How riparian forest integrity influences anuran species composition: a case study in the Southern Brazil Atlantic Forest

Riparian forests are under legal protection in Brazil and provide essential ecosystem services yet have been historically degraded and reduced by deforestation. Consequently, the fauna of these riparian forests and associated ecosystems can be strongly affected, as is the case with amphibians. In this study we identify how anuran species composition varies in riparian forests with various levels of environmental integrity. The study took place in the Fritz Plaumann State Park (FPSP), a protected area with forest formations typical of the Southern Atlantic Forest. Our results suggest that the environmental integrity of the sampling sites influenced where each species was found. The most preserved habitats, with large areas of riparian forest and fewer anthropic impacts, promoted greater species diversity and allowed for the maintenance of species with specific environmental requirements. Two species registered are on the list of endangered amphibians (Boana curupi and Vitreorana uranoscopa) and one is an exotic invasive species (Lithobates catesbeianus). Because it preys on native amphibians and may act as a pathogen vector, this species is a potential threat to the native amphibian populations inside the park. Even though large portions of the FPSP consist of forests in a secondary stage of succession, the connection with better–preserved areas of primary forest allows for the general occurrence of more demanding species that are usually associated with well–preserved habitats. On a regional level, these habitats occur only inside the park and in their absence, these species will most likely become locally or regionally extinct.