National Parks Traveler Podcast · Kurt Repanshek

National Parks Traveler Podcast | Bison Benefits

·47 min·4 clips

Bison grazing boosts soil nitrogen, improving forage quality and ecosystem health in Yellowstone.

This episode of the National Parks Traveler Podcast features host Kurt Repencheck interviewing Professor Bill Hamilton, a biology professor from Washington and Lee University and co-author of a new study on bison. They examine the ecological role of bison and the potential for expanding their populations on public lands. The conversation centers on an eight-year research project in Yellowstone National Park, from 2015 to 2022, which compared grazed and ungrazed grasslands using movable exclosures. The study found that large, free-moving bison herds improve grassland ecosystems without depleting soil organic matter or above-ground plant productivity. Bison grazing was shown to stimulate microbial activity in the soil, enhancing nitrogen recycling and forage quality in areas called "grazing lawns." Professor Hamilton contrasts this with cattle overgrazing, which can reduce soil organic matter, though he clarifies his research did not find evidence of bison overgrazing in Yellowstone. The discussion explores the historical context, noting bison numbers plummeted from tens of millions to between 400,000 and 500,000 today, with most in commercial herds. Potential expansion sites mentioned include Thunder Basin National Grassland in Wyoming and Buffalo Gap National Grassland in South Dakota. The interview references the American Prairie Reserve in Montana, which aims for a herd of 10,000 bison, and tribal initiatives like the Intertribal Buffalo Council. A surprising insight is that bison movement in Yellowstone covers about 1,000 miles annually but within a constrained 50-mile migratory range, unlike historic migrations. Hamilton suggests bison grazing could contribute to carbon sequestration in grasslands, though this was not a focus of the published paper. The tone is conversational and educational, blending scientific explanation with personal anecdotes from the researcher. Listeners interested in wildlife ecology, grassland restoration, or national park management would find this episode compelling. Those seeking fast-paced narrative or debate might find the detailed scientific methodology less engaging.

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