Composição, riqueza e abundância de espécies de anfíbios na região do médio rio Xingú

Abstract

This study aimed to identify the amphibian fauna of different habitats in the region of the Middle Rio Xingu. We selected six sites, with samples taken from three breaths, between November 2007 and March 2008, totaling 48 days. We identified six types of habitats in the region: terra-firme forest, seasonally flooded forest (lowland), banks of the river, "pedral”, pond area and area with antropic disturbance. For data collection were used two field sampling methods: pitfall traps with drift fences and visual surveys. The traps were installed only in areas of terra-firme forest, while visual survey was employed in all types of habitats identified. The sampling resulted in the record of 56 species of amphibians and eight species were identified and recorded in previous studies in the area. Species diversity and richness were higher in Caracol site, where the predominance of the terra-firme forest was observed, and lower in the Ilha Grande, which is dominated by seasonally flooded forest. Nine reproductive modes were recorded in the study area, all found in the terra-firme forest and only three in the "pedral" which may reflect the low environment heterogeneity of this area. Two tests of similarity were performed to compare study sites, one for each method of collection. Similarity analysis of the data from visual surveys showed more similarity for species composition between areas of terra-firme forest than the other habitats. Cluster analysis between this study and other surveys conducted in the Amazon grouped the study area to another area also located in the Middle Xingu.