Bat and rodent diversity in a fragmented landscape on the Isthmus of Tehuantepec, Oaxaca, Mexico

We assessed the patterns of diversity, richness, abundance, and dissimilarity in rodent and bat communities for four sites on the Isthmus of Tehuantepec in Oaxaca, Mexico, an important region given the enormous number of endemic Neotropical species. The main objective was to examine rodent and bat community parameters relative to habitat diversity and human habitat disturbance in a fragmented landscape. We captured 1,133 individuals of 13 rodent species and 26 bat species from January to August 2006. The site (landscape unit) with greatest habitat diversity also had the highest diversity of rodents. Species dissimilarity was low between sites that had similar degrees of human disturbance. For rodents, species dissimilarity between habitats on the Isthmus of Tehuantepec landscape was generally high; therefore, the species are not distributed evenly across the entire landscape. For bats, the degree of species dissimilarity between the different habitats of the landscape was low. The distribution of bat species across the landscape is a reflection of their high vagility and the spatial structure of the landscape. The results show the importance of a diversity of habitats to the patterns of richness, abundance, and dissimilarity of mammals in the study area.