Plagiochila_2005 by PARQUE NATURAL MADEIRA

Nova Hedwigia

3—4

449—461

Stuttgart, November 2005

The genus Plagiochila (Dumort.) Dumort. (Plagiochilaceae, Hepaticophytina) in Madeira Archipelago Molecular relationships, ecology, and biogeographic affinities by

Manuela Sim-Sim1, Maria da Glória Esquível2, Susana Fontinha3 and Michael Stech4 1

Universidade de Lisboa, Faculdade de Ciências de Lisboa, DBV, Centro de Ecologia e Biologia Vegetal, C2, Campo Grande, 1749-016 Lisboa, Portugal, msimsim@fc.ul.pt 2

Centro de Botânica Aplicada à Agricultura, Instituto Superior de Agronomia, Universidade Técnica de Lisboa, 1349-017 Lisboa, Portugal

Centro de Estudos da Macaronésia. Serviço do Parque Natural da Madeira. Quinta do Bom Sucesso, 9050-251 Funchal, Madeira, Portugal 4

Institut für Biologie - Systematische Botanik und Pflanzengeographie -, Freie Universität Berlin, Altensteinstr. 6, D-14195 Berlin, Germany With 3 figures

Sim-Sim, M., M.G. Esquível, S. Fontinha & M. Stech (2005): The genus Plagiochila (Dumort.) Dumort. (Plagiochilaceae, Hepaticophytina) in Madeira Archipelago - Molecular relationships, ecology, and biogeographic affinities. - Nova Hedwigia 81: 449-461. Abstract: Plagiochila is one of the most frequent bryophyte genera in Madeira, inhabiting almost all habitats of the Madeiran laurel forest (Laurisilva). Results on the biodiversity, ecology and molecular relationships based on nuclear ribosomal ITS1 and ITS2 sequences of all Plagiochila species referred to Madeira Archipelago are summarized with the aims to provide (i) a first molecular confirmation of a species inventory of a bryophyte genus in a specific geographic region and (ii) a bryophyte example for displaying biogeographic affinities of the Madeiran laurel forest. The molecular analyses confirm the presence of nine species in Madeira, which belong to four sections: Plagiochila sect. Arrectae, sect. Rutilantes, sect. Vagae and sect. Plagiochila. Section Arrectae is represented in Madeira by five species, P. bifaria, P. punctata, P. retrorsa, P. spinulosa, and P. stricta. Section Rutilantes is represented by P. exigua and the Macaronesian endemic P. maderensis, which is reported for the first time to Canary Is. The sections Vagae and Plagiochila are represented by a single species each, P. virginica and P. porelloides, respectively. The molecular data indicate strong biogeographic affinities of the Madeiran Plagiochila flora with Central and northern South America, and to a lesser extent with Africa and Continental Europe. The environmental conditions found in Madeira Island, especially

DOI: 10.1127/0029-5035/2005/0081-0449

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habitat stability and the stable climate in the laurel forest, may have favored the development of populations of Plagiochila species from neotropical sections. Key words: Plagiochila, Madeira Archipelago, Laurisilva, ITS, molecular relationships, ecology, biogeographic affinities

