AbstractsGeography &GIS

Includes abstract. Albany Subtropical Thicket (AST) is a species-rich biome restricted to the coastal lowlands of the southern Cape region of South Africa. Its Quaternary history is poorly understood, but climatic changes associated with Pleistocene glacial cycles may have profoundly affected the distributions, gene flows, and demographies of species. The glacial refugia hypothesis predicts that AST retracted into fragmented refugia during glacial cycles. The evolutionarily discrete drainage basin (EDDB) hypothesis suggests that the prevailing topography played an important population-structuring role. I evaluate these two hypotheses by combining community and species distribution models with multigene comparative phylogeography of three AST species Pappea capensis, Nymania capensis, and Schotia afra. Distribution models support the glacial refugia hypothesis, with highly reduced and fragmented distributions postdicted for the Last Glacial Maximum. These models, projected onto two climate scenarios for 2050, give a positive outlook for the future of AST, with no dramatic shifts or reduction in appropriate climate...