Aspen Recovery in Yellowstone Spurred by Wildlife Shifts

In Yellowstone National Park in 2012, bison had increased as elk had decreased, but these trends had not prevented a general aspen recovery beginning in the eastern part of the northern range. Aspen in this photo show the historical gap (saplings and mature trees) in recruitment and also the new young aspen that are now above the reach of elk and bison. (Photo: Luke Painter)
In Yellowstone National Park in 2012, bison had increased as elk had decreased, but these trends had not prevented a general aspen recovery beginning in the eastern part of the northern range. Aspen in this photo show the historical gap (saplings and mature trees) in recruitment and also the new young aspen that are now above the reach of elk and bison. (Photo: Luke Painter)

Wildlife in Yellowstone National Park is undergoing dramatic shifts with consequences that are beginning to return the landscape to conditions not seen in nearly a century. In the park’s northeast section, elk have decreased in number in their historic winter range in the Lamar Valley and are now more numerous outside the park.

Aspen recovery is widespread in much of the northern range, but where elk are still numerous, aspen stands are heavily browsed and stunted.

“Without wolves this would not have happened,” says Luke Painter, an instructor at Oregon State University and lead author of three recent papers that describe the results of his fieldwork monitoring vegetation growth patterns in the park. “Wolves caused a fundamental change, but certainly they are interacting with other factors such as bears, climate, fire and human activity.”

Painter teaches in the Department of Fisheries and Wildlife. He conducted his Ph.D. research with William Ripple in the OSU College of Forestry. (For more on carnivore ecology, see “High Alert,” Terra, spring 2007)

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See an OSU news release about Luke Painter’s research.