Michigan Department of Natural Resources August 2019 trail camera image of a gray wolf in the Upper Peninsula.

WASHINGTON (AP) – Environmentalist Rolf Peterson remembers driving isolated stretches of road in Michigan’s Upper Peninsula and seeing areas strewn with deer carcasses. But that changed after the arrival of gray wolves to the region from Canada and Minnesota.

“When wolves moved in in the 1990s and 2000s, collisions between deer and vehicles declined dramatically,” said the Michigan Tech researcher.

Recently, another team of scientists gathered data on road crashes and wolf movements in Wisconsin to quantify how the arrival of wolves there was affecting the frequency of deer-car collisions. They found that it created what scientists call “A landscape of fear.”

“In a fairly short period of time, once wolves colonize a county, vehicle collisions with deer decrease by about 24%”, said Dominic Parker, a natural resources economist at the University of Wisconsin, Madison and co-author of their new study published Monday in the journal Proceedings of the National Academy of Sciences.

Thinning of the deer population by wolves and behavioral changes in fearful deer are factors in the decline, Parker said.

“When you have a major predator nearby, it has an impact on the behavior of the prey”, he said. “Wolves use the linear features of a landscape as travel corridors, such as roads, pipelines and stream beds. Deer learn this and can adapt by staying away.

Gray wolves, among the first species protected under the Endangered Species Act in 1973, were reintroduced to Yellowstone National Park in 1995. But in other parts of the United States, gray wolves have dispersed naturally. ; the population of the lower 48 states now stands at about 5,500.

The new study said the presence of wolves, decried by ranchers whose livestock suffer from predation, can also save money by indirectly reducing collisions between deer and vehicles. In 2008, a US Department of Transportation study estimated that these accidents cost more than $ 8 billion per year.

“Most of the economic studies on wolves have been negative, focusing on livestock losses,” said Dave Mech, a senior scientist for the US Geological Survey in Minnesota, who was not involved in the new study and praised it. “But wolves are also reshaping ecosystems in so many ways, even though that’s hard to measure economically.”

Some studies have looked at the tourism income generated by wolf watchers in Yellowstone, but that money doesn’t go directly to communities living alongside wolves, said Jennifer Raynor, a natural resources economist at Wesleyan University and co-author. of the new study.

“We wanted to look at other ways that wolves have impacted the region,” Raynor said. “These auto crashes do or don’t happen in rural areas, just like damage to livestock.”

Michigan Tech’s Peterson, who was not involved in the research, said: “If anything, the researchers underestimated the value of collisions between deer and vehicles. The deeper dimension of these collision costs can include significant medical bills and, sometimes, human deaths. “

A 2016 study found that cougars reduced the number of vehicle crashes with deer by about 22% in parts of the eastern United States.

The study of the wolf “Adds to the growing awareness that scientists should consider both the costs and benefits of having large carnivores in the landscape,” said Adrian Treves, a University of Wisconsin conservation biologist not involved in the study.