Beaudrot, Lydia2024-08-302024-082024-08-01August 202https://hdl.handle.net/1911/117812Tropical and subtropical moist forests are home to over half of all extant vertebrate species worldwide, yet they face increasing anthropogenic pressures that are degrading multiple facets of their diversity. High tropical species diversity has been hypothesized to have resulted from an evolutionary history of high species diversification in stable environments relative to temperate regions. However, recent studies have found that varying degrees of environmental variability and historical extinction of large-bodied vertebrates likely lead to the uneven distribution of species richness and body sizes among tropical regions (i.e., tropical diversity disparity) on different continents. However, little is known about how evolutionary history, historical extinction, and environmental variability have shaped the geographic differences among tropical regions in other facets of their diversity. This limited knowledge not only hinders our ability to unravel fundamental questions about drivers of biodiversity distributions but also to assess biodiversity changes that have implications for conservation given ongoing anthropogenetic pressure and environmental change. Hence, to address this research gap, I tested the relative effects of evolutionary and macroecological drivers on 1) community structure, 2) predator-prey interactions, and 3) functional diversity of vertebrate assemblages in tropical and subtropical moist forests globally. I focused on mammals because this well-studied vertebrate class has species-level functional trait data, a well-resolved phylogeny, and community composition data available from both in-situ observations and the reconstructed ranges of extinct species. First, using in-situ observations from 15 protected tropical forests worldwide, I found that the coupled phylogenetic and functional community structure of ground-dwelling mammals has been shaped by slow niche evolution, and phylogenetic clustering tendencies were predicted by colonization time. Second, I found geographic differences in the dietary breadth of carnivoran predators among 380 large mammal communities in the Neotropical, Afrotropical, and Indomalayan realms, for which speciation rates and present temperature seasonality supported dietary niche generalization while historical extinction led to dietary niche specialization. Thirdly, I found geographic differences in the vulnerability to functional diversity loss of tropical and subtropical moist forest mammals from historical and predicted future extinctions. Functional vulnerability to loss increased in mammal assemblages with slower niche evolution but decreased under greater present environmental variability. By integrating evolutionary and macroecological approaches, this dissertation has unraveled the essential roles of evolutionary history, extinction, and present environmental variability in shaping multiple facets of the diversity of extant forest mammals in the global tropics and subtropics.application/pdfencommunity ecologymacroecologymacroevolutionniche evolutionThesis2024-08-30