Introduction Due to its insular characteristics the Madeira Archipelago shows an important floristic diversity. Its main forest formation, the Laurisilva, is considered a relict of the forests of the Tertiary period that dominated southern Europe and northern Africa millions of years ago. Madeira Island comprises the largest extant area of such laurel forest, an estimated 15,000 hectares which was designated a UNESCO World Heritage in 1999 and incorporated in the Natura 2000 Network. Nowadays, Madeiraâ&#x20AC;&#x2122;s Laurisilva is mainly located on the cloudy slopes on the northern side of the island, from 300 to 1,300 m above sea level, which are exposed to the NE prevailing winds and thus have more than 3,000 mm annual rainfall and high humidity levels (7590%) nearly all-the-year. On the southern slopes, only restricted niches of laurel forest remained (Menezes et al. 2004). The Laurisilva hosts a rich and diverse bryoflora including several species endemic to Madeira and to Macaronesia (Sim-Sim et al. 2000, Fontinha et al. 2001). Plagiochila is one of the most frequent bryophyte genera in Madeira, inhabiting almost all habitats of the Laurisilva and often forming large mats on the slopes, rocks and tree trunks. The study of herbarium material and recent collections, mainly from the slope formations located along water-courses allowed an extensive survey of the genus Plagiochila in Madeira Archipelago. At present, nine Plagiochila species are known for Madeira, P. bifaria (Sw.) Lindenb., P. exigua (Taylor) Taylor, P. maderensis Gottsche ex Steph., P. porelloides (Torrey ex Nees) Lindenb., P. punctata (Taylor) Taylor, P. retrorsa Gottsche, P. spinulosa (Dicks.) Dumort., P. stricta Lindenb. and P. virginica A. Evans (Heinrichs et al. 1998, 2002, 2004a, 2004c, 2005b, Grolle & Long 2000, Rycroft et al. 2001, 2002, 2004, Sim-Sim et al. 2003, 2004, 2005, Figueiredo et al. 2005). The presence of five of these species in Madeira were confirmed by our previous molecular analyses (Sim-Sim et al. 2004, 2005). In the present study we aim to summarize our results on the biodiversity, ecology and molecular relationships of Plagiochila in Madeira Archipelago. A molecular analysis including all nine referred Plagiochila species is performed based on nuclear ribosomal ITS1 and ITS2 sequences, with the aims to provide (i) a first molecular confirmation of a species inventory of a bryophyte genus in a specific geographic region and (ii) a bryophyte example for displaying biogeographic affinities of the Madeiran laurel forest. Material and methods Plant material. Fieldwork was carried out between August 2002 and July 2004 at 23 forest areas corresponding to 46 UTM squares of 1x1 km (Fig. 1). About 400 Plagiochila populations were sampled mainly on the slope formations located along watercourses. These slopes were of natural

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Fig. 1. Map of sampled sites for the biodiversity study of slopes in Madeira and Porto Santo Islands. Plagiochila populations were collected in more than 90% of the sampled sites.

origin or man-made, being in this case localized along the “levadas”. For most of the populations sampled, position (UTM squares 1x1 km), altitude, and the main vascular plant formation, as well as ecological characteristics of the site such as humidity and lightness were recorded. In order to update the distribution of the different Plagiochila taxa in Madeira, 200 herbarium specimens from B, BM, INA, LISU, MADJ, MADS, PC, PO, S, T and Herbarium Rin were also revised. The nomenclature follows Grolle & Long (2000) for liverworts, Corley et al. (1981), Corley & Crundwell (1991 and Hedenäs (1992) for mosses and mostly Press & Short (1994) for vascular plants. Acronyms of herbarium collections follow Vitt et al. (1985). Molecular analysis. A dataset of 51 ITS sequences from 22 Plagiochila species was compiled, including 40 sequences from previous analyses (Groth et al. 2003, Heinrichs et al.2004b, 2005a, 2005b, Lindner et al. 2004, Rycroft et al. 2004, Sim-Sim et al. 2004, 2005), which provided a sound basis for the present study, and 11 newly determined sequences deposited in LISU or the private herbarium of M. Stech, respectively. The latter comprised Plagiochila bifaria (LISU 203603), P. exigua (LISU 182260, 203601), P. maderensis (Stech et al. 04-90), P. porelloides (LISU 203599), P. punctata (LISU 203754, Stech et al. 04-371), P. retrorsa (LISU 182245) and P. virginica (LISU 203600) from Madeira as well as P. bifaria (LISU 203602) and P. porelloides (LISU 189207) from Portugal mainland. Cleaning of plant material, DNA extraction, PCR and sequencing was performed by the methods described in Sim-Sim et al. (2005). Sequences were deposited in GenBank under the following accession numbers: Plagiochila bifaria AY541608, DQ159992, P. exigua DQ159995, DQ159996, P. maderensis DQ159991, P. porelloides DQ159993, DQ159994, P. punctata DQ159989, DQ159990, P. retrorsa DQ159988 and P. virginica DQ159997.

