As the mountain lions of Southern California approach what some experts call an “extinction vortex,” environmentalists are demanding that state officials grant the big cats protective status — a move that could potentially ban development on thousands of acres of prime real estate.

Mountain lions as a species are not threatened in California, but a petition submitted Tuesday to the state Fish and Game Commission argues that six isolated and genetically distinct cougar clans from Santa Cruz to the U.S.-Mexico border comprise a subpopulation that is threatened by extinction.

The petition, which is co-sponsored by the Center for Biological Diversity and the nonprofit Mountain Lion Foundation, argues that Central and Southern California mountain lions comprise an “evolutionarily significant unit” that should be declared threatened under the state Endangered Species Act.

Recent scientific studies suggest there’s an almost 1 in 4 chance that Southern California mountain lions could become extinct in the Santa Monica and Santa Ana mountains within 50 years.


“This petition will be controversial,” said Justin Dellinger, senior environmental scientist with the Wildlife Investigations Laboratory at the California Department of Fish and Wildlife.

“It will raise a lot of eyebrows amongst developers and others who will point out that, overall, mountain lions are doing OK,” he said. “But the weight of the scientific evidence suggests that in certain places they are in serious trouble. So, listing those lions as threatened is not an outlandish notion.”

Tiffany Yap, a biologist at the Center for Biological Diversity and lead author of the petition, said time is running out for the lions.

“We’ve reached a critical point for mountain lions in Southern California,” Yap said. “Individual lions face horrible deaths from car collisions or rat poison, while their populations become increasingly isolated and inbred in ever-shrinking islands of habitat hemmed by freeways and sprawl.”


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Cougars in the Santa Monica and Santa Ana mountains are poised to enter an “extinction vortex” and could disappear from those areas in the next 50 years, new research says. Here, an adult mountain lion leads three youths along a truck trail in the Santa Anas in 2014. (Irvine Ranch Conservancy)

The effect of such a designation would be far reaching.

If the state Fish and Game Commission agrees, the California Department of Transportation would not be allowed to build or expand highways in core mountain lion habitat without implementing adequate measures to ensure habitat linkages and safe passage under or over them.


In addition, large-scale residential and commercial development could be prohibited or limited in mountain lion habitats within a region covering roughly a third of the state. Mountain lions are not threatened elsewhere in California, the petitioners say, but they are legally classified as a “specially protected species” by the state Department of Fish and Wildlife.

A preliminary decision by the commission is expected by the end of the year.

Developers and their attorneys dismiss the petition’s proposals as absurd.

“Property owners and developers will face higher costs because of the reduction of available developable land,” said Jonathan Wood, an attorney at the Pacific Legal Foundation. The foundation has represented such groups as the California Building Industry Assn. and the Property Owners Assn. of Riverside County in land-use disputes involving the gnatcatcher, which the state has declared as threatened.


“It is not clear what the ultimate benefits will be for the species — which is thriving statewide,” Wood said. “Focusing attention on protecting the mountain lions of Southern California may be at the expense of other species that need help even more.”

The evolutionarily significant unit concept is not new. In 2005, the U.S. Fish and Wildlife Service listed the California’s Central Coast population of coho salmon as federally endangered. Earlier this year, the first ESU mammal was listed as a state threatened species: the Southern Sierra Nevada of the Pacific fisher.

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In the meantime, Southern California is watching its mountain lions decline steadily in the Santa Ana, San Gabriel, San Bernardino, Santa Monica, Santa Cruz and Tehachapi mountains.


Habitat fragmentation by urban development and highways, extremely low levels of genetic diversity, disease, territorial battles, rodenticide poisoning, vehicle collisions and human-caused wildfires are serious problems shared by lions in each of those ranges.

The plight of the mobile and efficient predators will only worsen with continued development, widening of existing highways and construction of new ones.

The “greatest concern for the long-term health of mountain lion populations in the national forests of Southern California is loss of landscape connectivity between mountain ranges and large blocks of open space on private land,” according to an environmental review of land management plans conducted by the U.S. Forest Service.

The petition points out that the Los Angeles County Board of Supervisors in April approved a proposal to develop 1,330 acres near the community of Castaic, despite concerns by the Santa Monica Mountains Conservancy that it would degrade a wildlife linkage between the Angeles National Forest and Los Padres National Forest.


Similarly, the board recently approved the controversial proposed 12,000-acre Centennial development on the unincorporated northern fringe of the county, overlooking objections that it would sever a habitat linkage between State Route 14 and Interstate 5.

There is no reliable estimate of mountain lion abundance in California today. But state wildlife authorities are currently conducting surveys to determine the statewide population, which is believed to have fallen below 6,000.

In historic terms, scientists say mountain lions once had the most extensive range of any New World terrestrial mammal, roaming dense forests, deserts, savannahs and swamplands.

Their decline was decades in the making. Indiscriminate killing of mountain lions, encouraged by bounties, was once the rule. California voters banned mountain lion hunting in 1990.


Its range has been reduced to 15 mostly western states, and a small remnant population in Florida, where continued hunting and development have pushed the species to shrinking patches of rural mountainous areas.

As U.N. warns of widespread extinction, California is already losing species »

Years of political and social struggle over such wildlife as northern spotted owls, California gnatcatchers, desert tortoises and mountain yellow-legged frogs has left the state keenly aware of what happens when old ways of resource management come into conflict with modern preservation laws.

Even some optimists say the petition’s proposals will probably send all sides rushing to state courts and the Legislature.


“Our goal is to increase survival rates and stabilize genetic diversity among mountain lion populations,” Lynn Cullens, executive director of the nonprofit Mountain Lion Foundation, said. “That can only happen when they are not constantly getting hammered.”

In the Santa Monicas, the 101 Freeway exists as a near impenetrable barrier to gene flow for a group of 10 mountain lions. In the Santa Anas, the 15 Freeway limits the movement of a family of 20 cougars.

Traffic is also taking its toll. Since National Park Service biologists began researching pumas in the Santa Monica Mountains in 2002, motorists have struck and killed 17 of the large predators in the study area, federal officials said.

Statewide, an estimated 100 “nuisance” mountain lions are eliminated annually with special depredation permits, officials said.


“When it comes to protecting mountain lions, there are strong arguments on all sides,” Dellinger said. “And it may be that even if the petition is not approved, the discussions it triggers will shed light on the issue and enable state wildlife officials to work more collaboratively with developers and Caltrans.

“In any case,” Dellinger said, “the debate that begins today with the filing of this petition will tell the tale.”

Louis.Sahagun@latimes.com

@LouisSahagun