American bison once numbered in the millions, perhaps between 25 and 60 million by some estimates, and were possibly the most numerous large land animal on earth. However, by the late 1880s, they had been hunted to near-extinction throughout
North America. The Yellowstone bison herd was the last free-ranging bison herd in the United States, being the only place where bison were not extirpated. The Yellowstone bison herd is descended from a remnant population of 23 individual bison that survived the mass-slaughter of the 19th century in the Pelican Valley of Yellowstone Park. To assist in the species' revival, in 1896 the United States government added one bull and seven cows from the
Lincoln Park Zoo to the Yellowstone herd. In 1902, a captive herd of 21
Goodnight plains bison was introduced to the park and then moved to the
Lamar Valley and managed as livestock until the 1960s, when a policy of natural regulation was adopted by the park. Only a few bull bison traversed outside Yellowstone National Park prior to 1975, but as bison numbers increased, groups of bison began migrating across the northern and western boundaries of Yellowstone to expand their winter range and pioneer new territory in the Greater Yellowstone Ecosystem. Over the years, the
National Park Service and states bordering the park have implemented various plans to limit exposure of bison to cattle herds outside the park. Efforts have included hunting, hazing bison back into the park, vaccinations, and exporting excess bison to other locations.
Brucellosis is known to exist in the
elk and bison of the Yellowstone ecosystem. State and federal officials face pressure to prevent the spread of the disease, as ranchers worry it could lead to Montana losing its brucellosis-free status. Montana state law does not allow the transport of wild bison exposed to brucellosis except to meat processing and research facilities within the state. By 2016, state and federal officials were rounding up most bison that wandered outside the park every winter, with up to 900 being removed annually. Some were captured and shipped to slaughter facilities, while others were shot by hunters or state agents. Montana managed a state-licensed bison hunt outside the boundaries of the park from 1985 to 1991, but the number of bison migrating outside of the park continued to increase, prompting the National Park Service to develop management plans to control bison near the park boundaries. Intense controversy grew between environmentalists, livestock interests and agency managers. During harsh winters, bison found convenient grazing on several
U.S. Forest Service allotments that were used for cattle in the summer. In 1995, the Montana state legislature designated Yellowstone bison as a species in need of disease management and the state sued the National Park Service for allowing bison to leave the park. After five years of litigation and mediation, the state of Montana and the federal government developed the Interagency Bison Management Plan (IBMP) to guide the management of bison in and around Yellowstone.
Interagency Bison Management Plan The Interagency Bison Management Plan is a cooperative, multi-agency effort that guides the management of bison and brucellosis in and around Yellowstone National Park. The National Park Service, USDA-Forest Service, USDA-Animal & Plant Health Inspection Service, Montana Department of Livestock and Montana Fish Wildlife & Parks adopted the first plan in 2000. Since 2009, the
Confederated Salish and Kootenai Tribes, the Inter Tribal Buffalo Council, and the
Nez Perce Tribe have participated in the planning. The plan is aimed at: • Maintaining a wild, free-ranging bison population; • Reducing the risk of brucellosis transmission from bison to cattle; • Managing bison that leave Yellowstone National Park and enter the state of Montana; • Maintaining Montana's brucellosis-free status for domestic livestock. Management is focused on keeping the Yellowstone bison population at levels that limit migration outside the park. Methods include slaughter and exporting excess bison to other suitable habitats. In the decades since the IBMP was created, the bison population has ranged between 2,400 and 5,500 animals. There have been no cases of bison transmitting brucellosis directly to cattle, in part due to efforts by federal and state agencies to maintain separation between these animals. The state of Montana now allows bison to occupy some habitat adjacent to the park that was previously off-limits, including year-round in some areas, which is a major conservation advancement. However, the lack of tolerance for wild bison in most areas outside Yellowstone continues to limit restoration. Large parts of their historic winter ranges are no longer available due to human development and states only allowing limited numbers of bison in areas near the park. Initially, most of the bison were sent to slaughter with the meat being distributed to participating
Native American tribes, along with limited hunting. The IBMP plan includes allowing bison to enter the Bison Conservation Transfer Program as space allows.
