Biogeografia de morcegos (Chiroptera) em área de transição floresta-campo no sudeste da América do Sul

Abstract

The variation on the richness species in regional scales has been debated a lot. Three of the hypotheses mot frequently discussed as determinants of regional variability in richness species are energy, contemporary climatic conditions and habitat heterogeneity. Studies at mesoscale are very important to discover different patterns that underlying the variability in richness species. As the bats are so common in whole world and ecologically diverse, these organisms are excellent environmental characterized. On this basis, the goals of this study were to link the bat species composition with the vegetation in forest-grassland transition area in the Southeastern of South America and to assess the space influence on the bat species richness by environmental variables. The study area includes the southeastern of South America. Species distribution data were obtained by museums, review and database on line .The distribution s estimate for each species was done on a map with 139 cells 1º latitude by 1º longitude. It was collected distribution data to 79 bat species. Rain Forest and Seasonal Forest had the largest species richness. The cluster analysis based on the cells revealed three major clusters: the Forest cluster (at north), the Araucaria cluster (at middle), and the Grassland cluster (at south). The Araucaria cluster was associated to the Grassland cluster. The cluster analysis based in the phytogeographic zones revealed four clusters, where the Araucaria Forest was associated with the forested regions. The contemporary climatic conditions hypothesis was the best explained the variability on the richness data, where the mean annual temperature the main predictor variable, followed by extent of relief and AET, respectively. With the whole variables, the OLS regression also indicated the mean annual temperature as the main predictor variable, followed by AET. These same variables also explained the variability in the species richness in Phyllostomidae, Molossidae and Vespertilionidae. The Araucaria Forest is a filter area to the dispersal of tropical species into subtropical and temperate areas of South America, because the hard winters in that area, what may be explained likely for the intolerance of some species in colder climates.