Diversity and Distribution of Vascular Epiphytes in an Insular Brazilian Coastal Forest
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Diversity and distribution of vascular epiphytes in an insular Brazilian coastal forest Rodrigo de Andrade Kersten1, Marília Borgo2 & Sandro Menezes Silva3 1. Pontifícia Universidade Católica do Paraná, CCBS, Herbário HUCP, Rua Imaculada Conceição 1155, CEP 80215- 901, Curitiba, Paraná, Brazil; [email protected] 2. Sociedade de Pesquisa em Vida Selvagem e Educação Ambiental (SPVS), R. Isaias Bevilacqua, 999, CEP 80430-040, Curitiba, Paraná, Brazil; [email protected] 3. Conservation International Brazil (CI), Rua Paraná, 32, CEP 79020-290, Campo Grande, Mato Grosso do Sul, Brazil; [email protected] Received 21-VIII-2008. Corrected 15-X-2008. Accepted 16-XI-2008. Abstract: The study was carried out in a 3 000m2 area of coastal Atlantic rain forest at Ilha do Mel island (25o30’’S 48o23’W), on 100 assorted trees separated into 2 meter-high strata starting from the ground. In each stratum all of the occurring epiphytic species were recorded. The sampled species were grouped into three categories: exclusive, preferential, and indifferent, according to their abundance in each strata, and selective, preferential and indifferent, according to abundance on the forophytes. Intermediate strata registered the high- est diversity. Six species were considered exclusive to one or two strata, 15 were restricted to some strata and 5 presented a broad distribution. No epiphytic species showed uniform horizontal distribution on the area. The epiphyte richness in a host tree varied from zero to 30. Regarding to fidelity on host tree species, few selective or preferential, and mainly indifferent epiphyte species, were found. A total of 82 epiphyte species were sampled in the surveyed tree, and the Wittaker plot indicate a highly dominant assemblage. Rev. Biol. Trop. 57 (3): 749- 759. Epub 2009 September 30. Key words: epiphyte ecology, spatial distribution, host preference, coastal Atlantic forest. Stratification in tropical forests is closely total rain retention and rearrangement, which related to the vertical environmental variance also influences the distribution of epiphytes found from the forest floor to the canopy (Parker 1995). In addition to environmental (Johansson 1974). This variation influences characteristics, intra and interspecific interac- not only the distribution of plant but also of tions can also control the distribution patterns birds, mammals and insects, some of them of some species (Yeaton & Gladstone 1982, exclusive to the canopy (Nadkarni 1994). Like Hietz & Hietz-Seifert 1995). any other kind of life, epiphytes are influenced Distribution of epiphytes among differ- by the forest. Temperature, moisture and light ent host species is related to factors such as incidence, for instance, are important factors moisture retention, chemical composition and in distribution patterns definition (Benzing bark morphology, which can be decisive on the 1995). establishing and developing of some species The distributions of epiphyte depend on (Benzing 1990). the forophyte species, age and characteristics The objective of this study was to describe such as shape, bark texture, branching patterns the vascular epiphyte community, its spatial and height (Freiberg 1996). Also crown shape, distribution patterns and composition on differ- size of leaves and canopy density, affect the ent host tree species. Rev. Biol. Trop. (Int. J. Trop. Biol. ISSN-0034-7744) Vol. 57 (3): 749-759, September 2009 749 MATERIALS AND METHODS Statistical analyses: The abundance of the species was evaluated by its frequency Study Site: The research was carried out on the strata and on the forophytes. The total at Estação Ecológica da Ilha do Mel, Ilha number of species registered on each stratum do Mel Island, southern Brazil (25º 30”S was added-up to get the number of observa- 48º 23’W). This protected area consists of tion per tree, with was considered analogous to 2.241ha of coastal plain forest. The sampled dominance. A rank-abundance plot (Wittaker 2 area (3 000 m ), had its’ tree community struc- Plot - Magurran 2004) for the epiphyte species ture (Silva and Britez 2005) and vascular was elaborated using a log10 scale. The spatial epiphyte checklist (Kersten & Silva 2006) pre- distribution was considered to be the vertical viously analyzed. Its semi-hydromorphic soil (on strata) and horizontal distribution (on indi- is flooded during the rainy seasons, the forest vidual forophytes and on forophyte species). contains three main strata: lower stratum con- To analyze vertical distribution patterns tains herbaceous plants, leaf litter and shoots, tree α-diversity index (alpha-diversity, Chao’s middle stratum with bushes and samplings, and estimator of the absolute number of