There are few places in the United States where you can drive down the highway at 70 mph and literally crash into a bison – the national mammal of the United States. Highway 191 in Montana, just northwest of Yellowstone, is one of those places.
Last month, 13 bison from Yellowstone National Park were killed trying to cross Highway 191 when a semi-trailer truck collided with the animals. Although the death toll was high, it wasn’t the worst on this stretch of road. This distinction dates back to 2009, when 16 bison were killed over a weekend.
“This sad incident underscores the urgency and importance of finding migratory routes for wildlife to reach critical habitats while ensuring people are able to travel safely throughout the region,” said Shana Drimall, chief wildlife conservation officer for the Greater Yellowstone Alliance.
The recent deaths prompted the nonprofit Buffalo Field Campaign, a bison advocacy group, to start a petition urging federal officials to push for measures to reduce bison vehicle collisions in the area. So far, about 2,100 signatures have been collected, according to Tom Woodbury, director of communications at the BFC.
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The group is calling for lower speed limits on a 10-mile stretch of highway, as well as a wildlife crossing near the Madison River, a historic wildlife migration corridor.
Bison move across the highway on a stretch between West Yellowstone and Duck Creek. They cross to get to Horse Butte, on the west side of 191. In the spring, Horse Butte provides a historic area for bison calving. In the winter, it is an optional feeding yard when deep snow floods the garden.
The BFC’s call to action follows Congress’ approval of $350 million for Wildlife Crossing as part of the Infrastructure Investment and Jobs Act. The Federal Highway Administration could seek its first application for such proposals soon.
The request also aligns with a recent push to improve wildlife migration corridors across the West.
“If you want to provide connectivity for the bison, it is, or it has been made into a complex issue in our society,” Marcel Hujser, senior research ecologist at Montana State University’s Western Transportation Institute, said in an email.
Unlike other wild animals, however, when bison leave Yellowstone National Park and migrate to Montana, they are not welcomed by some state and Department of Livestock officials. While other wildlife is allowed to roam, including elk with brucellosis that can cause pregnant cattle to miscarry, bison are largely confined within Yellowstone because they carry the same disease. There are some exceptions that allow bison to enter federal lands beyond the north and west entrances to the park, including near where the collision occurred in December.
The Yellowstone bison is also unique in that it is being reviewed by the US Fish and Wildlife Service for consideration as a “distinguished population” deserving of protection under the Endangered Species Act.
The petitioners who requested the review “provided reliable information to point to potential threats to (bison) from reductions in their range due to loss of migratory routes, intolerance of bison outside Yellowstone National Park, and habitat loss,” the agency said in its report, citing findings last summer.
A recent study by the Utah Museum of Natural History, published in the journal Scientific Reports, finds that creating wildlife corridors between national parks like Yellowstone and Glacier can dramatically increase the chance that isolated wildlife populations will survive in the face of climate change and habitat development. .
Huijser has studied wildlife crossings around the world, including working along Highway 191 as it passes through Yellowstone in the far north. He said the wildlife crossing would be valuable along Highway 191 as the Buffalo Field campaign asked for action.
A 2012 study by two WTI researchers, Ashleigh Dupree and Isabella DiMambro, came to the conclusion that some kind of mitigation would be guaranteed along the highway. The researchers found that an animal detection system, which alerts drivers to wildlife on the road, would be a cost-effective mitigation measure.
“It is important to note that the ADS system does not remove animals from the highway, but rather alerts motorists of their presence,” the researchers wrote.
Seasonal warning signs and the enforcement of a 55 mph minimum speed limit were other considerations for the researchers.
“These mitigation measures have had very limited effectiveness in previous studies,” Dupree and Dembrow write.
The cost of the bridge with the fence to divert the animals into the structure was considered unfeasible due to the high cost. However, the researchers lacked the data to calculate these costs because there are no other collision studies involving bison. Instead, they were asked to speculate based on the costs of the moose car collision.
