Structure of a caatinga anuran assemblage in northeastern Brazil

Abstract

Based on data on diet and microhabitat use, we investigated the importance of current (ecological) and historical factors (phylogenetic) in the organization of an anuran assemblage in temporary ponds in a Caatinga area in Northeastern Brazil. The objective of this study was to verify how diet and microhabitat use influence the community structure, and their determinants. Niche breadth based on microhabitat use was relatively low for all species; thus, we also observed a spatial segregation between Hylidae and other families. The closely related species exhibit a more similar diet; the main prey categories used by Caatinga anurans were Coleoptera, insect larvae and Formicidae. The pseudo-community analysis based on diet and microhabitat use revealed that the observed niche overlap did not differ statistically from random, indicating a lack of detectable competition for these resources. The Canonical Phylogenetic Ordination (CPO) analyses revealed no significant phylogenetic effect on the assemblage, neither for diet nor for microhabitat use. Results suggest that predation and hydroperiod may be the most important factors in determining assemblage patterns, but more studies are needed to support this hypothesis.