Mausolf v. Babbitt

Jeffrey Mausolf and other snowmobiling enthusiasts (snowmobilers) (plaintiffs) engaged in snowmobiling at Voyageurs National Park (park). The National Park Service (park service) (defendant) oversaw the park and had regulatory objectives including protection of natural resources pursuant to its statutory authority granted by the United States Congress. In 1991, the park service proposed a wilderness plan that reduced the park areas available for snowmobiling. In 1992, the Fish and Wildlife Service (Fish and Wildlife) provided the park service with a biological opinion regarding the effects of snowmobiling on animal populations in the park, including the gray wolf population. Fish and Wildlife concluded that snowmobiling disrupted wolves while hunting prey and could lead to significant negative effects if frequent disruptions occurred although isolated disruptions were insignificant. Later in 1992, the park service closed many of the park’s areas to snowmobiling. In 1994, Fish and Wildlife supplemented its previous biological opinion. The supplemented biological opinion stated that the closures to snowmobiling were intended to minimize the harassment and taking of gray wolves and to reduce adverse contact between humans and wolves. Fish and Wildlife reasoned that snowmobiles provided access to remote wolf-habitat areas although the snowmobiles themselves did not adversely impact the gray wolf. Several incidents of harassment and harm to gray wolves constituting takings had been reported within the several years prior to the 1994 supplement to the biological opinion, and in each incident, access to the gray wolf habitat was gained by a motorized vehicle, such as a snowmobile. The snowmobilers sued the park service, claiming that its closures of areas to snowmobiling was arbitrary and capricious because Fish and Wildlife’s biological opinion did not support such closures. The Voyageurs Region Park Association (association) intervened in the action. The district court granted summary judgment in favor of the snowmobilers and enjoined the enforcement of the snowmobiling restrictions. The association appealed.