Abstract/Summary

Since the Late Pleistocene at least 610 birds have gone extinct, including 165 since 1500 CE. Extinctions on this scale vastly exceed those seen in the fossil record, and erode ecosystem processes, threatening ecosystem stability and resilience. Amid ongoing species loss, we have limited understanding of how projected extinctions will affect the diversity of species morphology, referred to as functional diversity. Functional diversity is underrepresented in conservation efforts, even though it often responds differently to human activity than traditional measures of biodiversity such as species richness. Large-scale studies of functional diversity were previously limited by data availability, but the release of a near-complete trait database for birds, and the development of methods which can handle large quantities of continuous, multivariate data provides an opportunity to assess functional diversity change at a scale not before possible. In this thesis I quantify the impact of projected extinctions on avian functional diversity and propose new approaches for tracking functional diversity change, to support the preservation of biodiversity in its entirety. To do this I, 1) show that current data and methods are sufficient to estimate functional diversity at large scales across many taxa; 2) demonstrate that both species richness and functional richness are threatened by human activity, and additional conservation measures will be needed to protect functional diversity; 3) develop a metric to track progress in the conservation of functional diversity from local to global scales. My findings support the need to monitor functional diversity alongside species richness and show that conservation strategies which focus on species richness are inadequate to conserve functional diversity in its entirety. Future work should integrate functional diversity and ecosystem functioning research across scales to fully harness trait-based approaches for understanding the consequences of global change.