Animal richness, community composition, and phylogenetic community structure (PCS) vary across the modern landscape. Animal communities vary from phylogenetically clustered (i.e. higher relatedness amongst co-occurring species than is expected by chance) to phylogenetically even (i.e. co-occurring taxa are more distantly related than expected by chance), which is explained by abiotic or climatic filtering and competitive exclusion, respectively. Under this model, the contribution of historical origination and extinction events to modern animal PCS remains relatively unknown. Because origination and extinction determine the make-up of the terrestrial community, the study of historical changes in animal PCS is tantamount to understanding formation of modern communities. In the present study, we test the effects of macroevolution and climate changes on 'hoofed mammals' (i.e. perissodactyl and artiodactyl) PCS from the late Cenozoic of North America because they experience large, phylogenetically dispersed extinctions of browsing species and phylogenetically dispersed originations of grazing species associated with the evolution of grassland ecosystems during the late Miocene. We show that the loss of numerically dominant nonhypsodont (putatively browsing and mixed feeding) clades and phylogenetically dispersed origination of less speciose clades following the mid Miocene climatic optimum led to an increase in phylogenetic evenness at the regional scale that is well explained by global climate changes. Phylogenetic evenness and a reduced richness during the late Cenozoic may have facilitated reduced niche overlap among co-occurring hoofed mammal species as global climates cooled.

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Biological Journal of the Linnean Society
Department of Biology

Fraser, D. (Danielle), Gorelick, R, & Rybczynski, N. (2015). Macroevolution and climate change influence phylogenetic community assembly of North American hoofed mammals. Biological Journal of the Linnean Society, 114(3), 485–494. doi:10.1111/bij.12457