Predictions of elk, chronic wasting disease dynamics, and socioeconomics under alternative D at the National Elk Refuge in Jackson, Wyoming, and surrounding areas

This chapter presents a description and quantitative evaluation of a collaborative alternative (alternative D) focused on near-term elk population reduction and chronic wasting disease (CWD) monitoring as part of winter elk and bison feedground operations on the National Elk Refuge adjacent to Jackson, Wyoming. Alternative D was developed by the U.S. Fish and Wildlife Service, the lead agency of an Environmental Impact Statement, in consultation with cooperating agencies, including the National Park Service, U.S. Forest Service, and Wyoming Game and Fish Department. In evaluating alternative D, the U.S. Geological Survey considered four distinct scenarios that incorporated whether the agencies were able to meet their elk population reduction goals, and the effects of the U.S. Fish and Wildlife Service stopping feeding after CWD prevalence was measured at or above 7 percent in the Jackson Elk Herd Unit. The modeled scenarios in which the U.S. Fish and Wildlife Service stopped feeding elk at 7 percent CWD prevalence had higher elk population sizes and generally lower CWD prevalence overall at the end of the 20-year simulation period. Further, three of the four alternative D scenarios resulted in fewer elk-use days on sensitive aspen, willow, and cottonwood habitat types compared to continuing to feed; the 7 percent CWD trigger scenario resulted in higher elk-use days on cottonwood and willow habitats compared to continued feeding, but fewer elk-use days on aspen habitats. When considering brucellosis risk, alternative D scenarios without the 7 percent CWD stop feeding trigger had lower risk than the alternative that stopped feeding elk immediately.