Composition and threats for conservation of anuran amphibians from Itapeva State Park, Municipality of Torres, Rio Grande do Sul, Brazil

Abstract

A species inventory is the first step to develop conservation strategies. The Itapeva State Park (PEVA) is a protected area located in a narrow zone between RS-389 (Estrada do Mar) and the Itapeva beach, near Torres city, extreme north of the coastal plain of the Rio Grande do Sul State (29º 21' S and 49º 45' W). The Park is covered by mobile dunes, fixed dunes, marshy forest, grasslands, dry forests, wetlands and streams. The aim of this study is to list the anuran species of PEVA, to describe their habitats, and to identify possible impact on these anurans inside the Park. The anuran fauna survey occurred from March 2000 to March 2003. The field trips were monthly from May de 2000 to March 2001 after this period, eigth adicional field trips were done. The surveys comprised two nights and two days. The sampling methods included periodic visits to all environments with potential anuran incidence, wet areas, pools, temporary pools, streams and wetlands. During the day we looked for animals under logs, stones, tiles, and near houses. Nocturnal collections were from 8:00 to 11:00 PM. Eight environments were sampled: primary sand dunes (DP), wetlands (BD), movel dunes (DM), fixed dunes (DF), wet grasslands (CA), "capoeira" (regenerating forest), (CP), marshy forest (MP) and dry grasslands (CS). Twenty-nine anuran species from eight families were recorded: Hylidae (11 spp.), Leiuperidae (6 spp.), Bufonidae (4 spp.), Leptodactylidae (3 spp.), Brachycephalidae (2 spp.), Cycloramphidae (1 sp.), Microhylidae (1 sp.) e Ranidae (1 sp.). To date the PEVA is the area with the third highest number of species in Rio Grande do Sul State.Two species are threatened in Rio Grande do Sul: Haddadus binotatus and Melanophryniscus dorsalis. The main observed threats were: forest drainage, forest fragmentation, presence of invasive species and wetland degradation.