Anuran fauna in a Peripheral Depression area in the middle-west of São Paulo State, Brazil

Abstract

In the last eight decades, São Paulo state has been a center of anurans research. However, at central-west of São Paulo state, studies in Peripheral Depression (PD) communities are scarce. In order to bring new information, our objectives were surveying frogs in PD area, linking our results with other data and comparing with known results from crest of the Botucatu cuesta. The inventory was conducted during 13 months (December 2008 to December 2009), and data has obtained in 24 days sampling. The frogs were investigated in sites that anurans currently using for reproduction, by traditional field methods, based on visual-encounter survey and auditory. We recorded 29 species into 12 genera and six families. The high frog diversity was considered because this area has suffered human action. Although the most of the species has been identified in open areas, we associated this high number due to forest remnants in interfluves. Therefore, the differences between our study and others at the same region were due low number of related species on the forest environment. The absence of similar topography at PD probably was a determinant factor for the low number of species in forest habitat. The amphibian activity was higher during hot and humid period and a decrease in the cold and dry period. The most part of anurans had a restricted activity during rainy season; however, each species has its own period and peak of calling activity. The similarity results indicate the most part of higher clusters was observed between species that different requirements for habitat and microhabitat. We believe that, differences in temporal pattern distribution of organisms in the community are of great importance in sharing resources and adjusting the species in the community, which contributed to the high number of amphibians and observed the coexistence of taxa in the study area.