Abundance data of anuran species in forest fragments

Understanding the effects of random versus niche-based processes on biodiversity patterns is a central theme in ecology, and an important tool for predicting effects of habitat loss and fragmentation on biodiversity. We investigated the predictive power of random processes to explain species richness and species dissimilarity of amphibian assemblages in a fragmented tropical landscape of the Atlantic Forest of South America.

We analyzed a large database of amphibian abundance and occupancy, sampled in 21 forest fragments ranging in size from 1.9 to 619 ha. We compared observed species richness and species dissimilarity with the outcomes of two null (random placement) models: 1- the traditional Coleman’s area-based model and 2 – an abundance-based model (based on the number of individuals observed in each fragment). We applied these models for all species combined, and separately for forest‐dependent and habitat-generalist species.

The abundance-based model fitted the observed spec...