Tadpole community structure in lentic and lotic habitats: richness and diversity in the Atlantic Rainforest lowland

The analysis of species richness and community composition provides basic information to understand the structure of species assemblages. Here, we compared species richness and composition, compositional similarity and species turnover of tadpole communities in 14 lentic and eight lotic habitats in the Atlantic Rainforest of southeastern Brazil. Because the occurrence in lotic habitats requires some degree of morphological or behavioural specialisations of tadpoles to fast flowing water, we expected to find low species richness and species turnover in lotic than in lentic habitats. We compared species richness using abundance and sample-based rarefaction and species composition by PERMANOVA. We analyzed the Species Abundance Distribution (SAD) in each habitat type using a Whittaker diagram. To assess the similarity in species composition, we used a hierarchical cluster analysis. We compared the beta diversity between lentic and lotic habitats using Whittaker index and the species turnover using Jaccard index. We recorded 26 anuran species in the larval stage belonging to seven families. The highest species richness was recorded in lentic habitats (20 species), whereas only seven species occurred in lotic habitats. The species composition also differed markedly between lotic and lentic habitats, with only one shared species (Aplastodiscus eugenioi). Both habitats had few dominant and rare species and a greater proportion of species with intermediate abundance, but different processes are underlying this distribution abundance pattern in each type of habitat. Our results indicate that species richness, abundance, and occurrence are associated to habitat type (lentic and lotic), indicating a possible effect of the environmental filtering process associated to different life history strategies.