Efeitos da quantidade de habitat sobre a diversidade de formigas na Amazônia Central

Abstract

Studies on habitat fragmentation often assess how patch size and isolation affect species’ richness at the patch scale. The Habitat Amount Hypothesis seeks to unify these two variables into one, the habitat amount, predicting that species richness is more strongly influenced by the total amount of habitat in the landscape rather than by patch size and isolation per se. Here, we tested the Habitat Amount Hypothesis using data on ant assemblages collected at the experimental area of the Biological Dynamics of Forest Fragments Project in the central Amazon. Ant data was collected in nine forest fragments, varying both in size (from 1 to 100 ha) and in the amount of forest in the surrounding landscape. Our analysis indicates that the total amount of forest in the landscape is more important than patch size in explaining the observed variation in ant species richness. In addition, the amount of habitat in the surrounding landscape was the only significant predictor of the observed variation in species composition. Overall, our results suggest that habitat loss was already a determining factor to the diversity of species in the past, while providing new perspectives on the relationship between habitat amount and the structure of ant assemblages in the Amazon.