Wildlife Habitat Periled by Fire : Ecology: A wind-fanned blaze blackened 1,200 acres in Lytle Creek Canyon in the San Gabriel Mountains.

A weekend wildfire fanned by relentless Santa Ana winds spared a subdivision and caused only two minor injuries but could have devastating consequences for wildlife, officials said Sunday.

The blaze erupted at about 9:30 p.m. Saturday in Lytle Creek Canyon, a rugged gash in the San Gabriel Mountains north of Fontana. Although its origin remains under investigation, a U.S. Forest Service spokesman said the fire appears to have been man-caused, possibly by someone tossing a cigarette out of a car window.

After briefly threatening a cluster of homes under construction north of Interstate 15 and east of Rancho Cucamonga, the blaze abruptly switched directions and began burning westward across uninhabited forest lands.

By sunset Sunday, the hot, seasonal winds that at one point gusted up to 50 m.p.h. had subsided, and firefighters had high hopes that the blaze would be contained by today.

In its path, the fire left more than 1,200 charred acres of chaparral, meadowlands and coniferous trees that officials say constituted perhaps the most important wildlife habitat remaining in the San Bernardino National Forest.

The loss was particularly critical, federal resource experts said, because that corner of the forest was still recovering from two other major fires in the last 18 years. Moreover, the blaze represents a sort of double-whammy for wildlife suffering from the long-running drought.

“When we heard the fire was in Lytle Creek, our reaction was, Oh, no, not again. Any place but there,” said Steve Loe, chief biologist for the San Bernardino National Forest. “Because of these earlier fires, there is very little mature, productive habitat left up there. So what remains is extremely valuable. Losing any of it is dramatic.”

Because it is less steep and rocky than much of the San Gabriel range, the Lytle Creek area is favored and heavily populated by mule deer, black bears and many smaller animal species. Loe said the area hosts one of the nation’s largest populations of Nelson bighorn sheep, a protected species in California, and is home to goshawks, Cooper’s hawks and other sensitive bird species.

Repeated wildfires cause a destructive cycle that has eliminated much of the protective cover and food supply upon which these and other species depend, Loe said.

The dozen varieties of chaparral are key food sources for deer and bighorn sheep and shield rabbits and other small species from predators. Manzanita produces berries consumed by bears and birds, and the mountains’ Douglas firs, sugar and Jeffrey pines and oaks provide nesting opportunities as well as acorns and seeds that feed a host of species.

“Wildfires can have a rejuvenating effect--unless they are too intense or happen too frequently,” Loe said. “This area has burned much too often in fires that have destroyed 80% to 100% of the vegetation. The effect of that can be devastating.”

While many animals can escape a fire by fleeing or hiding in a burrow, survival after the flames are put out can be a cruel challenge, biologists say. Rodents emerge from below ground to find a blackened landscape devoid of food, and deer and sheep are forced to relocate in search of forage--a difficult quest because shrinking habitat already has made competition in the mountains intense.

Hawks and other birds of prey initially gorge themselves on carcasses, but it’s a short-term thing because rodents--the birds’ standard meal--have no food and soon perish, Loe said.

In October, 1988, 12,000 acres were burned near Lytle Creek, halting the area’s recovery from another large fire about 15 years earlier. In addition to the stress they place on wildlife, the fires--and the firebreaks bulldozed by firefighters--strip the land of vegetation needed to prevent erosion and flooding.

Sunday’s fire, for example, began in the Lytle Creek watershed and later burned portions of another watershed feeding two canyons that empty out in Fontana and Rancho Cucamonga.

To prevent winter rains from causing floods, forest service officials will quickly reseed the charred acreage and create berms designed to slow and divert runoff.