BAT SPECIES RICHNESS AND ABUNDANCE IN TROPICAL RAIN-FOREST FRAGMENTS AND IN AGRICULTURAL HABITATS AT LOS-TUXTLAS, MEXICO

Faced with the rapid and extensive conversion of tropical rain forests to pasture lands and agricultural fields and with the need to preserve the remaining mammalian fauna, it is imperative to determine how the different species that form the mammalian community have responded to the anthropogenic alterations of their natural habitats. To provide data in this direction, we sampled bats in 45 forest islands, in 20 agricultural habitats representing five types of vegetation (cocoa, coffee, mixed, citrus and allspice), in four live-fence sites and in four pasture sites at Los Tuxtlas, Veracruz, Mexico. Sampling effort resulted in the capture of 2587 bats representing 35 species. In forest habitats we detected 32 species. We did not capture any bats at the four pasture sites, but the at the other agricultural habitats studied, we captured 38% of the bats and 77% of the species recorded. Thirty-four percent of the species recorded were present at the live-fence habitats. Isolating distance was an important variable influencing species richness in forests and in agricultural habitats. Only 10% of the species recorded occurred in all the habitats studied, but 77% of the species occurred in a habitat other than rain forest. Recaptures of bats indicated inter habitat movements in the fragmented landscape. We discuss the conservation value for the bat fauna of agricultural islands of vegetation as elements reducing isolating distances among forest fragments.