Ecologist Rolf Peterson remembers driving remote stretches of road in Michigan's Upper Peninsula and seeing areas strewn with deer carcasses. That changed after gray wolves arrived in the region from Canada and Minnesota. "When wolves moved in during the 1990s and 2000s, the deer-vehicle collisions went way down," said the Michigan Tech researcher. Recently, the AP reports, another team of scientists has gathered data about road collisions and wolf movements in Wisconsin to quantify how the arrival of wolves there affected the frequency of deer-auto collisions. It created what scientists call "a landscape of fear," they found. "In a pretty short period of time, once wolves colonize a county, deer-vehicle collisions go down about 24%," said Dominic Parker, a natural resources economist at the University of Wisconsin-Madison and co-author of their study published Monday in the journal Proceedings of the National Academy of Sciences.
Both thinning of the deer population by wolves and behavior changes in fearful deer are factors in the drop-off, Parker said. "When you have a major predator around, it impacts how the prey behave," he said. "Wolves use linear features of a landscape as travel corridors, like 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 regions of the US, gray wolves have dispersed naturally; the population in the lower 48 states now totals about 5,500. The study said the presence of wolves, maligned by ranchers whose livestock suffers predation, also can save money by indirectly reducing deer-vehicle collisions. In 2008, a study for the US Department of Transportation estimated those crashes cost more than $8 billion annually. "If anything, the researchers underestimated the value of the deer-vehicle crashes," Peterson said, pointing out the cost of medical bills and even human fatalities.
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