Bison Reintroduction Restored Kansas Prairie Diversity

A long-term study at the Konza Prairie Biological Station confirmed bison grazing significantly increased native plant richness.

Updated on Oct. 10, 2026 in Botany

A group of bison grazes in a wide, golden-hued tallgrass prairie under a clear morning sky. — A 29-year study at the Konza Prairie Biological Station confirmed that reintroducing bison to Kansas prairies increased native plant species richness by 103 percent. AI Illustration. Upload story photo >

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Data gathered over 29 years showed that reintroducing bison to the Kansas prairie resulted in a 103 percent increase in native plant species richness compared to ungrazed areas. The herd, which grew from 30 to 300 animals, helped maintain plant diversity even through extreme regional drought conditions.

Why it matters

Bison grazing limits the dominance of grasses like big bluestem that outcompete other native species, effectively fostering a more diverse prairie ecosystem. This management practice also helps inhibit tree expansion in unburned areas, preserving the integrity of remaining tallgrass habitats.

The study spanned 29 years across the 8,600-acre Konza Prairie Biological Station, utilizing watersheds managed with bison, cattle, or no grazers. Native plant richness was found to be 97 percent higher in bison-grazed uplands and 38 percent higher in lowlands than in ungrazed controls.

The players

Konza Prairie Biological Station

This 8,600-acre research site located in the Flint Hills of Kansas serves as a primary hub for studying tallgrass prairie ecosystems.

The details

Bison improve biodiversity by consuming dominant grasses, which increases the light and space available for other native species. By repeatedly returning to specific areas, the animals create heterogeneous grazing lawns that keep vegetation short and diverse.

October 1987: Thirty bison were introduced to the Konza Prairie.
2022: Initial study results covering 29 years of data were published.

The Big Picture

This research marks a significant shift in restoration ecology by proving that large herbivore grazing is essential for maintaining tallgrass prairie biodiversity. It challenges the traditional view of passive land management by demonstrating how bison-led disturbances prevent the loss of native plant variety in the face of grass dominance.

The findings suggest that utilizing bison as a natural management tool could be more effective than conventional cattle grazing for ecological restoration. For land managers, this points to a scalable strategy to maintain plant diversity in regions where tallgrass prairie is threatened by encroachment.

The takeaway

Restoring natural grazing behaviors is a proven method for increasing plant diversity in grassland ecosystems. Readers interested in conservation can support local prairie restoration projects that prioritize native species management over simple land maintenance.