Characterizing an organism's evolutionary history and population structure as well as understanding the forces shaping that divergence is crucial to conservation biology. A clear understanding of the patterns of diversity and divergence are imperative for the best management of the organism, while an awareness of what drives these patterns can lead to better predictions of how organisms will respond to future climate change. Historical climate changes and associated sea level change are among the main forces driving divergence in many species. To examine how effects of climate changes may have driven patterns of intraspecific divergence, I examined Mole Skinks, Plestiodon egregius, a semi-fossorial lizard of conservation concern. First, I characterized P. egregius evolutionary history and population structure using multiple data sources: morphological characters, mitochondrial sequences (mtDNA), and genome-wide single nucleotide polymorphisms (SNPs). I determined that SNP data distinguished population structure at a finer resolution than morphology or mtDNA. From these data, I defined six conservation units within P. egregius, three of which are consistent with current subspecific taxonomy. Next, I used statistical phylogeography to examine how the effects of historical climate change in the southeastern United States (US) may have driven patterns of intraspecific divergence in P. egregius. I devised a set of alternative hypotheses regarding the historical distribution and dispersal of P. egregius to test using genome-wide SNP markers. I found support for a historical refugia within the southern scrub ridges in Florida followed by expansion into the Florida peninsula and mainland US. Synthesizing the results from both studies, I evaluate the current subspecific taxonomy and discuss the conservation of P. egregius. Overall, I conclude that P. egregius evolutionary history has been driven by historical sea level changes in the southeastern US, and that insular populations should be the focus of conservation efforts.
Master of Science (M.S.)
College of Sciences
Length of Campus-only Access
Masters Thesis (Open Access)
Mercier, Kathryn, "Unearthing the Past and Present of a Semi-fossorial Lizard: Conservation Genetics, Phylogeography, and Taxonomy of Plestiodon egregius." (2018). Electronic Theses and Dissertations, 2004-2019. 6028.