderia hapalotricha and Chusquea angustifolia also predominate, with variable densities of rosettes of Ruilopezia lopez-palacii and Puya aristeguietae, prostrate herbs and a variable density of woody individuals among which the single-stemmed leptophyllous dwarfshrub (1.5 m) Hypericum juniperinum stands out. Towards the highest altitude (2900–3100 m), the open páramo vegetation of the (new) association Rh y n cho sp o ro gollmeri– Ru ilo p ezietu m jabo n ensis, located on concave slopes or in small depressions, is present. In this, the small (prostrate and erect) shrubs are absent (or very rare) and the ‘frailejón’ that dominates is the ground rosette Ruilopezia jabonensis. Cushion Cyperaceae, like Rhynchospora gollmerii, and prostrate herbs occur more commonly. Another vegetation type present in Páramo de Guaramacal is the bamboo-páramo (‘chuscales’) of the Carici bonplandii–Chusqueetum angustifoliae association (Cuello & Cleef, 2009b), characterised almost exclusively by Chusquea angustifolia. The ‘chuscales’ of this association are located on humid, slightly sloping, ground of valleys or adjacent to lakes. They are considered azonal vegetation since they are periodically inﬂuenced by ﬂood. As one moves away from the chuscales, the density of individuals of Hypericum juniperinum increases, the number of clumps of Chusquea angustifolia bamboos decreases, and other grasses, rosettes and small shrubs appear conforming the vegetation of the corresponding association which is either Cortaderio h apalo trich ae–Hy p ericetu m jun iper inum or that of P u y o aristeguietae–Ruilo p ezietum lop ez-p alacii.

Zonal subpáramo plant communities Interpretation of the TWINSPAN table allowed recognition of 5 vegetation communities at association level, grouped into two alliances and one order (Table 1). The zonal subpáramo plant communities recognized in Ramal de Guaramacal are summarized as follows: A. Ruilopezio lopez-palacii–Chusqueetalia angustifoliae ord. nov. prov. I. Hyperico paramitanum–Hesperomeletion obtusifoliae all. nov. 1. R u il o p e z io p a l to ni o i de s– N e u rol epidet u m g l o me ra ta e ass. nov. 1.1. variant of Disterigma alaternoides 1.2 variant of Ugni myricoides 2. D is t e r i g mo a c u m i n a tu m – Arc y top h y lle t u m n i t id um ass. nov. 2.1. pentacalietosum cachacoensis subass. nov. 2. 2. subassociation typicum nov. II. Hyperico cardonae–Xyridion acutifoliae all. nov. 3. C o r t a d e r io h a p a l o tri c h a e – H yp e ri cetum j u n ip e r in um ass. nov. 3.1. subassociation typicum nov. 3.2. disterigmetosum acuminatum subass. nov. 4. P u y o a r iste g ui e ta e – Ru i l op e z i e tu m lop e z - p a la c i i ass. nov. 5. R h y n c h o s p oro g ol l m e ri – R ui l o pe z ietum j a b o n e n s i s ass. nov.

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Lower Subpáramo The zonal vegetation of the Guaramacal subpáramo corresponds to very dense shrub formations, growing on concave or wind protected slopes, forming the transition to high Andean forest (Subalpine rain forest or SARF). The subpáramo vegetation is represented by the new alliance H yp e ri c o pa ra m i tanu m– H e s p e r o m e l e t i on ob tusi fo l i a e , composed of two new associations Ru i l op e z i o pa l ton i oides– N e u r o l e p id e t u m g l o m e ra ta e and D i ste r igmo a c u m i n a t u m – Arc y top hy l l e tu m n i ti du m. Several species of small trees (typical) of the high-Andean forest are common, especially from the Ru i l op ezio

Upper Subpáramo

Ruilopezio lopez-palacii–Chusqueetalia angus tifoliae ord. nov. prov. Representative alliance: Hyp erico p aramitanum– Hesp eromeletion o b tu sifoliae (this study).

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Provisional order of zonal humid lower páramo of Ruilopezia lopez-palacii and Chusquea angustifolia / Orden provisional de páramo húmedo bajo zonal de Ruilopezia lopez-palacii y Chusquea angustifolia. Physiognomy and composition: A vegetation mosaic of very humid subpáramo and páramo, with rosettes and bamboos growing among patches of ecotonic dwarf forest. A variety of growth forms is characteristic, including: acaulescent and stem rosettes, dwarf trees, small (upright and prostrate) shrubs; epiphytic, erect prostrate and trailing herbs, and grass tussocks and bamboos. Also noticeable are a variety of ferns and a dense cover of bryophytes and lichens. Locally appear patches of reddish Sphagnum mosses. Diagnostic species are: Chaetolepis lindeniana, Chusquea angustifolia, Cortaderia hapalotricha, Daucus montanus, Geranium stoloniferum, Hymenophyllum trichomanoides, Jamesonia imbricata, Lycopodium contiguum, Pernettya prostrata, Rhynchospora guaramacalensis, R. macrochaeta and Ruilopezia lopezpalacii. Syntaxonomy: This provisional order is deﬁned on the basis of 91 line-intersect surveys with 85 vascular species. This order groups both the alliances of humid shrub subpáramos of Hyperico paramitanum–Hesperomeletion obtusifoliae and Hyperico cardonae–Xyridion acutifoliae of shrub páramos and grassy lower subpáramos. Ecology and distribution: The order uniﬁes all communities of zonal vegetation (excluding dwarf forests) present in the summit region of Ramal de Guaramacal between 2800 and 3130 m.

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Hyperico paramitanum – Hesperomeletion obtusifoliae all. nov. Typus: Ruilopezio paltonioides–Neurolepidetum glomeratae (this study). Shrub páramo of the Hypericum paramitanum and Hesperomeles obtusifolia alliance / Subpáramo de arbustales de la alianza de Hypericum paramitanum y Hesperomeles obtusifolia. Physiognomy and composition: This alliance groups vegetation communities with a high proportion of shrubs and dwarf tree species. The shrubpáramo displays variable densities of Ruilopezia paltonioides and R. lopez-palacii stem rossettes, within a matrix of Cortaderia hapalotricha tussock grasses and Chusquea angustifolia bamboos. These shrub formations can reach heights of 1.5–2 m, occasionally reaching upwards of 3 m in wind protected areas. In the understorey, very common low shrubs of Hypericum paramitanum and prostrate shrubs of Disterigma acuminatum are present. A variable density of the tall and wide-leaved bamboo Neurolepis glomerata and an abundant turf cover of Sphagnum and other bryophytes are distinctive Dwarf tree species of high Andean forest (or subalpine rain forest, SARF) are common, such as: Cy-

bianthus laurifolius, C. marginatus, Gaultheria erecta, Hesperomeles obtusifolia, Ilex guaramacalensis, Libanothamnus griffinii, Miconia tinifolia, Myrsine dependens, and Vaccinium corymbodendron. Also present are typical open páramo dwarf treelets, such as: Ageratina theifolia, Hypericum juniperinum and Hesperomeles sp. Between the shrubs, and distinctive in the sequence of abundance, are: Hypericum paramitanum, Chaetolepis lindeniana, Arcytophyllum nitidum, Ugni myricoides, Disterigma alaternoides, Pentacalia cachacoensis, Valeriana quirorana, Gaultheria anastomosans, Diplostephium obtusum, Pentacalia greenmaniana, Hypericum juniperinum x cardonae. Small ericaceous prostrate shrubs including: Disterigma acuminatum, Pernettya prostrata, Gaultheria hapalotricha, Themistoclesia dependens and Sphyrospermum buxifolium are also present. Apart of the prominent bamboos Chusquea angustifolia and Neurolepis glomerata are also important tussocks of Cortaderia hapalotricha, Rhynchospora guaramacalensis and R. macrochaeta. Other species include herbs like Daucus montanus, Epidendrum frutex, Hypericum cardonae, Geranium stoloniferum, Nertera granadensis and ferns and clubmosses such as: Elaphoglossum cf. lingua, Eriosorus flexuosus, Huperzia amentacea, Jamesonia imbricata, Lycopodium clavatum subsp. contiguum, Polypodium funckii, Hymenophyllum myriocarpum, H. trichomanoides, Melpomene flabelliformis, M. moniliformis and M. xiphopteroides. The trailings Rubus acanthophyllos and Muehlenbeckia tamnifolia are also present. Syntaxonomy: Thirty-eight line-intersect surveys are recognized as belonging to this alliance with a total of 65 vascular species accounting for species richness. Diagnostic species for the alliance are: Blechnum schomburgkii, Cybianthus marginatus, Hesperomeles obtusifolia, Hypericum paramitanum, Libanothamnus griffinii and Neurolepis glomerata. This new provisional alliance contains two associations: Ru ilo p ezio p alto n ioides–Neu rolepidetum glo meratae and Disterigmo acuminatum–Arcyto p h y lletum nitid u m. Ecology and distribution: This alliance groups zonal vegetation characteristic of humid shrub subpáramo in the páramo-forest ecotone. Vegetation of this type is situated mainly on predominantly convex slopes between 2830 and 3080 m, with slopes between 5 to 48 degrees. The soils are, in general, comparatively deep, with a layer of organic matter, sand-muddy textures and acidic (average pH 3.8) in the superficial layers. The associations of this alliance share many species in common with those of dwarf forests alliance of Ruilo p ezio p alto n iod es–Cy b ian thion marginatus, and may be contiguous in the field, however, differences in ecology (soil depth, light exposition, humidity level in underbrush) and the presence of proper open páramo diagnostic species in the

The páramo vegetation of Ramal de Guaramacal, Trujillo State, Venezuela. 1. Zonal communities

shrub páramo associations help to difference between alliances. 1. R u il o p e z io pa l ton i oi d e s– N e uro l e p i detu m g l o m e r a t a e ass. nov. Typus: Rel. No. 3 (Cuello L48b). Table 1. Fig. 2. Photo 1. Humid shrub páramo of Ruilopezia paltonioides and Neurolepis glomerata / Pajonal-arbustal de subpáramo húmedo de Ruilopezia paltonioides y Neurolepis glomerata. Physiognomy and composition: Shrub community with a high density of tall tussock grasses and wideleaved bamboos (1–1.5 m) and between 35–50 % cover, growing among a layer of dwarf trees and dispersed shrubs (Fig. 2). Tall conspicuous espeletioid stem rosettes reaching 2 (3) m with 15 to 25 % cover are also present. The upper layer is composed of discrete Chaetolepis lindeniana, Hesperomeles obtusifolia, Hypericum paramitanum and Ugni myricoides shrubs, together with tall (2–3 m) Ruilopezia paltonioides stem rosettes and lower ones of Ruilopezia lopez-palacii and Blechnum schomburgkii. In the tall grass layer, ad-

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ditional to the dominance of Neurolepis glomerata (20–40 % cover), Chusquea angustifolia and Cortaderia hapalotricha are also present. Further, there is also a low herb layer containing prostrate shrubs Disterigma acuminatum and Pernettya prostrata, the sedges Rhynchospora guaramacalensis and R. macrochaeta, small herbs like Daucus montanus, and the ferns Jamesonia imbricata and Lycopodium clavatum subsp. contiguum, growing over a turf of Sphagnum sparsum and S. meridense among other bryophytes. Syntaxonomy: This association is defined on the basis of 10 line-intersect surveys, with a total of 41 vascular species. Ruilopezia paltonioides and Neurolepis glomerata are diagnostic. Other diagnostic species in this association include: Disterigma alaternoides, Pentacalia greenmaniana and Sphyrospermum buxifolium. Two provisional variants are distinguished for this association: a variant of Disterigma alaternoides and a variant of Ugni myricoides. Ecology and distribution: Transitional ecotonic shrubby vegetation of the humid subpáramo located close to the upper forest line, consisting of (subalpine rain forests or SARF sensu Grubb, 1977) of Libanothamnus griffinii, and Gaultheria anastomosans and Hesperomeles obtusifolia dwarf forests (Cuello & Cleef, 2009a). This association has been observed between 2860 to 3000 m on concave or convex slopes with NW-SE exposition and slope angles between 18 and 30 degrees. This community can also be found near rock outcrops or along fractured rocks crossed by small streams. The soils are 38–106 cm deep, loamy to loamsandy loam in texture, with gray to brown yellowish colours and of pH 3.6 to 3.9 in the upper layer. 1.1. variant of Disterigma alaternoides Physiognomy and composition: Dense shrubbygrass vegetation dominated by Neurolepis glomerata bamboo clumps (1–1.5 m, 35–40 % cover), a layer of discrete shrubs and dwarf trees (2–3 m, 20–25 % cover) and small prostrate shrubs in the interior. Species composition is as described for the association. Diagnostic species are Disterigma alaternoides, Sphyrospermum buxifolium, Pentacalia greenmaniana and Vaccinium corymbodendron. This variant is distinguished from the variant of Ugni myricoides by the low presence of Cortaderia hapalotricha and a greater presence of Chusquea angustifolia. Ecology and distribution: This variant corresponds to the vegetation of the association of Ruilopezia paltonioides and Neurolepis glomerata located at altitudes of around 3000 m, generally transitional and adjacent to dwarf forests of Libanothamnus griffinii.

Photo 1. Closer view of a shrub páramo vegetation of the R u i l o p ezio p altonioides–Neurolepidetum glomera t a e on the border of a patch of dwarf forest at ~2890 m in Páramo de Guaramacal, Ramal de Guaramacal, Andes, Venezuela. Notice the dominance of the tall stem rosette Ruilopezia paltonioides.

1.2 variant of Ugni myricoides Physiognomy and composition: Dense shrubbygrass vegetation of high Neurolepis glomerata clumps (15–20 %), dispersed shrubs (15–20 %) and a high

302

N. L. Cuello A. & A. M. Cleef

Table 1. Phytosociological table of zonal pĂĄramo vegetation of Ramal de Guaramacal, Andes, Venezuela. Releve number ReleveÂ´ (field number)

47a 47b 48b 32b 48a 39a 39b 11a 32a

10 3a

12a 12b

13 2a

19a 19b

16 2b

46a 46b

19 3b

45a 45b 29b 37a 29a 18b 34a 34b 43a 43b 18a 31a 31b 49b

34 7a

17a 17b 37b

38 7b

(m)

Slope exposition

NW NW

Slope angle (degrees)

NW NW NW 30

NW NW 13

SW SW

NW NW 24

Slope shape

Soils depth (cm)

106

>90

>80

>55

35 >110 53

3.5* 3.5* 3,70 3,7

3,7

4,5

3,7

3,8

4,2

3,8

3,7

3,4

3,7

FLA

FaL

4,0

3,7

4,0

3,6

3,9

3,7

3,9

3,7

3,8

4,0

3,3

3,5

3,7

3,9

4,0

4,1

Soils texture

FAa

Fla

FaL FaL

FLa

No. vascular species

15 17 10 12 14 12 17 19 16 17 18 18 16 22 17 20 19 11 13 18 17 21 17 14 18 18 14 16 17 15 11 15 16 17 13 13

% outcrops and/or bare soil

% Cov. Shrubs & dwarf trees >60 cm

100

<1 20

% Cov. Grasses & rosettes > 10 cm

100

% Cov. Ground < 10 cm (including Cryptogams)

% Cov. Small shrubs < 60 cm

Order

HYPERICO PARAMITANUM - HESPEROMELETION OBTUSIFOLIAE

Alliance

1. Ruilopezio - Neurolepidetum glomeratae

Association

2. Disterigmo acuminatum - Arcytophylletum nitidum 2.1. pentacalietosum cachacoensis

subasociacion

2.2. typicum

Variant

1. Ruilopezio paltonioides - Neurolepidetum glomeratae Ruilopezia paltonioides . 4 . . 3 Disterigma alaternoides 1 . 1 Nertera granadensis 1 . 2 Pentacalia greenmaniana . . 2 Sphyrospermum buxifolium . 2. Disterigmo acuminatae - Arcytophylletum nitidum . . Disterigma acuminatum 1 . . Gaultheria hapalotricha 1 . . Arcytophyllum nitidum 1 . . Ageratina theifolia . . . Galium hypocarpium . . . Polypodium funckii . . . Eriosorus flexuosus . . . Hymenophyllum myriocarpum . 2.1. pentacalietosum cachacoensis . . Pentacalia cachacoensis . 4 3 Vaccinium corymbodendron . . . Melpomene moniliformis . . . Gaultheria anastomosans . . . Themistoclesia dependens . Hesperomeles sp. . . . 2.2. typicum . . Ugni myricoides . . . Rubus acanthophyllos . . . Ilex guaramacalensis . . . Valeriana quirorana .

