Effects of vegetation structure on the diversity of bats in remnants of Brazilian Cerrado savanna

Abstract

The Brazilian Cerrado savanna has a considerable diversity of bat species. Given current trends in the loss and fragmentation of habitat, understanding the structure of bat communities will contribute to the preservation of the group. We investigated the effects of spacing and temporal variation in vegetation structure on the structure of bat communities. We inventoried the bat communities of nine Cerrado fragments and analyzed alterations in the vegetation over a 5-year period using a time series of Enhanced Vegetation Index (EVI) values, with spatial filters to evaluate spatial autocorrelation. We found that the temporal variation in vegetation structure and the spatial autocorrelation had a negative effect on total beta diversity and its turnover fraction. The species composition was most similar in the fragments closest together where the vegetation was densest in the past. Given the influence of the environment and spacing on local bat communities, we concluded that the metacommunity is structured according to the mass-effect model, with the bat species being substituted along an environmental gradient, although this pattern is diluted by dispersal. As the bat communities respond to temporal alterations in the vegetation, we conclude that it will be necessary to monitor this variation systematically to guarantee the long-term diversity of chiropterans in the Cerrado. This finding is especially relevant given the progressive and ongoing anthropogenic degradation of Cerrado habitats observed in recent decades.