Bat diversity and abundance as indicators of disturbance in neotropical rainforests

Evaluating the degree of disturbance of any region to determine its relativ e importance for conservation purposes requires procedures that are relativ ely inexpensive and that yield accurate results fast. Because bats are abun dant diverse, and easy to sample, especially in the Neotropical rainforest, they fulfill several of the requirements of indicator species as identifie d in the literature. For 10 months we sampled bat communities in the Selva Lacandona in Chiapas, Mexico, at 15 sites representing five habitats. We al so measured 10 variables representing vegetation structure and diversity at each site. With fuzzy-set techniques we produced a gradient classification of disturbance for the 15 sites based on the vegetation data. We explored the relationship between vegetation conditions, described as the membership degrees in the construct "fuzzy forest set" (the complementary fuzzy set o f "disturbance"), and four bat community variables. Bat species richness, n umber of rare bat species, and the bat diversity index were positively corr elated with the vegetation scores, and relative abundance of the most abund ant bat species was negatively correlated with vegetation scores. A high nu mber of phyllostomine species in a community is a good indicator of low lev els of disturbance. Although a single indicator group will probably not be sufficient for decision-making processes in conservation, evaluating bat po pulations may be a good first step in assessing an area's conservation valu e especially in rainforest regions.