BILLINGS, Mont. — A federal judge has given U.S. wildlife officials 18 months to decide if wolverines should be protected under the Endangered Species Act, following years of dispute over how much risk climate change and other threats pose to the rare and elusive predators.

The order from U.S. District Judge Donald Molloy comes after environmentalists challenged a 2020 decision under the Trump administration to withhold protections for the animals in the lower 48 states, where no more than 300 of the animals are thought to remain.

Environmentalists argued that wolverines face localized extinction as a result of climate change, habitat fragmentation and low genetic diversity. Warming temperatures are expected to diminish the mountain snowpack that wolverines rely on to dig dens to birth and raise their young.

The Fish and Wildlife Service received a petition to protect wolverines in 2000 and first proposed protections in 2010. It later sought to withdraw that proposal, but was blocked by a federal judge who said the snow-dependent animals were "squarely in the path of climate change."

The 2020 rejection of protections under former President Donald Trump was based on research suggesting the animals' prevalence was expanding, not contracting. Officials at the time predicted enough snow would persist at high elevations for wolverines to den in mountain snowfields each spring despite warming temperatures.

Government attorneys in February told Molloy that wildlife officials wanted to re-evaluate the 2020 decision and asked that it stay in effect while that review was completed. But the judge rejected that request and struck down the decision.

That means a 2013 determination from officials that made wolverines eligible for potential protections is back in effect.

“We are hoping this time is the charm and the Fish and Wildlife Service will follow the courts’ directives to rely on the best available climate science to make the right call to protect wolverines in the lower 48 states,” said Matthew Bishop, an attorney with the Western Environmental Law Center.

Wolverines, also known as “mountain devils,” were wiped out across most of the U.S. by the early 1900s following unregulated trapping and poisoning campaigns.

Wildlife officials have previously estimated that 250 to 300 wolverines survive in remote areas of Montana, Wyoming, Idaho and Washington state. The animals in recent years also have been documented in California, Utah, Colorado and Oregon.

The animals need immense expanses of wildland to survive, with home ranges for adult male wolverines covering as much as 610 square miles (1,580 square kilometers), according to a study in central Idaho.

Fish and Wildlife officials did not immediately respond to Molloy's order.

The Center for Biological Diversity released the following information:

In a victory for wolverines, a Montana District Court decided late Thursday to restore the species as a candidate for protection under the Endangered Species Act. The court agreed with conservation groups that wolverines need additional protections while the U.S. Fish and Wildlife Service reconsiders its 2020 decision not to protect the species as threatened or endangered.

“The wolverine deserves protection under the Endangered Species Act, and this is a step toward ensuring the species does not suffer additional harm before that happens,” said Amanda Galvan, associate attorney with Earthjustice’s Northern Rockies office. “FWS previously ignored key studies that illustrate the threats the wolverine continues to face due to global warming. By reviewing a more complete picture of the species’ circumstances, we are hopeful that the agency will identify the need for increased protections.”

“Wolverines desperately needed this good news, but it’s time to follow the science and finally grant them the full life-saving protections of the Endangered Species Act,” said Collette Adkins, carnivore conservation director at the Center for Biological Diversity. “With wolverines facing dire threats like climate change and habitat loss, the Fish and Wildlife Service can’t waste any more time.”

As a candidate species, the wolverine will be afforded certain protections under the Endangered Species Act. Federal agencies must confer with the Service on any action they take that might harm wolverines. The health and safety of wolverines and their habitat must also be considered in planning decisions that could destroy or degrade their critical habitat.

“The wolverine is a test case. How do we protect snow-dependent species in the era of climate change?” said Joseph Vaile from the conservation group KS Wild in southern Oregon. “One thing is certain. Without federal protections, this majestic species will be another climate change casualty.”

“This decision is a victory for wolverines, paving the way for desperately needed protections,” said Jonathan Proctor, Rockies and Plains program director with Defenders of Wildlife. “With Endangered Species Act protections, the wolverine might finally have a fighting chance at survival.”

“The Fish and Wildlife Service has been dragging its feet for far too long,” said Brad Smith, North Idaho director for the Idaho Conservation League. “It’s time to protect wolverines and develop a recovery plan that prevents these amazing animals from going extinct.”

“Wolverines are subject to considerable threats from a warming climate, shrinking snowpack, and increasingly fragmented habitat,” said Dave Werntz, science and conservation director at Conservation Northwest. “Endangered Species Act protections help focus resources and actions to ensure wolverines have a future in the west’s wild landscapes.”

“Today’s decision gives us hope that wolverines could once again roam Colorado’s high country,” said Megan Mueller, conservation biologist at Rocky Mountain Wild. “Wolverines need the protection of the Endangered Species Act to return to Colorado, where high elevation, snowy habitat could help these elusive and fascinating animals survive in the face of climate change.”

Conservation groups filed suit in December 2020 to challenge the Service’s decision to withhold Endangered Species Act protections from wolverines in the lower 48 states, where no more than 300 wolverines remain. The snow-dependent wolverine, which is the largest terrestrial member of the weasel family, is threatened with massive habitat losses due to global warming.

In response to the lawsuit, the Service agreed to reexamine its 2020 decision but did not commit to setting it aside. The court’s decision Thursday requires the agency to return the wolverine to the protected status it held before the agency made its flawed decision.

Earthjustice represents a broad coalition of conservation groups in the lawsuit — the Center for Biological Diversity, Conservation Northwest, Defenders of Wildlife, Friends of the Clearwater, Idaho Conservation League, Jackson Hole Conservation Alliance, Klamath-Siskiyou Wildlands Center, Greater Yellowstone Coalition, Sierra Club and Rocky Mountain Wild.