A main goal of comparative phylogeography is to examine the evolutionary history of multiple species in order to determine the processes that have driven patterns of speciation and biodiversity across a landscape. We combine ecological niche modeling, and ecological experimentation to address the mechanisms driving range distributions of lineages and species. We emphasize a quantitative approach to phylogeography (e.g., Lapointe and Rissler 2005, American Naturalist), and much of our work focuses on California and the southern Appalachians. (Check out this recent feature article on our lab in Bioscience!)