PINEDALE, Wyoming—Driving through an ocean of sagebrush on the Pinedale Anticline in June, Wyoming Game and Fish wildlife biologist supervisor Brandon Scurlock was struck by the sparseness of the population on the landscape.
In past summers, tawny pronghorn littered the hillsides, grazing and bounding freely, he said. But last summer, clusters of fur and bones dotted the range where the dead animals decomposed after a record-setting winter in the western part of the state.
“We got a call to come out here one day last February, and we picked up 20 carcasses,” he said, pointing at a gas well pad through the window of his Ford pickup. “Got a call the next day, 20 more. The day after that, we went back and picked up 20 more.”
Wyoming Game and Fish surveys show an estimated 50 percent of the Sublette pronghorn herd—Wyoming’s largest, with more than 40,000 animals— died between November 2022 and May 2023, Scurlock said. Starvation, heavy snowpack and pneumonia outbreaks thinned out the herd. Of its famed Grand Teton subherd, Scurlock estimated 90 percent—more than 600 members—perished.
Scurlock was devastated by the losses, but said snowmelt will offer abundant forage for surviving Sublette pronghorn that use migratory corridors to return to the area each winter to repopulate the herd. However, growing development near these corridors means it’s not guaranteed the herd will recover to its pre-winter population.
Big-game animals across the West are known for long-distance migratory corridors, the pathways they have learned for millenia to reach seasonal feeding grounds. Wildlife biologists say these corridors are critical for the survival of robust game herds in the region, which help them survive shocks like severe weather and disease. Yet Wyoming and other western states have stalled in establishing strong legal protections for these corridors on their public lands, where they are developing high-value energy and mineral projects and providing grazing ranges for ranchers.
This led conservationists and outdoor recreation advocates to seek federal solutions to potential blockages of Wyoming’s wildlife corridors.
Groups like Backcountry Hunters and Anglers, the Wyoming Outdoor Council and the Theodore Roosevelt Conservation Partnership see potential in the “public lands” rule proposed by the Bureau of Land Management, which would allow industry to offset a project’s environmental damages by paying to restore big-game habitat elsewhere on BLM land.
However, Western state leaders, energy trade organizations and ranchers oppose the rule, arguing the BLM overstepped its authority by elevating conservation as a vaguely-defined use of public lands without Congressional approval, or regional input. They are urging the agency to withdraw it.
“I think this rule is so nebulous, and it raises so many different questions, that I don’t think it should have been put out as a proposed rule,” said Western Energy Alliance President Kathleen Sgamma in a June Congressional hearing.
Advocates for the rule note that, while it might have shortcomings, it is a key first step in an important and ongoing journey.
“We’re trying to scuttle this before it even gets off the ground,” said John Gale, vice-president of policy and government relations at outdoor recreation group Backcountry Hunters and Anglers. “Let’s do the best we can for now, assume positive intent, and be at the table.”
Renee Seidler was awestruck the first time she saw a group of Sublette pronghorn migrating north for the summer.
“They were almost on the horizon, and they were all just walking,” said Seidler, the executive director of the Jackson Hole Wildlife Foundation. “Like they have a purpose. These are feats of strength.”
Migrations are nothing extraordinary to the region’s ungulates—hooved mammals like mule deer, pronghorn and elk—they’re a fact of life. The U.S. Geological Survey has mapped roughly 150 of these species’ migratory corridors in the West stretching across 11 states, with 35 in Wyoming.
Each corridor consists of summer and winter ranges, the migratory pathway itself and stopover ranges where animals refuel during their journey. High-altitude summer ranges provide the most nutritious forage, while low-altitude winter ranges have less snowpack, so animals can get to food during the colder months.
In the Greater Yellowstone Ecosystem, one Wyoming mule deer travels more than 240 miles each way to get to its seasonal ranges, while other big-game animals in Wyoming have shorter routes and some don’t migrate at all. These differing behaviors encourage resilience to population shocks like extreme weather, starvation and disease, Scurlock said.
As these big game species move through their corridors, they recycle nitrogen into the soil through urination and serve as food for apex predators like wolves, cougars and grizzly bears, helping the ecosystem function. They also fuel the outdoor recreation industries that comprise large parts of Western economies, accounting for roughly $154 billion in economic output across 11 western states in 2022, and more than $2 billion in Wyoming.
Tribal nations have been benefiting from the corridors for even longer.
The Shoshone and Ute are among the 26 tribes that have tracked long-distance migrations in the Mountain West for centuries, said Eastern Shoshone tribal historic preservation officer Joshua Mann. There are archeological sites along the corridors with cultural significance to those who made Wyoming their home long before it was a state, he added.
Migration corridors are the “veins and arteries” of the Greater Yellowstone Ecosystem and the larger Mountain West, according to Pat Hnilicka, a Wyoming-based U.S Fish and Wildlife Service fish and wildlife biologist.
“When people think of Wyoming, you think of bison in Yellowstone, you think of big-game hunting, deer and elk,” Hnilicka said. “If you don’t have those migration pathways for these animals, it would radically change things.”
