SREL Reprint #3734

Raccoon densities across four land cover types in the southeastern United States

Jacob E. Hill1, James L. Helton2, David A. Bernasconi2, Wesley C. Dixon2, Matt T. Hamilton3,
Richard B. Chipman4, Amy T. Gilbert5, James C. Beasley2, Guha Dharmarajan6,
and Olin E. Rhodes Jr.7

1Savannah River Ecology Laboratory, University of Georgia, Drawer E, Aiken, SC 29802, USA
2Savannah River Ecology Laboratory, Warnell School of Forestry and Natural Resources,
University of Georgia, Drawer E, Aiken, SC 29802, USA
3Forestry and Natural Resources, Purdue University, Lafayette, IN 47907, USA
4National Rabies Management Program, USDA, APHIS, Wildlife Services, Concord, NH 03301, USA
5National Wildlife Research Center, USDA, APHIS, Wildlife Services, Fort Collins, CO 80521, USA
6School of Interwoven Arts and Sciences, Krea University, Sri City, AP, India
7Savannah River Ecology Laboratory, Odum School of Ecology, University of Georgia,
Drawer E, Aiken, SC 29802, USA

Abstract: Raccoons (Procyon lotor) are the primary reservoir for rabies virus in eastern North America. Management of rabies in raccoons is achieved primarily with the use of oral rabies vaccination (ORV) and effective ORV bait densities are determined in part by the densities of raccoons. Decisions regarding ORV bait densities, however, are limited by an incomplete understanding of raccoon densities across the spectrum of landscapes they occupy. We carried out a markrecapture study of raccoons on the Savannah River Site in South Carolina, USA, from 2017-2019, to develop sex- and landscape-specific raccoon density estimates across 4 rural land cover types in the southeastern United States: bottomland hardwood, riparian forest, isolated wetland, and upland pine (Pinus spp.). We captured 404 unique raccoons 773 times over the 3-year trapping period. Estimated densities were 5.44 ± 0.37 (SE) animals/km2 in bottomland hardwood forest, 2.62 ± 0.32 animals/km2 in riparian forest, 2.19 ± 0.29 animals/km2 in isolated wetlands, and 2.14 ± 0.23 animals/km2 in upland pine. Densities were significantly higher in bottomland hardwood than all other land cover types, whereas densities among the remaining cover types were similar. These patterns are likely the result of landscape fragmentation and configuration, with riparian forests typically embedded in a matrix of less suitable cover types, leading to low densities despite presumably high resource availability. There were higher densities of males than females in every cover type except upland pine, where the sex ratio was balanced. Densities on our site were low compared to other rural areas, which likely results from the lack of human influence in terms of agriculture or development. The financial cost of baiting for ORV distribution may be reduced by considering the comparatively low densities of raccoons in these rural landscapes in the southeastern United States.

Keywords: disease ecology, mark-recapture, oral rabies vaccination, population density, Procyon lotor, rabies virus, resource availability

SREL Reprint #3734

Hill, J. E., J. L. Helton, D. A. Bernasconi, W. C. Dixon, M. T. Hamilton, R. B. Chipman, A. T. Gilbert, J. C. Beasley, G. Dharmarajan, and O. E. Rhodes Jr. 2023. Raccoon densities across four land cover types in the southeastern United States. The Journal of Wildlife Management 87(8): e22480.

This information was provided by the University of Georgia's Savannah River Ecology Laboratory (srel.uga.edu).