Free-Roaming Bison Enhance Yellowstone Ecosystem Nutrients, Biodiversity

Recent research from Washington and Lee University, the National Park Service, and the University of Wyoming highlights the critical ecological role of free-roaming, migratory bison herds in Yellowstone National Park. Tracking the movements and grazing patterns of approximately 5,000 bison over six years, scientists found that these large herds accelerate the nitrogen cycle, enriching soil fertility and increasing the nutritional quality of plants by over 150%, which benefits diverse herbivores. Although their grazing may superficially appear to cause overgrazing, it actually promotes plant growth and creates a patchwork of habitats that enhance biodiversity and ecosystem health. The bison undertake nearly 1,000 miles of migration annually, concentrating in river valleys during spring and summer to feed on nutrient-rich forage, which significantly influences grassland dynamics. This research challenges traditional conservation efforts that focus on small, managed herds by demonstrating the broader landscape-level benefits of large, migratory bison populations to grassland ecosystems and carbon sequestration. Their role as a keystone species is vital to restoring and maintaining the vitality of North American prairie ecosystems.