Date of Award

Spring 2019

Project Type

Dissertation

Program or Major

Earth and Environmental Sciences

Degree Name

Doctor of Philosophy

First Advisor

Marian K Litvaitis

Second Advisor

Thomas Foxall

Third Advisor

Erik A Hobbie

Abstract

Bobcats (Lynx rufus) are the most widely distributed wild felids in North America, ranging across the contiguous United States, southern Canada, and northern Mexico. In the New England region (NER) bobcat populations endured nearly two centuries of intense harvest pressure and land use change that nearly led to their extirpation in parts of the region. However, they are currently experiencing a population resurgence despite large-scale increases of anthropogenic impacts on the landscape in the last 60 years. In this dissertation, I sought to understand the resurgence of bobcats in the NER by studying several aspects of bobcat ecology in relation to human land use.

Bobcats present a unique system in which to study anthropogenic impacts on wildlife. The NER is near the northern edge of their range. Combined with their history of fluctuating abundance, this provides a dynamic demographic landscape. They are reclusive, typically avoiding human contact, but are also highly adaptable to varied habitats including human-dominated areas. Their habitat preferences can widely vary based on local conditions and biological factors. They are a wide-ranging and charismatic species with great public appeal, which makes them an ideal umbrella or flagship species for regional conservation efforts and provides ample opportunity for engagement with public stakeholders.

Chapter 1 of this dissertation explores genetic patterns across the NER over the past 60 years. I compare genetic structure, diversity, effective population size, and gene flow between a historic (1952-1964) and a contemporary (2009-2017) time period. My results suggest that bobcat populations in the region are robust, but development and edge-of-range dynamics play a significant role in population structure. Chapter 2 compares the diet of bobcats in the NER between the same time periods. I found that historically, bobcats were highly dependent on lagomorphs but their diet diversified in the contemporary time period. In Chapter 3, I explore the effect of land use on bobcat stress levels using hair cortisol as an indicator of stress. Anthropogenic land use was a better predictor of cortisol levels in bobcats than their preferred undeveloped land cover types. Finally in Chapter 4, I integrate data from the first three chapters to explore how the genetic structure, diet, and stress physiology of bobcats in the NER interact with one another and with the landscape, particularly anthropogenic land use. I also developed a framework for further study to elucidate precise mechanisms that explain those interactions.

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