But protecting Wyoming’s wildlife migration corridors has been challenging.
Cutting up Corridors
Jon Beckmann, a wildlife supervisor for the Kansas Department of Wildlife and Parks, said big game animals have passed these corridors from one generation to the next over thousands of years. They are highly loyal to their learned pathways, but will abandon corridors where development encroaches too heavily.
An estimated 75 percent of migratory corridors for elk, bison and pronghorn in the Greater Yellowstone Ecosystem have already been lost to agricultural, energy and housing projects. Meanwhile, state lands and federal lands managed by the Bureau of Land Management—which collectively make up roughly 35 percent of Wyoming’s land—feature growing amounts of development.
The BLM has been mandated to manage its lands and lease them for multiple uses and “sustained yield” since the Federal Land Policy Management Act was signed in 1976.
Historically, the state and BLM have leased their lands to high-value mineral and energy projects designed to maximize revenue for the state’s public schools and state services, which are funded in part by mineral royalties. The industries added over $12 billion to Wyoming’s GDP in 2021, and more than $2.7 billion in public education and infrastructure funds alone. The state and BLM have also issued just over 2,000 livestock grazing permits on public lands in the state, accounting for more than $200 million in economic benefits.
But the lands generating this revenue often overlap with key winter ranges for big-game animals, and state leaders say it is a challenge to balance these competing interests.
“What often is not talked about is how preventing development affects human beings,” said Chuck Gray, Wyoming’s Republican secretary of state, in a recent Office of State Lands and Investments hearing on migration corridors. “When our industry is not able to reach its full potential, what is the human cost of that?”
Big-game species can tolerate some energy and mineral development near their migratory corridors, said Meghan Riley, a public lands advocate at the Wyoming Outdoor Council. But, scientists don’t know exactly how much development causes these corridors to break down.
Economic interests and industry indifference toward migratory corridors have led the state to approve energy and mineral projects that cut off these corridors, bearing adverse impacts across Wyoming, Beckmann said. And renewable energy projects can have as big an impact as fossil fuel development. In 2019, a Sweetwater County solar development cut off a Sublette pronghorn migration corridor, forcing 1,000 of the animals to migrate along the highway and endanger drivers.
“There’s always something new on the horizon in terms of technology or development that wildlife is facing,” he said. “We have to think about some places that we’re just going to say, ‘enough is enough. We’re gonna leave this for a while.’”
Path of the Pronghorn
Wyoming is home to the lone federally-recognized migration corridor, known as the Path of the Pronghorn. And in Joel Berger’s eyes, the corridor is about much more than the pronghorn themselves.
“It’s about a concept. It’s about a dream,” said Berger, the Barbara Cox Anthony University Chair of Wildlife Conservation at Colorado State University. “We need a success story where the public is behind it, and we have legislation to protect it.”
Every year, 400 to 800 Sublette pronghorn in Grand Teton National Park leave in the late autumn, moving into the Gros Ventre Range and Bridger-Teton National Forest as snow starts to fall.
The herd then moves into a mix of private and BLM land near Pinedale, cutting through the Normally Pressured Lance and Jonah natural gas fields—two of the largest in the country—before reaching the Upper Green River Valley. The herd overwinters there, before making the return trip to Grand Teton in the spring.
The one-way trip covers up to 165 miles of mountains, forests, streams and grasslands. After spending years tracking the herd’s movements with GPS radio collars, Berger and former Grand Teton National Park senior wildlife biologist Steve Cain published a paper in 2006 documenting the migration.
Cain and Berger started an awareness campaign that helped the Path of the Pronghorn gain national recognition in 2008. This campaign led to a memorandum of understanding between the National Park Service and the Forest Service to actively discourage and mitigate development on public lands close to the upper two-thirds of the corridor.
Yet, the BLM’s Wyoming office and the State of Wyoming, which oversee the land in which the southernmost third of the corridor resides, never participated in those discussions. Instead, they have deferred to Wyoming Game and Fish, saying that they will not recognize the path’s presence on their lands without the state doing so first. Since then, the federal agency has issued several mineral leases obstructing the corridor.
Wyoming has a state-level migration corridor designation process, established in 2016, which would force the state’s land use planners to account for recognized migration corridors in evaluating the environmental impacts of development. However, Wyoming Governor Mark Gordon redesigned it through an executive order in 2020, after energy and agricultural industry representatives expressed concerns over property rights.
After the state recognized three mule deer herds, corridor designations stalled in 2020, when the Sublette pronghorn herd was next in line for a migration corridor designation. Wildlife advocates like Seidler say “politics are at play” in designating these corridors, yet Angi Bruce, deputy director of Wyoming Game and Fish, said this slowdown is due to advancements in migration modeling research, which necessitated more study.
“I know people were in a hurry for us [to designate corridors], but we have been leaders in the nation in recognizing these important movements,” she said. “We’re not going to jeopardize our reputation by using a method that we knew was not going to actually show what was happening on the ground.”