3 2 . 1 .

4 2 . . .

2 . . . .

. . 1 . .

4 . . . .

3 . . . .

3 . 1 . .

2 . . . .

. . . . .

. 5 . . .

. . . . .

. 3 . . .

3 . . . .

. . . . .

4 . . . .

. . . . .

1 . . . .

. . . . .

3 . . . .

. . . . .

1 . . . .

. . . . .

. . . . . . . .

1 . . . . . . .

3 . . . . . . .

. . . . . . . .

4 . . . . . . .

4 1 . 2 . . . .

5 1 . 1 . 1 . .

3 1 . . . . . .

4 2 4 1 . . . .

4 2 2 . . . 1 .

2 1 . . . . . .

5 1 4 . . . . .

4 . 2 . . . . .

4 . . 1 . . . .

5 . . . . . . .

2 1 . . 1 . . 1

2 . . 2 . . . .

3 1 . . 2 . . 1

4 1 4 . . . . .

3 . . . . . . .

4 1 . . . . 1 .

3 1 1 . . . . .

4 . 1 . . . . .

2 . 2 . . . . .

4 1 3 . . . . .

4 . 2 . . . . .

2 . 2 . . . . .

4 . 1 3 . . . .

4 2 4 . . . . .

4 . . . . . . .

1 . 4 . . 1 . .

. . . . . .

. . 1 . 2 .

. 1 1 2 . .

1 1 1 2 . .

2 1 . 2 . .

. 4 . 2 . .

. . 1 . 1 .

3 2 1 . 3 .

2 2 1 1 . .

2 2 3 . . .

. . . . . .

1 . . . . .

2 1 . . . .

3 . . . . .

3 . 1 1 . 2

. . . . 1 .

. . . . . .

. . . 2 . .

. 2 . . . .

. . . . . .

3 . . . . .

. . . . . .

. . . .

1 . . .

3 . . .

. . . .

2 . . .

. . . .

1 . . .

. . . .

2 . . .

. . . .

3 1 . .

. . . .

1 2 . .

. 2 . .

3 . 1 .

1 1 1 .

. . . .

2 1 . 1

2 1 . .

. . . 5

. . 1 .

. . . .

2 . . .

. . . .

. 1 5 . . . 2 . . . . . . . .

1 2 5 1 . 2 2 . . . . . . . .

2 3 3 . . 3 . . . . . . . . 3

2 3 . . 1 . . . 4 . . . . 3 .

2 2 2 5 . . . . 2 1 . . 2 . .

. 2 1 3 3 6 . . . . . . . . 2

1 2 2 4 5 . . . . . . . 2 . .

. 3 1 . 4 6 . . . . . . . . 2

3 2 2 1 4 6 . . . . . . . 1 .

4 1 4 4 4 . . . . . . . . 3 .

4 2 2 1 2 . . . . 2 2 . . . .

4 2 . 4 2 . 4 1 . . . . . . .

5 2 . 2 2 2 . . . . . . . . .

2 4 . 4 . . 3 . . . . . 1 . .

. 4 . . 2 . 3 . . . . . . . .

2 4 . . 2 . . . . . . . 1 . .

4 1 . . . . 5 . 3 . . 1 2 . .

5 . . . . . . 1 . . . . . . .

4 1 . 4 . . 4 . . . . . . . .

4 2 1 . 2 . . . . . . . . . .

5 . . . . . . 1 . . . . . . .

4 . . . . . . . 1 . . . 1 . .

4 4 4 1 1 4 . . . . . . . . .

4 3 . . . . . . . . . . . . .

. 2 4 . . . . 1 . . . . . . .

4 1 3 1 . . . . . . . . . . .

4 2 5 . . . . . . . . . . . .

. 3 . . . . . . . . . . . . .

3 3 . . . . . . . . . . . . .

. 1 . . 1 . . 1 . . . . . . .

. 3 . . 1 . . 1 . . . . . 4 .

2 . . . . . . . . . . . . . .

2 3 . . . . . . . . . . . . .

HYPERICO PARAMTANUM - HESPEROMELETION OBTUSIFOLIAE Blechnum schomburgkii 1 3 3 3 . 3 4 Hypericum paramitanum 1 Neurolepis glomerata 5 5 5 . . . . Cybianthus marginatus . Hesperomeles obtusifolia 4 3 . 4 Sphagnum meridense 4 3 2 . . . . Libanothamnus griffinii 1 Elaphoglossum cf. lingua . . . 1 Puya sp. . . 2 .

eschweizerbartxxx ingenta

. . . . . .

. 1 1 . . .

1 . . . 2 .

4 2 5 1 . . . . 1 . . . . . .

. . . . . . . Paepalanthus pilosus . 4. Puyo aristeguietae - Ruilopezietum lopez-palacii . Puya aristeguietae . . Chusquea tessellata . . Castilleja fissifolia . . Festuca guaramacalana . Monnina sp. . . . Bejaria aestuans . . Rhynchospora lechleri . . Oreobolus venezuelensis . 5. R. gollmeri - Ruilopezietum jabonensis . Ruilopezia jabonensis . . Rhynchospora gollmeri . . Isidrogalvia robustior . . Gentianella nevadensis .

. . . .

. 1 . .

. . . .

2 . . .

. . . .

2 . . .

. . . .

1 2 . .

. . . .

4 . . .

1 . . .

1 1 . .

. . . .

. . . . . . . .

3 . . . . . . .

. . . . . . . .

2 . . . . . . .

. . . . . . . .

. . . .

. . . . .

. 1 . . .

. . . . .

. 1 . . .

. . . . .

1 . . . .

. . . . .

Miconia tinifolia Muehlenbeckia tamnifolia Epidendrum frutex Myrsine dependens Diplostephium obtusum Rhynchospora sp.

. . . . . .

3.Hypericetum juniperinum Hypericum juniperinum Orthrosanthus acorifolius Calamagrostis sp. A

HYPERICO CARDONAE - XYRIDION ACUTIFOLIAE Xyris subulata var. acutifolia . Hypericum cardonae Carex bonplandii Ruilopezia viridis Calamagrostis planifolia

. . . .

. . . . .

The pรกramo vegetation of Ramal de Guaramacal, Trujillo State, Venezuela. 1. Zonal communities

41a 41b 13a 15b 22a 22b 25b 40a 40b

27a

16a 16b 24a

50a 50b 38a 11b 21a 21b 14a 14b 24b

NW NW

13b

28a 28b 35a 35b 38b 42a 42b

SW SW

15a 25a 49a 10a 10b

20a 20b 23a 23b 44a 44b

303

115

120 120

115

120

106

120

4,1

3,9

3,8

4,0

3,7

4,2

4,0

3,8

3,3

4,2

3,9

3,7

3,5

3,6

3,7

4,2

3,9

4,0

3,8

4,0

4,1

3,7

3,8 4,05 4,3

3,9

4,5

4,7

4,9

3,7

3,9

3,6

3,7

4,1

4,4

3,6

4,1

4,0

3,9

4,2

3,9

3,8

4,0

4,1

FLA

FaL

FLa

12 14 13 11 18 15 13 14 17

15 11 14 10 11 15 14 11 16 10 12 15 19 13 15 11 13 10

14 16 10 11 15 12 14 10 10 10 12 17 12 12 12

12 11 10

<1 10

<1 5

2 15

1 5

5 10

1 30

2 10

5 20

20 20

5 50

5 15

1 40

2 45

<1 20

<1 50

1 20

15 20

<1 30

aF <1 3

aF <1

5 0

<1 10

1 25

5 0

15 0

10 0

100 100

RUILOPEZIO LOPEZ-PALACII - CHUSQUEETALIA ANGUSTIFOLIAE HYPERICO CARDONAE - XYRIDION ACUTIFOLIAE 3. Cortaderio hapalotrichae - Hypericetum juniperinum 3.1. typicum

4. Puyo aristeguietae - Ruilopezietum lopez-palacii

5. R. gollmeri - Ruilopezietum jabonensis

3.2. disterigmetosum acuminatum

. . . . .

. . 1 . .

1 . . . .

. . . . .

3 . . . .

. . . . .

. . 2 . .

. . 1 . .

. . . . .

. . 1 . .

. . . . .

. . 1 . .

. . . . .

. 3 . . .

. . . . .

5 . . . .

. . . . .

. . . . . . . .

. . . 1 . . . .

. . . . . . . .

. . . 1 . . . . . . . . . . . .

. . . . . . . .

. . . 2 . . . .

. . . . . . . .

. . . 1 . . . .

. . . . . . . .

. . 4 . . . . .

2 . . . . . . .

1 . 3 . . . . .

3 1 1 . . . . .

2 . 4 . . . . .

3 . 3 . . . . .

4 . 2 . . . . .

3 . . . . . . .

2 . . . . . . .

1 . . . . . . .

. . 1 . . . . .

1 . . . . . . .

. . . . . . . .

3 . . . . . . .

. . . . . . . .

2 . . . . . . .

. . . 1 . . . .

. . . . . . . .

. . 1 . . . . .

. . . . . . . .

. . . . . 1

. . . . . .

. 2 . . . .

. . . . . .

. 1 1 . . .

. 1 . 2 . .

. . . . . .

. 1 . 3 . .

. . . 2 . .

. 4 . . . .

. . . . . .

. 1 . . . .

. . . . . .

. 1 . . . .

. 2 . . . .

. . . . . .

. . . 1 . .

. . . . . .

. 4 . . . .

. . . . . .

. . . .

1 . . .

. . . .

2 . . .

. . . .

. . . 3

. . . .

2 . . .

1 . . .

. . . .

. . . 1

. . . .

. . . 1 . . . . . . . . . 5 .

. . . . . . . . . . . . . 4 .

. 1 . . . . . . . . . . . . .

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

. 2 . . 1 . . . . . . . . . .

. 4 . . . . . . . . . . . . .

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

. . . . . . . . . . . . . 1 1

. . . . 2 . . . . . . . . . 1

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

. . . . 3 . . . . . . . . . .

. . . . . . . . . . . . . . 3

. . . . . . 4 . . . . . . . .

. . . . 1 . . . . . . . . 1 .

. . . . 1 . . . . . . . . . .

1 . . . . . . . . . . . . . .

. . . 1 1 . 3 . . . . . . . .

2 . . . 2 . 5 . . . . . . . .

1 1 . . 2 . . . . . . . . . .

. . . . 2 . 3 . . . . . . 3 1

5 . . . . . . . . . . . . . .

. . . . 1 . . . . . . . . . .

. . 3 . 4 . . . . . . . . . .

1 . . . . . . . . . . . 3 . .

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

. . . . . . . . . . . . . . 2

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

1 . . . . 3 . . . . . 1 2 . .

2 . . . . . . 1 . . . . . . .

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

. 2 . . . . . . . . . . 1 . .

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

. 1 3 . . . . . . . . . . . .

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

1 2 . . . . 3 . . . . . . . 3

. 1 . . . . . . . . . . . . .

1 1 . 1 . . . . . . . . . . .

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

. 2 . . . . . . . . . . . . .

. . . 2 . . . . . . . . . . .

. 1 . . . . . . . . . . . . .

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

3 . . 2

4 . . .

. . . .

4 2 . .

1 2 . .

4 . 1 .

5 1 . .

2 3 2 .

4 . . .

2 3 1 .

2 1 . .

1 . . 1

4 2 . .

5 . . .

2 . . .

4 . . .

2 . . .

. . . .

3 . . .

2 . . .

2 3 . .

2 . . .

. . . .

2 . . .

. . . .

1 . . .

4 . . .

. . . .

2 . . .

. . . .

. 1 . .

. . . .

1 . . .

. . . .

1 . . .

2 . . .

. . . .

. . . . . . . .

3 . . . . . . .

. . . . . . . .

1 . . . . . . .

4 . . . . . 2 2

2 . . . . . . .

3 . 1 . . . . .

3 . . . . . . .

2 . . . 2 2 . .

3 . . . . . . .

. 5 . . . . . 1

. 4 . . . . . .

3 . . . . . . .

. 4 . . . . . .

. 3 . . . . . .

4 . . . . . . .

. . . . . . . .

. . 1 1 . . . 1

3 . 1 2 . . . .

. . . . . . . .

. . . . . . . 1

. . . . . . . .

. . . . . . . 1

. . . . . . . .

. . . . . . . 2

. . . .

. 1 . .

. . 1 .

. . . .

2 . . .

. . . .

3 . . .

. . . .

. . 1 .

. . . .

5 2 2 .

5 2 2 1

5 1 . .

5 3 . .

5 1 . .

5 1 . 1

4 . . .

5 . . .

2 5 . .

5 1 3 . .

4 1 1 . .

3 2 . . .

1 1 . 4 .

4 1 . 1 .

1 1 . . .

2 1 2 . .

3 . . . .

. 1 . . .

. . . . .

2 1 . . .

. 1 . . .

1 . . . .

. . . . .

2 . . . .

. . . . .

. . 1 . .

1 1 . . .

. 1 . . .

. . . 3 .

. . . . .

1 . . . .

4 . . . .

. . . . .

1 . . . .

. . . . .

2 . . . .

3 . . . .

4 1 . . .

. 1 . 2 .

. 1 . . .

2 . . . .

2 . . . 1

4 1 . . .

3 1 . . .

4 1 . . 1

5 . . . .

1 1 . . .

2 1 . . .

1 1 . . .

2 . . . .

3 . . . .

. . . . .

5 . 1 . .

eschweizerbartxxx ingenta

304

N. L. Cuello A. & A. M. Cleef

Table 1. Phytosociological table of zonal páramo vegetation of Ramal de Guaramacal, Andes, Venezuela. Releve number Releve´ (field number)

47a 47b 48b 32b 48a 39a 39b 11a 32a

10 3a

12a 12b

13 2a

19a 19b

16 2b

46a 46b

19 3b

45a 45b 29b 37a 29a 18b 34a 34b 43a 43b 18a 31a 31b 49b

34 7a

17a 17b 37b

38 7b

(m)

Slope exposition

NW NW

Slope angle (degrees)

NW NW NW 30

NW NW 13

SW SW

NW NW 24

Slope shape

Soils depth (cm)

106

>90

>80

>55

35 >110 53

3.5* 3.5* 3,70 3,7

3,7

4,5

3,7

3,8

4,2

3,8

3,7

3,4

3,7

FLA

FaL

4,0

3,7

4,0

3,6

3,9

3,7

3,9

3,7

3,8

4,0

3,3

3,5

3,7

3,9

4,0

4,1

Soils texture

FAa

Fla

FaL FaL

FLa

No. vascular species

15 17 10 12 14 12 17 19 16 17 18 18 16 22 17 20 19 11 13 18 17 21 17 14 18 18 14 16 17 15 11 15 16 17 13 13

% outcrops and/or bare soil

% Cov. Shrubs & dwarf trees >60 cm

100

<1 20

% Cov. Grasses & rosettes > 10 cm

100

% Cov. Ground < 10 cm (including Cryptogams)

% Cov. Small shrubs < 60 cm

Order

HYPERICO PARAMITANUM - HESPEROMELETION OBTUSIFOLIAE

Alliance

1. Ruilopezio - Neurolepidetum glomeratae

Association

2. Disterigmo acuminatum - Arcytophylletum nitidum 2.1. pentacalietosum cachacoensis

subasociacion

2.2. typicum

Variant

RUILOPEZIO LOPEZ-PALACII - CHUSQUEETALIA ANGUSTIFOLIAE Cortaderia hapalotricha . . . 4 . Chusquea angustifolia 3 4 1 4 5 Lycopodium clavatum subsp. contiguum . . 2 . 1 Ruilopezia lopez-palacii Geranium stoloniferum Pernettya prostrata Rhynchospora guaramacalensis Rhynchospora macrochaeta Jamesonia imbricata Chaetolepis lindeniana Daucus montanus Sphagnum sparsum Hieracium avilae Hymenophyllum trichomanoides Hypericum sp.

