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According to a new study led by the University of Michigan School for Environment and Sustainability (SEAS), herbivores, omnivores and carnivores in the southwestern U.S. have seen their suitable habitat shrink due to drought. 

Lead author Kirby Mills, who was a postdoctoral researcher at the U-M Institute for Global Change Biology and is now with the Institute for Wildlife Studies in California, says, "The take-home message is that the effects of drought are huge and widespread." 

The researchers used 12 years' worth of data collected by GPS collars worn by mule deer, black bears and cougars—herbivores, omnivores and carnivores, respectively—in Nevada and Utah and found that during severe drought conditions, each species saw at least a 10% reduction in the area of highly selected, or highly suitable, habitat. The study, which was supported by federal funding from NASA, also showed that under extreme drought, the number of new fawn mule deer per doe can decline by more than 30%. 

“What we’re seeing is that drought is having a major impact not just on habitat suitability, but also on fitness, on the survival of wildlife,” says Martin Leclerc, who co-led the study as a postdoctoral researcher at SEAS, and is now an assistant professor at the University of Quebec at Chicoutimi.

Neil Carter, associate professor at SEAS and a senior author of the study, adds, “The study highlights the growing intersection of climate patterns, including drought and wildfire, with landscape planning and management, natural resource management, vegetation dynamics, wildlife behavior and management—all of these things that are often looked at separately. Now we’re finding that they’re enmeshed so tightly and that demands different management strategies moving forward.”

Study: Extreme droughts shrink suitable habitats and reduce fitness for large mammals in the American West (DOI: 10.1038/s43247-026-03530-y)

Read the full press release on the Michigan News website.