Rare California red fox added to endangered species list in ongoing extinction crisis

In the midst of a climate crisis in California, another species has been added to the endangered species list: the Sierra Nevada red fox, a subspecies of red foxes found only in California.

With an estimated population of about 18 to 39, California’s distinct red fox population is now in critical danger of extinction, joining a list that includes the California condor and salt-marsh harvest mouse.

This is part of a trend across the globe, where the rate of flora and fauna extinction is accelerating, according to a United Nations report published in 2019. Native plants and animals have declined by about 20% in the last 120 years. One million animals are on the brink of extinction and could disappear within decades, according to the report’s projections.

“Most scientists agree we’re in an extinction crisis,” said Noah Greenwald, the endangered species director at the Center for Biological Diversity, a nonprofit dedicated to protecting endangered species and their habitat.

Currently, the Endangered Species Act protects over 1,600 plant and animal species in the United States. The California Endangered Species Act designates over 300 plant and animal species as rare, threatened or endangered.

The Tecopa pupfish and Santa Barbara song sparrow are among the animals that have already disappeared from California, a fate wildlife biologists and managers hope to avoid for one population of the red fox.

The Sierra Nevada distinct population segment of the Sierra Nevada red fox is now listed as endangered under the federal Endangered Species Act, according to a United States Fish and Wildlife Service announcement on Aug. 2. The listing decision was published in the Federal Register on Aug. 3, but it will not go into effect until Thursday.

Sierra Nevada red foxes have been declining since the 1930’s, but according to the forest service, the reasons why remain largely unknown. The foxes’ remote subalpine habitat, small population and tendencies to avoid humans make them difficult for scientists to study.

“There just in general hasn’t been a lot of formal study of red foxes,” said Cate Quinn, a postdoctoral researcher at UC Davis.

In 1980, the Sierra Nevada red fox was listed as threatened in California, but sightings of these elusive foxes continue to be rare. In 2015, a fox was spotted in Yosemite National Park for the first time in nearly 100 years. After over a decade of attempts, researchers finally captured a fox in 2018 near Lassen Volcanic National Park.

Historically, the fox subspecies ranged from the Oregon-Washington border to the southern end of the Sierra Nevada mountains, but today the Sierra Nevada red fox lives in California’s Sierra Nevada region and the southern Cascade Range of Oregon and California.

Characterized by heavy snow, short growing seasons and a mixture of open and forested areas, the fox is likely well adapted to its native subalpine habitat, Quinn said. Above the treeline, these foxes live in solitary across the landscape.

Despite its name, the Sierra Nevada red fox can be red, black or a greyish brown “cross phase.” Black-backed ears, white-tipped tails and their smaller size (a little lengthier and taller than a housecat) distinguish them from other foxes, Quinn said.

Researchers said the greatest threat to these foxes is their small population size. With so few left, the foxes have a high risk of being wiped out by catastrophic events, like wildfire and drought. With a smaller population, there is a greater chance of inbreeding that could jeopardize their future.

The endangered species listing will help researchers acquire more funding and continue conservation efforts, said Josh Hull, the supervisor of the listing and recovery division at the Sacramento Fish and Wildlife Office for the United States Fish and Wildlife Service.

“It’s really a tiny number for a population of mammals,” Hull said.

Why is the fox population endangered?

While there is good evidence that there are few Sierra Nevada red foxes left, the reasons for their small population remain unclear.

According to the service’s official announcement, wildfire and drought, competition with coyotes, decreases in prey levels and widespread breeding with non-native fox subspecies (known as hybridization) are among the reasons for the fox population’s high vulnerability.

Some researchers, including Hull, said climate change is not specifically to blame for the populations’ small size. Instead, the foxes likely never recovered from when they were trapped and poisoned in the early 1900’s, Hull said.

Even though hunting and trapping these foxes was banned in California in 1974, it’s likely the subspecies never recovered. As a result of the small population, the foxes became inbred and produced fewer young. In turn, the current population is dangerously small.

Today, Greenwald and others at the Center for Biological Diversity believe climate change is one of the most serious threats for the fox subspecies. The fox is “a harbinger for climate change,” he said.

Climate change also may make foxes more open to predators. Snow in the subalpine is melting earlier and predators of the foxes, such as coyotes, can now get higher up into mountains where the foxes live. Also with less snow, there will also be fewer places for the foxes to hide, Greenwald said.

Quinn said that while many endangered species are listed due to habitat loss, it’s likely not the case for these foxes. Based on her research, there’s plenty of habitat for red foxes.