2 . 1 1 . . . . . . . .

. . 1 2 . 2 . 1 . . . . 0 0 0 0

. . 1 2 . . 1 . . . . . 0 0 0 0

2 . 2 1 . 1 3 . . . . . 0 0 0 0

3 . 4 4 . 1 . 3 2 . . 5 . . .

. . 2 . . . . . . . . . 0 0 0 1

0 0 0 1

Cybianthus laurifolius? 3a(1) Gaultheria erecta 34b(1) Greigia sp. 44a(1)

4 . 4 3 . 1 . 4 1 . . 6 . . . 0 0 1 0

5 3 4 . . 1 . . 2 2 1 . . . . 0 0 1 0

3 4 3 3 . 1 3 . 2 . . . . . 1 0 0 1 1

2 2 4 . . 1 3 . . . . . . . . 0 0 1 1

4 5 . . . . . . . 1 . . . . . 0 0 1 1

2 4 . . . . . . . 1 . . . . . 0 1 0 0 0

5 . 3 4 . 1 . . 4 2 1 . . . . 0 1 0 0 0

4 . 2 . 1 1 . . . 2 . . 1 . . 0 1 0 0 0

4 . 1 . 1 2 . . . . . . . . . 0 1 0 0 1

4 1 1 1 . . . . . 1 . . . 1 . 0 1 0 0 1

2 . . . 2 1 . . . . 1 . . . . 0 1 0 0 1

3 . 1 1 3 1 2 . . 2 1 . 1 . 1 0 1 0 0 1

Huperzia amentacea 3b(1) Hymenophyllum sp. 34a(1) Melpomene flabelliformis 17a(1)

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cover of low tussocks (25–30 %) with a dominance of Cortaderia hapalotricha. See for species composition the association. The diagnostic species in this variant are Ugni myricoides and Disterigma acuminatum. The presence of Cortaderia hapalotricha is also signiﬁcant and a greater presence and cover of Lycopodium clavatum subsp. contiguum, Ruilopezia lopez-palacii and Jamesonia imbricata distinguish this variant. Ecology and distribution: This variant corresponds to the vegetation of the association of Ruilopezia paltonioides and Neurolepis glomerata located at altitudes of 2800–2900 m. Stands are generally adjacent to both dwarf forests of Libanothamnus grifﬁnii or those of Gaultheria anastomosans and Hesperomeles obtusifolia (Cuello & Cleef 2009a), in addition to their presence along small streams. 2. Disterigmo acuminatum–Arcytophylletum nitidum ass. nov. Typus: Rel. No. 31 (Cuello L31a). Table 1. Fig. 3. Humid Disterigma acuminatum and Arcytophyllum nitidum shrub páramo / Arbustal de páramo húmedo de Disterigma acuminatum y Arcytophyllum nitidum.

4 2 2 2 . 2 2 . 1 3 1 . . . . 0 1 0 0 1

2 . 2 . 5 3 2 . . . . . . . . 0 1 0 1 0

4 2 1 . 4 4 3 . . . . . . . . 0 1 0 1 0

3 4 . 2 . 1 . 1 . 2 . . . . . 0 1 0 1 0

1 3 4 1 4 2 . . . 2 . . . . . 0 1 0 1 1

0 1 0 1 1

2 3 1 4 . 1 . 1 2 2 1 . . . .

4 1 1 4 2 1 3 . . 2 1 6 1 . .

2 4 1 4 . 2 3 . . 2 . . . . .

3 4 2 4 . 1 3 . . 2 . . 1 . .

4 4 2 . . 2 2 . 1 2 . . . . .

3 4 . . 1 . 4 . 2 2 . . . . .

4 2 2 5 2 1 1 . 1 1 2 3 . . .

2 2 2 4 . 3 . 2 . . . . . . .

2 4 2 . . 2 . 3 1 . 2 . . . .

. 5 3 1 . 4 . 3 3 . 2 6 . . .

. 5 2 4 2 1 . 3 2 3 1 5 . . .

3 3 3 4 4 1 . 1 . . 1 5 . . .

4 4 . 2 1 3 . 2 . . . 4 . 1 .

4 5 2 2 3 1 . 3 . 4 . . . . .

4 5 3 3 2 1 . 1 . . 2 6 . . .

0 1 1 0 0

0 1 1 0 1

0 1 1 1 0

0 1 1 1 1

Melpomene xiphopteroides 17b(1) Polypodium sp. 34b(1) Utricularia alpina 21b(1)

Physiognomy and composition: Dense shrubby vegetation, with a variable frequency of tall stem rosettes and tussock grasses. The aspect is a layer of shrubs and dwarf trees around 1–1.5 (3) m tall, with 20–40 % cover, and a layer of tall tussock grasses that reach up to 1.5–2 m with 20 to 25 % cover. In the dwarf shrub layer are ericaceous prostrate shrubs (30–50 cm and 15–18 % cover), other grasses (15–45 cm and 2–6 % cover) and a ground layer consisting of cushions species of Sphagnum and other bryophytes (60–80 % cover). Among the shrub and dwarf tree (dt) species with substantial cover are Arcytophyllum nitidum, Chaetolepis lindeniana, Cybianthus marginatus (dt), Disterigma alaternoides, Hesperomeles obtusifolia (dt), Hypericum paramitanum, Libanothamnus grifﬁnii (dt), Pentacalia cachacoensis (dt), Ugni myricoides and Vaccinium corymbodendron (dt). Among the bamboo and tussock grasses are Chusquea angustifolia and Cortaderia hapalotricha in the shrub layer; Rhynchospora guaramacalensis, R. macrochaeta, Orthrosanthus acorifolius and Xyris subulata var. acutifolia are present in the herb layer. The stem rosettes of Blechnum schomburgkii, Ruilopezia lopez-palacii and Ruilopezia paltonioides

The páramo vegetation of Ramal de Guaramacal, Trujillo State, Venezuela. 1. Zonal communities

41a 41b 13a 15b 22a 22b 25b 40a 40b

27a

16a 16b 24a

50a 50b 38a 11b 21a 21b 14a 14b 24b

NW NW

13b

28a 28b 35a 35b 38b 42a 42b

SW SW

15a 25a 49a 10a 10b

20a 20b 23a 23b 44a 44b

305

115

120 120

115

120

106

120

4,1

3,9

3,8

4,0

3,7

4,2

4,0

3,8

3,3

4,2

3,9

3,7

3,5

3,6

3,7

4,2

3,9

4,0

3,8

4,0

4,1

3,7

3,8 4,05 4,3

3,9

4,5

4,7

4,9

3,7

3,9

3,6

3,7

4,1

4,4

3,6

4,1

4,0

3,9

4,2

3,9

3,8

4,0

4,1

FLA

FaL

FLa

12 14 13 11 18 15 13 14 17

15 11 14 10 11 15 14 11 16 10 12 15 19 13 15 11 13 10

14 16 10 11 15 12 14 10 10 10 12 17 12 12 12

12 11 10

<1 10

<1 5

2 15

1 5

5 10

1 30

2 10

5 20

20 20

5 50

5 15

1 40

2 45

<1 20

<1 50

<1 30

aF <1 3

aF <1

5 0

<1 10

1 25

5 0

15 0

10 0

100 100

RUILOPEZIO LOPEZ-PALACII - CHUSQUEETALIA ANGUSTIFOLIAE HYPERICO CARDONAE - XYRIDION ACUTIFOLIAE 3. Cortaderio hapalotrichae - Hypericetum juniperinum

4. Puyo aristeguietae - Ruilopezietum lopez-palacii

5. R. gollmeri - Ruilopezietum jabonensis

3.2. disterigmetosum acuminatum

3.1. typicum

3 . 1 . . 2 . 1 . . . . . . .

5 . 3 . . 2 . 2 . 3 1 . . . .

4 4 3 . 5 3 . 1 . . . . 1 . .

4 3 3 5 3 2 . 3 1 . . . . 3 .

5 . 3 2 5 1 . 2 . 1 . . 1 . .

4 1 3 . 5 2 . . . 2 . . . . 2

5 2 3 4 4 2 . 1 1 . . . . . .

5 4 3 2 . 3 . . . 2 2 . . . .

4 5 3 1 . 4 . . . 1 3

1 0 0 0 0

1 0 0 0 1

Soil texture: F franco (loamy) a arena (sand) A arcilla (clay) L Limo (mud/silt)

. . .

1 3 3 5 2 3 . 1 . . . 5 . . .

3 4 2 3 4 2 . 3 . 5 . 3 . . .

5 2 3 4 4 4 . . . 2 . . . . .

4 . 2 . 5 1 . . . . . 3 1 . .

5 3 4 3 3 1 . . 1 . . . . . .

3 . 2 . 5 2 3 . 2 . . . . . .

3 5 3 . 4 1 2 . 1 . 1 . . . .

4 4 2 . 5 3 . 2 1 . . . . . .

4 4 2 . 5 4 . . . 2 . . . . .

3 4 2 4 3 3 2 . 3 1 . . . . .

4 . 4 . 4 3 4 . . . . . . . .

5 3 3 . 5 1 1 . . . 2 . . . .

5 2 3 1 5 2 . . . . 2 2 . . .

3 3 2 4 3 1 . 3 1 2 . . 1 1 .

4 . 1 5 4 3 . 3 2 . . . 1 . .

2 5 3 3 . 3 . 3 3 1 1 6 . . .

5 3 4 5 . 2 . 3 3 . . . . . .

4 2 4 5 . 1 . 1 1 . . . . . .

5 1 3 5 2 1 . . . . . . . . .

4 5 4 4 . . 4 . . . . . 1 . .

4 3 4 5 . . 3 . . . . . . . .

5 4 2 3 . 3 4 . 1 . . . . . .

5 3 3 5 . 2 4 . 2 1 . . . . .

4 5 2 5 3 1 1 . 3 . . . 1 . .

4 1 3 5 . . 4 . 2 . . . . . .

4 3 1 5 2 1 4 . 2 2 . . . . .

3 3 4 5 1 2 . 1 . . . . . . .

4 5 3 3 . 1 . 2 2 . 4 6 . . .

2 5 . 5 . 1 . 2 4 . 1 . . . .

4 . 3 5 2 1 3 . 1 . . . 1 . .

5 . 5 . . 1 . . 1 . . . . . .

5 . 4 5 . 1 4 . 1 . . . 2 . .

4 . 3 5 . 1 3 . 4 . . . 1 . .

5 3 2 4 1 . . 2 . . . . 1 . .

5 3 3 . 2 1 . 1 . . . . . . .

5 3 1 . 1 1 . 3 . . . . 1 . .

4 1 2 . . . . 1 . . . . . . .

5 4 4 . . . . 1 . . . . . . .

4 5 2 . 2 1 . 1 2 . . . . . .

5 4 2 . . . . 2 . . . . . . .

5 4 2 . 3 1 . 3 1 . . . . . .

4 3 3 . 3 . . . 1 . . . . . .

5 5 . 4 1 . . 3 2 . . . . . .

1 5 . . . . . . . . . . . . .

1 0 0 0 1

1 0 0 1 0

1 0 0 1 1

1 0 1 0 0

1 0 1 0 1

1 0 1 1 0

1 0 1 1 1

1 1 0 0 0

1 1 0 0 1

1 1 0 1

1 1 1

Slope shape:

1 convex 2 concave

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are conspicuous. Common small shrubs include Disterigma acuminatum, Gaultheria hapalotricha, Hypericum cardonae, Pernettya prostrata and Themistoclesia dependens, and scandents or climbers like Muehlenbeckia tamnifolia and Rubus acanthophyllos. Further, the tall erect terrestrial orchid Epidendrum frutex, small or prostrate herbs like Daucus montanus, Galium hypocarpium, Geranium stoloniferum, and a diversity of ferns and club mosses, such as Elaphoglossum cf. lingua, Eriosorus ﬂexuosus, Huperzia amentacea, Hymenophyllum myriocarpum, H. trichomanoides, Jamesonia imbricata, Lycopodium clavatum subsp. contiguum, Melpomene moniliformis, M. ﬂabelliformis, M. xiphopteroides and Polypodium funckii, are also present, among others. Syntaxonomy: This is a highly diverse association represented by 28 line-intersect surveys with 61 species of vascular plants. Diagnostic species are Arcytophyllum nitidum, Ageratina theifolia, Disterigma acuminatum and Gaultheria hapalotricha. Two subassociations are distinguished, pentacalietosum cachacoensis and the typicum one.

Ecology and distribution: This subpáramo bamboo shrub is generally found surrounding areas of dwarf forests (SARF), at edges of slopes or hill tops, and in contact with communities of Ruilopezia paltonioides and Neurolepis glomerata. It represents humid shrub páramo, transitional between forest and páramo. Disterigmo acu min atum–Arcyto p h y lletum n itid u m 2.1. pentacalietosum cachacoensis subass. nov. Typus: Rel. No. 17 (Cuello L46a). Table 1. Fig. 4. Pentacalia cachacoensis subassociation / Subasociación de Pentacalia cachacoensis. Physiognomy: Dense shrubby vegetation in a matrix of tussock grasses of Cortaderia hapalotricha and bamboos of Chusquea angustifolia and Neurolepis glomerata; shrubs, dwarf trees (1–1.5 (3) m) and prostrate shrubs are present at high density. There is a carpet of species of Sphagnum, together with other mosses, as well as the presence of liverworts, such as Scapania portoricensis and species of Plagiochila. Composition and syntaxonomy: This subassociation is represented in 13 line-intersect surveys containing 50 vascular species. Diagnostic species are Pentacalia

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N. L. Cuello A. & A. M. Cleef

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Fig. 2. Physiognomy of the vegetation of the association R u i l o p e z i o p a l t o n i o i d e sâ&#x20AC;&#x201C; N e u ro l e p i d e t u m g l o m e ra t a e var. Disterigma alaternoides (L48b 3000 m). Bs: Blechnum schomburgkii; Cha: Chusquea angustifolia; Chl: Chaetolepis lindeniana; Da: Disterigma alaternoides; Ef: Epidendrum frutex; Hp: Hypericum paramitanum; Mp: Muehlenbeckia tamnifolia; Ng: Neurolepis glomerata; Ngr: Nertera granadensis; Pg: Pentacalia greenmanniana; Pp: Pernettya prostrata; Rgu: Rhynchospora guaramacalensis; Rp: Ruilopezia paltonioides; Sb: Sphyrospermum buxifolium; Vc: Vaccinium corymbodendron.

The páramo vegetation of Ramal de Guaramacal, Trujillo State, Venezuela. 1. Zonal communities

307

Fig. 3. Physiognomy of the vegetation of the association D i st e ri g m o a c u m i n a t u m – A rc y t o p h y l l e t u m n i t i d u m subass. typicum (L31a 2960 m). An: Arcytophyllum nitidum; Bs: Blechnum schomburgkii; Cha: Chusquea angustifolia; Cm: Cybianthus marginatus; Da: Disterigma acuminatum; Dm: Daucus montanus; Gh: Gaultheria hapalotricha; Hp: Hypericum paramitanum; Ji: Jamesonia imbricata; Lc: Lycopodium clavatum subsp. contiguum; Ng: Neurolepis glomerata; Pp: Pernettya prostrata; Ra: Rubus acanthophyllos; Rl: Ruilopezia lopez-palacii; Rm: Rhynchospora macrochaeta; Um: Ugni myricoides; V: Valeriana quirorana.