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Alignment of the ITS1 - 5.8S - ITS2 region was performed manually in the Alignment Editor Align32 (Hepperle 1997). Phylogenetic analyses according to the maximum parsimony principle were conducted with winPAUP 4.0b10 (Swofford 2002). Pedinophyllum interruptum (Nees) Kaal. and Plagiochilion mayebarae S. Hatt. were chosen as outgroup representatives according to Rycroft et al. (2004). A heuristic search under parsimony was performed with the following options: all characters unweighted and unordered, multistate characters interpreted as uncertainties, gaps coded as missing data, performing TBR branch swapping, collapse zero length branches, MulTrees option in effect, maxtrees = 10,000. A heuristic bootstrap search was performed with 1,000 replicates with 10 addition sequence replicates per bootstrap replicate. Further measurement of support for individual clades was obtained using AutoDecay 4.0 with 100 random addition cycles (Eriksson 1999). Maximum likelihood analyses were performed using the settings (GTR+G model) calculated by winModeltest v.4b (Posada & Crandall 1998): Basefreq = (0.1739 0.2494 0.3327), Nst = 6, Rmat = (1.0000 3.9640 1.0000 1.0000 5.4650), Rates = gamma, Shape = 0.7218, Pinvar = 0. Likelihood bootstrap searches were performed with 100 replicates using the â&#x20AC;&#x153;fast bootstrapâ&#x20AC;? option.

Results Molecular relationships. The alignment comprised 965 positions (ITS1 positions 1-449, 5.8S gene 450-609, ITS2 610-965). Of these, 154 positions (86 of the 5.8S gene and 68 of the ITS2) were excluded from the phylogenetic analyses due to incomplete sequencing or ambiguous alignment. Of the remaining 811 included positions, 347 (42.8%) were variable, and 219 of the variable positions (63.1%, or 27.0% of the total number of included positions) were parsimony-informative. In the strict consensus tree of 2,558 most parsimonious trees (lengths = 690 steps, consistency index CI [excluding uninformative characters] = 0.540, retention index RI = 0.847), the four included sections of Plagiochila are resolved as monophyletic with 99-100% bootstrap support (BS), respectively, and decay indices (DI) of 5-14 (Fig. 2). Well-supported sistergroup relationships are indicated for sections Arrectae/ Rutilantes (96% BS, DI = 3) on the one hand and Plagiochila/Vagae (98% BS, DI = 7) on the other hand. Within sect. Arrectae, Plagiochila bifaria, P. spinulosa, P. retrorsa and P. stricta, including the specimens from Madeira and Portugal mainland, form monophyletic clades that receive 78-96% BS except for the clade of P. stricta. In contrast, relationships between these clades and the three clades composed of specimens of P. punctata remain ambiguous. The Madeiran specimens of P. punctata are most closely related to the other European sample from the UK (98% BS, DI = 5). Within sect. Rutilantes, close relationships between P. exigua, P. cuneata Lindenb. & Gottsche and P. steyermarkii H. Rob. (100% BS, DI = 13) and a sistergroup relationship of this clade and that of both P. maderensis specimens (100% BS, DI = 24) are indicated. Relationships within sect. Plagiochila are almost unresolved. The samples of Plagiochila porelloides from Madeira and Portugal mainland are part of a polytomy Fig. 2. Strict consensus tree of 2,558 most parsimonious trees (lengths = 690 steps, CI [excluding uninformative characters] = 0.540, RI = 0.847) inferred from ITS1 and ITS2 sequences of Plagiochila species using Pedinophyllum interruptum and Plagiochilion mayebarae as outgroup representatives. Bootstrap values >50% and decay indices (on a black background) are depicted above the branches. Specimens in bold originate from Madeira Island, asterisks indicate newly sequenced specimens.

