## Facts

- Congress created Voyageurs National Park to preserve natural and wilderness values; snowmobiling continued in the park after its establishment.
- The National Park Service (NPS) adopted restrictions reducing areas open to snowmobiling, citing its conservation mandate and wildlife-impact concerns.
- The U.S. Fish and Wildlife Service (FWS) issued a 1992 biological opinion noting snowmobiling could disrupt gray wolves, with potentially significant negative effects if disruptions were frequent.
- A 1994 FWS supplement stated closures were intended to minimize wolf harassment and ESA “take,” emphasizing that snowmobiles enabled human access to remote wolf habitat.
- Snowmobilers and a snowmobiling association sued federal officials, alleging the restrictions exceeded statutory authority and were arbitrary and capricious under the Administrative Procedure Act (APA), including as inconsistent with FWS’s opinions.
- Conservation organizations intervened as defendants to defend the restrictions.
- The district court granted summary judgment to the snowmobilers and enjoined enforcement of the restrictions.
- The intervenor-defendants appealed.

## Issues

1. Whether intervenor-defendants must demonstrate Article III standing to participate and to maintain an appeal, and whether the conservation organizations satisfied standing.
2. Whether the conservation organizations met the requirements for intervention as of right under Federal Rule of Civil Procedure 24(a).
3. Whether the NPS snowmobiling restrictions were arbitrary, capricious, or contrary to law under the APA in light of the NPS conservation mandate and FWS biological opinions.
4. Whether the district court erred by enjoining enforcement of the restrictions.

## Decision

- The court held intervenors must satisfy Article III standing when they seek relief or maintain an appeal, and it found the conservation organizations had standing based on threatened environmental and use-related injuries from invalidating the restrictions.
- The court held the conservation organizations satisfied Rule 24(a) because they had a protectable interest, the action threatened to impair that interest, and the federal defendants might not adequately represent it.
- The court reversed the district court’s summary judgment for the snowmobilers and vacated the injunction.
- The court upheld the restrictions as a lawful exercise of NPS authority and not arbitrary or capricious under APA review, given reliance on FWS opinions and resource-protection objectives.

## Legal Principles

- Intervenors in federal court must independently satisfy Article III standing when pursuing relief or maintaining an appeal (injury in fact, causation, and redressability).
- Intervention of right under Rule 24(a) requires a timely motion, a direct and legally protectable interest, potential impairment of that interest, and a showing (with a minimal burden) that existing parties may not adequately represent the applicant’s interest.
- Under APA arbitrary-and-capricious review, courts uphold agency regulation of park uses when the agency acts within delegated authority and provides a reasoned explanation grounded in the record and relevant statutory mandates.
- The NPS may restrict recreational activities to conserve park resources and to reduce risks to protected wildlife, including measures informed by expert biological assessments addressing potential ESA “take” through harassment or increased human access.

## Conclusion

The Eighth Circuit concluded that conservation groups could intervene and appeal only if they met Article III standing, found standing satisfied on threatened environmental harm to their members’ interests, approved intervention under Rule 24(a), and upheld NPS snowmobile restrictions as a reasoned and lawful conservation measure, reversing the injunction that had blocked enforcement.


Mausolf v. Babbitt, 125 F.3d 661 (8th Cir. 1997), cert. denied, 524 U.S. 951 (1998)