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Fig. 4. Physiognomy of the vegetation of the association D i st e ri g m o a c u m i n a t u m – A rc y t o p h y l l e t u m n i t i d u m subass. pentacalietosum cachacoensis (L46a 3080 m). An: Arcytophyllum nitidum; Bs: Blechnum schomburgkii; Ch: Cortaderia hapalotricha; Cm: Cybianthus marginatus; Da: Disterigma acuminatum; Dm: Daucus montanus; El: Elaphoglossum lingua; Ga: Gaultheria anastomosans; Gh: G. hapalotricha; Gm: Geranium stoloniferum; Ho: Hesperomeles obtusifolia; Hp: Hypericum paramitanum; Lg: Libanothamnus grifﬁnii; Mm: Melpomene moniliformis; Pc: Pentacalia cachacoensis; Pp: Pernettya prostrata; Vc: Vaccinium corymbodendron.

308

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cachacoensis and Vaccinium corymbodendron, together with Ageratina theifolia, Cybianthus marginatus, Gaultheria anastomosans, Hesperomeles obtusifolia, Themistoclesia dependens and the fern Melpomene moniliformis. The ground layer of this vegetation unit is dominated by Sphagnum meridense and S. sparsum and among them Breutelia rhythidioides and Cladonia furcata can also be found. Other epiphytes on small trunks are species of Riccardia (2955), Frullania (3038, 3039) and Plagiochila (2957). Some facies may be distinguished for this subassociation: a facies of Vaccinium corymbodendron, characterized also with a prominent presence of Melpomene monniliformis and Gaultheria anastomosans and another facies with a greater presence of Libanothamnus grifﬁnii. Ecology and distribution: The shrub páramo of the subassociation of Pentacalia cachacoensis is located at altitudes between 2920–3080 m, and occurring on the edges of convex or concave slopes of 10–37 degrees. The soils attain a depth of 4–80 cm, with mixed textures predominantly sandy (sand-muddy to sandsilty or silt-sand-loam), with pH 3.3–4.1 and dark colors in the superﬁcial layers, varying in color until reddish and grayish with a high clay content at increased depth. D i s t e r ig m o ac u m i n a tu m – Arc y top hy lletu m n it i d u m 2. 2. subassociation typicum nov. Typus: Rel. No. 31 (Cuello L31a). Table 1. Figure 3. Subassociation of Arcytophyllum nitidum / Subasociación de Arcytophyllum nitidum.

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Physiognomy: Shrubs and dwarfed trees dominate (up to 2 m, 20–40 % cover); with a presence of tall stem rosettes of up to 3.5 m. Composition and syntaxonomy: The subassociation is represented in 15 line-intersect surveys with a total of 50 vascular species. Diagnostic species are the same as the association as well as Ugni myricoides and Rubus acanthophyllos. Rhynchospora guaramacalensis also being a further diagnostic species. In the vegetation of this subassociation a ground layer of high bryophyte cover is common and comprised mainly Sphagnum sparsum and S. meridense. Other common species are Breutelia squarrosa, Campylopus ﬂexuosus, C. nivalis, Scapania portoricensis, Herbertus sp. (2980), Plagiochila tabinensis and other species of Plagiochila and Frullania. Epiphytic bryophytes are also present on the smaller trunks. Some lichens, such as Cladia aggregata and Cladonia squamosa, can be found in the ground layer or over rocks. Peltigera neopolydactyla is found also on the dry leaves of Blechnum schomburgkii. Some variants may also be distinguished for this subassociation, one variant characterized with a dominance of Rhynchospora guaramacalensis and a greater presence of Ruilopezia paltonioides; the other variant dominated by Rhynchospora macrochaeta.

Ecology and distribution: The shrubs of the subassociation typicum are located at altitudes of 2850– 3040 m, at the base of convex slopes, with slopes between 10–37 degrees. Soils are 17–75 cm deep and consist of sandy, loam-sandy to silt-sandy textures, with dark brown grayish colours and pH of 3.4–4.5 in the upper layers. Hyperico cardonae–Xyridion acutifoliae all. nov. Typus: Co rtaderio hapalo trich ae–Hy p ericetu m ju n iperin u m (this study). Hypericum cardonae – Xyris subulata var. acutifolia alliance / Alianza de Hypericum cardonae y Xyris subulata var. acutifolia. Physiognomy: This alliance includes zonal open grass páramo, with a high proportion of rosettes, whitin a variable density matrix of tussock grasses and bamboos. The presence of a few species of shrubs and dwarf trees varies from total absence to extreme densities. Composition and syntaxonomy: This alliance is deﬁned on the basis of 53 line-intersect surveys represented by 64 vascular species. Diagnostic species are: Xyris subulata var. acutifolia and Hypericum cardonae. Although less frequent, Ruilopezia viridis is also a diagnostic occurance. The dwarf tree species Hypericum juniperinum is present in this alliance, present at very variable densities among the different associations. The most important species, in sequence of cover, are: Ruilopezia lopez-palacii, Cortaderia hapalotricha, Chusquea angustifolia, Geranium stoloniferum, Lycopodium clavatum subsp. contiguum, Hypericum juniperinum, Xyris subulata var. acutifolia, Pernettya prostrata, Rhynchospora guaramacalensis, Jamesonia imbricata, Puya aristeguietae, Libanothamnus grifﬁnii, Rhynchospora macrochaeta, Disterigma acuminatum, and Chusquea tessellata, among others. This alliance contains three associations, Puyo aristeguietae–Ruilo p ezietu m lo p ez-p alacii; Cor taderio h apalo trich ae–Hy p ericetum ju n i perin u m and Rh y n cho sp o ro go llmeri– Ru ilo p ezietu m jabo n ensis. Ecology and distribution: The vegetation of the associations of the alliance of Hypericum cardonae and Xyris subulata var. acutifolia can be found between 2820 and 3060 m, located over ample extensions or forming small patches, on convex or concave slopes between 5 and almost 50 degrees. 3. Cortaderio hapalo trich ae–Hy p ericetum ju n iperin u m ass. nov. Typus: Rel. No. 45 (Cuello L25b). Table 1. Fig. 5. Photo 2. Cortaderia hapalotricha – Hypericum juniperinum shrub-grass páramo / Páramo de arbustal-pajonal de Cortaderia hapalotricha e Hypericum juniperinum.

The páramo vegetation of Ramal de Guaramacal, Trujillo State, Venezuela. 1. Zonal communities

309

Fig. 5. Physiognomy of the vegetation association Co rt a d e ri o h a p a l o t ri c h a e – Hy p e ri c e t u m j u n i p e ri n u m (L9a, 2910 m). Páramo El Pumar. At: Ageratina theifolia; Ch: Cortaderia hapalotricha; Cha: Chusquea angustifolia; Chl: Chaetolepis lindeniana; Ga: Gaultheria anastomosans; Gm: Geranium stoloniferum; Hc: Hypericum cardonae; Hj: Hypericum juniperinum; Lc: Lycopodium clavatum subsp. contiguum; Oa: Orthrosanthus acorifolius; Pp: Pernettya prostrata; Rl: Ruilopezia lopez-palacii; Rm: Rhynchospora macrochaeta; Vc: Vaccinium corymbodendron.

Physiognomy and composition: Páramo vegetation with low density and diversity of shrubs and dwarf trees in the upper layer. Leptophyllous dwarf treelets of Hypericum juniperinum, 0.8–1.5 (2) m, 20–25 % cover, with slender twigs and canopies oriented in the wind direction are noticeable. A dense grass layer is present at 10–60 cm in height, dominated by tussock grasses and small shrubs with some rosettes. The ground layer is dominated by Geranium stoloniferum and a variable cover of mosses and lichens. Rocky outcrops and areas of bare ground are common. In the upper layer, the dominance of Hypericum juniperinum is particularly noteworthy, together with a few other species of small trees like Hesperomeles obtusifolia, Arcytophyllum nitidum and Chaetolepis lindeniana. In the medium layer common Hypericum paramitanum grows among Chusquea angustifolia bamboos, Cortaderia hapalotricha and Rhynchospora guaramacalensis tussock grasses. There are also the prostrate shrubs Disterigma acuminatum and Pernettya prostrata. Among the ground rosettes Puya aristeguietae and Ruilopezia lopez-palacii are more frequent and abundant, Ruilopezia jabonensis and R. viridis are occasionally present. In the herbaceous layer Orthrosanthus acorifolius, Hypericum cardonae, Jamesonia imbricata, Daucus montanus, Hieracium avilae and Lycopodium clavatum subsp. contiguum are present, among others. In narrow valleys and humid areas, dense carpets of Sphagnum sparsum and a diversity of lichens and bryophytes are present growing over rocks and bases of trunks, such as Cladia aggregata, Cladonia squamosa, C. andesita, C. pyxidata, C. arcuata, Jamesoniella rubricaulis, Herber-

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Photo 2. Landscape of Páramo El Pumar in the surrounding areas of Laguna El Pumar, 2880–2950 m, Ramal de Guaramacal, Andes, Venezuela.

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N. L. Cuello A. & A. M. Cleef

tus juniperoides, Breutelia squarrosa, Plagiochila spp. (2961), Campylopus insignis and, Riccardia spp. (2965). In these conditions, individuals of Hypericum juniperinum and Chusquea angustifolia are found to reach their greatest heights of up to 2–2.5 m. Syntaxonomy: This association is deﬁned on the basis of 25 line-intersect surveys containing 50 vascular species. Diagnostic species are Cortaderia hapalotricha, Geranium stoloniferum and Hypericum juniperinum. Orthrosanthus acorifolius is also diagnostic. Two subassociations are recognised, the subassociation typicum and that of disterigmetosum acuminatum. Ecology and distribution: The association Cortaderio hapalotrichae–Hypericetum juniperinum is widely distributed between 2820 to 3060 m covering the entire upper ridge of Páramo of Guaramacal and Páramo El Pumar. The vegetation of this associaction extends over convex slopes with inclinations of 5 up to almost 50 degrees on hilltops or slope ridges exposed to wind. Patches of this vegetation additionally located on slope bases, concave sloping ground, or at the bottom of small valleys with slopes of 7–23 degrees. The soils are variable in depth, 9–115 cm, with predominantly sandy textures, (sandy-loam, sand silt, silt-sandy, loam-sandy), pH 3.3–4.2 and dark grayish brown colors in the upper layers. Cortaderio hapalotrichae–Hypericetum juniperinum 3.1. subassociation typicum nov. Typus: Rel. No. 45 (Cuello L25b). Table 1.

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Co rtaderio hapalo trich ae–Hy p ericetu m jun iperin u m 3.2. d isterigmeto su m acumin atum subass. nov. Typus: Rel. No. 56 (Cuello L23b). Table 1, Fig. 6. Subassociation of Disterigma acuminatum / Subasociación de Disterigma acuminatum. Physiognomy and composition: The physiognomy and species composition is in agreement with that of the association. Composition and syntaxonomy: This subassociation is represented in 12 line surveys with 36 vascular species. Diagnostic species are Arcytophyllum nitidum, in the shrub layer, as well as Rhynchospora guaramacalensis and Disterigma acuminatum, in the underbrush. Ecology and distribution: The subassociation disterigmetosum acuminatum is found at altitudes from 2820 to 3060 m, on the convex and steep slopes (5 to almost 50 degrees) of hilltops, edges and other wind exposed areas. The soils are mostly shallow, 13–41 (86) cm, in depth; consisting of sandy, dark colored, textures with small fragments of quartz, having pH from 3.6 to 4.2 in the upper layers. 4. P uy o aristegu ietae–Ruilo p ezietu m lopezpalacii ass. nov. Typus: Rel. No. 65 (Cuello L10b). Table 1, Fig. 7, Photo 3. Puya aristeguietae-Ruilopezia lopez-palacii grass páramo / Pajonal del páramo con rosetas de Puya aristeguietae y Ruilopezia lopez-palacii.

Composition and syntaxonomy: This subassociation is represented in 12 line-intersect surveys with a total of 37 vascular species. The diagnostic species are the same as for the association. Orthrosanthus acorifolius, Xyris subulata var. acutifolia and Hypericum cardonae are also diagnostic in the herb layer. The presence of Calamagrostis sp. A, Paepalanthus pilosus and Carex bonplandii, as well as some cryptogams like Breutelia rhythidioides, Frullania sp. (2976), Cladia aggregata and Cladonia isabellina are distinctive. Diagnostic also is the absence of Arcytophyllum nitidum.

Physiognomy: Páramo vegetation with great abundances of ground and stem rosettes with dominance of tussock grasses and some bamboos. The layer of big Puya aristeguietae and Ruilopezia lopez-palacii rosettes, (terminal inﬂorescences up to 1.5–2.5 m) attains 30–40 % of cover. A layer of tall tussock grasses reaches up to 90–125 cm with a cover of 35–45 %. Small rosettes and other tussocky monocots attain 45 cm. Additionally, a few low shrubs of 55–60 cm tall, 5–10 % cover are present. The ground layer (4–10 cm) consists of prostrate herbs and some bryophytes. The presence of a few outcrops of rock (1.3 m) covered by abundant lichens and bryophytes is common.

Ecology and distribution: Vegetation belonging to this subassociation was observed at altitudes of 2890–3050 m, at the tops of hills and on convex slopes of low inclination (8–21 degrees), generally with S, SE, NE exposition. The soils are shallow, 9–30 cm in depth, on outcrops of bedrock, with sandy textures, dark grayish brown colours and pH in the range 3.3– 4.2 in the upper layers. In this subasociation, shrub communities (1.5 up to 2 m), located in wind-protected areas at the base of the slopes, or along and to the base of small valleys with gently slooping ground (8– 16 degrees), are also included. Soils are sandy-loam in texture, dark brown grayish or gray dark in colour and pH from 3.8 to 4.1 in the upper layers. Soil depth is 60 to 115 cm.

Composition and syntaxonomy: This association is deﬁned on the basis of 17 line-intersect surveys with 45 vascular species. Diagnostic species are Ruilopezia lopez-palacii, Puya aristeguietae and Rhynchospora guaramacalensis. The dominant grasses in this association are Cortaderia hapalotricha (20–90 cm), and the bamboo Chusquea angustifolia (50–125 cm), followed by others, such as: Chusquea tessellata, Festuca guaramacalana, and Rhynchospora guaramacalensis. Calamagrostis bogotensis and C. planifolia are common species, but conspicuous only when fertile at the beginning of the rainy season. Among the herbs Castilleja ﬁssifolia, Daucus montanus, Hypericum cardonae, Hieracium avilae and Jamesonia imbricata are common. Also present are prostrate herbs like Ge-

The páramo vegetation of Ramal de Guaramacal, Trujillo State, Venezuela. 1. Zonal communities

ranium stoloniferum and Lycopodium clavatum subsp. contiguum as well as small cushions of Oreobolus venezuelensis and Xyris subulata var. acutifolia. Among the bryophytes Breutelia rhythidioides, small cushions of Campylopus subjugorum, and Herbertus pensilis as well as Campylopus richardii growing over rocks are distinguished. Isolated and dispersed individuals of shrubs or dwarf trees 1–1.5 (2.5) m, like

311

Bejaria aestuans, Disterigma alaternoides, Hypericum juniperinum, H. paramitanum, Ugni myricoides, and Vaccinium corymbodendron are occasionally present. Ecology and distribution: The open páramo vegetation of the association of Puya aristeguiate and Ruilopezia lopez-palacii extends over large surfaces of Páramo de Guaramacal between 2800–3040 m. It

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Fig. 6. Physiognomy of the vegetation of the association C o rt a d e ri o h a p a l o t ri c h a e – H y p e ri c e t u m j u n i p e ri n u m ; subass. disterigmetosum acuminatum (L23b, 3030 m) An: Arcytophyllum nitidum; Ch: Cortaderia hapalotricha; Cha Chusquea angustifolia; Da: Disterigma acuminatum; Gm: Geranium stoloniferum; Ho: Hesperomeles obtusifolia; Hj: Hypericum juniperinum; Ji: Jamesonia imbricata; Lc: Lycopodium clavatum subsp. contiguum; Ng: Nertera granadensis; Pp: Pernettya prostrata; Rj: Ruilopezia jabonensis; Rm: Rhynchospora macrochaeta; Vc: Vaccinium corymbodendron.

