Controlled Burn Clears Way for Endangered Mouse

A slow-moving “prescribed fire” swept five acres of San Onofre State Beach on Tuesday, charring decades-old coastal sage scrub and clearing sandy habitat for the endangered Pacific pocket mouse.

A coalition of state and federal agencies coordinated the controlled burn, which was about one mile from the coast and about three miles from the San Onofre nuclear power plant.

Natural fires usually burn chaparral habitats about every 15 years, but the lack of fire at this spot meant that some of the scrub was up to 70 years old.

“The habitat right now is not suitable. Our concern is that [the mice] will not survive such dense vegetation,” said Annie Hoecker, a biologist with the U.S. Fish and Wildlife Service, before the fire, which burned for about two hours.

Orange County Fire Authority spokesman Paul Hunter said the controlled burn will also reduce the amount of built-up tinder that could fuel a wildfire, which could engulf homes in San Clemente.

The burn was originally scheduled for last spring but was put on hold after a controlled burn set by National Park Service officials in New Mexico swept out of control into the city of Los Alamos and onto the grounds of the federal nuclear laboratory there.

Despite last year’s disaster at Los Alamos, state officials said, the proximity of Tuesday’s burn to the San Onofre nuclear power plant was not a concern because of the size of the fire and the weather. About 90 firefighters and five fire engines were on the scene Tuesday, ready to battle the blaze if it got out of control.

Controlled burns are regularly used by state and federal agencies to reduce the potential for wildfires and to improve habitat. In 1999, the U.S. Fish and Wildlife Service set 1,224 prescribed fires across the nation that burned 274,058 acres. Nearly half of those fires were for habitat maintenance.

Forestry experts say fire is part of the natural life cycle of an ecosystem.

“This past century, fire was demonized. That’s just a colossal ecological folly,” said Timothy Ingalsbee, director of the Western Fire Ecology Center of Eugene, Ore. “Fire has a vital ecological function. . . . It’s just as essential in some cases as sunlight, soil and water.”

Deborah Bieber, a wildlife biologist with Camp Pendleton’s environmental security department, said that while controlled burns are a common method of improving habitat for endangered species, this was the first such effort for the mice.

The small, silky mouse with fur-lined cheek pouches was listed as endangered in 1994. Its range once stretched from Marina del Rey to Mexico. There are now three small populations left, including about 40 mice in the state park.

“We want to monitor the Pacific pocket mouse habitat and mouse populations to see how the population responds to the controlled burn,” Bieber said. The group of biologists will hold off on further burns until they have evaluated the effectiveness of this one.

The fire will probably make the sage scrub uninhabitable by the mice for a year, and it may have killed a few mice. But Bieber said it was necessary to “harm a few to benefit the many, hopefully.”

The threatened coastal California gnatcatcher birds who like to nest about a meter above the ground in sage scrub will have to use other scrub in the surrounding 2,800 acres, something state officials don’t believe will be a problem. New scrub will grow one meter tall in two to three years.

Gnatcatchers and endangered Southwestern arroyo toads present in the area during the fire probably escaped, officials said.

David Hogan of the Center for Biological Diversity, who has successfully sued the U.S. Fish and Wildlife Service numerous times to force it to designate critical habitat, said that federal officials ought to be taking far stronger steps to preserve habitat for the pocket mouse than burning a few acres.

“Fish and Wildlife is, unfortunately, far more willing to carry out heavy-handed management of this tiny preserve instead of using its authority to limit destruction of important habitat on private land and Camp Pendleton,” he said.

The service ought to limit development on sage scrub in Carlsbad, Dana Point and elsewhere, and limit military training on such habitat in Camp Pendleton, Hogan said.

“The only way to recover the species is to restore populations to currently unoccupied habitat,” he said.

Military bases, including Camp Pendleton, have been exempted from other critical-habitat designations because, federal officials say, national security is more important.

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Fire Objectives

Controlled burns are regularly used by state and federal agencies to reduce the potential for wildfires and to improve habitat.