Bison are having a moment across the American West. From the University of Colorado’s debut of its new Ralphie mascot, to wild bison crossing state lines from Utah into Colorado, to new legislation making the species fully protected within the state, public attention has returned to an animal once central to North American ecosystems. Behind the visibility, however, a quieter scientific effort is reshaping what large-scale bison restoration can realistically achieve.
At the center of that effort is research led by scientists at Colorado State University, where reproductive and veterinary science is removing one of the longest-standing obstacles to bison conservation: brucellosis. The bacterial disease, historically associated with bison descended from Yellowstone National Park herds, has restricted where bison could be relocated due to concerns about livestock transmission. While actual transmission risk is low, regulatory limits have constrained restoration efforts for decades.
That barrier is now changing. CSU researchers successfully developed brucellosis-free bison by selectively managing reproductive material from Yellowstone-descended animals. The result is a herd that retains its wild genetic lineage while meeting health standards required for relocation beyond tightly controlled zones. These disease-free bison are already being transferred to other states to support restoration projects and strengthen overall population resilience.
The work was led in part by Jennifer Barfield, an associate professor in CSU’s College of Veterinary Medicine and Biomedical Sciences. Her interest in bison reproduction began through collaboration with land managers from the City of Fort Collins, Larimer County, and the U.S. Department of Agriculture, who sought to restore bison north of the city using animals directly descended from Yellowstone stock. That partnership evolved into a broader conservation application with national reach.
Ecologically, the implications extend well beyond population numbers. Bison function as a keystone grassland species. Their grazing patterns, movement, and soil disturbance promote plant diversity, improve nutrient cycling, and create habitat structure that supports insects, birds, and small mammals. Removing disease constraints allows bison to resume these roles across restored prairie landscapes rather than remaining isolated within a handful of protected areas.
Recent climate modeling suggests that much of the Northern Great Plains will face warmer temperatures, increased drought, and greater weather variability, trends that are expected to undermine the long-term ecological and economic viability of conventional agricultural systems. A study published in Frontiers in Ecology and Evolution found that these changes disproportionately affect communities whose livelihoods depend directly on marginal prairie lands, particularly Native American nations whose reservations often encompass large but environmentally constrained landscapes. In this context, bison restoration offers a functional alternative. As ecosystem engineers, bison shape plant communities, improve soil structure, and enhance landscape resilience to climate stress. Indigenous-led bison restoration initiatives are demonstrating how species recovery can support both ecological function and long-term land stewardship capacity, aligning conservation outcomes with the realities of a changing climate.
Conservation Takeaway
Large-scale restoration requires removing real constraints, not symbolism. Eliminating brucellosis allows bison to move beyond preserves and function as working ecological drivers, restoring prairies through grazing and natural disturbance instead of mechanical intervention.