Abstract

Plethodon welleri is a species of endangered terrestrial salamander found in western North Carolina, eastern Tennessee, and southwestern Virginia, primarily in areas of high-elevation spruce-fir forest. These forests harbor many endemic plant and animal species yet are highly threatened by climate change and invasive species. Endemic species such as P. welleri may be especially threatened by climate change as their preferred environments get pushed into higher elevations by warming temperatures— isolating populations on mountaintop “islands.” Analyzing genetic data for P. welleri allows us to ascertain the extent of genetic diversity and population connectivity/divergence among mountaintop “island” populations, providing valuable information to conservation planners. Using over 60 previously collected samples of this species, plus several my own samples collected over the last 2 years, I generated and analyzed genetic data from P. welleri populations on Unaka and Grandfather mountains in North Carolina as well as Whitetop Mountain and Mount Rogers in Virginia. I examined a 1,100bp fragment of the mitochondrial DNA ND2-NADH locus for each of these samples using distance-based and phylogeographic analyses to determine their degree of genetic differentiation. I found that these populations were each genetically distinct, with North Carolina and Tennessee populations sharing a more recent common ancestor than those from Virginia as predicted by geographic distances alone. I further found that Unaka mountain harbors a considerable amount of genetic diversity relative to the other populations. Finally, I describe microhabitat characteristics of locations were P. welleri were found on Unaka Mountain. These data suggest a trend of P. welleri preference for high-elevation areas of Picea rubens forest corresponding to an increasing pH gradient with increasing elevation on Unaka Mountain.

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