Date of Award
M.S. in Biological Science
Ryan C Garrick
John S. Brewer
Phylogeography has recently benefited from incorporation of coalescent modeling to test competing scenarios of population history of a species. Ecological niche modeling has also been useful in inferring areas of likely suitable habitat during past climate conditions. Several studies have examined the population history of biota in the Southern Appalachian Mountains and how they responded to climate change associated with the end of the Last Glacial Maximum (~18,000 years ago), though few studies have focused on understory plants. This study redressed that knowledge gap thorough examination of the phylogeographic history of the understory plant Chimaphila maculata, which is native to the Appalachian Mountains. Three microsatellite loci were developed and used in genetic analyses to assess how genetic diversity varied along a latitudinal gradient, and also to examine the number and geographic range of genetically distinct population clusters. An ecological niche model for C. maculata was generated to identify areas of past suitable habitat. Coalescent modeling was used to test four competing scenarios relating to past refugia and recolonization routes. Genetic variation was found to be higher in northern latitudes, though coalescent modeling was unable to discern one refugia and recolonization scenario for another. Four genetically distinct clusters were detected, and their geographic distribution showed similar patterns as other studies of the region. Results of this study were informative to the direction future studies could take to answer unresolved research questions regarding C. maculata in the Southern Appalachian Mountains.
Banusiewicz, John Daniel, "Historical refuges and recolonization routes in the Southern Appalachian Mountains, inferred through phylogeographic analysis of the spotted wintergreen (Chimaphila maculata)" (2017). Electronic Theses and Dissertations. 1275.