Taxonomic and Functional Diversity of Bird Communities in Mining Areas Undergoing Passive and Active Restoration in Eastern Amazon

The advance of land-use change processes in the Amazon rainforest has modified its natural landscape, resulting in losses of biodiversity and ecological functions. Under this scenario, some reforestation methods have been proposed and tested in degraded areas aiming to reverse environmental damage. We assess the efficiency of three reforestation methods by investigating the taxonomic and functional diversity of birds in a post-mining landscape located in the eastern Brazilian Amazon. We counted birds in 56 sites located in both forest and areas under the process of ecological restoration through natural regeneration, planting seedlings, and nucleation. Species composition and richness differed significantly between forests and areas under recovery. Nucleation showed distinct species composition from planting seedlings or natural regeneration areas, which can be explained by the difference in environmental structure in the areas recovering by this method. Although age did not influence species richness, we observed different species composition between old and young areas that received planting of seedlings. In general, we found no differences in functional diversity and functional richness between the methods of recovery. We conclude that the three recovery strategies evaluated herein showed a similar efficiency. However, it is necessary to consider that perhaps eight years is a short period to observe significant differences in the structure of the areas recovered by the different methods and, consequently, the structure of bird communities. Also, the diversity patterns of the current bird communities located in the post-mining areas were far from those found in forest areas, indicating the need for maintaining long-term recovery programs.