Compensatory dynamics on the community structure of fruit-feeding butterflies across hyper-fragmented Atlantic forest habitats

Abstract

The creation of forest edges promotes a drastic extirpation of forest-dependent species across tropical fragmented landscapes. Yet, this loss of forest-dependent species can be compensated by the proliferation of disturbance-adapted species (winner-loser replacement) maintaining community-level attributes in altered habitats. Here, we test whether this replacement reflects a sort of compensatory dynamics, which alters patterns of species richness, abundance, ecological composition and β-diversity (multiplicative diversity decompositions of Hill numbers) of fruit-feeding butterflies between non-disturbed and disturbed habitats in two fragmented landscapes of the Brazilian Atlantic forest. Additionally, we examined the determinants of these compensatory dynamics analyzing the effects of patch (core area and edge density) and landscape structure (proximity index) on these community-level attributes. Our results show that (1) habitat loss and fragmentation can in fact reorganize natural communities (i.e., altering community level attributes) by favoring disturbance-adapted species, while negatively impacting forest dependent species; (2) disturbed habitats showed more species and individuals than non-disturbed habitats with a clear segregation in terms of species composition; (3) disturbed habitats exhibited lower β-diversity than non-disturbed habitats regarding dominant species, and (5) core area (positively) and edge density (negatively) were significantly related to forest-dependent species (in terms of abundance and diversity). Thus, our results indicate that compensatory dynamics is extrapolating the threshold of edge-affected habitats and highlight that the conservation value of human-modified landscapes depends on the nature of the ecological groups responsible for the increased β-diversity.