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together with P. asplenioides (L.) Dumort. and P. britannica Paton, but separated from a weakly supported clade of P. porelloides from Germany and the USA (53% BS, DI = 1). The clade of both P. virginica specimens (sect. Vagae) gains 100% BS and a DI of 10 and is sister to a clade of P. raddiana Lindenb. and P. tocarema Gottsche. The topology of the single optimal maximum likelihood tree (Fig. 3, lnL = 4875.25828) is similar to that of the parsimony consensus tree. The four Plagiochila sections each form a monophyletic group with 82-99% BS. Sistergroup relationships of sections Arrectae / Rutilantes and Plagiochila / Vagae are supported by bootstrap values of 74% and 86%, respectively. In contrast to the parsimony tree, P. punctata (sect. Arrectae) is resolved as monophyletic, although without statistical support, and P. maderensis occupies a basal position within sect. Rutilantes. Ecology and distribution in Madeira. Plagiochila bifaria is the most frequent species in the Madeiran Laurisilva, and was collected by us also in the adjacent island of Porto Santo. It occurs on rocks, boulders and stone walls in sheltered or exposed habitats along watercourses, forming loose to dense patches. Besides its frequent occurrence in the laurel forest (Clethro arboreae-Ocotea foetensis), P. bifaria is also found on slopes in deep valleys of the southern part of Madeira, which are dominated by the Semele androgynae-Apollonietum barbujanae, and more rarely in the high altitude arborescent heathlands (Polysticho falcinelli-Erico arboreae) (Capelo et al. 2004). Associated bryophyte species are Frullania tamarisci (L.) Dumort., Lejeunea patens Lindb., Marsupella profunda Lindb., Plagiochila exigua, P. stricta, Porella canariensis (F. Weber) Underw., Andoa berthelotiana (Mont.) Ochyra, Fissidens luisieri P. Varde and Ptychomitrium polyphyllum (Sw.) Bruch & Schimp. Plagiochila stricta is the second most frequent species in the Laurisilva on the northern slopes of Madeira. This species grows mainly on the shaded slopes located along rivulets, forming scattered or pure mats, and also on the bark of Persea indica (L.) K. Spreng., in association with other Plagiochila taxa, especially P. bifaria, as well as with Frullania teneriffae (F. Weber) Nees, Lejeunea eckloniana Lindenb., L. lamacerina (Steph.) Schiffn., Porella canariensis, Andoa berthelotiana, Echinodium prolixum (Mitt.) Broth., E. spinosum (Mitt.) Jur., Fissidens luisieri, Plagiothecium nemorale (Mitt.) A. Jaeger and Thamnobryum alopecurum var. maderense (Kindb.) Stech, Ros & O. Werner. Most of the vascular plants growing in the vicinity are endemics, relics or species threatened worldwide (cf. Sim-Sim et al. 2004). Plagiochila exigua, P. maderensis, and P. retrorsa are also common in the Madeiran Laurisilva, however, significantly less frequent than P. bifaria and P. stricta. The slender plants of Plagiochila exigua form loose turfs, growing on moist rock surfaces and slopes near watercourses as well as epiphytically, frequently associated with Frullania tamarisci, Harpalejeunea molleri (Steph.) Grolle, Lejeunea patens, Plagiochila bifaria, Porella canariensis, Andoa berthelotiana, Echinodium prolixum, Lepidopilum virens Cardot and Thuidium tamariscinum (Hedw.) Schimp. Most of the populations of Plagiochila maderensis were collected in shady and humid conditions, frequently on sheltered sites on the slopes and on streamside rocks or 454

Fig. 3. Single optimal maximum likelihood tree (GTR+G model, lnL = -4875.25828) inferred from ITS1 and ITS2 sequences of Plagiochila species using Pedinophyllum interruptum and Plagiochilion mayebarae as outgroup representatives. Bootstrap values >50% are depicted above the branches. Specimens in bold originate from Madeira Island, asterisks indicate newly sequenced specimens.

rocky slopes along trails. Like P. stricta, the species occurs frequently together with vascular plants that are endemics, relics or species threatened worldwide, and also the associated bryophyte species are basically the same as for P. stricta. This species 455

