A 700-acre fire swept across the north side of the Centennial Valley early in September, leaving the area completely clear of vegetation. A disaster? No. The prescribed fire will actually rejuvenate habitat for four rare plant species.
Four rare plants found in the Centennial Sandhills of southwestern Montana require the habitat associated with sand dunes. Painted milk vetch and pale evening-primrose grow on the crests and slopes of blowout areas. Sand wild rye occurs in sand-deposition areas of the dunes, and fendler cat's-eye is found in sparsely vegetated sites across the sand dunes. All of these species typically decline as perennial vegetation takes over areas of formerly open sand.
Changes in disturbance regimes--primarily fire suppression--have allowed sagebrush and bunchgrasses to overtake much of the Centennial Sandhills. The prescribed burn removed this vegetation, creating more favorable habitat for the special status species. It was the first step in implementing the special management identified in the Dillon Resource Management Plan for the Centennial Sandhills Area of Critical Environmental Concern. Follow up grazing treatments and an anticipated increase in pocket gopher activity are expected to further destabilize the dunes and maintain open sand habitat.
Early in the project, the Dillon FO partnered with The Nature Conservancy (TNC) and the U.S. Fish and Wildlife Service. They conducted an intensive pre-treatment inventory of the four rare plant species and established a baseline study to evaluate the special management proposal. The study will determine if selected treatment methods will promote and maintain early seral conditions of the Centennial Valley’s sandhills ecosystem, thus restoring these diminished habitats. Rangeland Management Specialist Brian Hockett and range technicians Erik Broeder and Matt Stoltenberg assisted in establishing the study. Brian and range technicians Tanya Thrift and Dominique Colberg assisted TNC and the USFWS with the rare plant inventory.
Prescribed fire burn boss George Johnson conducted the pre-burn briefing and led the interagency team of project personnel. The Forest Service, Montana Department of Natural Resources and Conservation, Lima Volunteer Fire Department, and TNC assisted with the burn.
Dillon Field Office staff participating in the burn included George Johnson, Kipper Blotkamp, Brian Thrift, Ryan Martin, Steve Armiger, Bart Howells and Kelly Bockting. Project proponent Brian Hockett was unable to assist due to an injury, but was on site with Wildlife Biologist Katie Benzel to observe and photograph the return of fire to the sandhills.
The Dillon FO will employ a target fire return interval of 20 -30 years coupled with follow-up monitoring and adaptive management to maintain habitat for rare plants in the Centennial Sandhills ACEC.