Date of Completion

4-26-2020

Embargo Period

4-26-2020

Keywords

Salamander, Plethodontidae, Plasticity, Spatial variation, Adaptation, Herpetology, Coloration, Color morph, Temperature, Selection

Major Advisor

Dr. Elizabeth Jockusch

Co-Major Advisor

Dr. Mark Urban

Associate Advisor

Dr. Morgan Tingley

Associate Advisor

Dr. Kentwood Wells

Field of Study

Ecology and Evolutionary Biology

Degree

Doctor of Philosophy

Open Access

Open Access

Abstract

Global climate is changing at an alarming rate and how species will respond to the associated environmental changes remains largely uncertain. The multidimensional selective pressures created by climate change often make it difficult to determine both if and how species are likely to respond. Spatial and temporal changes in environmental conditions, particularly temperature, often have a disproportionate impact on amphibians, which typically require cool, moist conditions to survive. My dissertation research examines how climate change, specifically temperature, influences the ecological and evolutionary responses of a color polymorphic salamander, Plethodon cinereus. This salamander has two main color morphs, striped and unstriped, which vary spatially in their relative abundances and show a variety of physiological, dietary, and behavioral differences. These differences suggest that these color morphs may have different ecological or evolutionary strategies and hence may respond differently to stressors associated with climate change. Through a combination of field observations, controlled lab experiments, and ecological modelling my dissertation extends our knowledge into how temperature impacts the ecology and evolution of P. cinereus. In Chapter 1, I resurveyed P. cinereus populations originally surveyed in the 1970s to determine how climate change has impacted morph proportions. My results suggest climate is important across space, although we observed no significant changes in relative morph proportions in response to climatic changes over time. Chapter 2 expands on this work by determining whether forest cover interacts with climate to buffer salamander populations from recent climate changes. My results show that forests are buffering salamander populations, but also suggests that forest cover alone cannot explain spatial and temporal variations in morph frequencies across New England. In Chapter 3, I tested whether temperature affected the coloration and development of P. cinereus. I found evidence that developmental temperature influences hatchling coloration– either via plasticity or differential mortality. Finally, in Chapter 4 I tested the thermal sensitivity of various physiological traits to determine whether color morphs differed physiologically. All the physiological traits I measured were sensitive to temperature and I found that morphs differed in some, but not all physiological traits.

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