Overview

• A peer‑reviewed paper published Aug. 28 in Science reports that grazed patches in Yellowstone regrow with about 150% more crude protein than ungrazed areas.
• Researchers attribute the boost to a feedback loop in which clipping, urine and dung, and plant‑stimulated soil microbes increase plant‑available nitrogen.
• From 2015 to 2021, the team ran experiments at 16 sites using exclosures, soil and plant chemistry, microbiology, satellite imagery and GPS collar data to map effects across the landscape.
• Roaming herds create short, dense, nitrogen‑rich grazing lawns detectable at large scales, with soils maintaining nutrient storage and plant diversity increasing along the corridor.
• Scaled across the migration route, the authors estimate bison generate more than three million kilograms of additional crude protein, supporting calls to restore large, free‑moving migrations.