Top Down Effects and Resource Selection by Coyotes in South Carolina

Author

Alex JensenFollow

Date of Award

5-2023

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Forestry and Environmental Conservation

Committee Chair/Advisor

Dr. David Jachowski

Committee Member

Dr. Michael Childress

Committee Member

Dr. Cathy Jachowski

Committee Member

Dr. John Kilgo

Abstract

Top predators play important roles in functioning ecosystems, including regulating the populations of prey species and competing with other predators. However, in the face of global change, many top terrestrial predators have declined in both range and abundance, making room for some smaller predators to expand into new niches. Coyotes (Canis latrans) in North America are a prime example of this – they have rapidly expanded their range in the last 120 years, raising concerns about their impacts on both domestic and wild species. In eastern North America, research has centered around their effects on white-tailed deer (Odocoileus virginianus), which are an important game species and particularly vulnerable to coyotes during the first few weeks of life. Despite efforts by governments and citizens to kill coyotes across much of their new range, they are now established, and managers are looking for ways to quantify and reduce their effects on native species. Critical questions remain about variability within coyote populations and how exactly they respond to temporary foods on the landscape. To address these questions, we studied coyote spatial and community ecology in the Piedmont region of South Carolina, USA. In Chapter 1, we used GPS data to investigate variability in habitat selection and movement. At the population level, coyotes avoided risky areas (i.e., open and developed habitat), especially during risky times. However, we found differences across seasons, behavior states, and sexes, highlighting the importance of both extrinsic and intrinsic factors in predicting movement. In Chapter 2, we quantified coyote diet, focusing on the summer months when fawns were available. Coyotes largely switched to temporarily available foods during the summer and fall, suggesting that alternative foods (i.e., summer fruits) could buffer predation on fawns. In addition, using genetics, we found that most of the individuals in our population switched to these temporary foods, indicating that targeted removal would likely not decrease fawn mortality. In Chapter 3, we investigated whether coyotes changed their foraging tactics for different foods and also described coyote movement surrounding fawn predation events. We compared foraging patterns for fawns, blackberries, and small mammals and found relatively few differences in when and how coyotes moved, yet differences in where they foraged. Linking fawn predation events to coyote GPS data showed that coyotes tended to move relatively fast and linearly prior to killing a fawn, then would quickly move away from the kill site and rest for several hours. In Chapter 4, we broadened our investigation into top-down effects by using a field manipulation to test how coyotes influenced smaller carnivore scavenging behavior, relative to other hypothesized factors. We found that coyotes only directly influenced bobcat behavior, while forest structure (particularly understory cover) seemed to modulate risk from coyotes, highlighting the complexity of interactions among carnivores. Taken together, our findings highlight that 1) coyotes have diverse, yet context-dependent top-down effects and that 2) temporary foods shape their behavior and diet (particularly in the summer). More broadly, our findings suggest that habitat management which promotes alternative foods and accounts for human shields may be a viable strategy to influence the behavior of large-herbivore predators. Generalist carnivores will likely continue to thrive in the Anthropocene, necessitating continued research into their effects on other species and management strategies to best coexist.

Recommended Citation

Jensen, Alex, "Top Down Effects and Resource Selection by Coyotes in South Carolina" (2023). All Dissertations. 3312.
https://open.clemson.edu/all_dissertations/3312

Author ORCID Identifier

0000-0003-0340-7765