Hunting While hunting is not allowed within the park, it mainly occurs within an area outside the northern boundary near
Gardiner as designated by the state. Removal numbers are decided each year, with tribal and state hunters being allowed a quota. Montana issues hunting permits and 4 tribes have long standing treaty rights to hunt Yellowstone bison. By 2016, the population had grown to approximately 5,500 animals. In the winters of 2016/2017 and 2019/2020 the park service
reduced the herd size by at least 900 animals. A 2022/2023 hunt culled over 1,100 individuals, leading to criticism over the necessity of such a hunt.
Bison Conservation Transfer Program Yellowstone bison are exceptional because they form the nation's largest bison population on public land. Developing a quarantine program that complied with Montana state law was critical to getting brucellosis-free animals from Yellowstone to conservation herds. Quarantine was talked about in the 1990s during the negotiations on the IBMP. During 2005–2012, Animal and Plant Health Inspection Service (APHIS) developed and verified procedures for identifying Yellowstone bison that don't have brucellosis. Quarantine worked as bison that repeatedly tested negative for the disease stayed that way and could be certified as brucellosis-free. The initial plan was for the bison that completed the pilot program to be moved to public or tribal lands but the state was not ready to approve any of the proposed locations in 2010. After Montana Governor
Brian Schweitzer invited
Ted Turner to submit an offer to care for the animals, Turner Enterprises Inc. reached an agreement in February with the Montana Department of Fish, Wildlife and Parks Commission to care for the bison and their offspring for five years on a of the Flying D ranch. Tribal and state officials signed an agreement in 2012 allowing the transfer of bison that were also in the 2005-2012 pilot study. Sixty-three animals from the Yellowstone quarantine corrals were transferred in March to the
Assiniboine and Sioux Tribes who started a conservation herd at their Fort Peck Reservation. A legal challenge blocked further transfers until the state supreme court ruled in June 2013 that the Montana law in question did not apply to tribal lands. The state was asked to move the bison by November 2014 that been regularly tested for brucellosis while being quarantined on behalf of the Montana Fish, Wildlife and Parks at the Bozeman-area ranch owned by Ted Turner. In October, the commission decided to move the animals to the Fort Peck Reservation as the commission recognized that the Fort Peck Fish and Game Department had done a good job of managing the bison including the disease testing. In November, 139 of the Yellowstone bison at the Flying D ranch joined the conservation herd at the Fort Peck Reservation. Certification involves a multi-year process including holding animals in fenced pastures near the park boundary. The quarantine program approved by IBMP has three phases. First, bison are trapped at the Stephens Creek Bison Capture Facility where they are sorted by age and sex into different enclosed pens. A blood sample is also taken and they are tested for brucellosis with only about 30% of animals qualifying for the program. Bison that test negative can go into quarantine. Next, testing protocols continue until the animals can be certified as disease free. Finally, assurance testing involves another year in isolation with two more tests before the quarantine period is finished. The first two phases currently must be done in a supervised area in the vicinity of the park. APHIS and the Montana Department of Livestock established the final structural specifications and biosecurity requirements for quarantine facilities in June 2017. Two pens in a Yellowstone bison trap were made into quarantine corrals with two layers of fencing in 2017. The two facilities are located at Stephens Creek and
Corwin Springs. Quarantine facilities are managed by APHIS who coordinates the transfers with the state of Montana and the Fort Peck tribes. The final phase of assurance testing can be performed at the
Fort Peck Indian Reservation in northeastern Montana. During the revision of the Bison Management at Yellowstone National Park by the National Park Service, it was expected that the use of the bison conservation transfer program to restore bison to Tribal lands would be expand. ==Genetics==