Feral swine (Sus scrofa) are present in every county in Florida with an estimated population of over 500,000. They are considered an invasive species and have negative impacts upon native vegetation, agricultural crops, wildlife, and increase the risk of livestock disease transmission. Ongoing collaborative projects have been established to quantify impacts of feral swine on rangelands, and understand economic costs of feral swine to the ranching community. The following questions are being asked:
How dense are feral swine populations?
What are their movement patterns and habitat preferences?
What is their contact rate with livestock or point sources?
How does rooting impact forage production and how are native plant communities shifted from feral swine impacts?
What diseases are shared among feral swine, wildlife and livestock and what is the risk of transmission?
How often do feral swine depredate ground nesting birds (Turkey, Bob-white Quail and Sand-hill Cranes)?
Do wildlife prefer areas where feral swine have been controlled and excluded?
What are the best control and exclusion methods?
Long-term Feral Swine Study to Estimate Population Size and Density
In May of 2015, we initiated a collaborative long-term feral swine monitoring study at Buck Island Ranch (MacArthur Agro-ecology Research Center) to collect much needed data to establish feral swine population sizes and densities. This study will also allow for the calculation of effort and costs required to reduce the population, how long populations take to recover after control efforts and establish accurate costs associated with strong feral swine control.
To achieve the required data collection we:
Trapped and individually marked all swine captured with ear tags, collar bands and some with GPS devices
Established an array of 44 motion-activated cameras (one every 1 km2) across the property to re-sight swine
Along with photographs of marked and unmarked swine, the motion-activated cameras record photographs of other wildlife species. Although feral swine will be a focus of the study, the array could very easily be used to study other wildlife in a similar manner, for example, estimating white-tailed deer abundance.
By tagging and collaring the feral swine, we can begin answering questions regarding swine population size and density in Florida rangeland, as well as space use and habitat selection. Three different mathematical models will be employed to estimate swine density. These models will examine number of photographs of marked individuals compared to the number of unmarked individuals across the thirty-one 1 km2 grid cells. GPS collared individuals (typically one sow within a sounder) will provide us with how often and how far feral swine are “off” grid allowing accurate calculations of swine numbers per unit area. We will also be able to study social group behavior, space utilization, social interactions and territoriality among groups, and habitat use. Ultimately, this is a major scientific study that will fill many gaps in general knowledge about feral swine ecology, which is essential for management.
In addition, Connor Crank is examining competition between feral swine and white-tailed deer for food resources and space on Florida rangelands for her graduate project. Wes Anderson is conducting his graduate research on the impacts feral swine have upon tadpoles (larval frogs) that inhabit seasonal wetlands within Florida rangelands.
These projects were made possible by funding and collaboration with the USDA Veterinarian Services and Renewable Resources Extension Act. Collaborators: Ryan Miller, Dan Grear, USDA. Matt Farnsworth, Jesse Lewis, CSP. Samantha Wisely, Marty Main, UF-WEC. Contributors: The MacArthur Agro-ecology Research Center.