PORTLAND — Environmental groups are suing the Trump administration to protect a rare, weasel-like carnivore found along a narrow strip of coastal forests in Southern Oregon and Northern California.

The Center for Biological Diversity and the Environmental Protection Information Center filed the lawsuit May 4 against Interior Secretary David Bernhardt, the U.S. Fish and Wildlife Service and agency director Aurelia Skipwith for not listing the Humboldt marten under the Endangered Species Act.

Fewer than 400 Humboldt martens exist today in four isolated populations across their historic range, the lawsuit states. The species was once commonly found in the coastal mountains from California’s Sonoma County north to the Columbia River in Oregon, though wildfires and logging have fragmented its habitat.

Humboldt martens are so rare now that they were once presumed extinct in 1994.

“It wasn’t long ago that we thought Humboldt martens were extinct, and the Trump administration’s inexcusable delays mean we could lose them for good this time,” said Quinn Read, Oregon policy director at the Center for Biological Diversity. “The administration has to act now to provide the protection martens desperately need to thrive again in our ancient forests.”

Humboldt martens are classified as a species of concern by the Fish and Wildlife Service. In October 2018, the agency proposed listing the species as threatened — eight years after groups initially petitioned the government for ESA protections.

But since then, the plaintiffs say the administration missed a 2019 deadline to make a final ruling and continues to drag its feet. Tom Wheeler, executive director of the Environmental Protection Information Center in Arcata, Calif., said the Fish and Wildlife Service is “failing at its charge to protect America’s native wildlife.”

“Delay after delay, the Humboldt marten has been put at peril to placate the timber industry,” Wheeler said.

Plaintiffs say the Humboldt marten is at high risk of extinction due to logging of old-growth forests where the mammals live, combined with climate change driving larger wildfires. Martens are also frequently hit by cars and killed by rat poison from marijuana cultivation.

The lawsuit, filed in federal court in Oakland, Calif., states that existing regulations are “wholly inadequate” to protect the Humboldt marten. More than 50% of the species’ habitat is on private industrial timberland, while state and federal lands are not being managed properly to conserve marten habitat.

Lawson Fite, an attorney for the American Forest Resource Council, a timber industry trade group, pushed back against the notion that logging is to blame for the species’ decline. He said new science shows Humboldt marten habitat is compatible with active forest management.

A 2019 study by the U.S. Forest Service, Bureau of Land Management, National Council for Air and Stream Improvement and Weyerhaeuser, a private timberland company, found that Humboldt martens use young forests with dense and interconnected patches of shrubs. That means martens could be comfortable in a broad range of forest environments and management types, Fite said.

“It’s the same playbook these groups have been using for over 15 years,” Fite said. “The fact is we’re not doing enough forest management to preserve these ecosystems and support these species.”

Fite said he is confident the Fish and Wildlife Service will make a scientifically supported decision about whether to list the Humboldt marten.

Martens are related to minks and otters, and grow up to 2 feet long but weigh under 3 pounds and must eat a quarter of their body weight daily to keep up with their high metabolism. In turn, they are eaten by larger mammals and raptors.

In April, environmental groups including the Center for Biological Diversity also announced their intentions to sue the Trump administration seeking protections for another small coastal mammal in Oregon, the red tree vole, which they argue is similarly at risk of going extinct due to habitat fragmentation from logging and fires.