Niche differentiation of an anuran assemblage in temporary ponds in the Brazilian semiarid Caatinga: influence of ecological and historical factors

摘要

The investigation of historical factors which determine assemblage structure is largely based on the idea that closely-related species have similar ecological characteristics due to a shared evolutionary history. We used a Pseudocommunity Analysis (PA), Principal Component Analysis (PCA) and Canonical Phylogenetic Ordination (CPO) to evaluate the influence of phylogeny on microhabitat use, diet composition and morphology in an assemblage of 15 anuran species occupying temporary ponds in the semiarid Caatinga. Closely-related species used the same microhabitats, although at different proportions, and showed a high diet niche overlap. The PA showed that competition does not appear to regulate the assemblage. Closely-related species showed a high degree of morphological similarity, suggesting that body shape is a conservative trait. The CPO analysis revealed a historical influence on microhabitat use in the Hylidae and Leptodactyliformes dichotomy, and in the diet composition of the genus Physolaemus and Leiuperinae. Although resource use patterns reflect phylogenetic relationships among species, our results suggest that ecological factors such as competition further shaped the studied anuran assemblages.