Date of Award
Master of Science (MS)
Forestry and Environmental Conservation
David S. Jachowski
Susan C. Loeb
Small carnivore assemblages have been a topic of interest for many years because of their potential top-down effect on communities. However, mesopredators are a challenge to investigate because of their small sizes and elusive behavior. Advances in technology, such as non-invasive trail cameras and smaller GPS tracking devices, have increased the success in monitoring these communities, and we are learning that some of these species’ populations have drastically declined, are currently declining, or the population status is unknown.
Adding an attractant to remote camera sites has become a popular method to increase detections of mesopredators. However, there is an ongoing debate about whether or not baiting remote cameras biases the behavior and detection of these species. We investigated how baiting remote cameras with canned sardines affects mesopredator detection probabilities and temporal activity in two areas in North Carolina. We used an experimental design in which we baited half our camera sites and then switched the unbaited and baited camara sites halfway through the survey season. We estimated detection probability for each species using occupancy models, and we used kernel density estimations to evaluate changes in temporal activity at baited and unbaited sites. We found that baiting remote camera stations increased the detectability for coyotes, raccoons, opossums, and eastern spotted skunks by up to 5 times but had little or no effect on bobcats and striped skunks detectability. Moreover, baiting camera sites did not alter the temporal activity of the species we most frequently detected (coyotes, raccoons, and opossums). Our results suggest that the efficacy of baiting remote cameras to increase carnivore probability of detection is species-specific, and despite increasing the total number of detections, using baits generally does not bias species temporal behavior.
Managing for eastern spotted skunks (Spilogale putorius) is of particular interest because of the large population declines since the 1940s. We investigated how fine-scale habitat features influenced eastern spotted skunk den site selection in two areas in North Carolina. We radio-tracked spotted skunks from January-August 2018-2020. We identified two available den sites for every used den site and assessed selection using discrete choice models. Male spotted skunk den selection was associated with a broad range of variables including low basal area, high canopy closure, closer distances to drainage channels, low forb and grass groundcover, larger den entrance sizes, and steeper slopes. Female spotted skunk den selection was associated with low basal area and rocky outcrop substrates. Our findings suggest that predation and competition could be strong drivers of spotted skunk den site selection and highlight the importance of managing forests for vegetative cover and closure to increase den site availability for eastern spotted skunks.
Siegfried, Anna, "Mesopredator Detection and Eastern Spotted Skunk Den Site Selection in North Carolina" (2021). All Theses. 3636.