has been considered a Madeiran endemic but was recently identified by us in three collections from Canary Islands named as P. spinulosa. Plagiochila retrorsa grows in large and dense mats on rocky slopes and on faces of damp boulders, frequently in the vicinity of temporary lagoons and swamps. It is found associated with Frullania tamarisci, F. teneriffae, Lejeunea eckloniana, Porella canariensis, Radula carringtonii J.B.Jack, Tylimanthus madeirensis Grolle & Perss., Andoa berthelotiana, Brachythecium rutabulum (Hedw.) Schimp. var. atlanticum Heden채s and Echinodium prolixum. Plagiochila punctata was less frequent in the collections of the present study as well as in herbarium material from the Laurisilva, however, we suggest that other habitats, like epiphytic ones, should be surveyed in more detail to get an accurate distribution of this species in Madeira. Specimens of P. punctata were collected on shaded rocks or rocky slopes near streams or ravines forming small mats in association with Frullania tamarisci, Lejeunea lamacerina, P. bifaria, P. spinulosa, Radula nudicaulis Steph., Andoa berthelotiana, Fissidens luisieri and Hookeria lucens (Hedw.) Sm. The revision of herbarium specimens from Madeira resulted in 11 records of P. porelloides. In addition, the species was recently collected on the slopes of Laurisilva at two different sites. The collected specimens were growing on moist and shady rocks, forming isolated and small mats aside of populations of other bryophytes such as Andoa berthelotiana, Fissidens luisieri, Thamnobryum alopecurum var. maderense, Porella canariensis and Plagiochila bifaria. In the course of this investigation we found P. virginica only once, as an epiphyte in a humid and shady region of the the Laurisilva on the northern slope, mainly associated with Frullania microphylla (Gottsche) Pearson, Harpalejeunea molleri, Lejeunea lamacerina, Lejeunea patens, Plagiochila exigua, Neckera intermedia Brid., Hypnum uncinulatum Jur. and Echinodium prolixum. The study of herbarium material allowed the confirmation of three specimens of P. virginica altogether. Since we have not found P. virginica on the studied slopes, and having not found any reference on the herbarium labels seen, we tend to accept that this species is probably more frequent as an epiphyte. Plagiochila spinulosa, the rarest species of Plagiochila in Madeira, grows mainly on the shaded slopes, forming scattered or pure mats. The only two sites where the species was found are above the limits of the laurel forest, between 1,300 and 1,400 m, in the mesotemperate hyper-humid bioclimatic zone. These areas are dominated by communities of Erica platycodon (Web. & Berthel.) Rivas-Mart. et al. subsp. maderincola (D.C.McClint.) Rivas-Mart. et al., Erica arborea L. and Vaccinium padifolium Sm. ex Rees (Vaccinio padifolii-Ericetum maderinicolae, Capelo et al. 2000), which form a transitional community from Laurisilva to the high altitude arborescent heathlands (Polysticho falcinelli-Erico arboreae sigmetum) (Capelo et al. 2004). As for P. stricta, most of the vascular plants growing in the vicinity are endemic, relic or species threatened worldwide (cf. Sim-Sim et al. 2005). Plagiochila spinulosa occurs in association with P. bifaria and P. exigua as well as with Aphanolejeunea microscopica (Taylor) A.Evans, Drepanolejeunea hamatifolia (Hook.) Schiffn., Frullania teneriffae, Microlejeunea ulicina (Taylor) A. Evans, 456

