Photos by Joseph A. Garcia / Star staff E.J. Remson, senior program manager with The Nature Conservancy, discusses paths through Simi Valley that could be used to link mountain ranges. A proposal would link open spaces from the Sierra Nevada to the Mexican border.

Ray Sauvajot stood on the hillside between the Los Padres and Santa Monica mountain ranges, gazing at the vast expanse between the two. Beneath him thousands of houses and roads crisscrossed the verdant hills and valleys that are home to mountain lions and coyotes, bobcats and mule deer.

Without some way for the animals to move through the sprawling suburbia, the two mountain ranges are islands where critters are stranded with little chance to breed or expand their populations.

But Sauvajot, the chief of resources management for the Santa Monica Mountains National Recreation Area, and

others have an idea on how to fix that problem.

"The goal is to get these mountains connected to those mountains and in order to do that, you've got to get around the 118, the 126, the 101 and the 23," Sauvajot said of the maze of freeways.

A group called South Coast Wildlands has drawn an extensive and ambitious map of linkages that would connect all the isolated patches of open space from the Sierra Nevada to the Mexican border by stitching together a series of private and public lands. The idea is that the corridors would allow animals to roam around Southern California as they did before those vast ribbons of concrete impeded their travels. Animals in isolated populations face all kinds of problems, from inbreeding and overcrowding to not having anywhere to run in a disaster.

Perhaps there is no place where that challenge is as great or the needs as important as the sprawling megalopolis of Southern California.

"It's a huge challenge but if we can do it here, we can do it anywhere," said Kristeen Penrod, the conservation director of South Coast Wildlands, who has been spearheading the project for the past seven years.

Penrod and others who worked on the project are expected to unveil today their grand map of how more than 19 million acres could be connected to create a patchwork of private and public property that makes one enormous corridor where animals could roam.

"If we conserve these connections, someone could walk from the southern Sierra Nevada to Baja, Mexico," she said. And if people can do it, so can the animals that need room to survive.

About 94 percent of the more than 19 million acres needed is already in some form of conservation, whether it is parkland, open space, conservation easements or other types of commitment that protect the land. About 1 million acres still needed could be added through purchases, conservation easements or other means.

The link between the ocean off Ventura County and Los Padres National Forest and the Sierra Madre Range encompasses about 125,000 acres, 34 percent of which is already in some type of conservation.

The map of the critical areas now can help guide the preservation of land, said Paul Edelman, deputy director of natural resources and planning with the Santa Monica Mountains Conservancy. His agency is looking at negotiating deals with landowners near the Ronald Reagan Presidential Library and Museum to help create a linkage through Simi Valley.

E.J. Remson, senior program manager with The Nature Conservancy, said he's spoken to five landowners in Simi Valley who are open to either selling their land or creating an easement on it. About four more are needed to complete the link, he said.

"It's like a chain," Remson said. "One missing link and the whole thing is shot."

Edelman said the time to act is now, before the land is developed.

But even if all the land is protected, there is still the issue of roads. If a mountain lion wanted to move from the ocean to the mountains in Ventura County, it would have to cross at least three major highways and scores of minor roads.

The California Department of Transportation is exploring how to build a multimillion-dollar underpass beneath Highway 101 near Liberty Canyon Road, which would be the main thoroughfare for large mammals to move to and from the Santa Monica Mountains. Radio-collared mountain lions sit on the hillside above the noisy highway, presumably looking for a way to cross it and get to open habitat on the other side, Sauvajot said.

Karl Price, with Caltrans' Environmental Planning department, said the idea of wildlife corridors around roadways is relatively new, but the agency is looking into what it can do. Helping animals stay off the roadways is good not only for the animals but also for the people driving, he said.

During current improvements to Highway 23, fencing was installed to funnel animals to a cleared culvert under the road. The famous tiger that escaped from its Moorpark handlers in 2005 once crossed through a culvert under Highway 23 in the days before it was shot by officials, Sauvajot said. Photographs taken at underpasses on Highway 118 have captured bobcats and mountain lions passing through.

Counties also are taking notice of the linkage plan.

In Ventura County, the linkage plan is consulted before any major projects are approved, said Liz Chattin, a contract biologist with the county Planning Department. Though the county had expressed an interest in incorporating linkages, the new maps give the department guidance as to where they are most important, she said.

Penrod said Los Angeles County officials have contacted her about incorporating the map into the county's general plan.

Developers historically like the plan because they are often required to set aside land for conservation and this gives them a road map of where they should protect it, she said.

Sauvajot said the linkages are vital for the health of many of the animals that the public has spent so much time trying to protect.

He estimates there are about 10 mountain lions living in the Santa Monica Mountains, five in the Simi Hills and a dozen in the Santa Susana Mountains. If all those islands of habitat were better linked, the populations would be even more robust and able to withstand the pressures of living in an urban landscape.

"If you provide a connection," he said, "there is no reason to think they wouldn't take it."