1School of Human Evolution and Social Change, Institute of Human Origins, Arizona State University, 2School of Human Evolution and Social Change, Arizona State University, 3Department of Anatomy, Arizona College of Osteopathic Medicine, Midwestern University, 4Graduate Group in Ecology and Department of Anthropology, University of California-Davis
Saturday 3:30-3:45, Ballroom A
Numerous mechanisms have been proposed for contributing to the structure of primate communities, including historical circumstance, competition, climate, habitat, and resource limitation among others. Many researchers have analyzed community structure from an ecological perspective, but fewer studies have explored communities in the context of phylogeny. We analyzed 206 African large mammal communities, as well as three subsets: primates (135), carnivores (199), and ungulates (183) to derive net relatedness (NRI) and nearest taxon (NTI) indices. Significantly low NRI/NTI values (i.e. phylogenetic overdispersion) are indicative of past interspecific competition, resulting in competitive exclusion among closely related species. Alternatively, significantly high NRI/NTI values (i.e. phylogenetic clumping) would suggest that closely related species have similar ecological requirements, resulting in their coexistence. Communities may also exhibit phylogenetically random species compositions, yielding NRI/NTI scores not significantly different from zero. We found that in African large-mammal communities, 63% exhibited a random phylogenetic structure, 25% were overdispersed, and 12% were clumped. Within the taxonomic subsets, 86% of primates, 92% of carnivores, and 72% of ungulates exhibited random phylogenetic structure. Overdispersion accounted for 12% of primate, 4% of carnivore, and 21% of ungulate communities, while phylogenetic clumping only accounted for 2% of primate, 4% of carnivore, and 7% of ungulate communities. For primates, overdispersion occurs in mosaic habitats, whereas clumped communities are close to borders of biogeographic provinces. We suggest that past interspecific competition or habitat filtering has affected a relatively small proportion of African mammal communities, however, we also explore the differences in community structure among phylogenetic groups.