Date of Award
Master of Science (MS)
Forestry and Environmental Conservation
Wild pigs (Sus scrofa), which are invasive in much of the world, can alter ecosystems and compete with native species through interference competition and resource exploitation. We assessed the potential for interspecific interactions between invasive wild pigs and other wildlife in the Piedmont region of South Carolina by examining their spatiotemporal overlap in a correlational field study and an experimental field study. Our correlational study used data from wildlife cameras in seasonal occupancy, N-mixture, and temporal overlap analyses. Both deer (Odocoileus virginianus) and coyote (Canis latrans) site use were negatively associated with wild pig activity in the fall, when they had high temporal overlap, indicating spatial partitioning could reduce interference competition with wild pigs in this season. Deer site use was positively associated with wild pig activity in the winter, suggesting higher spatial overlap may be necessary if resources are limited. These results highlight the importance of investigating spatiotemporal overlap between wild pigs and other species over time, as the potential for interactions likely changes with fluctuating resources. Special consideration should be given to species in seasons where they have high niche overlap with wild pigs. We further assessed the potential for interactions between wild pigs, deer, and coyotes by examining their responses to supplemental feeding in the spring and summer, when we expected greater sensitivity to competitive and predatory interactions due to rearing young. Using a stratified random sampling design, we deployed 15 wildlife feeders paired with cameras across a gradient of wild pig site use intensity, monitoring feeders unfilled for six weeks and then active for eight weeks. In addition to assessing supplemental feeding effects on the relative and temporal activity of these species, we used data from GPS-collared does and coyotes to examine space use in relation to feed. Adult deer and wild pig relative activity increased with feed, were inversely related, and were juxtaposed by high temporal overlap. Fawns rarely visited feeders and had lower temporal overlap with wild pigs, but showed increased evening activity at feeders. Resources were likely abundant during this study, enabling spatial partitioning between deer and wild pigs, but overlap at baited sites could change with more limited resources. Does did not discover feed outside of their home range and coyotes did not show a spatial response to feed, but effects of supplemental feeding on prey and predators should continue to be assessed, as predators could key in on concentrated prey use of feed over time. By integrating correlational and experimental studies across seasons, we can improve our knowledge of dynamic species interactions.
Saldo, Elizabeth A., "Effects of Invasive Wild Pigs and Supplemental Feeding on Wildlife in the Piedmont Region of South Carolina" (2022). All Theses. 3774.
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