Oregon’s coastal martens (Martes caurina humboldtensis) are adorable, fierce, and extremely rare. Sadly, new research suggests that if something doesn’t change soon for these secretive, enchanting mammals, they may become extinct in the state within a few decades.
Martens are “mustelids,” small carnivores like weasels and otters. Coastal martens—only about the size of a ten week-old kitten—look like someone fluff-dried a ferret. But don’t let their size and weapons-grade cuteness fool you: because of their high metabolism, martens mean business.
“They need to eat about a quarter of their body weight every day, and that makes them really feisty and really hungry,” Katie Moriarity, wildlife biologist and lead co-author on the study, told Earther.
But their tenacity hasn’t been enough to save them from humans. Coastal martens once ranged all over the lush, oceanside rainforests of Oregon and northern California, but historical fur trapping and habitat loss shrank their numbers dramatically. Most remaining martens are strung along the Oregon-California border, but one small pocket persists in the Oregon Dunes National Recreation Area on the central Oregon Coast, completely disconnected from the southern populations. Now, a team of researchers from Oregon State University and the U.S. Forest Service has determined that these Dunes martens are flirting with extinction.
To figure out the size of the population, the team trapped adult martens, fitted them with radio collars with individualized visual markers, and released them. They used remotely activated cameras that could ID different collars on individuals, and then used statistical models to estimate the number of martens based on how often unique individuals passed by cameras.
The researchers found that the size of marten population was only about 80 individuals, and that the little guys were limited to a surprisingly meager corridor of shore pines and dense shrubs sandwiched between the Dunes’ sandy expanses and busy Highway 101.
“It was assumed that martens were east of the highway and they were getting hit as roadkill as they dispersed westward,” Moriarty said. “We found the opposite, that martens were west of the highway in this narrow, one kilometer band, and they were moving east.”
The team also calculated that the martens are teetering on the edge of extinction, with population collapse likely with only modest levels of human-caused marten deaths. They found one of the Dunes subpopulations had between a 32 and 99 percent chance of extinction within 30 years if only two or three extra martens died annually.
The study provides new evidence that the Oregon coastal martens are exceptionally vulnerable, and deserving of protection, says Tierra Curry, senior scientist at the Center for Biological Diversity.
In 2010, the Center for Biological Diversity petitioned for the coastal marten subspecies to be listed under the Endangered Species Act, but the U.S. Fish and Wildlife Service withdrew consideration in 2015.
“They assumed that the Oregon population was large, healthy, and connected, because there hadn’t been any published science about them,” Curry told Earther.
Since the U.S. District Court for Northern California denied this withdrawal last year, Fish and Wildlife is currently collecting data on marten populations for a listing decision to be made in October. The findings from Moriarty and her colleagues—published in the open-access journal PeerJ—will be an important input, Curry said.
At the state level, the subspecies only benefits from a trapping ban in California, but in Oregon it has zero protection. So, on the heels of the new study, the CBD—along with four other Northwest conservation groups—has petitioned the Oregon Department of Fish and Wildlife to ban trapping of coastal martens.
Long-term survival of Oregon’s coastal martens depends on steps that provide strategic connections between the two major populations via habitat restoration, according to Moriarty.
“On a more individual basis, it would be helpful if we did not kill them,” she added. Motorists simply slowing down on the Dune-adjacent highway would be a start.
Moriarty notes that if these coastal martens are lost, so too is a strange branch of the marten evolutionary tree.
“The Dunes population really is globally unique,” Moriarty said. “There are rarely these kinds of alpine, snow-associated species that live next to the ocean.”