Regardless of the modeling advancements, the slow pace of designating migratory corridors like the Path of the Pronghorn on public lands in Wyoming is leading local wildlife advocates to look to the federal government for a solution.
“There needs to be a kind of happy medium where the federal government supplies the roadmap, so that states and local communities can raise it up at the grassroots level,” Beckmann said.
BLM “Conservation Leases” Draw Attention
Riley, of the Wyoming Outdoor Council, knows that when an agency proposes a rule, it’s just the first step in changing policy. Still, she said the Bureau of Land Management’s Conservation and Landscape Health Rule is “a big deal.”
The rule was proposed in March, and would clarify conservation as a valid use of public lands under the BLM’s multiple-use mandate, issued in the Federal Land Policy and Management Act of 1976.
The agency, the largest federal land administrator in the country, oversees 58 million acres in the West. Previously, it viewed conservation as a guiding principle of land use, but not equivalent to uses like grazing, energy development or mining.
The rule would also create a “conservation leasing” program, in which parties may rent parcels of BLM land for conservation and restoration projects for 10-year periods. These leases could be purchased by industry groups seeking to mitigate damages from other development, or by local advocacy groups and nonprofits looking to perform “restoration activities” on degraded lands.
Local BLM offices would be responsible for determining whether leasing a given piece of land for conservation would be appropriate. The rule would not affect existing leases on BLM lands, and, in most cases, projects would not shut down public access.
“It will keep natural resource values from falling by the wayside,” Riley said. The rule could help perform weed removal on corridors and stopover range to encourage habitat connectivity if clearer language about linking natural territories is provided in the final rule, she added.
Gale, of Backcountry Hunters and Anglers, said the public lands restoration credit market component of conservation leases is an unprecedented opportunity for industry, conservationists and the outdoor recreation economy to partner on high-quality public lands restoration work.
He said that projects will be required to go through National Environmental Protection Act approval processes, ensuring careful planning, and could include building highway overpasses and removing cheatgrass—a highly flammable invasive species—on degraded migratory corridors.
Currently, the BLM does not have the financial resources needed to restore land health at a massive scale, said Madeleine West, director of the Center for Public Lands with the Theodore Roosevelt Conservation Partnership.
She supports the rule because the mitigation component of the conservation rule will help the agency incentivize industry to engage in quality restoration work, she said, a “win-win-win” for the crucial big game winter range that the agency oversees.
“It really does take everybody working to try to improve our degraded lands out here in the West for the betterment of everybody,” West said.
“Threatening the Western Way of Life”
Those who oppose the rule say the BLM has no intention of including “everybody” in managing Western lands.
Politicians like U.S. Rep. John Curtis, a Republican from Utah, and Governor Mark Gordon of Wyoming argue the Bureau of Land Management is meddling with the region’s economic drivers without accepting input from local stakeholders. They also say it overstepped Congressional oversight by adding conservation as a use to the Federal Land Policy and Management Act without their consultation, which could jeopardize access for existing public lands users.
“The BLM is threatening to open its multiple-use mandate and the Western way of life,” Curtis said in a June Congressional hearing on the rule.
“This rule has the potential to undermine how public lands are managed, and threatens the essential economies of my state, and our country,” Gordon said in the same hearing.
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Conservation-related activities won’t generate economic development on these lands at the same rate as fossil fuel projects, said Colin McKee, Petroleum Association of Wyoming regulatory affairs director, in a comment on the rule. He requested they withdraw the rule, and said he expects to see it challenged in court.
The Association of Clean Power, which represents the views of the Wyoming renewable energy industry, expressed appreciation for the landscape health goals of the rule. But the group expressed “significant concerns” that conservation, as defined in the rule, would slow the renewable energy transition.
Jim Magagna, executive vice president of the Wyoming Stock Growers Association, said ranchers in western Wyoming are dependent on public land grazing leases to make ends meet, due to the “checkerboard” layout of public and private parcels of land in the area.
He added that Wyoming ranchers are making efforts to embrace conservation and protect migratory corridors, and expressed concern those efforts would fall off if conservation leasing were put into effect.
Even some environmentalists have trepidation about the rule. Seidler said the rule must come with reform in local BLM offices to ensure it is utilized properly. She also expressed worries that conservation leases and mitigation banking could become tools used to authorize significant environmental degradation by industry, allowing development on critical seasonal ranges that mitigation activities would rarely compensate for.
She urged the BLM and Congress to instead develop a national migratory corridor designation process, as Rep. Don Beyer of Virginia and Sen. Tom Udall of New Mexico, both Democrats, have proposed in the past.
Riley, of the Wyoming Outdoor Council, says she understands the skepticism around the language of the rule, yet she is reserving judgment until she sees the final result in 2024. In the meantime, she was preparing the State of Wyoming’s long-awaited draft migratory designation for the Sublette pronghorn herd, which was released in November.
“I think anything that upholds landscape intactness and health in turn is going to keep Wyoming and the Rocky Mountain West the exemplary place that it’s been for wildlife, which brings people here from all over the country,” Riley said.