2013 Update: Elk Refuge Manages Invasive Plants


The National Elk Refuge managed by the U.S. Fish and Wildlife Service is located on the edge of Jackson, Wyoming. Established as an elk sanctuary in 1912, it is home to the world’s largest concentration of wintering elk and is one of the most visible wildlife refuges in the United States. 

Visitors can observe the refuge’s thousands of wintering elk from their cars or along walking paths just outside the refuge. One of the most popular methods to view and photograph the elk is by taking horse-drawn sleigh or wagon rides among the elk herd. This winter adventure is available to visitors usually from mid-December through early April.

Excellent photographic opportunities and high visibility makes the Jackson Hole elk herd one of the most popular attractions in the area. “People in Jackson love wildlife and the Refuge is a great place to see a variety of different species,” says Erika Edmiston. Edmiston and Aaron Foster with the Teton County Weed and Pest District, help manage invasive plant species on the wildlife refuge in a unique partnership with the U.S. Fish and Wildlife Service. 

The National Elk Refuge has a rich history of wildlife conservation and habitat management. “We view managing invasive plants such as spotted knapweed (Centaurea stoebe) and Canada thistle (Cirsium arvense) important to protect and preserve wildlife habitat,” says refuge manager Steve Kallin. “I’m pleased with the level of management of invasive plants on the refuge, and consistent and accurate record keeping in our partnership with Teton County Weed and Pest District.” Kallin has been the refuge manager since 2007 when he transferred from the National Bison Range in Moise, Montana. 

The Gros Ventre River corridor forms the northern boundary of the refuge and both the Grand Teton Nation Park and the Bridger-Teton Nation Forest. “Although we have some relatively large infestations of spotted knapweed along the Gros Ventre River, the level of invasive plants in most of the rest of the refuge is relatively low,” says Kallin. “Our goal is to contain the knapweed to the river corridor and protect our upland sites and meadows from further invasion of this weed and newly invading species.” 

Each year, the U.S. Fish and Wildlife Service contracts with the District to hire, train, and supervise summer employees to manage weeds on the refuge. This arrangement allows refuge employees to concentrate on other aspects of wildlife and habitat management and ensures that invasive species have consistent, long-term attention. “The people we hire and supervise through our partnership with the refuge spend the entire summer managing invasive plants to meet refuge goals and objectives,” says Foster. 

The refuge consists of diverse vegetation including grassy meadows and marshes spread across the valley floor, timbered areas bordering the Gros Ventre River, and sagebrush and rock outcroppings along the foothills. This habitat diversity provides a variety of food, water, and shelter that supports the rich mixture of wildlife species found at the refuge. Maintaining and protecting this diversity is an important consideration in managing invasive plants. “We use an integrated approach to manage invasive plants on the refuge,” says Foster. “Volunteers hand pull and chop some of the weeds especially in sensitive areas. The trained summer crew uses backpack and ATV equipment to spot treat newly invading weed species, and we have an extensive release program for biological control agents on spotted knapweed, Canada thistle, and musk thistle (Carduus nutans) to reduce seed production and impact plant vigor. We hope that the insects in combination with our herbicide treatments will improve overall control. Inventory and mapping is also an important component of the integrated program and helps measure effectiveness of various control methods and develop management strategies.” 

The highest priority of the program is early detection and complete containment and control of new invaders such as diffuse knapweed (Centaurea diffusa) and Russian knapweed (Acroptilon repens), and containment of spotted knapweed and Canada thistle. “We have been using Milestone® herbicide to control knapweed and thistle on the refuge and are really pleased with the results,” agree Edmiston and Foster. “Since Milestone can be used in riparian areas and up to the water edge, the herbicide gave us the flexibility to contain spotted knapweed along the river floodplain and completely control new infestations of Russian, diffuse, and spotted knapweed. We have also been able to protect elk feeding grounds and meadows from Canada thistle invasion by using Milestone.” The district is applying Milestone at the label rate of 5 or 7 fl oz/acre and is achieving greater than 90% control on treated sites. “Milestone along with our other management efforts helps us reach our invasive plant management goals on the refuge,” says Foster. 

Each year members of the Jackson Hole Weed Management Association including Teton County Weed and Pest District, the Teton Conservation District, U.S. Forest Service, National Elk Refuge, Bureau of Land Management, the Jackson Hole Land Trust, National Park Service, private applicators and volunteers partner in a three day invasive plant control effort along the Gros Ventre River. There are up to 50 volunteers that work with federal agencies and local landowners to manage invasive plants along about 10 to 15 miles of the Gros Ventre River from the U.S. Forest Service boundary on the north end of the refuge to the Snake River on the southern boundary. 

Since the cooperative spray days began twelve years ago, the group has reductions in knapweed frequency and density in some areas, but it continues to be an area requiring the focused attention. Edmiston believes that use of Milestone® has been a key factor in allowing the refuge to contain knapweed infestations along the river corridor and keep the weed from spreading to upland sites.



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Published October 2013; trademark updated June 2019.