Forest structure predicts species richness and functional diversity in Amazonian mixed-species bird flocks

Background

Secondary forests between forest fragments are valuable sources of biodiversity during the regeneration process. In the Brazilian Amazon, understory birds are often an indicator of forest regeneration and overall health. Functional diversity is an important component of ecosystem health and services, yet little is known about the role it plays in the return of mixed-species bird flocks.

Goals and Methods

The authors aim to determine if vegetation structure influences species richness and functional diversity of mixed-species bird flocks. In addition, they ask if vegetation structures have different influences on bird flocks depending on the successional state of the forest. The authors track several mixed-species bird flocks over three dry seasons, and measure indicators of avian functional diversity. LiDAR technology is used to record elevation as well as forest canopy height and structure.

Conclusions and Takeaways

Denser and more complex vegetation structure is correlated with greater bird species richness and functional diversity in primary forest. In secondary forests, denser vegetation reduced bird species richness.  The authors conclude that secondary forests can host a substantial, although lesser, degree of bird functional diversity compared to primary forests. Certain vegetation structure characteristics vary in importance between elevation and forest succession stage and the authors state that this gives valuable insight for people looking to enhance bird populations.