Vascular epiphytes of the Atlantic Forest in the Sinos River basin, state of Rio Grande do Sul, Brazil: richness, floristic composition and community structure.

Md Barbosa,Dfp Becker,S Cunha,Jl Schmitt,A Droste

doi:10.1590/1519-6984.0913

Abstract

The Atlantic Forest, which has a vast epiphytic richness, is a priority area for preservation, listed as one of the five most important world hotspots. Vascular epiphyte richness, composition and community structure were studied in two fragments, one of the ombrophilous (29º43'42"S and 50º22'00"W) and the other of the seasonal (29º40'54"S and 51º06'56"W) forest, both belonging to the Atlantic Forest biome in the Sinos River basin, Rio Grande do Sul, Brazil. In each fragment, 40 trees, divided into four ecological zones, were analyzed. In each zone, the occurrence of the species was recorded, and the importance value of each species was calculated according to the frequency of phorophytes and intervals, and cover scores. The Shannon index was calculated for the two communities. In the fragment of the ombrophilous forest (F1), 30 epiphytic species were recorded, and in the seasonal forest (F2), 25. The highest importance value was found for Microgramma squamulosa (Kaulf.) de la Sota in both fragments. The diversity indexes for F1 (H'=2.72) and F2 (H'=2.55) were similar and reflected the subtropical location of the areas. The decrease in mean richness in both fragments in zone 3 (internal crown) to zone 4 (external crown) may be associated with time and space availability for epiphyte occupation and microclimate variations. Exclusive species were found in the areas, which suggest that a greater number of preserved fragments may result in a greater number of preserved epiphytic species in the Sinos River basin.

Highlights

Epiphytes account for a substantial part of forest diversity and up to 10% (Kress, 1986) to 50% (Kersten and Silva, 2005) of all vascular plants in tropical forests
The present study evaluated the richness, composition and community structure of vascular epiphytes in two fragments in the upper and lower sections of the Sinos River basin, belonging to ombrophilous and semi‐deciduous forests, respectively
This study was conducted in two secondary forest fragments located in the Sinos River basin in the state of Rio Grande do Sul, Brazil: (a) fragment 1 (F1) was in the upper section of the basin, in a rural area, next to the source of the Sinos River, in the municipality of Caraá (29°43’42”S and 50°22’00”W; 408.1 m alt.); 60 ha of predominantly dense ombrophilous forest with some remaining mixed ombrophilous forest; (b) fragment 2 (F2) was in the lower section of the basin, in the municipality of Novo Hamburgo (29°40’54”S and 51°06’56”W; 16.4 m alt.), in the Henrique Luís Roessler park, formally declared a Preservation Area in 2009, in the category of Relevant Area of Ecological Interest

Summary

Introduction

Epiphytes account for a substantial part of forest diversity and up to 10% (Kress, 1986) to 50% (Kersten and Silva, 2005) of all vascular plants in tropical forests. The Atlantic Forest, listed as one of the five most important world hotspots, has 20,000 species of vascular plants (Myers et al 2000), and 3,000 to 4,000 of them are epiphytic (Kersten, 2010). Epiphytic plants have been used to classify the successive regeneration stages of plant formations in the Atlantic Forest of Rio Grande do Sul, according to the CONAMA Resolution no. Epiphytic plants have been used to classify the successive regeneration stages of plant formations in the Atlantic Forest of Rio Grande do Sul, according to the CONAMA Resolution no. 33/94 (Brasil, 2012)

Methods

Results

Conclusion