Carnivore Ecology

Across the globe populations of large carnivores have significantly declined due to a multitude of human-related factors. In contrast, some smaller carnivores (e.g., raccoons, red fox, coyotes) have thrived in landscapes dominated by human activity and thus are often a significant source of human-wildlife conflict. As a result, carnivores are an important group of species of both conservation and management concern. We are interested in all aspects of carnivore ecology, with particular emphasis on spatial ecology, disease management, population monitoring, and human-wildlife interactions. We are particularly interested in understanding the effects of anthropogenic activities (e.g., habitat fragmentation, urbanization) on population dynamics, spatial ecology, and disease transmission dynamics. Our research includes a diversity of projects, both in the U.S. and abroad, ranging from studies assessing mesopredator ecology in human-dominated landscapes to studies of wolf spatial ecology and carnivore occupancy within the Chernobyl Exclusion Zone.

MOVEMENT ECOLOGY OF COYOTES IN THE SOUTHEAST

SREL Collaborators: Jim Beasley, Sarah Webster

Outside Collaborators: Michael Chamberlain (UGA), Joseph Hinton (UGA)

Although historically absent from the eastern United States, coyotes (Canis latrans) have expanded their range across the continent and established populations in the southeastern U.S. since the early 1990s. Because of their generalist nature and variability in resource use, researchers have struggled to understand the finescale ecological processes driving coyote resource selection and movement ecology in the southeastern U.S. Further, the direct or indirect impacts of coyote presence on smaller, native mesopredators such as gray fox (Urocyon cinereoargenteus) are not well understood. We are currently collaborating with other UGA researchers to elucidate the impacts of territorial status (i.e. resident vs. transient animals), human persecution, and competition with native carnivores on coyote movement behavior and resource selection. In addition, we also are investigating the effects of coyotes on both gray and red fox. To accomplish this, along with our collaborators we have deployed dozens of GPS collars on coyotes across the southeastern U.S. and collecting a suite of biological samples from each individual handled as part of this research. These data will provide a greater understanding of ecological processes driving coyote resource selection and movement ecology in a diverse landscape.

INFLUENCE OF LURE CHOICE AND SURVEY DURATION ON SCENT STATIONS FOR CARNIVORE SURVEYS

SREL Collaborators: Jim Beasley, Sarah Webster, Caitlin Kupferman, Madeline Melton

Non-invasive, camera-based, scent station surveys have become a common approach to estimate population parameters for mammalian carnivores. Carnivores are particularly sensitive to olfactory cues, and as such the quality and quantity of odor attractant used during surveys significantly impacts the accuracy of the survey. Additionally, survey length is also an important consideration as many mammalian predators are highly mobile and elusive in nature. However, despite the widespread use of scent station surveys, there is considerable variation in methodology used among studies due to uncertainty regarding the most appropriate study design for conducting multi-species surveys. Using scent station surveys, our study aims to test the effects of lures commonly used to trap carnivores: fatty acid, fish oil, synthetic fermented egg, beaver castor, and skunk essence on visitation rates, visitation probability, and latency to visitation of multiple predator species. We are also examining carnivore visitation data collected from wild pig scent stations in both South Carolina and Texas to assess the efficacy of a broader range of attractants (from food-based to wild pig pheromones) in attracting carnivores through time, space, and across seasons. Using these data, we are estimating occupancy probability for carnivores using different survey lengths to determine the effect of survey period on the accuracy of occupancy estimates. From these surveys, we hope to determine optimal attractants and study designs to aid in the standardization of scent station surveys in the eastern U.S.

SPATIAL ECOLOGY, POPULATION DYNAMICS, AND PATHOGEN ASSEMBLAGE OF VIRGINIA OPOSSUMS

SREL Collaborators: David Bernasconi, Jim Beasley, Guha Dharmarajan, Olin Rhodes Jr.

Outside Collaborators: Richard Chipman (USDA), Amy Gilbert (USDA)

To contain and eradicate the rabies virus variant that infects raccoons (Procyon lotor) in the eastern United States, the USDA and a number of other state and federal agencies are utilizing the aerial deployment of oral rabies vaccination baits (ORV) in a swath that stretches from Alabama to Maine. The efficacy of the vaccination program critically depends on the proportion of deployed baits consumed by the target (i.e., raccoons) vs. non-target species. The Virginia opossum (Didelphis virginiana), a species that is refractory to infection with raccoon rabies, is a non-target species that has been identified as the dominant competitor for ORV baits in the Midwest. However, the importance of Virginia opossums as a bait competitor, and thus their impact on ORV program outcomes, in the Southeastern US remains unclear. The goal of this project is to determine the role of Virginia opossums on the control of raccoon rabies in natural populations in the Southeastern US. We are quantifying relative variance in Virginia opossum and raccoon population densities among four major habitat types found commonly in the Southeastern US using a spatially explicit capture-recapture live trap design. In addition to the trapping, we are modeling attributes of home range and habitat resource selection using data from over 100 Virginia opossums fitted with GPS collars over the course of two breeding and non-breading seasons. Finally, we will conduct a metagenomic analysis of pathogens present in the Virginia opossum.

opossum with Rhodamine B dye around mouth

ECOLOGICAL FACTORS AFFECTING THE SUCCESS OF RABIES ELIMINATION IN THE SOUTHEASTERN US

SREL Collaborators: Olin Rhodes, Jr., Guha Dharmarajan, Jim Beasley, David Bernasconi

Outside Collaborators: Richard Chipman (USDA), Amy Gilbert (USDA)

Rabies and other zoonotic diseases pose significant risks to humans and domestic animals, often resulting in substantial economic and public health burdens. Remote vaccination programs have shown promise for controlling the dissemination rabies among free-ranging mesopredator populations. However, seroconversion rates following vaccine bait distributions often are insufficient to break the transmission cycle of the disease, particularly in raccoons (Procyon lotor) and skunks (Mephitis mephitis), suggesting improvements in bait distribution methodology, or deficiencies in the vaccine and/or bait may be needed to improve seroconversion rates in free-ranging populations. We are collaborating with researchers at the USDA-APHIS National Wildlife Research Center to evaluate and improve uptake of rabies vaccine baits in mesopredators through experimental studies. Using biomarkers in combination with live capture and remote camera surveys, we are investigating uptake rates of baits by target and non-target species, and how local habitat attributes influence bait competition and raccoon population demography. Collectively, these data will be used to inform rabies management programs and improve vaccination rates in free-ranging mesopredator populations.

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