Respostas filogenéticas e funcionais de uma assembleia de aves aos gradientes de urbanização em uma metrópole amazônica

Abstract

Variations in biotic and abiotic characteristics within cities promote the formation of environmental gradients. In this study, we investigated how these urban environmental gradients influence the phylogenetic and functional components of bird assemblages. We used data obtained from bird censuses conducted at 89 sites in the city of Manaus that cover various environmental gradients. We quantified phylogenetic and functional diversity through taxonomic structure and 22 ecological and morphological traits. Phylogenetic diversity of the total assemblage of birds was negatively affected by edge density, but not by forest cover. The most diverse lineage of birds (Passeriformes) showed significant loss of phylogenetic diversity along the forest cover and noise gradient. Approximately half of the functional traits tested showed differences along the forest cover gradient. The traits filtered by urban environmental gradients are mainly related to nesting, foraging, and morphology. Furthermore, different components of functional diversity (richness, regularity, dispersion and divergence) were affected by environmental gradients. Categorical ecological traits were apparently more sensitive than morphological traits to environmental changes along forest cover gradients. Urbanization affects the phylogenetic and functional components of bird assemblages in Manaus, as reported in other cities around the world. However, the phylogenetic and functional responses to urban environmental gradients in Manaus were complex and heterogeneous. Our results suggest that the best urban space management strategy for birds is to preserve areas with greater forest cover that are more connected and with little edge effect in places with little noise.