Wildlife's Trial by Fire Is Just Beginning

Times Staff Writers

For Jim Bauer, it was a search for life in the valley of death.

Charred remains of scrub jays and woodpeckers and rabbits littered the ground. The towering pines were gone, so were the oaks. Yet as the wildlife biologist moved through the eerie stillness of the smoldering state park in the mountains east of San Diego, he picked up a faint, telltale signal of hope.

And then another and another. All told, seven of 11 deer outfitted with radio collars were alive in Cuyamaca Rancho State Park. Just outside the park, two of six mountain lions equipped with transmitters were on the prowl.

"Looking at that fire, I wouldn't have guessed that any survived," said Bauer, a wildlife biologist who is participating in a UC Davis study of lions, deer and bighorn sheep in the area. "Mountain lions need a huge chunk of country, and when you have this fragmented and altered habitat to begin with, a big fire like this will have some impacts."

Although wildfires are part of the natural cycle in Southern California, scientists are worried about the cumulative impact of so much scorched earth on top of other stresses: the steady advance of urban development, pollution, invasive fire-prone plants, persistent drought and climate change.

With all of these strains on the environment, what will grow back now that wildfires have wiped the landscape clean? Will pine forests be replaced by chaparral or oak trees, as some experts suspect? What will be the impact on Southern California's ecological health and how will it affect humans?

A change in the forest canopy can rob animals of shelter and nourishment. Without pine trees, for instance, ground temperatures can rise and the moist forest floor can dry up, making it inhospitable for some creatures.

One team of scientists is studying how the plume of smoke sent toxic heavy metals and pesticides sifting down with the flurries of ash throughout Southern California.

They expect, as past studies have suggested, that tons of copper, lead and zinc particles will get washed into streams, rivers and the ocean, poisoning aquatic life and edging their way up the food chain.

"Aside from the obvious effect on everyone's breathing, these toxic compounds fall out of the sky, wash down and affect aquatic life," said Keith D. Stolzenbach, a UCLA professor of civil and environmental engineering. He noted that copper is so toxic to fish that it's used to clean out ponds and painted on boat hulls to keep barnacles from growing. Lead, which tends to sink to the ocean floor, can work its way up to humans who eat fish.

Another area of concern scientists plan to investigate is what it means to burn so many holes in the region's umbrella of foliage. Across the burned landscape, the holes add up to a gap bigger than Rhode Island.

"Trees are like sponges, filtering pollutants out of the air, intercepting rainfall" and helping replenish groundwater supplies, said Greg McPherson, director of the U.S. Forest Service's Center for Urban Forest Research at UC Davis. "Burning up those trees is like losing one of your lungs. The air quality isn't going to be the same. The runoff isn't going to clear. The system is going to be perturbed."

It is wildlife that may have taken the greatest hit.

"Think of it as a major refugee problem for many of these species," said Mark Borchert, the chief U.S. Forest Service ecologist for Southern California. "Some of these burns cover thousands of acres, and there is no place for some species to flee."

As fire swept across Summit Valley in the San Bernardino Mountains last week, rabbits and other animals were on the run, some dodging headlights, in their panic to escape the curtains of flame.

In Lake Arrowhead, kangaroo rats congregated on the only ground not on fire -- the roadway -- only to be run over by firetrucks and TV news vans. In San Diego County, firefighters found a deer burned to death near a barbed-wire fence it may have sought to hurdle to flee the flames. Most animals tend to persevere. They evolved with this fire-prone landscape and have strategies to make it to safety or burrow deep enough underground to escape the scorching heat.

Some profit from fires. Throughout the week, red-tailed hawks and ravens could be seen over burned brush, diving for prey exposed by lack of cover.

Yet, the fate of animals deeper in the backcountry remains largely a mystery.

Researchers who had spent years tracking habits of mountain lions, bighorn sheep and deer began fretting -- sometimes unnecessarily -- that years of study had gone up in smoke.

As wildfires raced through the San Bernardino Mountains, Chanelle Davis paced nervously in her Chino Hills office. A biologist with the California Department of Fish and Game, Davis' job is to restore the remnant population of Nelson's bighorn sheep in the local mountains. The herd was once the largest in the Southwestern United States. But even before the fires, fewer than 100 of the animals remained. "I'm anxious to get up there and see if my guys are still alive," Davis said. "The sheep are in pretty remote areas but the fire has covered most of the canyons where they are located," she said. "Instinctively, these animals will run away from fire. Sometimes they can get cut off or disoriented."