Photo 3. Páramo vegetation of the association of Puyo a ri st e g u i e t a e – R u i l o p e z i e t u m l o p e z -p a l a c i i , at ~2850 m in Páramo de Guaramacal, Ramal de Guaramacal, Andes, Venezuela.

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Fig. 7. Physiognomy of the vegetation of the association of P u y o a ri st e g u i e t a e – R u i l o p e z i e t u m l o p e z -p a l a c i i (L10b, 2840 m). Bs: Blechnum schomburgkii; Ch: Cortaderia hapalotricha; Cha: Chusquea angustifolia; Da: Disterigma acuminatum; Dal: D. alaternoides Ji: Jamesonia imbricata; Lc: Lycopodium clavatum subsp. contiguum; Md: Myrsine dependens; Ov: Oreobolus venezuelensis; Pa: Puya aristeguietae; Pp: Pernettya prostrata; Rle: Rhynchospora lechleri; Rm: Rhynchospora macrochaeta; Rsp: Rhynchospora sp.; Rl: Ruilopezia lopez-palacii; Um: Ugni myricoides.

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is present both on convex and concave slopes varying between 5–18 degrees. The soils are comparatively deep, 30–120 cm, with sandy, sand-loam to silt-loam textures of brown-grayish color and pH from 3.6 to 4.1 in the upper layers. 5. R h y n c h o s p o ro g o l l m e ri – Ru i l op e zietu m j a b o n e n s i s ass. nov. Typus: Rel. No. 82 (Cuello L14b). Table 1, Fig. 8, Photo 4. Ruilopezia jabonensis-Rhynchospora gollmeri grass páramo / Pajonal de páramo con Ruilopezia jabonensis y Rhynchospora gollmeri. Physiognomy: Low bunchgrass páramo with a high density of small ground rosettes, cushion grasses and the presence of a few bamboos. Shrubs are absent and the dominating silvery-leaved rosette species is Ruilopezia jabonensis. The upper layer is composed of dispersed and low Chusquea angustifolia bamboo clumps and bunches of Cortaderia hapalotricha of around 40–50 cm in height with 5 to 20 % cover. The layer of rosettes reaches about 20–30 cm in height, covering approximately 65 %. There is a layer of small tussock and cushion grasses of up to 10 cm in stature and 30–40 % cover. An open and discontinuous ground layer (2–3 cm) consists of mosses and small prostrate herbs (1 %). The presence of rocks outcrops (1 %), bare ground and senescent material (3 %) after ﬁre is common.

Composition and syntaxonomy: The association is represented by 11 line-intersect surveys with 22 vascular species. The diagnostic species are: Ruilopezia jabonensis, Rhynchospora gollmeri, Isidrogalvia robustior and Gentianella nevadensis. Other species with lower density and cover are small herbs, like: Carex bonplandii, Geranium stoloniferum, Hypericum cardonae, Lycopodium clavatum subsp. contiguum and Pernettya prostrata, the grasses Calamagrostis planifolia and Polypogon elongatus together with the terrestrial orchid Pterichis multiﬂora. In the ground layer the mosses Campylopus richardii, Rhacocarpus purpurascens and Sematophyllum swartzii, the lichens Cladia aggregata, species of Cladonia, as well as Rimelia reticulata growing over the rocks, are present. Ecology and distribution: The vegetation of Rhyncho sp o ro go llmeri–Ru ilo p ezietu m jab onensis is always located at altitudes superior to 2900 m. Generally, it forms small patches, on concave slopes, or in small depressions, on gently slooping ground (11–28 degrees). The vegetation of this association is in downslope contact with that of the association of P uy o aristeguietae–Ruilo p ezietu m lopezp alacii var. Chusquea tessellata and upslope with the association of Co rtaderio h apalo trichae– Hyp ericetu m ju n iperin u m. It also borders the azonal vegetation association of Carici b o n pland ii–Chu sq u eetu m angustifoliae (Cuello &

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313

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Photo 4. Páramo vegetation of the association Rhyncho sp o ro g o l l m e ri – R u i l o p e z i e t u m j a b o n e n si s at ~2950 m in Páramo El Pumar, Ramal de Guaramacal, Andes, Venezuela.

Fig. 8 Physiognomy of the vegetation of the association R h y n c h o sp o ro g o l l m e ri – R u i l o p e z i e t u m j a b o n e n si s (L14b, 2960 m). Ch: Cortaderia hapalotricha; Cha: Chusquea angustifolia; Gm: Geranium stoloniferum; Ha: Hieracium avilae; Hc: Hypericum cardonae; Ir: Isidrogalvia robustior; Lc: Lycopodium clavatum subsp. contiguum; Rm: Rhynchospora macrochaeta; Rg: Rhynchospora gollmeri; Rj: Ruilopezia jabonensis; Rl: Ruilopezia lopez-palacii; Xs: Xyris subulata.

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Cleef, 2009b). The soils are of variable depth, 18– 115 cm (average 49.6 cm), and are of sandy, sand-loam to sand-silt-loam texture, of gray and light colour and of pH from 3.8 to 4.2 in the upper layers. Flora diversity and composition A total of 91 vascular plants, 33 species of bryophytes and 20 species of lichens have thus far been documented from ﬁfty 10 m-line intercept transects in zonal páramo vegetation in Páramo de Guaramacal, Ramal de Guaramacal. The vascular plants include 49 species belonging to 36 genera and 18 families of dicots; 24 species, 15 genera and 8 families of monocots and 18 species, 12 genera and 9 families of ferns. All plant species recorded in the studies of páramo vegetation from Ramal de Guaramacal are listed in Appendix 1. It is expected that ongoing sampling will yield further other bryophyte and lichen species. Table 2 presents the most speciose families and genera for the páramo vegetation of Ramal de Guaramacal based on the line-intersect data of this study. Asteraceae and Ericaceae are the most speciose families followed by Poaceae and Cyperaceae. The most diverse genera are Ruilopezia of the Asteraceae,

Rhynchospora of the Cyperaceae and Hypericum of the Clusiaceae. The ﬂora diversity and most diverse families for each vegetation type are presented in Table 3. Diversity decreases from the most diverse shrub páramo association of Disterigmo –Arcy to phylletum to the open grass páramo of Rh y n cho sporo gollmeri–Ru ilo p ezietu m jabo n ensis. Life forms and growth forms Species number for each life and growth forms for each vegetation association registered from the lineintersect data from the páramo vegetation of Ramal de Guaramacal are presented in Table 4 (a and b, respectively). Generally the most representative life form in terms of both number of species and cover in the study area are the phanerophytes, especially of the microphanerophytic type, followed by hemicryptophytes of caespitose habit. The growth forms with the highest species richness are upright shrubs, represented mainly by members of the Clusiaceae, Ericaceae, Rubiaceae and Asteraceae families, followed by tussock plants of the Poaceae, Cyperaceae, Xyridaceae and Iridaceae fami-

Table 2. Most diverse plant families and genera in zonal páramo of Ramal de Guaramacal, Venezuela. FAMILY

# GENERA

# SPP.

ASTERACEAE

Hypericum

ERICACEAE

Rhynchospora

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GENERA

# SPP.

POACEAE

7 (+3 indets)

Ruilopezia

CYPERACEAE

Melpomene

3 (+2 indets)

CLUSIACEAE

Gaultheria

MELASTOMATACEAE

Hymenophyllum

Pentacalia

MYRSINACEAE

ROSACEAE

RUBIACEAE

GRAMMITIDACEAE

3 (+2 indets)

BROMELIACEAE

Table 3. Flora diversity and most diverse families for each páramo vegetation association found in Ramal de Guaramacal, Venezuela. Association

# Families

# spp

Most diverse families

1. Ruilopezio paltonioides – Neurolepidetum glomeratae

Ericaceae (7), Asteraceae (5), Clusiaceae, Cyperaceae, Myrsinaceae and Poaceae (3)

2. Disterigmo acuminatum – Arcytophylletum nitidum

Ericaceae (8), Asteraceae (6), Clusiaceae (4)

3.Cortaderio hapalotrichae – Hypericetum juniperinum

Asteraceae (8), Cyperaceae, Ericaceae, Poaceae (5), Clusiaceae (4)

4. Puyo aristeguietae – Ruilopezietum lopez-palacii

Asteraceae, Ericaceae and Poaceae (6), Cyperaceae (5)

5. R. gollmeri – Ruilopezietum jabonensis

Cyperaceae (4), Asteraceae and Clusiaceae (3)

The páramo vegetation of Ramal de Guaramacal, Trujillo State, Venezuela. 1. Zonal communities

lies. The shrub páramo association of D i ste rigmo – A r c y t o p h y l le tu m shows the greatest diversity of growth forms and species.

315

slope angle (negative relationship), and the second CCA axis to altitude. This means that slope angle and altitude are signiﬁcantly related to species composition in the zonal páramo vegetation, and appear more important than other variables such as pH, and soil depth and humus thickness. The ordination diagram of the ﬁrst CCA axis against the second CCA axis with the samples (transect lines) labeled by vegetation types (Fig. 9) shows a

Ordination analysis The standard canonical coefﬁcients as well as the intra- or interset variables (Ter Braak 1986) (Table 5) show that the ﬁrst CCA axis is mostly related to

Table 4. Number of species for life forms (a) and growth forms (b) for each vegetation association registered from line-intersect data from páramo vegetation of Ramal de Guaramacal. 1. R u i l o p e z i o p a l t o n i o i d e s– N e u ro l e p i d e t u m g l o m e ra t a e ; 2. D i s t e r ig mo acuminatum–Arcytophylletum nitidum; 3. C o rt a d e ri o h a p a l o t ri c h a e – H y p e ri c e t u m j u n i p e ri n u m ; 4. P u y o a risteguietae–Ruilopezietum lopez-palacii; 5. R h y n c h o sp o ro g o l l m e ri – R u i l o p e z i e t u m j a b o n e n si s. Table 4.a Life forms

Number of species by vegetation type (1)

(2)

(3)

(4)

(5)

phanerophyte

Total spp. 8

microphanerophyte

nanophanerophyte

phanerophytic ligniﬁed grass

rosullate phanerophyte

hemicryptophyte

caespitose hemicryptophyte

climbing hemicryptophyte

chamaephyte

frutescent chamephyte

reptant chamaephyte

epiphyte

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Total phanerophytes

Total hemicryptophytes

Total chamaephytes

Total spp.

Total life forms

(4)

(5)

Total spp.

Table 4.b Growth forms*

Number of species by vegetation type (1)

(2)

(3)

upright shrubs

tussocks

erect herbs

dwarf trees

prostrate herbs

ground rosettes

prostrate shrubs

cushions

stem rosettes

trailing herbs

epiphitic herbs Total spp.

* Adapted from Ramsay & Oxley, 1997 and Hedberg & Hedberg, 1979

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Table 5. Standard canonical coefﬁcients and interset variables of CCA ordination axis for páramo vegetation of Ramal de Guaramacal. Canonical Coefﬁcients Standardized

Original Units

Variable

Axis 1

Axis 2

Axis 3

Axis 1

Axis 2

Axis 3

S. Dev

1 altitude

0.135

0.389

-0.124

0.002

0.005

-0.002

0.774E+02

2 slope angle

-0.495

0.018

-0.059

-0.053

0.002

-0.006

0.940E+01

3 soils depth

-0.054

-0.012

-0.326

-0.002

0.000

-0.011

0.302E+02

0.075

-0.100

-0.035

0.269

-0.361

-0.125

0.278E+00

-0.054

-0.031

0.181

-0.006

-0.003

0.019

0.952E+01

4 pH 5 humus depth

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Fig. 9. CCA ordination diagram of 91 vascular species recorded in 91 páramo vegetation samples (labeled by vegetation types) in Ramal de Guaramacal, Andes Venezuela. Vegtypes: 1. R u i l o p e z i o p a l t o n i o i d e s– Ne u ro l e p i d e t u m g l o m e ra t a e ; 2. D i s t e r ig mo acuminatum–Arcytophylletum nitidum; 3. C o rt a d e ri o h a p a l o t ri c h a e – H y p e ri c e t u m j u n i p e ri n u m ; 4. P u y o a ristegu ietae–Ruilopezietum lopez-palacii; 5. R h y n c h o sp o ro g o l l m e ri – R u i l o p e z i e t u m j a b o n e n si s.

fairly good separation of vegetation communities established on the basis of the phytosociological table (Table 1). Vegtype 1 (Ruilopezio paltonioides– Neurolepidetum glomeratae), and to a lesser degree Vegtype 2 (Disterigmo acuminatum–Arcytophylletum nitidum), are separated from the others towards the left, suggesting that these vegtypes are associated with higher slope angles. Similarly, vegtypes 3, 5, and to a lesser degree 4, must have rather low values of slope angles. Vegtype 4 separates well along CCA axis 2, which suggests that this vegtype occurs at the lowermost positions along the slopes.

Discussion Phytosociological classification and methodological constraints The phytosociological classiﬁcation of zonal páramo vegetation of the Guaramacal range resulted in a provisional order (Ruilo p ezio lop ez-p a laciiChu sq u eetalia an gustifoliae prov.), two new alliances and ﬁve associations. Four new subassociations are described for two associations, two for each. Some variants have also been recognised. The zonal

The páramo vegetation of Ramal de Guaramacal, Trujillo State, Venezuela. 1. Zonal communities

317

Table 6. Presence degree table of zonal subpáramo plant communities of Ramal de Guaramacal. I (0–20 %), II (21–40 %), III (41–60 %), IV (61–80 %) and V (81–100 %).

Community group

1 10

2 28

2.1 13

2.2 15

3 25

3.1 12

3.2 13

4 17

5 11

IV II II I I I

II II . . . .

II I . . . .

I . . . . .

I . I . . .

I . II . . .

I I . . . .

. . . . . .

Disterigma acuminatum Gaultheria hapalotricha Arcytophyllum nitidum Ageratina theifolia Galium hypocarpium Polypodium funckii Eriosorus flexuosus Hymenophyllum myriocarpum

II I I . . . . .

V III III II I I I I

V IV II II I I I I

V III IV I I . I I

III I II I . . . .

. I . II . . . .

V I III . . . . .

II . . I . . . .

. . I . . . . .

Pentacalia cachacoensis Vaccinium corymbodendron Melpomene moniliformis Gaultheria anastomosans Themistoclesia dependens Hesperomeles sp. Huperzia amentacea

. I . . . . .

II II II II I I I

IV III III III I I I

I I . I I . .

. II I I . I .

. II I II . I .

. II . I . . .

. I . I . . .

. . . . . . .

Ugni myricoides Rubus acanthophyllos Ilex guaramacalensis Valeriana quirorana Gaultheria erecta Hymenophyllum sp. Melpomene flabelliformis Melpomene xiphopteroides Polypodium sp.

II . . . . . . . .

II II I I I I I I I

I . . . . . . . .

III II I I I I I I I

I . I . . . . .

. . . . . . . . .

I . . I . . . . .

. . . . . . . . .

Blechnum schomburgkii Hypericum paramitanum Neurolepis glomerata Cybianthus marginatus Hesperomeles obtusifolia Libanothamnus griffinii Elaphoglossum cf. lingua Puya sp. Miconia tinifolia Muehlenbeckia tamnifolia Epidendrum frutex Myrsine dependens Diplostephium obtusum Rhynchospora sp.

