A federal judge Tuesday overturned wolf delisting in Wyoming and reinstated federal protections.

U.S. District Judge Amy Berman Jackson invalidated the U.S. Fish and Wildlife Service's 2012 statewide Endangered Species Act delisting of the species and halts the management of wolves by Wyoming.

The 2012 delisting of wolves in Wyoming turned wolf management over to the state, which opened up over 80 percent of its land to unlimited wolf killing. Conservation groups challenged the delisting on grounds that Wyoming law authorized unlimited wolf killing in a “predator” zone that extended throughout most of the state, and provided inadequate protection for wolves even where killing was regulated.

The U.S. Fish and Wildlife Service is currently proposing to remove Endangered Species Act protection for most gray wolves across the United States, a proposal that the groups strongly oppose; a final decision could be made later this year.