The Bureau of Land Management issued a final decision late last week canceling a series of permits that had allowed the conservation nonprofit American Prairie to graze bison on federal land — a move that marks a significant setback for one of the most ambitious rewilding efforts in the American West.

The cancellation came after American Prairie and several allied organizations formally protested a preliminary BLM decision pointing in the same direction. That protest did not change the agency's course. The final ruling strips the nonprofit of the federal grazing leases it had been using to integrate bison into large tracts of public land in north-central Montana, a cornerstone of American Prairie's strategy for assembling a connected wildlife reserve spanning millions of acres.

American Prairie has spent years acquiring private ranch land and pairing it with adjacent public grazing allotments to build what it describes as a landscape-scale habitat corridor. The loss of the BLM permits disrupts that model directly, removing the federal land component that gave the bison herds room to roam beyond American Prairie's private holdings. The organization had faced sustained opposition from Montana's ranching community, which has long argued that free-roaming bison pose disease and competition risks to livestock operations.

The decision lands amid a broader federal posture under the current administration that has signaled less deference to conservation land uses on public lands. American Prairie has not yet publicly announced whether it will pursue further legal or administrative challenges to the ruling.