A multi-level modeling approach to guide management of female feral hogs in Great Smoky Mountains National Park

Abstract

We trapped, anesthetized, and fit 16 female feral swine (Sus scrofa) with Global Positioning System (GPS) collars in Great Smoky Mountains National Park (GRSM) to develop predictive summer and winter models for more effective population control efforts. Given the highly diverse habitat and topography in GRSM and the spatial extent of our dataset, we employed Step Selection Function (SSF) to evaluate resource selection at the 3rd-order level and Resource Selection Function (RSF) models at the 2nd-order level for both summer and winter seasons. The summer SSF and RSF models suggested relatively similar levels of selection, whereas the winter models differed by method. We created a straightforward consensus model to better visualize the agreement and constraints of each set of models. In summer, feral swine used lower slopes regardless of elevation, especially those closer to human-dominated spaces such as along paved and gravel roadways. In winter, feral swine maintained preference for lower slopes but preferred oak-dominated forest areas and selection for human development was less than in summer. Wildlife managers can use these models to better focus feral swine surveillance and management in GRSM. Managers can identify areas of high use by season and plan control activities that are both accessible and highly efficient. The combination and consensus framework presented here can be applied to other systems where species’ habitat selection may result in incongruous results across different levels of selection or seasons of interest.

Natural selection on feralization genes contributed to the invasive spread of wild pigs throughout the United States

“…Selection on olfaction would stimulate foraging behaviour in a similar way as increased neurological development, and perhaps these selective signals are the result of the same environmental selective pressure. Additionally, consistent population control efforts within GRSM since 1959 are likely to have led to antipredator behavioural responses associated with humans, potentially with adaptations in both morphology and physiology (Buderman et al, 2023;Mayer & Brisbin, 1991). The adaptive response to both environmental and anthropogenic selective pressures will lead to increasingly invasive animals due to the direct extension of fitness to the invasiveness of these introduced species.…”

“…The 1912 importation of wild boar to Hooper Bald, Graham County, North Carolina, adjacent to the present-day boundaries of Great Smoky Mountains National Park, was perhaps the most consequential of these introductions (Bratton & Power, 1975;Buderman et al, 2023;Mayer & Brisbin, 1991). When the Hooper Bald hunting preserve failed as a commercial enterprise in 1922, wild boar escaped and began to interbreed with the established feral pig populations, with hybrid populations establishing within the park by the late-1940s (Bratton & Power, 1975;Mayer & Brisbin, 1991;Stegeman, 1938).…”