The researchers also noted that a cost-benefit analysis should not be the only factor in determining whether or not a top lane is beneficial.
An underpass along the Madison River Highway Bridge would be too wet for bison to use, the researchers were told. Instead, the animals usually cross the road north of the river, walking along the drier ridgeline.
“Wildlife crossing structures – bridges and underpasses – with sufficient lengths of fences are very effective, and have been shown to not only reduce vehicular collisions between wildlife, but also to provide safe movement of wildlife/habitat connectivity across the road,” Rob Ament, Road Ecology Director program at the Western Transportation Institute, he wrote in an email.
“Low speeds and low speeds at night have not been shown to be very effective in reducing vehicular collisions between animals,” he added.
In Wyoming, where several highway underpasses and overpasses were recently installed, along with fencing to transport animals to the crossing, road vehicle collisions have been reduced by 80-90% in three areas, according to WTI.
Previous insurance studies have found that Montans have a 1 in 57 chance of colliding with a deer, compared to 1 in 80 in Wyoming.
In the United States, it is estimated that there are between one and two million wildlife vehicle collisions with large animals, primarily ungulates, and cost more than $8 billion annually, according to a WTI report.
Further north on Highway 191, where Duck Creek flows under the road, the researchers found fewer bison vehicle collisions, but more deer, elk and moose collisions with vehicles. The problem with the bridge or underpass at that location is its proximity to Highway 287, which provides access to Hebgen Lake.
The researchers again recommended an animal detection system with fencing and places for animals to jump off the road as the most cost-effective means of alerting motorists of wildlife crossing near Duck Creek.
The high rate of crossing of other wildlife near Duck Creek confirms that Highway 191 bisects a migration route commonly used by elk, deer, and even grizzly bears to travel between Yellowstone and the nearby Madison Range.
“In general, ecological connectivity within the larger Yellowstone ecosystem, including via highways, is needed and appropriate from a biological conservation point of view,” Huijser writes.
Over the past decade, the Buffalo Field campaign has also complicated bison collision analysis along Highway 191 by actively working to warn motorists when bison are on the road, Woodbury noted.
“Our efforts make him less likely to get bridge financing,” he said.
In the spring, when bison migrate to calves, BFC volunteers warn motorists along the highway to keep an eye on the bison. During the winter, they rely on others to alert them to the bison so they can warn drivers, because the road gets narrower as snow accumulates along the Borrow Hole.
Woodbury said his group recently joined Montanans for Safe Wildlife Passage to add their voice to a host of other conservation groups working with Montana Fish, Wildlife and Parks and the Montana Department of Transportation.
“We are involved in this process primarily to defend the value of the buffalo out of the park,” he said.
The Greater Yellowstone Coalition also participates in the coalition. GYC has been working to “raise wildlife considerations” as the Montana Department of Transportation has proposed projects, said Brock Schifrin, the group’s wildlife conservation coordinator.
She noted that MDT is already developing plans to replace it Cougar Creek Bridge7 miles northwest of Yellowstone, in a manner that would “take into account wildlife concerns, and in particular bison vehicle collisions.”
GYC’s Dreimal said the group “supports wildlife shelter measures along US 191 and as part of the Cougar Creek Bridge replacement project.”
MDT officials did not respond to requests for information on Highway 191 in time for this story.
With federal funds available, other groups are pressing for wildlife crossing projects at the mouth of Gallatin Canyon on the other end of Highway 191 due to an increase in elk vehicle collisions, in Paradise Valley and near Missoula. Meanwhile, the BFC is urging federal officials to advocate on behalf of the bison.
“The Madison River is the main migration corridor for the central bison herd in Yellowstone to the calving grounds of the Horseboat,” Woodbury said.
This decline in herd numbers is partly what prompted the US Fish and Wildlife Service to review threats to animals under the Endangered Species Act.
“We have to help this herd recover.”