More than 100 miles to the west, the California condor saw much of its prime habitat in the mountains of Ventura County burn.

As U.S. Fish and Wildlife officials ventured into the blackened Sespe Condor Sanctuary, they picked up signals of all but four of the two dozen condors that live in the area, said Bruce Palmer, head of the California Condor Recovery Program. One bird is believed to have perished, but Palmer said the death did not appear to be fire-related.

"All of the smoke and disruption is not good for the birds, just as it's not good for people," Palmer said. "They may have lost a lot of traditional roosts in pine trees on Hopper Mountain."

Yet he said that fire can also benefit the condors, clearing away brush so they can more easily spot dead animals, carrion, to feed upon.

In a natural world, fire can be helpful to many wild animals, reinvigorating plants that provide the nutrition that works its way up the food chain. Some animals are lost, but eventually their populations may rebound and even grow larger than before.

That's not always the case when their numbers are greatly diminished. California has more rare and endangered species than any state other than Hawaii, and some of them saw their prime habitat burned last week. The southern rubber boa, for example, resides only in the mountains around Lake Arrowhead.

The least Bell's vireo and the arroyo southwestern toad also appear to have lost habitat. Large wildfires that take out entire stands of pines are considered a threat to the California spotted owl and its prey, the San Bernardino flying squirrel.

For years, development including roads and fences has been squeezing many animals into what National Park Service fire ecologist Robin Wills calls "islands of habitat amid urbanization."

Ecologists note that such islands are notorious as places where wildlife is highly susceptible to inbreeding, disease and extinction. Such chronic problems become acute when wildfires burn through the entire island, as happened this last week in San Diego, Santa Barbara and Ventura counties.

Most ecologists see the unstoppable advance of development as the most serious problem for Southern California's remaining wildlife. San Diego County has had more than 100,000 acres converted to subdivisions and other forms of development since 1990, according to regional planners. Other counties have seen similar growth.

In an effort to preserve what's left, federal, state and local officials have been working with conservationists and developers to set aside the most biologically valuable wilderness that remains. The idea is to preserve essential habitats, the corridors that link them and the refuges that wildlife needs after fires. "We spent a decade carefully setting the most important remaining critical habitat," said Scott Morrison, an ecologist with the Nature Conservancy, a group that buys and protects habitat. "And in just a few hours it [largely] burned. I don't know a biologist who wasn't humbled by this."

What will grow back now that wildfires have wiped the landscape clean? What will happen to the pine forests of the San Bernardino Mountains, already stressed from drought, air pollution and burrowing beetles? Will native chaparral, sages and other shrubs lose out to nonnative grasses brought in from the Mediterranean?

Chaparral and coastal sage scrub, oak woodlands, even pine forests usually bounce back -- and even thrive -- after fires. Some plants have evolved to cope with wildfire by using the heat to open seeds that sit in the soil waiting -- sometimes years -- for a blaze. One biologist predicts that 50 to 100 species of wildflowers that are normally dormant will bloom next spring.

Yet, wildfire also creates opportunities for exotic plants to take hold.

Jon Keeley, a scientist with the U.S. Geological Survey, has studied how wildfire has allowed invading grasses such as wild oats and mustard to replace native plants. Those nonnative annual grasses are brown most of the year, he said, providing less food and shelter to animals. They reflect more heat from the sun, elevating temperatures and making the landscape susceptible to more frequent wildfires.

"I estimate that 25% of the coastal range has been displaced with alien grasses, and these wildfires are going to exacerbate the problem," Keeley said. "By the sheer size of what's burned, we are going to see greater displacement of native plants. That makes the animals very vulnerable and has the potential of increasing fire frequency."

In the remote King Creek drainage in Cuyamaca State Park and the Cleveland National Forest, the world's only stands of the naturally rare Cuyamaca cypress tree are believed to have burned this last week.

All of the 1,000 or so trees are presumed to have died.

Yet, biologists also believe that the wildfire will open pine cones from the trees that have been sitting in the soil, awaiting a fire. The cones will then release seeds into the blackened earth.

Given the right mix of oxygen, water, sunlight and nutrients -- and perhaps a little luck -- biologists are hopeful that the Cuyamaca cypress will rise again.

Copyright © 2019, Los Angeles Times
EDITION: California | U.S. & World
57°