ABSTRACT

In the current scenario of human transformation of natural landscapes, fragmentation and habitat loss is considered one of the major threats to biodiversity. The characteristics of altered landscapes and remaining habitat patches influence the persistence of species and, as a direct consequence, the functioning of ecological processes. The main focus of studies at landscape scale is to understand how human modifications in natural areas lead to changes in abundance and richness of species. However, such approaches do not directly describe the functional composition of communities, nor do they describe the functional responses to fragmentation and habitat loss. Birds are an interesting taxonomic group to explore this theme, since they present important, broadly-described ecological functions for human modified habitats (e.g., seed dispersal, pollination, and insect pest control). Thus, we aimed to explore the functional responses of birds to landscape characteristics. We selected 14 human modified landscapes of Atlantic forest, found within a radius of 30 km of Alfenas, Brazil. Each landscape was characterized by metrics describing landscape configuration and composition, such as forest percentage and mean connectivity. Birds were sampled in the central patches of the landscapes and classified into 15 functional groups, based on species' traits. We constructed Generalized Linear Models (GLM) and used Akaike's information criterion (AIC) to identify the best models that explained the abundance and richness of species in each functional group. Few groups had high functional redundancy, showing the fragility of the majority of functional groups in the current modified landscapes. Forest dependent functional groups were favored by connected landscapes, higher percentage of forest cover, and high percentages of coffee matrix. On the other hand, forest independent groups were favored by irregular habitat areas and negatively impacted by forest cover and sugar cane matrices. Consistent management of altered landscapes, based on functional responses, can assist the recovery and maintenance of natural areas. We highlight the complexity involved in landscape management, considering it requires simultaneous work on composition and configuration.

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