Idiosyncratic responses of Amazonian birds to primary forest disturbance.

As humans continue to alter tropical landscapes across the world, it is important to understand what environmental factors help determine the persistence of biodiversity in modified ecosystems. Studies on well-known taxonomic groups can offer critical insights as to the fate of biodiversity in these modified systems. Here we investigated species-specific responses of 44 forest-associated bird species with different behavioural traits to forest disturbance in 171 transects distributed across 31 landscapes in two regions of the eastern Brazilian Amazon. We investigated patterns of species occurrence in primary forests varyingly disturbed by selective-logging and fire and examined the relative importance of local, landscape and historical environmental variables in determining species occurrences. Within undisturbed and disturbed primary forest transects, we found that distance to forest edge and the biomass of large trees were the most important predictors driving the occurrence of individual species. However, we also found considerable variation in species responses to different environmental variables as well as inter-regional variation in the responses of the same species to the same environmental variables. We advocate the utility of using species-level analyses to complement community-wide responses in order to uncover highly variable and species-specific responses to environmental change that remain so poorly understood.