YELLOWSTONE NATIONAL PARK — On Dec. 31, the state of Montana filed a 51-page lawsuit against the National Park Service (NPS) demanding the bison population in Yellowstone National Park (YNP) be reduced from an estimated 5,400 animals to 3,000.
The lawsuit names the state of Montana, its governor, the Montana Department of Livestock and the Montana Department of Fish, Wildlife and Parks as plaintiffs and Deb Haaland in her official capacity as Secretary of the U.S. Department of the Interior and Charles F. Sams III in his official capacity as Director of the NPS as defendants.
The NPS confirms that archeological evidence indicates bison have lived in the Greater Yellowstone Area (GYA) for more than 10,000 years. But according to the lawsuit, the population size of the YNP bison herd has been a “source of constant strife” for Montana due to the switch from active herd management to “natural regulation” in the 1960s.
Montana alleges that the less restrictive management approach allowed YNP’s bison population to boom, and brucellosis-infected bison began spilling into Montana and threatening the livestock industry.
In 2000, YNP adopted an Interagency Bison Management Plan (IBMP) that identified a population target for the herd of 3,000 bison. On July 24, 2024, the YNP adopted a new Bison Management Plan (BMP) plan with updates from the original 2000 that primarily include managing bison within a population range of about 3,500 and 6,000 after calving, and averaging about 5,000 bison.
When the population reaches a threshold of 5,200 bison, the 2024 management plan mandates that the NPS will begin to manage for a declining bison population by relying primarily on Tribal and state harvests. This was also not in the original IBMP.
“The NPS is implementing this decision because of new scientific information about bison and brucellosis transmission and changed circumstances that include fewer cattle near the park, brucellosis regulations and Tribal hunting,” YNP wrote in its 2024 press release.
One piece of new scientific information driving the BMP is a 2020 National Academies of Sciences, Engineering and Medicine conclusion that infected elk had transmitted brucellosis to livestock in the GYA at least 27 times since 1998 with no transmissions attributed to bison.
Additionally, the new BMP differs from the IBMP by removing protocol to vaccinate bison against brucellosis. The NPS writes that it “based this conclusion on the lack of an easily distributed and highly effective vaccine and limitations of current diagnostic and vaccine delivery technologies. Remote vaccination by darting or bio-bullet has unknown yet potentially negative behavioral impacts on bison, and in turn, on visitor experiences such as watching wild animals.”
However, Montana is alleging that the new BMP was developed without “meaningful consultation and collaboration” with the state, which is listed as the first cooperating agency on the BMP final decision. Montana wants both vaccinations as part of management protocol and a reduction in herd size, hinging on the use of state “tolerance zones” aimed at reducing the chances of disease transmission by separating bison and cattle by fencing or distance.
Montana is arguing that the Environmental Impact Statement (EIS) used to develop the 2024 BMP presented bison management options all premised on the continued existence and use of tolerance zones. According to the lawsuit, Montana’s tolerance zones were expanded in 2011 and 2015, but the expansions were only to increase space and provide better opportunity for remote vaccination.
The state asserts that the tolerance zone expansions do not accommodate bison population expansion beyond the IBMP set size of 3,000 animals.
“Montana told YNP this was specious, given each alternative’s commitment to
increased population and reduced disease management conflicted with two key
purposes for Montana’s expanded tolerance (i.e. conflict management and remote
vaccination),” the lawsuit states.
Montana is aiming to have the BMP vacated by court order.
The Greater Yellowstone Coalition (GYC) published a blog post on Jan. 7, written by Executive Director Scott Christensen, arguing that Montana’s desired reduction of bison could “substantially decrease the genetic diversity of the herd and threaten the population’s long-term viability,” in addition to eliminating most Tribal and public hunting opportunities.
The NPS Record of Decision also points out that, contrary to what the state asserts, Montana was offered the opportunity by the NPS leadership to draft its own alternative management option to be considered in the planning process in 2022, and the state declined to do so.
