Assembleias de aves em florestas secundárias oriundas de agricultura familiar na Amazônia: explorando diferentes facetas da biodiversidade

Abstract

We investigate the effects of ecological succession of secondary forests growing after agriculture practices in the taxonomic, functional and phylogenetic diversity of bird assemblages in the Amazon. Birds were sampled through quantitative censuses carried out in replicate plots of secondary forests in the following stages of recovery: young secondary forests (< than seven years of abandonment), mid-age secondary forests (> 7 < 20 years) and old secondary forests (> than 20 years). We also made censuses in primary forests adjacent to secondary forests plots. Taxonomic diversity was measured as the total number of species, number of bird species from Passeriformes Order, and number of species highly sensible to environmental disturbance. Data on birds morphometric, foraging sites, diet and social behavior were used to measure functional richness, evenness, divergence and dispersal. Phylogenetic diversity was measure through the hierarchical linnean structure (p. ex. genus, families, orders) of species as proxies of its phylogenetic relationships. Different diversity metrics reveals distinctive aspects of bird assemblages. Number of bird species sensible to environmental disturbance was higher in primary forests compared to secondary ones. Also old secondary forests had more species in this category. In addition, richness of Passeriformes birds was also higher in primary forests. The functional evenness was higher in old and mid-age secondary forests. Functional dispersion, for the other side, was higher in secondary forests with more than 20 years of abandonment. The bird assemblages found in secondary forests presents higher phylogenetic diversity (phylogenetic dispersion) compared to primary forests (phylogenetic attraction), especially among the Passeriformes. The influence of forest types (primary vs. secondary) and ecological succession on different components of biodiversity is complexes and could be associate to different weight of abiotic and biotic filters along the processes of forest regeneration. This study reinforces the utility of a pluralistic approach integrating complementary dimensions of biodiversity to understand the complex process of ecological succession.