What is the Role of Heterogeneity and Spatial Autocorrelation of Ponds in the Organization of Frog Communities in Southern Brazil?

The composition of anuran communities is influenced by deterministic and/or stochastic factors. In this study, we tested whether the occurrence of anuran species in ponds differed from a null model of random placement, hypothesizing that environmental heterogeneity and spatial distribution of ponds have an influence on the structure of anuran communities in southern Brazil. Data were collected for 7 months from 14 ponds located in Turvo State Park, Rio Grande do Sul. To test whether distributions of species in the sampled ponds varied from random, the null model, SIM 2, was applied, while the roles of pond heterogeneity and proximity were evaluated by a redundancy analysis using environmental and spatial descriptors. Distributions of the 15 anuran species recorded in the studied ponds were clearly not random, corroborating our hypothesis that the species composition is influenced by environmental heterogeneity. Geographical proximity did not affect pond species compositions. However, the environmental descriptors had varying effects on anuran communities at different locations, indicating the need for studies to be carried out at local and/or regional levels in order to determine which environmental characteristics are most important for the conservation of anuran species.