The new plan, the first update released in about 25 years, allows for a slightly larger bison population in the park, between 3,500 and 6,000 animals, as well as more space for them to roam and increased capacity for people to hunt them.
The State of Montana is suing, alleging a lack of cooperation in planning. The conservation group Alliance for the Wild Rockies is also suing.
Mike Garrity, executive director of the alliance said, the plan's Environmental Impact Statement does not follow the most current science.
"We want the Park Service to do a new EIS that is honest," Garrity emphasized. "Then we could have an intelligent discussion and debate about wild bison."
The plan aims to prevent the spread of brucellosis, a bacterial disease that can lower birth rates in cattle, which is a priority for local ranchers. A report from the National Academies of Sciences, Engineering and Medicine showed all recent cases of the disease in cattle were transmitted by wild elk, not bison.
The Park Service plan received some praise for incorporating the Bison Conservation Transfer Program, which relocates some healthy animals to tribal nations across the U.S. but Garrity argued the plan needs work around hunting protocols, which lead to intensive hunting in one gulch which acts as a migration bottleneck.
"Hunters are just lining up and it's become a shooting gallery," Garrity explained. "It's not a 'fair chase' hunt."
Both the Alliance lawsuit and the state's will be heard in Montana's Billings Division U.S. District Court.
