Global climate change is threatening species with habitat loss and extinction, but specific mechanisms driving changes in species abundance are unclear, partly due to a lack of time-series data sets documenting population changes. In order to study these effects on amphibian species, we revisited Lotter and Scott’s 1977 study of color morph frequency in relation to climate in Plethodon cinereus (eastern red-backed salamander). 25 Massachusetts, New Hampshire, and Vermont localities were resampled during summer 2016, to quantify any changes in morph frequency since 1977. At 19 of the 25 localities, we were able to find ≥100 salamanders, and of those 19, five localities had significant changes in morph frequency since 1977. Previous work suggests that the unstriped morph is more heat- and drought-tolerant, and thus should be the morph that increases in relative abundance over time in areas where global climate change results in either higher temperatures, decreased precipitation, more prolonged periods of drought, or some combination of these factors. Collection of fine-scale climate data at each location from 1977 to today was beyond the scope of this study, so I only documented the patterns of morph frequency change. Despite a general warming trend in New England, I found a higher proportion of the unstriped morph at only 1 of the 5 localities with significant change; the others showed an increase in the striped or erythristic morphs. Lotter and Scott also suggested that there was differential mortality between striped and unstriped morphs, with unstriped morphs suffering higher juvenile mortality. We found no evidence of this pattern at 9 MA localities with 2016 age data, suggesting that the current morph frequency distribution is stable. I continue to work with collaborators to resample all 50 Lotter and Scott localities. Once all sites have been resampled, we plan to explore potential climate or land-use changes that may be driving changes in morph frequency.
M. Caitlin Fisher-Reid (Thesis Director)
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Original document was submitted as an Honors Program requirement. Copyright is held by the author.
Fossella, Mariah. (2017). Distribution of Plethodon cinereus Color Morphs in New England: 40 Years Later. In BSU Honors Program Theses and Projects. Item 194. Available at: http://vc.bridgew.edu/honors_proj/194
Copyright © 2017 Mariah Fossella