species, the upper stratum (canopy) with only few spe- Margalef’s α-diversity index) and two even- cies trees, which may reach over 20 m (Silva & ness measures (Simpson’s index and Shannon Britez 2005). evenness measure) were considered. According to species distribution, the epiphytes were Sampling: Ten forophyte individuals divided into groups: from each of the ten most important species were previously chosen: Tapirira guianensis 1. On the Strata (vertical distribution): (Anacardiaceae), Calophyllum brasiliense • Exclusive: species observed only in (Clusiaceae), Faramea marginata (Rubiaceae), one or two successive strata; Myrcia racemosa, Myrcia insularis and • Restrict: species with more than 50% Eugenia sulcata (Myrtaceae), Ocotea pul- of frequency in one stratum or more chella (Lauraceae), Alchornea triplinervia and than 60% in two or three successive Pera glabrata (Euphorbiaceae) and Schefflera strata; angustissima (Araliaceae). Acronyms were • Broad: when the total frequency of constructed with the first letter of the genera any three successive strata is less than and the two firsts of the epithet. Due to high 60%. mortality rate only 8 individuals from this last Only species observed more than 10 times specie were sampled. A total of 98 host trees (in number of forest strata) or more than 5 were then surveyed. Canopy access was real- times (when restricted to a single stratum) were ized with an aluminum leather (7.5 m) associ- considered in this analysis. ated with modified mountaineering technique Shannon’s diversity index (H’), based on and manual climbing. The names of the spe- Waechter (1998), was calculated using the spe- cies and authors were checked at TROPICOS cies abundance (number of times observed) on (2008) and the synonyms at World Cheklist of host trees. Selected Plant Families (2008). Host tree bark aspect was classified fol- 2. On host trees species: lowing Ribeiro et al. (1999). As epiphyte • Specialist – when found in only one individuals are not always discernible, we species of host tree; use the Kersten & Silva (2001) system of • Selective – when frequently found on 2-meter-vertical division (strata) from ground few species of host trees, and rarely to canopies, were every observed epiphyte spe- on other species (more than 40% on cies was recorded, young individuals were not one species, more than 60% on two considered. species, or 100% on three species); 750 Rev. Biol. Trop. (Int. J. Trop. Biol. ISSN-0034-7744) Vol. 57 (3): 749-759, September 2009 • Preferential – when found with higher acrocarpon and Peperomia urocarpa) were frequency on some host trees, but all observed on the 0-2 m stratum and species also with relevant frequency on other exclusive to two strata (Vriesea gigantea, V. species; vagans and Pleopeltis hirsutissima) were found • Indifferent - when found with similar on the 6-8 m and 8-10 m strata. Four restrict spe- frequency on the host tree species. cies occurred more frequently in only one stra- tum: Monstera adansonii (0-2 m), Epidendrum Spearman’s correlations between number rigidum and Serpocaulon catharinae (8-10 m), of species, abundance and host tree perimeter and Tillandsia tenuifolia (12-14 m). Eleven and height were analyzed, numbers higher than species (Microgramma vacciniifolia, Aechmea 0.6 when significant (α = 0.05) were consid- nudicaulis, Codonanthe devosiana, C. gracilis, ered to indicate associations. Clusia criuva, Prosthechea vespa, Epidendrum The similarity of epiphyte communities on latilabre, Pleurothallis spp, Acianthera saun- host tree species was evaluated by Ellenberg’s dersiana, Vriesea procera and Campyloneurum similarity index (Mueller-Dombois & Ellenberg nitidum) were found mostly in two or three 1974), that was used to make a dendrogram strata. Five species (19%) have broad distribu- (Ward) and by correspondence analysis using tion and occurred with similar frequency in forophyte specie as x-factor and epiphyte fre- many strata (Oncidium uniflorum, Peperomia quency of species as response. glabella, Philodendron corcovadense and Scaphyglottis modesta). RESULTS Distribuition on forophytes: Vascular Vertical Distribution: Intermediate strata epiphytes were not regularly distributed on registered highest diversity (Fig. 1 and 2). Six individuals or forophyte species. On individual species (7%) were considered exclusive, tree host trees the number of epiphytes varied from to one stratum and tree to two strata, 15 (18%) zero to 30 epiphyte species (average of 6 ± were restricted to some strata and 5 (6%) pre- 6.3). Highest richness was found at an Ocotea sented a broad distribution (Fig. 2); 56 (69%) low frequency species were not classified. The species exclusive to one stra- ta (Trichomanes krausii, Campyloneurum Fig. 1. Epiphyte diversity α registered in the studied strata. (α = alpha-diversity, Chao’s