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Master of Environmental Science and Management: Master's Group Project

Assessing the Impacts of Feedground Closure on Brucellosis Transmission Risk in Elk to Cattle in the Greater Yellowstone Ecosystem

Group Members: Katherine (Kat) Aristi, Delores Chan, Justine Lang, Samuel Desre

Faculty Advisors: Andrew MacDonald

Client: Property & Environment Research Center (PERC)




The Greater Yellowstone Ecosystem’s (GYE) iconic migratory elk herds rely on private ranchlands for winter-range habitat, but providing that habitat often comes with significant costs for ranchers. Ranchers in the GYE face unique risks associated with brucellosis, a bacterial disease that, when transmitted from elk to cattle, causes cows to abort their fetuses. The disease creates financial challenges for ranchers through cattle quarantine costs and depopulation. These challenges can increase ranchers’ intolerance for wildlife on their land, and can make it difficult to maintain the large, working landscapes that support habitat for elk and other species. In recent years, brucellosis rates in elk have been increasing along with the disease’s geographic extent. In the early-20th century, the federal government established feeding grounds to provide food for elk during harsh winters and to divert elk away from the ranchlands where they would come into contact with cattle. While this decreased the number of brucellosis cases in nearby cattle, the disease has increased tremendously in elk populations within and around the feedgrounds due to high elk density and the commingling of fed and unfed elk. With pressure from environmental groups to close feedgrounds to limit disease spread, there is concern surrounding how ranchlands will be impacted.

The objective of this project is to estimate changes to elk movement and brucellosis transmission, as well as the resulting impacts to stakeholders, in the event of a potential feedground closure in Wyoming. This project will investigate the Jackson Elk Herd and the National Elk Refuge, where an active feeding reduction plan has been initiated by the Wyoming Game and Fish Department and the U.S. Fish and Wildlife Service. We aim to 1) predict changes to elk movement and elk-cattle overlap from feedground closure through a Circuitscape habitat connectivity analysis, 2) use a multispecies disease transmission model to analyze elk-to-elk and elk-to-cattle brucellosis transmission following a potential shift in elk movement, 3) survey Wyoming ranchers to gain a qualitative understanding of stakeholder and rights holder interests, and 4) interview members of the Eastern Shoshone and Northern Arapaho tribes to gain their perspective on feedgrounds and methods of managing brucellosis. From these findings, we will create a financial risk assessment tool, which will be used to evaluate whether the Property and Environment Research Center’s Paradise Valley Brucellosis Compensation fund for ranchers could be successfully applied to areas of Wyoming.

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