(CN) — The U.S. Forest Service’s plan to swap rainbow trout with Yellowstone cutthroat trout in Montana’s Absaroka-Beartooth Wilderness violates federal wilderness laws, conservationists argued before Magistrate Judge Kathleen L. DeSoto on Wednesday morning.
“The case is not just about Buffalo Creek Watershed in the Absaroka Beartooth Wilderness,” said Daniel Brister, an attorney with plaintiffs Wilderness Watch. “It’s about preserving the integrity of the entire 111-million-acre wilderness preservation system.”
The Forest Service’s approved project, Brister argued, would poison 46 miles of streams and over 30 lakes over the course of five years to eradicate the rainbow trout population that was introduced to the area decades prior — and replace that species with Yellowstone cutthroat trout, in violation of the Wilderness Act.
Congress implemented that act in 1964 to protect wilderness or areas “untrammeled by man” and preserve natural conditions.
Wilderness Watch argues that the agency’s plan “epitomizes human ecological domination on a landscape scale” by introducing, eradicating and reintroducing fish to a naturally fishless area. The conservation group filed suit in November 2023. U.S. District Judge Dana Christensen referred the case to DeSoto.
Since 1978, the Wilderness Act has applied to the Absaroka-Beartooth Wilderness and its connective watersheds spanning between the Custer, Gallatin and Shoshone National Forests.
The Forest Service argues that the date the protections were applied to the over one million acres of remote, mountainous wilderness is a critical component of the case: Though the area may have been historically fishless, due to a waterfall preventing fish from traveling upstream, there were fish stocked in the waterways in 1978.
“Congress made a determination at that time, that even though there were stocked fish in this area, it still met the definition for designation as a wilderness area, that it had the requirements of the Wilderness Act imposed on those areas,” Justice Department attorney Shaun Pettigrew argued on behalf of the Forest Service.
The greatest threat to Yellowstone cutthroat trout is genetic introgression with introduced trout species, Pettigrew said.
The Forest Service cites Buffalo Creek as the main source of nonnative rainbow trout that are spreading downstream and hybridizing with native Yellowstone cutthroat trout — a species already hindered by predatory lake trout introduced to Yellowstone Lake illegally in the 1980s.
Pettigrew argued that the Forest Service’s plan will enhance the Yellowstone cutthroat trout population and preserve the wilderness area by providing dedicated areas for genetically pure species.
Wilderness Watch says the agency didn’t properly consider less intrusive alternative plans. Brister pointed to the agency’s minimum requirement decision guide, which scored alternative options numerically. The plan the Forest Service chose scored lowest among all the plans in terms of impact on wilderness character, Brister said.
DeSoto pointed out that multiple alternative plans had high negative scores — except for the alternative plan of taking no action in the area.
“If you fall under one of the exceptions, there are going to be at least short-term … negative consequences, when you run through the requirements of the Wilderness Act, yet they still may be appropriate under the Wilderness Act,” the judge said.
Brister argued that it came back to the amount of intrusion on an area, and focusing on the core principles of the act.
“A proposed action in a wilderness area must be justified on the basis of wilderness necessity, not project necessity,” he said.
The Forest Service meanwhile said the scores merely indicate transient effects, and must be weighed against long-term benefits to the area, which in this case would be the removal of a nonnative species.
“Even if it would result in some degradation of the wilderness character of the area, the balancing of the conservation purposes with the Yellowstone cutthroat trout is a separate justification for approval of this project under the Wilderness Act,” Pettigrew said.
Brister turned back to the scores, arguing that every plan’s negative score in impact on wilderness character illustrates a lack of specific consideration.
“It shows that this external project was brought in and grafted onto this wilderness area,” Brister said. “It’s not to benefit this wilderness.”
DeSoto didn’t indicate when she would issue recommendations.