Not long after white settlers arrived in the eventual United States, bison hunters overexploited the species’ population for meat, hides, and other products.
In addition to hunting, development created a big problem for bison—from railroads to towns and industry. “We have to acknowledge that what we did to the Plains Indians was to take out their food source,” Anderson said.
“Many of my friends and partners say, ‘This [bison] was our family.’ We pushed them onto reservations and destroyed the buffalo. We did a number on the species, so much so that we only had about 1,000 left.”
Many estimates are much lower, with a National Bureau of Economic Research paper suggesting there may have been fewer than 100 bison at one point.
As numbers increase within national parks, conservation projects and organizations have undertaken relocation efforts. But this work requires creativity, as grazing animals of this size need significant space to roam.
Complicating repopulation efforts is the fact that bison can be carriers for brucellosis, a disease that easily passes to livestock and causes abortions and stillbirths in those animals affected. Because of the potential for devastating effects of brucellosis on the agriculture industry, much effort has been put into ensuring bison—particularly animals carrying brucellosis—do not intermingle with cattle.
While the transmission is largely the result of contact with matter leftover from a bison birth, federal officials have claimed males may also carry brucellosis. Methods of testing for brucellosis are hardly foolproof. Testing is tricky and often faulty—between 1996 and 1999, 80% of all bison that field-tested positive for brucellosis and were killed tested negative in subsequent lab tests.
Bison repopulation is also highly political, stymied by a limited natural resource: grass.
Like wild bison, the agriculture industry depends on having massive spaces for growing food and for cattle farming. As bison numbers swelled through mid-20th-century conservation efforts, animals that wandered outside park property lines were met with scars of highways etched across the countryside, housing developments, and mile after mile of paddocks for domesticated grazing animals.
“We can do this together,” Anderson said, adding that restoring bison herds doesn’t necessitate tearing down farm fencing. “Cattle ranching is important out west,” Anderson said. “We can do both.”
One of the most ambitious repopulation efforts to date is The Bison Conservation Transfer Program, launched in 2019 by the NPS to identify bison that don’t have brucellosis and transfer them to new areas as an alternative to sending them to slaughter. Since 2019, 182 bison have been successfully transferred to the Assiniboine and Sioux Tribes of the Fort Peck Indian Reservation.
Tribal lands offer the space these animals desperately need and a culture that has respected bison since the beginning. “The transfer program is all about diverting animals from slaughter,” Anderson said, sending them to Fort Peck for quarantine, then we partner with the Intertribal Buffalo Council. Their mission is to take genetically viable herds and bring them to tribal lands as cultural herds.”