V V IV II II II I II I I I . I I

IV V II II III I II I I I I I I I

IV V III IV IV II I I I I I II I I

IV IV II I II I II I . . . I I .

. I I I III I . . . . . . I I

. II . I I . . . . . . . II I

II I I I IV II . . . . . . I I

II II I I . I I . . . I I . I

. I I . . . . . . . . . . .

Number of relevés 1. Ruilopezio paltonioides - Neurolepidetum glomeratae

Ruilopezia paltonioides Disterigma alaternoides Nertera granadensis Pentacalia greenmaniana Sphyrospermum buxifolium Cybianthus laurifolius 2. Disterigmo acuminatum - Arcytophylletum nitidum

2.1. pentacalietosum cachacoensis

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2.2. typicum

HYPERICO PARAMITANUM – HESPEROMELETION OBTUSIFOLIAE

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N. L. Cuello A. & A. M. Cleef

Table 6. Presence degree table of zonal subpáramo plant communities of Ramal de Guaramacal. I (0–20 %), II (21–40 %), III (41–60 %), IV (61–80 %) and V (81–100 %).

Myrsine dependens Community group Diplostephium obtusum Rhynchospora sp.

. 1I 10 I

I 2I 28 I

II 2.1 I 13 I

I 2.2 I 15 .

. 3I 25 I

. 3.1 II 12 I

. 3.2 I 13 I

I 4. 17 I

. 5. 11 .

Hypericum juniperinum Orthrosanthus acorifolius Calamagrostis sp. A Paepalanthus pilosus Greigia sp.

. . . . .

II I . . .

I I . . .

V II I I I

V III II I .

V I . I I

II . . . .

Puya aristeguietae Chusquea tessellata Castilleja fissifolia Festuca guaramacalana Monnina sp. Bejaria aestuans Rhynchospora lechleri Oreobolus venezuelensis Festuca sp. Utricularia alpina

I . . . . . . . . .

. . . . . . . . . .

I . . .

I . . . . . . . .

. . . . . . . . . .

I . . . . . . . . .

IV II II I I I I I I I

. . . . . . . II . .

Ruilopezia jabonensis Rhynchospora gollmeri Isidrogalvia robustior Gentianella nevadensis Calamagrostis planifolia

. . . . .

I I I . .

I . . . .

I . I . .

. . I . .

V IV I I I

Xyris subulata var. acutifolia Hypericum cardonae Carex bonplandii Ruilopezia viridis

. I . .

I I . .

. I . .

I . . .

III III I I

V V III I

II II I I

IV I . I

V III . .

Cortaderia hapalotricha Chusquea angustifolia Lycopodium contiguum Ruilopezia lopez-palacii Geranium stoloniferum Pernettya prostrata Rhynchospora guaramacalensis Rhynchospora macrochaeta Jamesonia imbricata Chaetolepis lindeniana Daucus montanus Hieracium avilae Hymenophyllum trichomanoides Hypericum sp.

III IV IV III . V III I III II I . . I

V IV IV IV III V II II II IV III I I I

V III IV III III IV II I I IV II I I I

V V V IV III V III III III III III I I .

V IV V III IV V I III II III II I I I

V IV V IV IV V . IV I III II I I I

V IV V III V V II II III II II II I .

V IV V V II V III II IV I I II . .

V V V I IV II . V II . . I . .

Number of relevés

3.Cortaderio hapalotrichae- Hypericetum juniperinum

4. Puyo aristeguietae - Ruilopezietum lopez-palacii

5. R. gollmeri - Ruilopezietum jabonensis

HYPERICO CARDONAE - XYRIDION ACUTIFOLIAE

. . . . .

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RUILOPEZIO LOPEZ-PALACII - CHUSQUEETALIA ANGUSTIFOLIAE

The páramo vegetation of Ramal de Guaramacal, Trujillo State, Venezuela. 1. Zonal communities

319

Table 7. Table of presence of the zonal Guaramacal Chusquea angustifolia bamboo páramo associations combined with that of the zonal Chusquea tessellata bamboo páramo community of the Colombian Cordillera Oriental based on unpublished relevés of the second author. The predominant genera are underlined. I (0–20 %), II (21–40 %), III (41–60 %), IV (61–80 %) and V (81–100 %).

Number of relevés

25 Cord. Oriental Colombia

Association

Ageratina Aragoa Arcytophyllum Azorella Bartsia Bejaria Blechnum Breutelia Calamagrostis Campylopus Carex Castilleja Castratella Chaetolepis Chusquea Cortaderia Cybianthus Cyperus Daucus Diplostephium Disterigma Elaphoglossum Epidendrum Eriosorus Eryngium Espeletia Festuca Galium Gaultheria Gentiana Gentianella Geranium Greigia Halenia Hesperomeles Hieracium Huperzia Hydrocotyle Hymenophyllum Hypericum

. . I . . . V

I . II . . . .

I . . . . I II

. . I . . . .

II . III . . . IV I .

. . . II IV III II . I I III I I . . . . . I . . . . . II . . . . V

. . . IV IV V II . III I V II I I . . . I III . . III . . III I I . I V

I . . III IV V I . II I III . . . . . . . I . . IV I . III I . . I V

. II . I V V I . I . II I I . . . I . .I . . II . . . II . . . III

I I

. . . . V V . . . . . . . . . . . . . . I IV . . . I . . . V

. I III I V . I IV V V II I I . V II . I . I II . . . I IV II . II IV I . I . I I I . I

Number of relevés

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25 Cord. Oriental Colombia

Association

Hypochaeris Ilex Isidrogalvia Jamesonia Laestadia Libanothamnus Lycopodium Lysipomia Melpomene Miconia Monnina Muehlenbeckia Myrsine Nertera Neurolepis Niphogeton. Oreobolus Oritrophium Orthrosanthus Paepalanthus Pentacalia Pernettya Plantago Polypodium Puya Rhacocarpus Rhynchospora Rubus Ruilopezia Scirpus Sisyrinchium Sphagnum Sphyrospermum Themistoclesia Ugni Utricularia Vaccinium Valeriana Xenophyllum Xyris

. . . III . II IV . I I . I . II IV . . . . . I V . . II . V . V . . III I . II . I . . .

. I . II . I IV . II I . I I . I . . . I . II V . I I . IV II IV . . III . I II . II I . I

. . I II . I V . I . . . . I I . . . II I . V . . I . V . V . . I . . I . II I . III

. . I IV . I V . . . I . I . I . I . . . . V . . IV . V . V . . I . . I . I I . IV

. . I II . . V . . . . . . . I . II . . . . II . . . . V . V . . . . . . . . . V

III . . I I . II I . . . . . II . I III III . I III I I . I II I . . I I III . . . I I I .

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subpáramo plant communities of Ramal de Guaramacal are summarized in Table 6. A class cannot yet be defined on the basis of the Guaramacal relevés alone (Table 1) and the complete lack of data from other Chusquea angustifolia bamboo páramo areas in the region and from elsewhere in Venezuela and Colombia. Regional comparison, therefore, presently remains impossible. However, in order to evaluate the pattern of associated plant species and their dominancy a comparison with zonal Chusquea tessellata páramos of the Colombian Cordillera Oriental (Cleef 1981) has been undertaken (Table 7). The relevés are from the Colombian data set of the second author. Typical Sphagnum bogs with Chusquea tessellata have been avoided. Inspection of Table 7 learns that zonal Chusquea angustifolia bamboo páramo of Guaramacal shares about half of the vascular genera with the zonal Chusquea tessellata bamboo páramo of Colombia. Most important, however, is that there is no general agreement in generic pattern between both bamboo páramos, except for Chusquea. Apparently the Guaramacal bamboo páramo has more woody species, also because of its low altitude. The Colombian relevés span an altitudinal range between about 3200 and 4040 m. In conclusion, the Chusquea angustifolia bamboo páramo of Guaramacal represents a proper vegetation type not studied elsewhere. The páramo vegetation of the Guaramacal study area has been described on the basis of a relatively low number of relevés (ninety one 5 m-line surveys). Sampling effort in páramo areas of Ramal de Guaramacal was concentrated in the by road accessible sector of Las Antenas of Páramo de Guaramacal. Las Antenas area evidences most different physiognomic formations in relatively close proximity, and with a larger altitudinal range (2820~3130 m). Only a limited number of surveys were conducted in the remote areas of Páramo El Pumar, where the zonal vegetation appears more homogeneous over large areas. There, little variation in vegetation types, with a constant species composition, was observed over a shorter altitudinal range (2880~2990 m). As indicated in the methods section, line transects were laid out in apparently homogeneous and representative páramo vegetation patches. A line of 10 m was employed. The classical Zürich Montpellier approach uses plots of different size according to the structure and diversity of the vegetation. The minimum area has to be established for the different vegetation types (see also Westhoff & van der Maarel 1973, Cleef 1981). In the case of the zonal páramo of Ramal de Guaramacal, with its limited total of vascular species and few different páramo vegetation types, the line of 10 m has always been employed for documenting the presence of different species under the line with their cover abundance. To our surprise, no apparent discrepancies appeared in the TWINSPAN analysis and the final classification of the páramo plant communities. We believe a similar result would appear when plot sampling has

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been used. This method has, in fact, been chosen by the first author following a 1990 field course in the savannas of Bolivia organized by Tratado de Cooperación Amazónica (Cuello et al. 1991). The method of line-intercept transects has been widely used in vegetation ecology since the papers by Canfield (1941) and McIntyre (1953). This method has been tested for laboratory teaching (Cummings & Smith 2000, Kercher et al. 2003). It is possible that the line intercept technique used here could yield higher cover estimates but lower species richness estimates than the plot method, since plots (of generally 5 m x 5 m) would cover larger area than single 10 m lines. We consider, however, the resulting páramo classification is clearly visible for Páramo de Guaramacal. Páramo communities at association level may be representative of most páramo areas of Ramal de Guaramacal. A greater sampling effort, in a balanced way, over the study area would be necessary to refine the classification into infra association level. Páramo flora composition and diversity From a total of fifty 10 m-line intersect surveys, it was possible to register at least 48.2 % from a total of 193 vascular species known to date, from páramo areas of Ramal de Guaramacal. With a limited altitudinal span (2820–3130 m), the Páramo de Guaramacal exceeds a total surface area of not more than 10 km2. Most species are, in general, located in the lower part of the páramo belt. However, taking into account the actual degree of isolation (presently separated ca. 30 km Southwest and 35 km Northeast from the nearest páramo zones), the limited surface area and altitudinal span, the presence of only some 200 vascular páramo species (alpha diversity), compared to the number of 1544 vascular species reported from Venezuelan páramos [1437 angiosperms species reported by Briceño & Morillo (2002, 2006) plus 107 fern species reported by Luteyn (1999)] is quite understandable. Judging from periglacial evidence in the Guaramacal páramo it is clear that glaciation took place during the Last Glacial Maximum (LGM), and that the páramo zone extended downslope. Connectivity to other páramos of the Cordillera de Mérida was probably more functional during the LGM than is the case today. Repeated isolation during interglacials in the past has triggered a number of endemic species, and maybe even the highest species diversity of Ruilopezia rosettes, thus far, reported in the Venezuelan Andes to date. Up to date, about 50 endemic vascular species are known from Ramal de Guaramacal which represent ca. 4 % from a total of about 1400 vascular species. Physiognomy: life forms and growth forms Páramo vegetation of Ramal de Guaramacal is dominated mainly by woody growth forms, particularly upright shrubs with bamboo groves and clumps,

The páramo vegetation of Ramal de Guaramacal, Trujillo State, Venezuela. 1. Zonal communities

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Fig. 10. Gradient SARF – Zonal páramo, 3000–3050 m, North of ‘Las Antenas’, Ramal de Guaramacal, Andes, Venezuela 1. R u ilo p ezio paltonioides–Neurolepidetum glomerat a e (var.1.1 Disterigma alaternoides); A. Libanothamnetum grifﬁnii; 3. Cortaderio hapalotrichae–Hypericetum juniperinum; 4. Puyo aristeguietae–Ruilopezietum lopez-palacii; 5. Rhynchosporo gollmeri–Ruilopezietum jabonensis.

which give an overall appearance of a mostly shrub páramo vegetation. Two out of ﬁve associations are dominated by the presence of upright shrubs, and two out of the three bunchgrass dominated associations, also contain a high number of shrub species. The only grass páramo community almost devoid of shrubs is that of the low diverse R hy nch o sp or o g o ll m e ri i – R ui l o pe z i e tum j a bo nensis. The only two shrubby species registered in this association may be a consequence of sampling near the border with the surrounding shrubby páramo of C o r t a d e r io h ap a l o tri c h a e – H yp e ri c e tu m jun i p e r in u m . The high relative humidity and the low altitudinal range, coupled with the close proximity of the dwarf forests of the upper forest line zone, may explain in part the dominance of shrubby growth forms in páramo vegetation of Ramal de Guaramacal. From other extremely wet páramos the predominance of shrubs has also been reported, e.g. the Biosphere reserve of Podocarpus in South Ecuador (Bussmann 2002, Richter 2003, Becking et al. 2004) and the Tatamá páramo in the West Cordillera of Colombia (Cleef et al. 2005).

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Phytosociological classification and environmental variables TWINSPAN clustering of Páramo de Guaramacal (Table 1) arranges vegetation types in a sequence from shrub páramo to open páramo. This sequence could be directly related to a decrease in temperature with

increasing altitude. Additionally, the CCA ordination analyses show that species composition in the zonal páramo vegetation is foremost related to slope angle and altitude. On a later occasion (Cuello in prep.) the results of the ordinations will be more detailed. In the studied altitudinal range from 2800–3100 m in Páramo de Guaramacal, it is generally observed that different vegetation types can be found occupying the same altitude, with the exception of the grass páramo of Rh y n cho sp o ro gollmeri–Ruilop ezietu m jab o n ensis, which is always found above 2900 m. Other vegetation types, however, can be present above this altitudinal range; particularly, the shrub páramo of Co rtaderio hapalo trichae– Hy p ericetu m jun iperin u m, which is always present at the top of slopes. In the sector surrounding Las Antenas area, as shown in Fig. 10, on North to East slope expositions of Páramo de Guaramacal, and upslope the edges of the high Andean dwarf forest association of Libanothamnetum grifﬁnii (around 2800–3000 m) (Cuello & Cleef 2009a), the ecotonic shrub páramo of Ruilo p ezio–Neuro lep idetum association is generally present on either convex or concave slopes with relatively deep soils of predominantly loamy textures. Next, the grass páramo of Puyo aristeguietae–Ruilo p ezietu m lo p ez-p alacii is found anywhere from c. 2800 m to ~3040 m, alternating with the shrub páramo of the Cortaderio hapalo trich ae–Hy p ericetu m jun iperinum. Probably it belongs to the upper subpáramo, but by burning incidences the original woody component

