Doctoral Dissertations

Orcid ID

Date of Award


Degree Type


Degree Name

Doctor of Philosophy


Ecology and Evolutionary Biology

Major Professor

Kimberly S. Sheldon

Committee Members

Daniel S. Simberloff, James A. Fordyce, Todd M. Freeberg


Current climate change is increasing global temperatures so that many organisms are now experiencing temperatures outside of their thermal tolerance, which threatens their survival. Organisms respond to physiologically stressful temperatures to reduce this threat. Organisms respond to warming through three main mechanisms: range shifts, adjustments via phenotypic plasticity, and evolutionary adaptation. Organisms vary in their ability to utilize these three mechanisms, leading to differences in the magnitude and success of their adjustments to temperature change. Here, I examine how organismal traits influence variation in species response to climate change. Chapter one addresses how physiological tolerance may influence the rate of range shifts across elevation using a meta-analysis of twenty published data sets. Next, in chapter two, I address how invasive versus native species may respond differently to climate change because of predictable differences in traits, specifically phenotypic plasticity. Since plasticity often plays an important role in invasion success, invasive species may have higher plasticity than their native cogeners. Therefore, climate change may be more detrimental to native species than invasive ones, exacerbating the negative effects of invasive species on native biodiversity. To address this possibility, I examine differences in plasticity between an introduced and a native Onthophagus dung beetle species living in the Southeastern United States. In Chapter three, I investigate native dung beetle communities of the Great Smoky Mountain National Park to better understand possible impacts of introduced beetles. Then, I address variation in physiological plasticity (chapter four) and behavioral plasticity (chapter five) between the native species, O. hecate, and the introduced species, O. taurus. Taken together, these studies indicate that species traits, including physiological tolerance, acclimation ability, and reproductive behavior influence species responses to warming. The introduced beetle, O. taurus, is more capable of withstanding warming than the native O. hecate due to differences in these traits, indicating that climate change may increase the impacts of O. taurus on native dung beetle communities.

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