The Stephens' Kangaroo Rat Recovery

 _{All photos were taken on Naval Weapons Station Seal Beach Detachment Fallbrook, CA, by Joel Sartore, Joel Sartore Photography, with assistance from the dedicated Department of the Navy, Environmental staff.} 

The best thing that could have happened to the endangered Stephens’ Kangaroo Rat (Dipodomys stephensi) just might be living near military explosives storage bunkers.

The kangaroo-hopping rodent is endemic to roughly 1,100 square miles in Southern California including areas of western Riverside County and northern San Diego County. In 1988, it was listed as endangered on the federal Endangered Species List as its population plummeted due to habitat loss from human development.

One of the animal’s last remaining strongholds is the 9,000-acre Naval Weapons Station Seal Beach Detachment Fallbrook, at Fallbrook, Calif., where decades of carefully planned and persistent management and protection efforts have paid off. In February 2022, the Stephens’ Kangaroo Rat was downlisted to threatened, due to a reduction of threats since listing and the implementation of conservation actions.

“They need a lot of open space and relatively low levels of development,” said Christy Wolf, biologist at the Fallbrook detachment. “The good news is (military installations) also tend to need a lot of open space and have relatively low levels of development.”

But there is a lot to balance, she said. Natural resources management must support and integrate with the military’s mission. There can be no net loss to the mission of the base.

Fallbrook’s mission is maintenance, storage, and transportation of ordnance. Storage bunkers of ordnance need expansive buffers and few roads to travel among them. So about 90% of the base is undeveloped natural landscape.

But even with relatively low human activity, the area needs resource management in order to maintain the native species that live there.

“In this day and age, you can’t manage land with a hands-off approach,” Wolf said. “For starters, it’s going to be taken over by invasives.”

Fallbrook provides habitat for seven federally listed species, including the Stephens’ Kangaroo Rat, the star of Fallbrook’s most recent success story.

This nocturnal little creature measures just over 11 inches long – about 7 inches of that being tail. Its role in the ecosystem is small but mighty. It digs complex burrows, which helps to aerate the soil, and it eats lots of seeds, which disperses native plants across the landscape in ways that wind or water can’t. And for predators, Stephens’ Kangaroo Rats are good eating. Rodents create a prey base.

Besides being important to the ecosystem, this animal has some unique adaptations, Wolf said. For example, it doesn’t need to drink water, as other mammals do. It extracts moisture from the plants and seeds it eats, and its behavior and physiology help prevent water loss. Its kidneys are designed to concentrate this moisture so that every bit is extracted to keep the animal hydrated.

They can leap several feet into the air from a standing position and kick like a kangaroo. A quick internet search reveals videos of one of these diminutive creatures leaping away from a rattlesnake with seemingly no effort – giving the snake a swift kick in the snout as it escapes.

They are adapted to thrive in semi-arid to arid conditions along gently sloping, open, native grasslands and bare ground. Oddly, providing bare ground is one of the biggest challenges, Wolf said.

Situated between Los Angeles and San Diego, Fallbrook is surrounded on three sides by Camp Pendleton, which is run by the U.S. Marine Corps. But the region still has a fair amount of urban interface. Invasive plant seeds blow in from beyond its borders, adding to the constant battles Wolf already wages against the non-native annual European grasses that already exist at Fallbrook.

Early California settlers wanted the lush green grasses of home, so they brought those seeds with them. Generations later, these grasses have a strong foothold across the formerly scrubby arid landscape that early human transplants considered barren and dead-looking.

One of the best ways to control these annual invaders is eliciting help from an unlikely partner – domestic cattle. In many parts of the West, generations of cattle grazing have decimated the tallgrass prairies and meadows on which native wildlife depend.

But at Fallbrook, Wolf said, cattle are used to keep the invasive grasses at bay. Reduced biomass and bare ground are beneficial for the Stephens' Kangaroo Rat, and leaves less fuel for wildfires, which plague Southern California.

“Cattle grazing supports the military’s mission by reducing fire risks,” Wolf said. “It’s a win-win.”

Although Wolf is ultimately in charge of natural resource management at Fallbrook, she doesn’t work alone. She’s quick to point out the success of her program depends on a larger Navy team, Command leadership, and essential contract support, and requires close coordination with many stakeholders. Her management plans must pass muster not only with the U.S. Navy, but also the U.S. Fish and Wildlife Service that is charged with protection of listed species, along with other federal and state natural resources agencies.

“It is an effort that requires good relationships,” said Peter Beck, a biologist with the U.S. Fish and Wildlife Service who works in the agency’s Carlsbad office. Beck works with Wolf and also biologists at neighboring Camp Pendleton to help create solutions for wildlife management.

While creating plans that satisfy several entities isn’t easy, Beck said working with the Department of Defense is, in many ways, easier than working with private interests.

“Their missions mesh very well with our objectives because they (military) don’t want a lot of development,” he said.

Beck and Wolf have worked together more than 21 years in a relationship built on respect for each other’s knowledge and objectives.

“(Wolf) knows what her mission is, and is good at providing feedback on what we can and cannot do,” Beck said.

One project that proved particularly challenging about three years ago was when officials at Fallbrook had to secure a holding yard in which vehicles loaded for ordnance transport were parked. Because of the highly sensitive cargo, the yard needed to be well-lighted 24 hours a day.

Such lighting is detrimental to the Stephens’ Kangaroo Rat’s typical nocturnal behaviors, Wolf said, and several burrows were found next to the yard. So she came up with a solution that Beck says illustrates Wolf’s creativity in accomplishing the best of both worlds.

In exchange for adding new lights at the vehicle storage yard, the military worked to remove outdated, excessively bright lighting – which creates disability glare and wastes energy – in other areas of Fallbrook and updated it with Dark Sky-compliant fixtures. This helped the displaced animals find new habitat, and also improved the security of areas that military officials didn’t necessarily need brightly lit, Beck said.

That effort was among those that garnered Fallbrook a Secretary of the Navy Environmental Award in 2020.

Wolf is proud of the award, she said, but she is more rewarded by the work they do every day to protect natural resources at Fallbrook.

“We are responsible for this land in the public trust,” she said. “How do we really and truly set these resources up for future generations? My goal is to leave it better than I found it.”