Butterfly assemblages from Amazonian flooded forests are not more species-poor than from unflooded forests

Abstract

The Amazonian flooded and upland forests harbour distinct assemblages of most taxonomic groups. These differences can be mainly attributed to flooding, which may affect directly or indirectly the persistence of species. Here, we compare the density, richness and composition of butterfly assemblages in vaorzea and terra firme forests, and evaluate whether terrain elevation and flooding can be used to predict the assemblage structure. We found that the total abundance and number of species per plot is higher in vaorzea than in terra firme forests. Vaorzea assemblages showed a higher dominance of abundant species than terra firme assemblages, in which low-flying Haeterini butterflies had higher abundance. After standardizing species richness by sample size and/or coverage, species richness estimates for vaorzea and terra firme forests were similar. There was strong turnover in species composition across vaorzea and terra firme forests associated with terrain elevation, most likely due to differences in the duration of flooding. Despite a smaller total area, less defined vegetation strata, more frequent disturbances and the younger geological age of floodplain forests, Nymphalid butterfly assemblages are not more species poor there than in unflooded forests.