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has decreased. The open grass páramo of R hyn cho s po r o g o l lm eri – Ru i l op e z i e tu m j a bo nen sis follows in altitude to that of Puy o a ri ste g u ietae– R u i lo p e z i e t u m l op e z -pa l a z i i . The lower grass páramo association is present predominantly on concave areas with coarse sandy soils close to the upper sections of slopes. Finally, the vegetation of C o rtad e r io h a p a lo t ri c ha e – H y pe ri c e tum j u nip erin u m is present at the top of the slope. The effect of past disturbance, such as ﬁres and the disruption of vegetation cover during or after the trail construction and installation of the telecomunication antennas, may explain the current distribution patterns of páramo vegetation in the Antenas sector. There is a fragmentation of the high Andean dwarf forests (SARF), evidenced by the current presence of some remnant islands surrounded by shrub páramo and open páramo vegetation. The grass páramo of Pu y o a r is t e gu i e ta e – R ui l o pe z i e tum lo p ezp a l a c ii seems to be a derived vegetation type from a past burning of the apparently original and extensive C o r t a d e r i o ha pa l otri c ha e – H y pe ri cetum j u n i p e r i n u m shrub páramo, which currently occurs on the borders of little valleys or near the top of slopes. The presence of a continuous cover of the open páramo, with single-stemmed Hypericum juniperinum shrub (in fact a dwarf tree) of the C ortad e r i o – H y p e r ic e tum j u ni p e ri n um , towards the apparently pristine areas of Páramo El Pumar, at the West of the summit of Ramal de Guaramacal, is indicative of a possible formerly more extensive presence in the Las Antenas area. Both the Corta derio – H y p e r i c e t u m and the Puy o– R ui l o pe z ietum associations share similar species composition; the C o r t a d e r i o – Hyp e ri c e tu m being typically more speciose. In Las Antenas area the vegetation of the C o r t a d e r i o – Hyp e ri c e tu m shows lower species richness than in El Pumar area, and the páramo of the Pu y o – R u i lo p e z i e tu m shows an absence, or very low presence of individuals of Hypericum juniperinum shrubs. On steeper South and Southwest slopes away from Las Antenas and along the mountain ridge towards the West, the altitudinal sequence of vegetation types that is contiguous upslope of the Libanothamnus grifﬁnii dwarf forest, or that of Gaultheria anastomosans-Hesperomeles obtusifolia (see Cuello & Cleef 2009a), is an alternation of shrub páramos of the D i s t e r ig m o – Arc yto ph yl l e tum association on concave or protected slopes, followed upwards by the shrub páramo of the arcytophylletosum nitidum subassociation of the Co rta d e ri o – H yp e ri cetum j u n ip e r in u m characteristic on steeper and wind exposed expositions. In Páramo El Pumar, at c. 2.5 km West from Las Antenas, the open shrub páramo of Corta derio– H y p e r i c e t u m abounds all over the altitudinal range from ~2880 to 3000 m. The continuity of the C o r t a d e r i o – Hyp e ri c e tu m dominated landscape of Páramo El Pumar is interrupted with the presence of some (azonal) bogs around glacial lakes (Cuello

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& Cleef, 2009b). Shrub páramo of the Disterigmo acu min atum–Arcyto p h y lletum n itid u m association is further present on concave, or protected slopes, as well as high Andean forest patches of the Geissan th o and ini–M icon ietu m jahn ii on sites with apparent local variation in topography and soils (Cuello & Cleef 2009a). Open páramo of Rh y n cho sp o ro go llmeri–Ru ilo p ezietu m jab o n ensis also occurs in small patches in depressions at borders or near the top of slopes over 2900 m, but is always surrounded by the shrub páramo of Cortaderio h apalo trich ae–Hy p ericetu m junip erin u m. Glacial morphology and páramo vegetation Evidence of the last glaciation is apparent nearly everywhere on the around the 3000 m ridge of Ramal de Guaramacal. The summit zone is generally narrow but slightly wider and highest near Antenas. The ridge in the area of Pumar is widest with a few small glacial lake basins and terminal moraines. Here a large glacier has been descending along the Llanos slope. Remnants of ground moraines and periglacial sediments are found outside the area of inclinated bedrock which is the most salient feature of the landscape. Roche moutonnée has also been locally observed. During the Last Glacial Maximum (LGM), the páramo zone probably extended to around 2000 m when interpolated from Laguna Pedro Palo from the Andes near Bogotá (Hooghiemstra & Van der Hammen 1993). The snow and glaciers would possibly have been restricted mainly to the ridge area; the Guaramacal páramo zone of the present. Slopes were too steep for the support of snow and ice, which probably collected at the base of these steep slopes; covered mainly today by upper montane and the subalpine dwarfed rain forests. Looking at the páramo landscape of the Guaramacal ridge, we can observe that the zonal vegetation of Cortaderio hapalo trich ae-Hyp ericetu m juniperin u m is most important in terms of the cover of the Guaramacal páramo (Photo 2). This open shrubby vegetation also covers most of the rocky surfaces of Páramo de Guaramacal with, in general, limited soil thickness ranging from between 5–10 to 115 cm. The vegetation of both associations of the alliance Hyperico paramitanu m-Hesperomeletion obtusifoliae are contiguous to the upper forest line, the humid shrub páramo of Ru ilo p ezio paltonioides-Neuro lep idetum glomeratae association is based on deeper soils (up to ca. 105 cm ) and is closer to the UFL and the shrub páramo of the association Disterigmo acu min atum-Arcy to phylletum n itid u m is contiguous to that of the latter. The nature of the large surface of exposed bedrock, and the climatic characteristics of the top effect, mean this area cannot support subalpine forest or upper montane rain forest, not even under a warming climate.

The páramo vegetation of Ramal de Guaramacal, Trujillo State, Venezuela. 1. Zonal communities

Comparison with other páramos As detailed in the introduction, Chusquea bamboo páramos have not yet been studied in Venezuela. They are distributed along the humid UFL on the Llanos slope of the Venezuelan Andes. Páramo de Guaramacal is also part of this unit. It is unknown if Chusquea bamboo páramos also occur along the UFL on the Maracaibo slope of the Cordillera de Mérida. Although Chusquea angustifolia has also been reported also from páramo areas in Zulia (Briceño & Morillo 2006) and specimens collected from Perijá are listed in MBG W3Tropicos database. On Avila and Naiguatá, Vareschi (1953, 1955) and Aristeguieta & Ramia (1951) described Chusquea spencei bamboos from the Libanothamnus neriifolius community (see also Steyermark & Huber 1978). Chusquea spencei has also been reported in the páramos of Cendé, Jabón and Las Rosas in Trujillo-Lara states border, North to Northeast of the Guaramacal range, as well as in Páramo El Zumbador and Tamá in Táchira, and in Páramo Los Conejos (La Culata) near Mérida (Monasterio 1980b). In humid areas of Páramo de Tamá, Bono (1996) describes the presence of Chusquea formations (a ‘Chusqueetum’ community of Chusquea angustifolia and Ch. tessellata) along small streams. It seems that Chusquea spencei prefers a drier páramo habitat (Monasterio 1980b) than Chusquea angustifolia, which determines the aspect of the Páramo de Guaramacal. In the Guaramacal páramo a few patches of Chusquea tessellata have also been documented. Chusquea angustifolia is present close to the UFL along the Llanos side of the Cordillera de Mérida and the Eastern Cordillera of the Andes in Colombia: Páramo de Sumapaz representing thus far its southernmost distribution. Chusquea angustifolia thrives in a clouded wet upper forest line habitat in comparison to its high altitude adapted relative Chusquea tessellata, which is a common species throughout the humid páramos of Colombia and Ecuador extending southwards to Bolivia (Luteyn 1999, Clark 2000). Chusquea angustifolia has smaller leaves but a greater density of leaves per branch than Chusquea tessellata. However, it is estimated that Chusquea angustifolia has an up to three times greater leaf surface area than Chusquea tessellata. This factor may also explain the dominance of Chusquea angustifolia in the wet Páramo de Guaramacal, which is also at lower altitude than most other zonal bamboo páramos as a function of top effect combined with the presence of bare rocky surfaces of the Guaramacal ridge. The limited knowledge on the presence and composition of Chusquea angustifolia bamboo páramos elsewhere, provides argument to rank the order described here as provisional. Species of Neurolepis bamboos are also highly indicative of wet environmental conditions. Associated with Chusquea angustifolia, Neurolepis glomerata occurs in the dwarf forests of the SARF-UMRF association of G a u l th e ri o a n a sto m o sa n s– H esp ero m e l e t u m o b t u si fol i a e (Cuello & Cleef 2009a)

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and in the zonal páramo of Ruilo p ezio paltonioides–Neu ro lep idetum glo meratae association described here. Neurolepis aristata is a low to tall bamboo occurring in association with Chusquea tessellata in bamboo páramo or as groves in protected sites near the UFL (Cleef 1981, Bussmann 2002). In the Guandera summit area in northern Ecuador an association of Neurolepis aristata bamboo vegetation was developed around 4000 m on the Amazon slope in an Espeletia pycnophylla–Calamagrostis effusa bunchgrass páramo (Moscol & Cleef 2009). The Podocarpus Park páramo in South Ecuador is probably the world’s most wet páramo. Bussmann (2002) described a number of páramo communities from its northeastern extremity with Neurolepis being present as the most dominant bamboo species: e.g. Neu ro lep idetum laegaardii Bussmann 2002. A number of bamboo species of Bussmann’s Neuro lep idion laegaardii alliance include: Chusquea tessellata, Neurolepis weberbaueri, and further Chusquea loxensis, Ch. leonardiorum, Ch. perligulata and Neurolepis nana. An association Neurolepid etum aristatae Bussmann 2002 has also been described from this rain-swept páramo. This is the ﬁrst time that Chusquea angustifolia has been referred to in a phytosociological context. Aside from the reference made by Bono (1996) in Páramo de Tamá, we are not aware of the bamboo vegetation of this species elsewhere or how this species interacts with the more common bamboo páramo species, Chusquea tessellata. The few clumps of Chusquea tessellata in Páramo de Guaramacal are supposed to be relatively recent arrivals in a setting occupied entirely by Chusquea angustifolia. Looking at the present-day distribution of Chusquea angustifolia, we assume that other unnamed associations in UFL in Páramos of Lara-Trujillo, Mérida, Tachira (Tamá), and Zulia (Perijá) where the species has been reported in Venezuela (Clark 1990, Briceño & Morillo, 2006), Arauca slope of Sierra Nevada del Cocuy, Páramo de Pisba, Chingaza and Sumapaz among other localities on the Llanos slope of the Colombian Eastern Cordillera are present. From páramos of Trujillo-Lara states, Páramos Cendé, Jabón and Las Rosas to the northeasternmost Venezuelan Andes, Monasterio (1980b) described the shrub páramo with a rosette community of Ruilopezia jabonensis or ‘Rosetal de Ruilopezia jabonensis’, as the most important Andean páramo vegetation “association” or community found within this area. This community was also referred as the driest páramo area of the country, receiving scarcely 600 mm/year rainfall at 3000–3400 m altitude. There, the Ruilopezia jabonensis vegetation community is present over large open areas and is surrounded by woodland communities of Libanothamnus neriifolius, and a shrubby bamboo páramo community dominated by Chusquea spencei and the endemic Pentacalia rigidifolia. According to Monasterio (1980b), the Ruilopezia jabonensis páramos of the Trujillo-

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Lara state border are composed mainly of a high ground rosette cover (50–60 %): with Arcytophyllum caracasanum, Hypericum caracasanum and H. laricifolium shrubs in addition to tussocks of Cortaderia nitida and Orthrosanthus chimboracensis. Niño et al. (1997), in a brief quantitative páramo vegetation survey utilising a 50 m line intersect transect in Páramo Cendé at 3200 m, studied a community dominated by Ruilopezia jabonensis, characterized by a high cover of Chusquea angustifolia bamboo, and a prominent abundance and diversity of bunchgrass species, such as Agrostis meridensis, Aristida sp., Cortaderia nitida, Danthonia secundiﬂora and an orchid species, Stenorrhynchos vaginatum (Niño et al. 1997). The silvery monocarpic rosettes of Ruilopezia jabonensis appear well adapted to higher elevations and drier conditions than those in Guaramacal. This may explain its limited presence on only small patches of the shrubless páramo of the Rh yn c h osp oro g ol l m e ri – R u ilo p e z ie t u m j a b o n e n si s association, occurring over well-drained coarse sandy soils, and restricted by the lower altitude of Ramal de Guaramacal from 2900 up to 3100 m. None of the bunchgrass companion species of the Ruilopezia jabonensis community of Páramo Cendé reported by Niño et al. (1997) are present in Páramo de Guaramacal. The presence of silvery rosettes is also curiously observed in disturbed páramos, e.g. Espeletia schultzii in Merida, Venezuela; Espeletia argentea near Bogotá in the Colombian Eastern Cordillera. The humid shrub páramo communities of Guaramacal show some generic compositional and physiognomic afﬁnities with some of the humid páramos areas of Táchira state (Monasterio 1980b, Bono 1996). From the shrub páramos of Táchira state, Monasterio (1980b) refered to a low and diverse páramo community of Ruilopezia jahnii–Puya aristeguietae, as being one of the most important communities occurring in locally wet (boggy like) areas in Páramo El Zumbador at 3200–3400 m. In this community, both Ruilopezia jahnii and Puya aristeguietae are codominant, forming patches surrounded by dense shrub páramo communities dominated by Blechnum aff. schomburgkii stem rosettes (Bono 1996) and shrubs, including: Arcytophyllum caracasanum, Clusia sp. and Hypericum caracasanum (Monasterio 1980b). Puya aristeguietae has been also reported from páramos of Trujillo (Guirigay), Lara, Merida (El Tambor, Pico Bolivar and La Carbonera) and Zulia (Holst, 1994), where we also assume the presence of other unnamed associations containing this species. This big ground rosette has also been documented for the northern páramos of the Colombian Cordillera Oriental (Cleef 1981). In Guaramacal, Puya aristeguietae is associated with the locally endemic Ruilopezia lopez-palacii in the Puy o a ri ste g u i e ta e – R u ilo p e z i e t u m l o p ez -p a l a c i i , and is also a dominant species in the Corta de ri o h a p a l o tri c h a e–Hy p e r ic e t u m j u n i p e ri n um .

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Natural disturbances, land use and conservation The summit of Páramo de Guaramacal has been affected by the construction of the road and the subsequent installation of the telecommunications antennas complex since the 1960’s. During those years, disturbance of the natural vegetation cover and fires have occurred. Before the construction of the road there was a path crossing the range North-South, located just between the current road (and to the side of it) and the location of the antennas. This track provided a commercial connection between the village of Guaramacal, located on the South slope of Ramal de Guaramacal, and the city of Boconó. It is also known that villagers of the past made extensive use of the páramo adjacent to the path as fields for pasture. Natural fires may also have occurred elsewhere in the summit zone of Ramal de Guaramacal, especially on the driest days of the year of high radiation, as was recently observed in Páramo El Pumar. Since 1988, Ramal de Guaramacal has been, and continues to be, protected as a National Park. Thus far, this has proves effective in, keeping the majority of human activities and their associated impacts outside the park borders. Only the area occupied by the antenna infrastructure, as well as the road and electrical pylons in Páramo de Guaramacal, are currently treated as a special use zone (‘Zona de Uso Especial’) where some limited (disturbance) activities are permitted. The more extensive and remote remainder of the Ramal de Guaramacal páramo ecosystem is free from human activities and very well conserved.

Conclusions Regardless of some methodological limitations, problems with accessibility and environmental conditions during the study of the páramo vegetation of Ramal de Guaramacal, the results of this study represent the first attempt at syntaxonomical classification and understanding of the floristic composition and patterns of bamboo páramos communities of the humid Llanos slopes of Venezuelan Andes. The mosaic-like distribution of shrub páramo, grass páramo and dwarf forest vegetation communities present on the summits of Ramal de Guaramacal may be the consequence of multiple factors, influenced by the top effect promoting a low UFL, permanently high relative humidity, and past disturbance events and fire dynamics. With the exception of some generic floristic affinities and physiognomic similarities, the páramo vegetation communities described for Ramal de Guaramacal cannot be directly related to any other of the named communities elsewhere in the Andes.