Porella inaequalis (Gottsche ex Steph.) Perss., Radula nudicaulis, Andoa berthelotiana, Daltonia splachnoides (Sm.) Hook. & Taylor, Echinodium prolixum, Fissidens luisieri, Thamnobryum alopecurum var. maderense and Tylimanthus madeirensis. Discussion Plagiochila is a characteristic genus of the Madeiran bryoflora that shows a high biodiversity in terms of species number and colonization of different habitats. Recent fieldwork revealed the high frequency of Plagiochila species in the Laurisilva, mainly on slopes and rocks, but also on the bark of different trees. The present study represents the first molecular confirmation of the species inventory of a bryophyte genus in a specific geographic region, in particular the Madeira Archipelago. The molecular trees support the presence of nine Plagiochila species in Madeira, which belong to four sections: Plagiochila sect. Arrectae, sect. Rutilantes, sect. Vagae and sect. Plagiochila. Section Arrectae, a mainly neotropical-Atlantic European clade with highest diversity in mountainous regions of South America (Heinrichs et al. 2005b), is represented in Madeira by five species, P. bifaria, P. punctata, P. retrorsa, P. spinulosa, and P. stricta. The neotropical section Rutilantes is represented by P. exigua and the Macaronesian endemic P. maderensis, the mainly (pan-)tropical section Vagae by the Eastern North American-Macaronesian disjunct P. virginica, and the holarctic section Plagiochila by P. porelloides. Recent morphological, phytochemical and molecular analyses resulted in broader species concepts and enlarged distribution patterns for several Plagiochila species, e.g., P. bifaria (Heinrichs et al. 2004a), P. corrugata (Heinrichs et al. 2004b), P. punctata (Heinrichs et al. 2005b), or P. stricta (Lindner et al. 2004). The present molecular study that includes specimens from Madeira confirms the monophyly of P. bifaria and P. spinulosa with >90% bootstrap support and of P. stricta and P. punctata (ML analysis only) without significant support, in accordance to the topologies in the previous analyses. However, intraspecific sequence variation seems to be a common phenomenon in the internal transcribed spacers in these widely distributed Plagiochila species. Plagiochila maderensis, P. retrorsa and P. virginica, which are analysed for the first time with more than one specimen, are also resolved as monophyletic with 80-100% support, whereas the circumscription of P. porelloides remains ambiguous. A possible polyphyly of P. porelloides and P. punctata (cf. Fig. 2) should be confirmed by further analyses as relationships in sect. Plagiochila and the respective clade of sect. Arrectae cannot be fully resolved with the ITS only. Concerning the biogeographic affinities of the European Plagiochila species, Heinrichs et al. (2004a) stated that Plagiochila taxa from Atlantic Europe are close to or conspecific with species from tropical America. In accordance with their results, the present data indicate a strong neotropical influence on the Plagiochila flora in Madeira. More than 50% of the Madeiran species also occur in the Neotropics, including four of the more frequent species of the Laurisilva, P. bifaria, P. retrorsa and P. stricta of sect. Arrectae as well as P. exigua of sect. Rutilantes. As Heinrichs 457

et al. (2005b) discussed for section Arrectae, tropical Africa and the Holarctic were possibly colonized by long range dispersal events originating from Neotropical populations, which could as well apply to P. exigua of sect. Rutilantes (cf. Groth et al. 2003). The Madeira Archipelago could have been served as a stepping stone for the spreading of Plagiochila species from Central and northern South America to Western Europe. Longe range dispersal could be mediated either by spores or by asexual diaspores (caducous leaves, flagelliform shoots) and might explain the wide-ranging distribution patterns, e.g., of P. exigua and P. punctata, which are present in all Macaronesian Islands and extend their distribution until Africa and Atlantic Europe as well as southern South America and East Asia (P. exigua). A similar direction of dispersal, from southeastern North America to Macaronesia, can be assumed for P. virginica of sect. Vagae, which is most closely related with neotropical species but separated from the palaeotropical species included in the molecular analyses (Figs. 2, 3). In contrast, P. porelloides of the holarctic sect. Plagiochila probably reached Madeira by a dispersal event from Continental Europe. More specifically, the molecular topology (Fig. 3) indicates a closer relationship of the specimen from Madeira with Southern Europe rather than Central Europe. Regarding P. maderensis and attending its recent addition to the bryoflora of the Canary Islands, we suppose that this Macaronesian endemic may have evolved in the Macaronesian islands from a tropical ancestor. The different frequencies of the Plagiochila species in the Madeiran Laurisilva may be related both with the dispersal capacities and the ecological requirements of the respective species. The highest frequencies of P. bifaria and P. stricta can be explained by the high capacity to develop spores in P. bifaria, together with the production of caducous leaves and flagelliform shoots in both species. In addition, P. bifaria has a much broader ecological amplitude than the other Plagiochila species and is the only species that was found on slopes in the southern part of Madeira and in Porto Santo Island. Although P. retrorsa is not as common as P. bifaria, in some places of Laurisilva the populations can cover large areas. Plagiochila exigua and P. punctata also have a high capacity of dispersal by vegetative diaspores; their very light flagelliform shoots are easily spread by wind or by water. Both species present a similar distribution pattern in the Madeiran Laurisilva, although the first is more frequent. The low frequency of P. spinulosa, a species from Atlantic Europe, may be related to its particular ecological requirements. The species was only collected in two localities above the limits of the laurel forest, between 1,300 and 1,400 m, in the mesotemperate hyper-humid bioclimatic zone, where the temperatures are in general lower and the precipitation is higher. Although P. porelloides is widespread in the Holarctic, it seems to be quite rare in the Madeiran Laurisilva. The general environmental conditions in the laurel forest may be not suitable for this species, or some of the potentially suitable habitats are occupied by other Plagiochila species that may have found optimal conditions for their development in the laurel forest. Plagiochila porelloides was found in some sites of high biodiversity, where several endemic, rare or threatened species were also present. The distribution and ecology of P. virginica seems to be incompletely known as the species is not common in the well-studied slope communities, but may be more common as an epiphyte according to preliminary observations. 458

