Large‐scale diversity patterns of vascular epiphytes in Neotropical montane rain forests

Abstract

Aim Epiphytes contribute up to 30% to the number of vascular plant species in certain global biodiversity hotspots, e.g. the Ecuadorian Andes. However, their large scale diversity patterns are still discussed on the base of results from a few, local epiphyte inventories. Consequently, explanatory models on epiphyte diversity concentrate on the impact of local climate on small scale epiphyte species richness. Our aim was to analyse large scale elevational patterns of epiphyte diversity integrating data from different geographic scales.Location Tropical America, with special emphasis on the Ecuadorian Andes.Methods Our study is based on two data sources. First, we analysed the elevational patterns of epiphyte diversity based on the Catalogue of the Vascular Plants of Ecuador and the Libro Rojo de las Plantas Endèmicas del Ecuador. Secondly, the floristic turnover between the epiphyte inventories of seven montane and four lowland study sites in the Neotropics was analysed. ResultsThe floristic turnover between Neotropical montane epiphyte floras is higher than the one between lowland epiphyte floras. Montane study sites located only a few kilometres apart from each other show considerable differences in their epiphyte species inventories. Irrespectively of their similar dispersal mode, the floristic turnover is much higher for orchids than for Pteridophyta. The Orchidaceae are the species richest group in all of the examined 11 Neotropical epiphyte floras. At the larger scale of the Ecuadorian Flora, c. 50% of the species in the elevational zone with maximum epiphyte diversity (between 1000 and 1500 m) are orchids. Elevational patterns of epiphyte diversity strongly reflect patterns of Orchidaceae.Main conclusions Our results support the observation of a 'mid-elevation bulge' of epiphyte diversity by Gentry and Dodson. It has been frequently shown that the high humidity in mid-elevations is suitable to maintan a high epiphyte species richness. Our findings show that in addition, large scale epiphyte diversity in montane rain forest is increased by the high floristic turnover at local and regional scale. Based on the importance of Orchidaceae for epiphyte diversity, we discuss that speciation processes corresponding to the highly diverse environment are a driving force for endemism, floristic heterogeneity and consequently for large scale epiphyte species richness in montane forests.

Epiphytic angiosperms in a mountain forest in southern Bahia, Brazil

“…Similar results were reported for the Neotropical region (e.g., Sudgen & Robins 1979, Gentry & Dodson 1987, Wolf & Flamenco-S 2003, Kü per et al 2004) and the tropical and subtropical Atlantic Forest (e.g., Fontoura et al 1997, Borgo & Silva 2003, Giongo & Waechter 2004, Kersten & Silva 2001, Buzatto et al 2008, Martins et al 2008, Menini Neto et al 2009, Mania & Monteiro 2010. Table 2 compares the SLNP and other Atlantic Forest areas with high epiphyte richness.…”

Floristic composition and community structure of epiphytic angiosperms in a terra firme forest in central Amazonia

“…Orchidaceae was recorded as the third most diverse family and ranked in fourth position in terms of FIV, a result that contradicts expectations and contrasts with the standard of most of the epiphytic flora inventories in Neotropical regions, since it is often cited in the first position Kelly et al 2004;Kuper et al 2004;Kromer et al 2005;Zotz & Schultz 2008). In the subtropical forests of Brazil, Orchidacae is also cited as the most diverse family (Alves et al 2008;Neto et al 2009;Kersten 2010;Blum et al 2011).…”

“…According to Rudolph et al (1998), Smith-Neuerburg (2002, Kuper et al (2004) and Benavides et al (2011), the epiphytic population is small and well distributed, since the majority of species has a low abundance and contributes less than 1% of individuals sampled. Often, more than 25% of species in a given area are represented by fewer than five individuals.…”

Species Richness and Abundance of Low-Trunk Herb Epiphytes in Relation to Host Tree Size and Bark Type, Eastern Amazonia

“…The epiphytic herb assembly at CNF showed a relatively low number of species (30-37) compared to studies carried out in Amazonia (NIEDER et al, 2000;BUSSMANN, 2001;LEIMBECK;BALSLEV, 2001;KREFT et al, 2004;KÜPER et al, 2004;BENAVIDES et al, 2005;ARÉVALO;BETANCUR, 2006;POS;SLEEGERS, 2010;IRUME et al, 2013) and the Guyanas (TER STEEGE; CORNELISSEN, 1989;FREIBERG, 1996). However, one should take into account the fact that only the understory was inventoried, and only herb species were considered.…”