Species diversity of bats (Mammalia: Chiroptera) in forest fragments, primary forests, and savannas in central Amazonia, Brazil

The exact number of species of bats in Brazilian Amazonia is not precisely known because relatively few sites have been surveyed in detail. Here we present an updated species list of the bats of Alter do Chao at the delta of the Tapajos River in Para State. Using mist nets and acoustic monitoring of echolocation calls we systematically surveyed 5 forest sites, 14 natural forest fragments, and 12 savanna sites. We captured 3978 bats representing 70 species, 40 genera, and 7 families. Fifty species were recorded in savannas, 44 in forest sites, and 41 in forest fragments. The mean capture rate was higher in savanna and forest sites (0.747 and 0.741 bats/mist-net-hour (mnh), respectively) than in forest fragments (0.483 bats/mnh). Our list includes new records for Brazil and extends knowledge of the distribution of some species. Species-accumulation curves and species-richness estimators indicate that 75-100 bat species occur at Alter do Chao, suggesting that our inventory recorded approximately 67-89% of the bat fauna there. Using cluster analysis we compared the bat fauna at Alter do Chao with the faunas from 17 other sites in the Neotropics. There was 65% similarity with the fauna from Manaus (Brazil), 60% with that from lwokrama (Guyana), and 57% with that from Paracou (Franch Guiana). Aspects of the conservation status of some species present at Alter do Chao are discussed.