Economic interests such as logging are less of a threat in the subalpine, which means these human industries are less likely to have a major impact on the foxes, Quinn said. However, it also means less attention is paid to them.

“It’s not so simple as just ‘they don’t have habitat,’ because the subalpine is one of the most protected eco-types that there is in Western North America,” Quinn said.

Greenwald said that although habitat loss is not the primary threat — “there’s a mix of threats” — foxes do face habitat destruction.

Critical habitat, areas essential to the subspecies’ conservation, was not designated for the Sierra Nevada red fox population. Greenwald worries a trail or ski area might be built in the foxes’ habitat, further threatening the species, he said.

“We think critical habitat would have been a good idea, even if habitat destruction isn’t the primary threat,” Greenwald said.

Which foxes should be protected?

Two distinct population segments of the Sierra Nevada red fox are recognized by the United States Fish and Wildlife Service: the Southern Cascade population, found in the Cascades to Mt. Hood in Oregon, and the Sierra Nevada population, ranging from Yosemite National Park to Kings Canyon National Park. The Cascade population segment is not protected under the Endangered Species Act.

Just one population of mammals can be listed, instead of a whole species, and therefore only the Sierra Nevada red fox made the list. Hull said there are more foxes in the Cascades, which are genetically different from the Sierra Nevada population, and do not face the same threats as those in the Sierra Nevada population.

The Center for Biological Diversity would like to see the entire subspecies protected. The center initially petitioned for the subspecies’ listing in 2011 and when the process was delayed, they filed lawsuits in 2013 and 2019 “to force the Service to decide on the animal’s protection,” according to the Center for Biological Diversity.

“To just protect that one population … from our perspective doesn’t make sense because the whole species faces threats and is small in size,” Greenwald said.

But with so little known about the subspecies, it’s difficult to understand threats they face and the extent to which they should be protected. Quinn said this is likely why only one population was listed.

Researchers, such as Quinn, are continuing to monitor the red fox through electronic tracking, monitoring camera footage and collecting scat. Quinn extracts DNA from scat to understand relatedness between the animals, which is important with the threat of inbreeding in small populations.

“There are genetic side effects when a population gets really inbred and then that can cause them to limit their growth and ability to rebound,” Quinn said.

What is the future for red foxes in the Sierra?

Across the world, climate change, logging, farming, mining and other human-caused activities create the damage necessary for these high extinction rates, the United Nations report found.

“We’re losing species at a rate 1000 times the level that historically would have occurred were it not for us because of all the habitat we’re destroying and now altering the climate itself,” Greenwald said.

As more species are lost, the health and diversity of ecosystems are weakened and in turn, human livelihoods are endangered, Greenwald said. Increasing numbers of declining and disappearing species “should be a warning sign” to act — these animals and plants depend on the same resources as humans, such as space to live, drinking water and clean air, he said.

“The fact that they’re going extinct reflects the fact that we’re depleting all those things at our own peril,” Greenwald said.

Even though researchers are still learning about the Sierra Nevada red fox, Quinn remains hopeful for their future.

“The upside is every piece of information that we learned is valuable and improves the picture,” Quinn said. “It’s exciting to see how quickly it’s moving now that there is more attention on the subspecies.”

Researchers know that red foxes are one of the few predators in the Western subalpine and therefore an integral part of the ecosystem, said Ben Sacks, a UC Davis professor who runs the Mammalian Ecology and Conservation Unit where Quinn works. Collaborative conservation efforts hope to bring this subspecies back from the brink of extinction.

“Anytime you have an organism that is distinctive and you lose it, you’re not going to get it back,” Sacks said. “Evolution proceeds much more slowly than extinction, so once you lose something it’s gone. We’re not going to get anything to take its place in the foreseeable future.”

Agencies have formed a conservation advisory team, including federal conservation agencies, the Department of Defense, state wildlife agencies, universities and the private sector, and are working on management plans to ensure long-term conservation of the fox’s habitat.

“With the work that those agencies are doing,” Hull said, “I think we’re going to see some improvement in the numbers of these animals in the next several years.”

While the Sierra Nevada red fox is just one Californian subspecies, it’s a microcosm of the extinction and climate change battles fought everywhere. As the world increasingly loses species “the more and more lonely our world becomes,” Greenwald said.

“If we lose this fox, it’ll personally be because we didn’t take seriously the impacts we have on the planet and correct our actions,” Greenwald said. “We’re changing our world in a profound and fundamental way that will have serious negative consequences.”