Overpasses and underpasses can lower animal road fatalities by around 90 percent, a huge benefit but only one piece of a complex puzzle.

The more scientists and biologists learn about wildlife migrations in this region the clearer it is how critical the freedom to move across the landscape is to the survival of the American West’s most cherished animal populations. Conservation biologist Dr. Matthew Kaufmann, who works for the U.S. Geological Survey and heads up the vaunted Wyoming Migration Initiative at the University of Wyoming, says the understanding of large mammal movements is only a rarely new phenomenon but is changing the way people think about the importance of landscape connectivity. His outfit has brought it to public awareness by tracking animals and putting them on maps. In Wyoming, it has led to growing public support for protecting migration routes.

Western landscape that had been the same for thousands of years has changed drastically in the last 100. In the middle of ancient migration pathways, towns such Jackson, Wyoming, or Gardiner and Bozeman, Montana, or Denver, Colorado, have ballooned, along with surrounding sprawl, fences, gas and oil development, and ever-increasing vehicle traffic.

Current regulations to protect critical habitat and movement corridors are few and far between in relation to the total landscape, although federal programs, state game and fish agencies, nonprofits and some landowners (think conservation easements on Ted Turner’s Flying D Ranch in Gallatin Gateway, which many smaller landowners also implement) are working together to make sure animals can still move as needed. “It can seem and feel like this place is so wild, but the human footprint is already everywhere. We think these distances are so vast, but it’s not much to these animals,” said Kyle Kissock, communications director of the Jackson Hole Wildlife Foundation, which works in western Wyoming to reduce the impacts of human activity on natural processes.

Around Yellowstone National Park, a globally renowned magnet for wildlife watching, an important piece of information that land managers and biologists still struggle to convey to visitors—and even many area residents—is that wildlife do not and cannot live exclusively within national parks. To survive and thrive requires a much more significant land area, over public and private land, with three components: summer range, winter range and an intact, navigable migration corridor that each herd has historically used.

Consider this: Yellowstone is about 2 million acres; the bulk of the landscape its animals actually use throughout the year in Greater Yellowstone covers at least 23 million acres.

With the core of the habitat—Yellowstone and Grand Teton national parks—under federal protection and until recently most of the rest of it relatively undisturbed, the area boasts some of the most famous and healthy wildlife populations—and a booming wildlife-watching tourism industry—that still exist in the modern world.

“As the concept of wildlife movement and migration [is] more widely recognized, many states realize the need to identify and conserve important habitat and movement areas,” said Elizabeth Fairbank, a road ecologist with the Bozeman-based Center for Large Landscape Conservation, known as CLLC. “Protected areas provide good core habitat for wildlife, but during these big seasonal movements to migrate or dispersal to establish their territory, they come across a multitude of barriers like human development, and linear features like roads, railroads and fences. These can be extremely difficult to overcome and can be a big source of mortality,” Fairbank added. “It is really important to understand where we need to maintain or restore habitat connectivity across linear features.

Biologists in the Intermountain West, along with teams from state game and fish agencies and university researchers, have used radio and GPS collars to prove that animals use the same exact routes over and over. Often, seasonal migrations are well over 100 miles each way, and biologists believe that many of today’s known routes were likely longer in the past but have been altered due to human impacts. Publicity efforts, such as those from WMI and CLLC, have significantly increased public interest in mitigation efforts like wildlife overpasses and underpasses on roads. Their work also highlights needs for habitat protection from development, including increasing housing sprawl and resource extraction, both of which negatively impact migrations and, ultimately, population numbers. Overpasses and underpasses can lower animal road fatalities by around 90 percent, a huge benefit but only one piece of a complex puzzle.

We know from GPS collar data that mule deer and other migratory wildlife have a high fidelity to existing migration routes, and when enough disturbance occurs, they stop migrating.

“Corridors, [the] larger mapped areas which surround known GPS routes, are of critical importance to conserving migrations across the West,” said Josh Metten, Wyoming community coordinator for the Theodore Roosevelt Conservation Partnership. Metten, also a skilled wildlife photographer, knows the conservation science and the popularity of migrations. “Mitigating human disturbance to migration corridors is critical. We know from GPS collar data that mule deer and other migratory wildlife have a high fidelity to existing migration routes, and when enough disturbance occurs, they stop migrating.”

