The utility of an index of biotic integrity for predicting terrestrial frog species diversity in a tropical forest

Indices of biotic integrity (IBI) summarize multiple habitat metrics and are useful for rapid ecological assessments of local-scale changes. While they are commonly applied to amphibians in wetlands and streams, their utility for predicting changes in tropical forest leaf-litter frog communities remains unclear. We tested how species richness, abundance, and composition of leaf-litter frogs relate to an IBI in an area of the Brazilian Atlantic Forest. Anurans were sampled using pitfall traps across 10 sites for 6 months. Species richness and abundance were modeled using Generalized Linear Models, and species composition with a Generalized Linear Latent Variable Model that accounted for interactions between body size and IBI. We recorded 14 species overall. IBI did not influence species richness, abundance, nor composition, explaining as little as 7% of their variation. However, species’ responses to IBI varied with body size: larger species were positively, though weakly, associated with IBI. The uniformly high biotic integrity and limited study area may explain the weak relationships. Our results offer new insights into the applicability of IBIs in evaluating terrestrial vertebrate responses to habitat change.