Our results indicate the wide-ranging distribution of tropical Plagiochila species in Madeira Island and confirm that the four Plagiochila sections present exhibit distinct phytogeographic affinities, namely with Central and northern South America, and to a lesser extent with Continental Europe and Africa. The environmental conditions found in Madeira Island, especially habitat stability and the stable climate in the laurel forest, may have favored the development of populations of Plagiochila species from neotropical sections. It can also be assumed that the extensive system of water channels (‘levadas’) pervading the Laurisilva, in some cases since the colonization period of the Island, are an efficient artificial transport mechanism contributing to the dispersal of propagules, especially from populations inhabiting the slopes along the ‘levadas’. In the future we can consider that the presence of Plagiochila in the Madeiran Laurisilva could be used as an indicator of floristic richness, becoming a useful tool for the recognition of Laurisilva sites more relevant for the conservation of bryophyte diversity. Acknowledgements We are indebted to Prof. Dr. W.Frey for his advice and encouraging support, to the herbarium curators for the loan of material, and to Ms. B. Giesicke for technical assistance with the molecular analysis. Thanks to Drª Ana Losada Lima and Ms. I.Hildebrandt for the loan of Plagiochila material and to Mr. F.Gutierres and Mr. H.Lünser for preparing Fig. 1. This study was funded by the cooperation protocol (GRICES/DAAD), contract nº 4.1.1. / DAAD project D/03/40407, which is gratefully acknowledged. References CAPELO, J., J.C. COSTA, M. LOUSÃ, S. FONTINHA, R. JARDIM, M. SEQUEIRA & S. RIVAS-MARTÍNEZ (2000): Vegetação da Madeira (Portugal). I- Aproximação à tipologia fitossociológica. - Silva Lus. 7: 257-282. CAPELO, J., M. SEQUEIRA, R. JARDIM & J.C. COSTA (2004): Guia da excursão geobotânica dos V encontros ALFA 2004 à Ilha da Madeira. - Quercetea 6: 5-45. CORLEY, M. & R. CRUNDWELL (1991): Additions and amendments to the mosses of Europe and the Azores. - J. Bryol. 16: 337-356. CORLEY, M., R. CRUNDWELL, M. HILL & A. SMITH (1981): Mosses of Europe and the Azores; an annotated list of species, with synonyms from the recent literature. - J. Bryol. 11: 609689. ERIKSSON, T. (1999): AutoDecay ver. 4.0 (program distributed by the author). - Bergius Foundation, Royal Swedish Academy of Sciences, Stockholm. FIGUEIREDO, A.C., M. SIM-SIM, M.M. COSTA, J.G. BARROSO, L.G. PEDRO, M.G. ESQUÍVEL, F. GUTIERRES, C. LOBO & S. FONTINHA (2005): Comparison of the essential oil composition of four Plagiochila species: P. bifaria, P. maderensis, P. retrorsa and P. stricta. Flavour Frag. J. 20 (in press). FONTINHA, S., M. SIM-SIM, C. SÉRGIO & L. HEDENÄS (2001): Briófitos endémicos da Madeira. Biodiversidade Madeirense: avaliação e conservação. - Secretaria Regional do Ambiente e Recursos Naturais, Direcção Regional do Ambiente, Funchal. 51 pp.

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