Seasonality and habitat influence on bat assemblage structure in an urban Atlantic Forest remnant from Southeastern Brazil

Abstract

Abstract The Brazilian Atlantic Forest is a severely threatened biodiversity hotspot and many remnants exist only as fragments. In order to understand how bat assemblage structure within a forest fragment surrounded by an urban matrix might respond to seasonality and different habitats, we sampled bats over 39 nights in the forest fragment of Gericinó-Mendanha Massif, Rio de Janeiro State. From February 2006 to January 2010, we captured 874 bats, belonging to 25 species and eight different feeding guilds. Frugivorous species were the most abundant, representing 83.33% of captures, and the gleaning insectivores were the least abundant (1.47%). We did not find changes in bat species composition between seasons, although capture rate was higher in the rainy season. However, we did find significant differences in species abundance between seasons. The habitat influence did not significantly differentiate the assemblages, but species richness was higher in the mature ombrophilous forest. The community composition indicates that this conservation unit is an important remaining fragment for maintaining the diversity and richness of bats, although it is possible that historical processes of environmental exploitation have already resulted in a loss of species.