Reduced ant diversity along a habitat regeneration gradient in the southern Brazilian Atlantic Forest

This study evaluates the response of the ant communities along a habitat regeneration gradient in the south Atlantic Forest comparing it with the ant fauna from a mature forest at the same biome. The survey was conducted according to standard collecting protocols, employing sardine baits and mini-Winkler apparatuses. The structure of the ground and litter-foraging ant community was compared in five habitats, representing a regeneration gradient within the Atlantic Forest. Furthermore, the composition of the leaf-litter ant fauna and the species richness were compared between the regeneration gradient and an area of mature forest. The results showed a higher number of leaf-litter ant species in the mature forest in comparison with the regeneration gradient habitat, as well a distinct species composition. There was a significant loss of ant diversity in the regrowth forest, compared to the mature Atlantic Forest. The composition of the ground-dwelling ant fauna does not consistently separate the sites of forest succession; but a gradient of ant species richness and composition was revealed when the leaf-litter ant fauna data set was included in the analysis. In this sense, the leaf-litter ant fauna is an important segment to characterize habitats also playing an important rule as bio-indicators. The data suggest that only primary forests (our data) and old secondary forests (in litt.) are capable of maintaining a substantial proportion of the biodiversity in areas of the Atlantic Forest.