A famed bighorn sheep herd in the Tetons is a good example of what can happen when humans impact a landscape. Development severed the herd’s migration and now an unnaturally small population remnant is trying to survive in the high peaks year round. In order to help recover their numbers and because the sheep’s situation has become so dire, Grand Teton National Park is considering closing more of the terrain the sheep still live on to human recreation.

“Jackson is what happens when we build in a valley that was a migration corridor bottleneck in the past,” said JHWF’s Kissock. “Now, animals have to try to get around the development or they lose the routes that help them survive. It’s the end game.” Similarly, development in Big Sky has encroached on important wildlife corridors and habitat from the Madison Range, and Gallatin Gateway development is on the cusp of blocking travel for elk, mule deer and other animals.

In 2018, the U.S. Department of the Interior released Secretarial Order 3362, which called for states to prioritize documenting and conserving migration routes for elk, mule deer and pronghorn, and would build on biologists’ work to document migrations into the future. “Habitat loss from residential, commercial and energy development, increased wildlife vehicle collisions, fencing barriers, and increasing human recreation are all important factors which can threaten migrations when not addressed properly,” Metten said.

Since that directive, the USGS—in conjunction with state researchers—has released two sets of maps, one outlining 42 migration routes in five states, and a more recent one with 65 new migration routes covering nine states and various tribal lands. While this is far from a complete picture, it’s a key step. This important data will impact conservation planning conducted by a wide array of state and federal stakeholders to reduce barriers to migration caused by fences, roads and other human development actions.

Montana Fish, Wildlife and Parks staff recently made an effort to engage and work with county land-use planning, sometimes at the request of county governments leading these efforts. But there is a lot of work to be done given that much of the land is in private hands, with ownership not obligated to consider wildlife. Gallatin County, for example, does not have countywide zoning, a critical regulatory tool to help wildlife benefit and survive. Nonetheless, as the county works toward developing a growth plan, Montana FWP is assisting conservation nonprofits in providing information on wildlife movement and migration.

Gallatin County provides a sobering example of human activity threatening the wild processes of the land, right under the noses of Bozeman’s human population, many of whom live there because of the wildlife and open spaces. Yet the increasingly busy landscape between Big Sky, Gallatin Gateway and Four Corners is proving a disaster for elk and mule deer. Here, as former agricultural land is quickly subdivided into homes and thousands of people drive through the area each day, elk and mule deer are losing a critical movement corridor—in real time. And moving through the space becomes increasingly dangerous or fatal.

Jackson is what happens when we build in a valley that was a migration corridor bottleneck in the past.

“We feel the squeeze here, and we feel it daily. But newcomers from much more developed places still just see wide-open spaces, and don’t understand how we’re losing critical habitat,” said Holly Pippel, a realtor, conservation supporter and archery hunter in the Gallatin Gateway area. There isn’t much most individuals can do in the face of an agricultural industry making it hard for producers to make a living, leading to them selling off their lands—that will be a federal task—but there is still hope for community action. In addition to depending on new regulations from local and federal agencies, Pippel says that by educating real estate industry professionals on the dos and don’ts of living alongside wildlife, they can in turn educate new residents, owners and renters on the importance of sharing the landscape, and how it can be optimized on each piece of land.

On the bright side, despite the increasing obstacles facing wildlife, there are some new collaborative efforts between nonprofits, state game agencies and academic researchers working to develop awareness and solutions for smarter future development and mitigate human impacts. Public interest in and support for wildlife migration crossings and landscape protection has increased dramatically through their communication and education campaigns. The CLLC and the Western Transportation Institute are working on an important assessment of Highway 191 between Four Corners and West Yellowstone. “This assessment will pull together datasets on wildlife-vehicle conflict, habitat, wildlife movement and identify priority areas to maintain or restore connectivity across a highway that bisects important wildlife habitat between YNP, Custer-Gallatin National Forest, and other areas,” said CLLC’s Fairbank. “Wildlife do not understand these boundaries.”

Those who are actively working on these efforts say progress is being made on preservation and are optimistic that momentum and support will grow as more citizens understand what is at stake.

“Time is of the essence to preserve the land,” Pippel said. “All the groups that should, and need, to talk about it aren’t meeting yet. It is so multifaceted and seems overwhelming. But I still think it can be done.”

Brigid Mander is a skier and a writer based in Jackson Hole, Wyoming. Her work regularly appears in publications ranging from The Ski Journal to The Wall Street Journal.