ABSTRACT Studies on habitat fragmentation often evaluate how habitat amount and isolation influence species richness at the local scale, mainly following the Island Biogeography Theory (IBT) framework. Alternatively, the Habitat Amount Hypothesis (HAH) proposes a unifying framework, suggesting that species richness is primarily determined by the total amount of habitat in the landscape rather than by fragment size and isolation per se. We tested this hypothesis using historical data on ant assemblages collected in the experimental area of the Biological Dynamics of Forest Fragments Project (BDFFP) in Central Amazon. Ants were sampled in nine fragments, which varied in size (from 1 to 100 ha) and in the amount of forest in the surrounding landscape. Our results indicate that the amount of forest habitat in the landscape influences species diversity in the fragments, especially among forest specialist species. Additionally, we found that the observed changes in ant species composition between fragments were also associated with differences in landscape forest cover, independently of fragment size. These findings highlight the critical role of habitat availability in shaping ant assemblages and the importance of multi‐scale approaches in conservation strategies, particularly in highly diverse and increasingly threatened ecosystems such as the Amazon Forest.
Ruaro et al. (Thu,) studied this question.