The páramo vegetation of Ramal de Guaramacal, Trujillo State, Venezuela. 1. Zonal communities

Resumen. Se estudiaron las comunidades de vegetación existentes en las cimas del Ramal de Guaramacal, estado Trujillo, Venezuela, con el fin de proporcionar un esquema de clasificación sintaxonómico basado en el análisis de la fisonomía, composición florística, relaciones ecológicas y distribución espacial de las diferentes comunidades vegetales. Mediante el levantamiento de cincuenta líneas de intersección de 10 m de largo, establecidas a cada 10 m de altitud, en la vegetación zonal entre 2800 y 3100 m, se encontraron un total de 91 especies de plantas vasculares, 33 de briofitas y 11 de líquenes. La interpretación de la clasificación con TWINSPAN permitió reconocer cinco comunidades de vegetación zonal al nivel de asociación, agrupadas en dos alianzas y un orden. Tres de las asociaciones son del subpáramo bajo arbustivo y dos del subpáramo alto con pajonal, dominadas por rosetas y hierbas en macollas. La alianza H y perico paramitanum–Hesperomeletion obtusifoliae agrupa las asociaciones de subpáramo arbustivo: Ruil o p e z i o p alto nioides–Neurolepidetum glomeratae and D i st erigmo acu minatum–Arcytophylletum ni t i d u m , presentes en vertientes protegidas del viento, a los bordes de bosques enanos o a lo largo de cursos de agua. La alianza H y p erico card onae–Xyridion acutifoliae agrupa una asociación de subpáramo arbustivo, la asociación Cort a d e ri o h ap alotrichae–Hypericetum juniperinum, ampliamente distribuida en el área y dos asociaciones de subpáramo alto con pajonal: Puyo aristeguietae–Ruilopez i e t u m l o pez-palacii, y Rhynchosporo gollmeri–Ruilo p e z i e tu m jabonensis, presentes sobre vertientes expuestas. Las familias Asteraceae y Ericaceae son las más ricas en especies seguido de Poaceae y Cyperaceae. Los géneros más diversos son Ruilopezia (Asteraceae), Rhynchospora (Cyperaceae) e Hypericum (Clusiaceae). Tanto la diversidad de especies como de formas de crecimiento es mayor en las comunidades arbustivas y disminuye en los pajonales-acaulirrosuletales. El análisis de correspondencia canónica (CCA) indica que la composición florística de las comunidades de vegetación zonal del Páramo de Guaramacal se relaciona principalmente con la pendiente y altitud, más que con otras variables observadas como profundidad y pH de los suelos. La composición genérica y de especies es propia de un páramo muy húmedo de bambúes.

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Acknowledgements. Financing and equipment for fieldwork was granted to the first author through the research projects: UNELLEZ SEI-23105102, FONACIT PEM-2001002165. INPARQUES and MARN are thanked for the corresponding permits, as well as the Superintendente of Guaramacal National Park TSU Amilcar Bencomo. Profile vegetation illustrations were drawn by Angelina Licata (UNELLEZ). Special thanks are extended to Wilfredo Albarrán (UNELLEZ) for collaboration during fieldwork and for taking care of logistics. Invaluable field assistance was provided by guardaparques Luis Zambrano†, Ramon Caracas and Guaramacal inhabitant Máximo Valladares. We acknowledge Joost Duivenvoorden for his help with the interpretation of the ordination analysis. Ross D. Morrison (University of Leicester, UK) kindly corrected and improved our English text. The UNELLEZ and Alberta Mennega Fund (Utrecht University) are acknowledged for financial contribution to the stay of the first author at IBED, University of Amsterdam, to work on the final elaboration of this publication.

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Addresses of the authors: Nidia L. Cuello A., Universidad Nacional Experimental de los Llanos Ezequiel Zamora (UNELLEZ-Guanare), Programa de Ciencias del Agro y del Mar, Herbario Universitario (PORT), Mesa de Cavacas, Estado Portuguesa 3323, Venezuela, e-mail: N.L.CuelloAlvarado@uva.nl; ncuello@cantv.net.

Antoine M. Cleef, Institute for Biodiversity and Ecosystem Dynamics (IBED), University of Amsterdam, Science Park 904, 1098 HX Amsterdam, The Netherlands, e-mail: cleef@uva.nl.

Appendix 1 Appendix 1. Checklist and vouchers of all plant species diversity recorded from the studies of páramo vegetation of Ramal de Guaramacal (including both zonal and azonal vegetation). All vouchers numbers correspond to N. Cuello et al. Lichenized Ascomycetes. Baeomycetaceae: Phyllobaeis imbricata (Hook. in Kunth) Kalb & Gierl 3173. Cladoniaceae: Cladia aggregata (Sw.) Nyl. 2966, 2977, 3067, 3148; Cladina arcuata (Ahti) Ahti & Follmann 2973; cf. Cladina rangiferina (L.)Nyl. 2973; Cladonia andesita Vain. 2971; Cladonia cf. pyxidata (L.) Hoffm. 2972; Cladonia corymbites Nyl. 3195; Cladonia crispata (Ach.) Flot. 3146; Cladonia didyma (Fee) Vain 3146; Cladonia furcata (Huds.) Schrad. 3036, 3049; Cladonia isabellina Vain. 2975; Cladonia squamosa (Scop.) Hoffm. 2964, Cladonia sp. 3068. Icmadophilaceae: Siphula pteruloides Nyl. 3145. Parmeliaceae: Rimelia reticulata (Tayl.) Hale & Fletcher 3015, 3172; Usnea sp. 3025. Peltigeraceae: Peltigera neopolydactyla (Gyeln.) Gyeln. 3162. Pertusariaceae: Pertusaria sp. 3165. Stereocaulaceae: Stereocaulon didymicum Lamb 3195. cf. Stereocaulon microcarpum Müll.Arg. 3024. Hepaticae. Aneuraceae: Riccardia spp. 2955, 2965. Herbertaceae: Herbertus pensilis (Tayl.) Spruce 2986; Herbertus grossispinus (Steph.) Fulf. 3129, 3236, 2950; Herbertus juniperoideus (Sw.) Grolle 3078, 3149, 3270, 2980; Herbertus acanthelius Spruce 3242, 3119; Herbertus subdentatus (Steph.) Fulf. 3246. Lepidoziaceae: Bazzania latidens (Gottsche ex Stephani) Fulford 3257, 3258; Bazzania spp. 3066, 3136. Metzgeriaceae: Metzgeria sp. 3250. Plagiochilaceae: Plagiochila cf aerea Taylor 3126; Plagiochila tabinensis Steph. 3071; Plagiochila spp. 2948, 2952, 2957, 2958, 2961, 2962, 2969, 2979, 2982, 2985, 3042, 3132, 3163, 3239. Scapaniaceae: Scapania portoricensis Hampe & Gottsche 3130, 2967, 3073, 3124, 3159. Jungermaniaceae: Jamesoniella rubricaulis (Nees) Grolle 2949, 2959, 2963, 3021. Jubulaceae: Frullania spp. 2970, 2976, 3022, 3038, 3039. Hepaticae indet. 2979, 3132. eschweizerbartxxx ingenta

Musci. Bartramiaceae: Breutelia rhythidioides Herz. 2978, 3035, 3075, 3099; Breutelia squarrosa Jaeg. 2954, 2960, 3030, 3110. Bryaceae: Bryum grandifolium (Tayl.) C. Muell., 2946, 3120. Dicranaceae: Campylopus albidovirens Herz. 3100, 3101, 3107, 3109; Campylopus cuspidatus (Hsch.) Mitt. var. dicnemioides (C. Muell.) J.-P. Frahm 3105, 3108; Campylopus flexuosus (Hedw.) Brid. 3065; Campylopus fragilis (Brid.) B.S.G. 3048; Campylopus insignis Herz. 2974 Campylopus nivalis (Brid.) Brid. 3072, 3128; Campylopus pilifer Brid. 3033, 3122; Campylopus richardii Brid. 3016, 3079;Campylopus subjugorum Herz. 3031, 3046, 3076; Campylopus trichophorus Hampe ex Herz., 2983, 3050; Dicranum frigidum C. Muell., 3118. Leucobryaceae: Leucobryum antillarum Schimp. ex Besch., 3055. Polytrichaceae: Polytrichadelphus longisetus (Hook.) Mitt., 3020; Polytrichum commune Hedw., 3098; Polytrichum juniperinum Hedw., 3103, 3117. Pottiaceae: Leptodontium viticulosoides (P. Beauv.) Wijk & Marg. var. panamense (Lor.) Zander, 3054. Rhacocarpaceae: Rhacocarpus purpurascens (Brid.) Par. 3017. Semathophyllaceae: Sematophyllum swartzii (Schwaegr.) Welch & Crum, 3018; Semathophyllum sp. 3077. Splachnobryaceae: Tetraplodon mnioides (Hedw.) B.S.G., 3121. Sphagnaceae: Sphagnum cuspidatum Ehrhart ex Hoffm. 3051, 3089, 3113; S. magellanicum Brid. 3041, 3104, 3115; Sphagnum meridense (Hpe.) C. Muell. 3074; Sphagnum recurvum P. Beauv. 3106; Sphagnum sancto-josephense Crum & Crosby; Sphagnum sparsum Hpe. 3114. Ferns. Blechnaceae: Blechnum schomburgkii (Kl.) C. Chr. 2937, 2940. Dryopteridaceae: Elaphoglossum appressum Mickel 2936; Elaphoglossum cf. lingua (C. Presl) Brack. 2893. Grammitidaceae: Lellingeria myosuroides (Sw.) A.R. Sm. & R.C. Moran 2933; Melpomene flabeliformis (Lag. Ex Sw.) A.R. Sm & R.C. Moran 2732, 2877; M. moniliformis (Lag. Ex Sw.) A.R. Sm & R.C. Moran 2720; M. xiphopteroides (Liebm.) A.R. Sm. 2896; Melpomene sp. 3157. Hymenophyllaceae: Hymenophyllum myriocarpum Hook. s.n. L-29; H. trichomanoides Bosch. 2728, 2895; Hymenophyllum sp. s.n. L-34; Isoëtaceae: Isoëtes karstenii A. Braun 3367, 3386; Lycopodiaceae: Huperzia amentacea (B.Øllg.) Holub.; H. riobambensis (Herter) B.Øllg. 2723; Lycopodium clavatum subsp. contiguum Kl. 2696. Ophioglossaceae: Ophioglossum crotalophorioides Walter 2931. Polypodiaceae: Polypodium funckii Mett. 2809; Polypodium sp. 3070. Pteridaceae: Eriosorus flexuosus (Kunth) Copel. var. flexuosus 2824, 2897, 2934; Jamesonia imbricata (Sw.) Hook. & Grev. 2722.

The páramo vegetation of Ramal de Guaramacal, Trujillo State, Venezuela. 1. Zonal communities

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Magnoliopsida. Apiaceae: Daucus montanus H. & B. ex Spreng. 2997. Aquifoliaceae: Ilex guaramacalensis Cuello & Aymard 2701, 2942. Asteraceae: Ageratina theifolia (Benth.) R.M. King & H. Rob. 2746; Diplostephium obtusum S.F. Blake 2748; D. venezuelense Cuatrec. 2688, 3096; Hieracium avilae Kunth 2890; Libanothamnus griffinii (Ruiz-Teran & Lopez-Fig.) Cuatrec. 2704; Pentacalia cachacoensis (Cuatrec.) Cuatrec. 2694; P. greenmaniana (Hieron.) Cuatrec. 2747; Ruilopezia jabonensis (Cuatrec.) Cuatrec. 2695, 2715; R. lopez-palacii (RuizTerán & López-Figueiras) Cuatrec. 2899; R. paltonioides (Standl.) Cuatrec. 2716; R. viridis (Aristeguieta) Cuatr. 2717; Asteraceae indet. 3299. Caryophyllaceae: Arenaria venezuelana Briq. 3082. Clusiaceae: Hypericum cardonae Cuatrec. 2700; H. juniperinum Kunth; H. paramitanum N. Robson 1388, 2831; Hypericum sp. Ericaceae: Bejaria aestuans L. Disterigma acuminatum (Kunth) Nied. D. alaternoides (Kunth) Nied. 2730; Gaultheria anastomosans (L.f.) Kunth 2724, 2752; G. erecta Vent. 3058; G. hapalotricha A.C. Sm. 2714; Pernettya prostrata (Cav.) DC. 2706, 2713, 2727; Sphyrospermum buxifolium Poepp. & Endl. 3321; Themistoclesia dependens (Benth.) A.C. Sm. 2733; Vaccinium corymbodendron Dunal 2708, 2729. Gentianiaceae: Gentianella nevadensis (Gilg.) Weaver & Rudenberg. 2915. Geraniaceae: Geranium stoloniferum Standl. 2913. Lentibulariaceae: Utricularia alpina Jacq. 2901. Melastomataceae: Chaetolepis lindeniana (Naud.) Triana 2705; Miconia tinifolia Naud. 2702, 3064; Monochaeteum discolor H. Karst. 2710, 2750. Myrsinaceae: Cybianthus laurifolius (Mez) G. Agostini; C. marginatus (Benth.) Pipoly; C. stapfii (Mez) Agostini 2703; Myrsine dependens (Ruiz & Pav.) Spreng. 2792; 2796. Myrtaceae: Ugni myricoides (Kunth.) O. Berg. 2721. Polygalaceae: Monnina sp. 3061. Polygonaceae: Muehlenbeckia tamnifolia (Kunth) Meisn. 2731. Rosaceae: Hesperomeles obtusifolia (Pers.) Lind. var. obtusifolia 2707; Hesperomeles sp. 3080; Lachemilla verticillata (Fielding & Gardner) Rothm. 3116; Rubus acanthophyllos Focke 3060. Rubiaceae: Arcytophyllum nitidum (Kunth) Schltdl.2718; Galium hypocarpium (L.) Endl. ex Griseb.; Nertera granadensis (Mutis ex L.f.) Druce 2734; Palicourea jahnii Standl. 2943; Scrophulariaceae: Castilleja fissifolia L.f. 2902; Valerianaceae: Valeriana quirorana Xena 2935, 3322. Liliopsida. Bromeliaceae: Greigia sp. s.n. L-44; Puya aristeguietae L.B. Sm. s.n. L-1; Puya sp. s.n. L-48; Cyperaceae: Carex bonplandii Kunth 2741; Eleocharis acicularis (L.) Roem. & Schult. 3088, 3368; Eleocharis sp. 3174; Oreobolus venezuelensis Steyerm. 2891; Rhynchospora gollmeri Boeck. 2739; R. guaramacalensis M. Strong 2889; Rhynchospora macrochaeta Steud. ex Boeck. 2697, 2740, 2743; Rhynchospora spp.2697, 2735. Eriocaulaceae: Paepalanthus pilosus (Kunth)Kunth 2996, 3097; Iridaceae: Orthrosanthus acorifolius (Kunth) Ravenna 2904; Sisyrrhinchium tinctorium Kunth 2911. Sisyrhynchium sp. 3391. Orchidaceae: Cyrtochilum ramosissimum (Rchb.f.) Kränzl. 3001; Epidendrum frutex Rchb.f. 2719; Pterichis multiflora (Lindl.) Schltr. 2916 Poaceae: Agrostis basalis Luces. 2803, 3085, 3389; A. perennans (Walter) Tucker 2917, 3189, 3084, 3092; Agrostis sp. B 3155, 3093; Calamagrostis bogotensis (Pilg.) Pilg.; C. planifolia (Kunth) Trin. ex Steud. 2905, 2914, 2925, 29991; Calamagrostis sp. A, 2926; Calamagrostis sp. 3388; Chusquea angustifolia (Soderstr. & C.E. Calderon) L.G. Clark 2941, 2995; Ch. tessellata Munro 3153; Cortaderia hapalotricha (Pilg.) Conert. 2737; Festuca guaramacalana Stančik 2900; Neurolepis glomerata Swallen 2726; Ortachne erectifolia (Swallen) Clayton 3390; Polypogon elongatus Kunth 2990; Indets. 3090, 3142.Tofieldiaceae: Isidrogalvia robustior (Steyerm.) Cruden. Xyridaceae: Xyris subulata Ruiz & Pav.var. acutifolia Heimerl. 2699, 2738. eschweizerbartxxx ingenta