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Author ORCID Identifier

https://orcid.org/0000-0002-2272-9770

AccessType

Open Access Dissertation

Document Type

dissertation

Degree Name

Doctor of Philosophy (PhD)

Degree Program

Environmental Conservation

Year Degree Awarded

2019

Month Degree Awarded

May

First Advisor

Curtice Griffin

Second Advisor

Kevin McGarigal

Third Advisor

Lisabeth Willey

Abstract

The primary goal of my dissertation was to investigate the adaptive capacity of mole salamanders in western Massachusetts, specifically marbled salamanders (Ambystoma opacum), to future changes in climate. This involved the analysis of two existing datasets including i) a nearly decade-long photograph capture-recapture dataset (first described by Gamble et al. 2009) and ii) a landscape genetics dataset (first described by Whitely et al. 2014). My dissertation also included two chapters focused on computer simulations to better understand the behavior and inferences from the statistical models fit to the empirical datasets I modeled and the effects of error in the data on model parameter estimates. Results of my research provide new insights regarding the adaptive capacity of A. opacum populations to future environmental change. First, genetic differentiation of A. opacum was found to be driven by roads and landscape curvature in our study area which has resulted in population clustering (K=3; Whiteley, McGarigal, & Schwartz, 2014). This suggests that A. opacum may have difficulty tracking future climate change if movement, dispersal and ultimately gene flow are restricted due to both anthropogenic and natural topographic features of the landscape. Second, multi-state survival model estimates suggested that climate change could directly reduce A. opacum survival through increases in summer precipitation amounts and indirectly reduce A. opacum survival through increases in the length of the breeding interval due to increases in fall temperature and decreases in precipitation as mortality rates at the vernal pool. Lastly, no evidence was found that individual A. opacum could pick up on environmental cues that breeding conditions would be “riskier” in a given year due to a longer breeding interval and “skip” breeding at higher rates (particularly females), to buffer the population from such environmental conditions.

DOI

https://doi.org/10.7275/13994024

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