Pumas, like all large Carnivores do not mix well with heavily traveled highways.................In Southern California between Los Angeles and San Diego (from Corona to Camp Pendleton in the Santa Rosa Plateau) the connectivity for Pumas navigating between the Santa Ana mountain range and Palomar mountain range is substantially less than Researchers had previously thought based on genetic results and GPS collar data..............The construction of sprawling housing tracts and shopping centers has wiped out large swaths of habitat................ And the paving of fast-moving, multilane superhighways such as I-15, Highway 91 and the Highway 241 toll road has penned in the estimated 15 to 27 Pumas calling this region home...............Without the construction of wildlife culverts and overpasses, this "penned in" population of "lions" faces the same problem of inbreeding and eventual blinking out as the 6 to 10 Pumas "penned" into the Santa Monica Mountains ringing Los Angeles

Pumas in Southern California
	TEMECULA: Freeway threat to mountain lions worse than thought Source: pe.com GPS collar data and genetics study show it is a very rare occurrence when a mountain lion safely crosses Interstate 15

TEMECULA: Freeway threat to mountain lions worse than thought

SARAH BURGE/STAFF

Winston Vickers, a wildlife veterinarian with the UC Davis Wildlife
 Health Center, and Fernando Najera set a trap for mountain lion
 on the Santa Rosa Plateau Ecological Reserve near Murrieta
on Monday, Jan. 27. Vickers had hoped to replace the tracking
 collar on the on a female cat estimated to be 4 to 5 years old
 that they have caught twice before.

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BY DAVID DOWNEY 

February 03, 2014; 07:15 PM

Related

• PERRIS: Mountain lion suspected in attack still on the loose

It is “extremely unlikely” the mountain lion that attacked a homeless man over the weekend wandered down from the Santa Ana Mountains of the Cleveland National Forest, according to an expert.

The attack occurred in west Perris, near Navajo Road and Highway 74. And Winston Vickers, a wildlife veterinarian tracking mountain lions in the range with GPS collars, said those cats would have to cross busy, dangerous Interstate 15 to reach Perris.

“We have not had any cross I-15 and they would have to do that to get over there,” Vickers said in a telephone interview Sunday, Feb. 2.

It is precisely the lack of documented I-15 crossings that has experts worried about the future of the 20 or so cats roaming the range that divides Riverside and Orange counties.

Researchers have long fretted about those mountain lions, also called cougars and pumas. They had pinned hopes for the population’s survival on a few finding their way across I-15 near Temecula, and breeding with cougars to the east.

Yet the latest phase of a 13-year regional study shows cougars routinely choose not to travel under the freeway — and die when they try to go over it.

“We’re finding that the connectivity between the Santa Ana mountain range and Palomar mountain range is substantially less than we had previously thought, based on our genetics analysis and GPS collar data,” said Vickers, who works for UC Davis Wildlife Health Center.

The finding, details of which are to be published this spring in a scientific journal, has grave implications for the top predator in the Santa Ana Mountains, which extend from Corona to Camp Pendleton and wrap in the Santa Rosa Plateau near Murrieta.

Vickers said a lack of gene mixing makes cats more susceptible to disease, and can lead to physical abnormalities that may affect the survival of an individual animal or whole population.

Vickers termed the situation in the Santa Anas a “classic recipe for population decline.”

Paul Beier, professor of conservation biology at Northern Arizona University, did some of the first significant studies on cougars there more than 20 years ago. Beier then estimated the population size at 15 to 27 cats. And he said there are probably as many today.

The narrow range along the Riverside-Orange county line and extending into San Diego County is a small home for an animal accustomed to roaming hundreds of square miles. But in the past, that wasn’t an issue because cougars traveled freely between the Santa Ana Mountains and other ranges.

It’s a huge problem today, though. The construction of sprawling housing tracts and shopping centers has wiped out large swaths of habitat. And the paving of fast-moving, multilane superhighways such as I-15, Highway 91 and the Highway 241 toll road has penned them in, Vickers said.

“These freeways and all their associated accoutrements of development are really starting to cut these habitats into blocks and isolating mountain lions,” he said.

Besides preventing healthy breeding habits, the ring of highways is a death trap. The single most common cause of death for cougars there is collisions with cars, Vickers said.

As for I-15, at least five cougars have tried to run across it since the early 1990s — and were run over instead, Vickers said.

The last known safe crossing came in 2010, when a male walked under the highway along Gopher Canyon Road, south of Fallbrook, Vickers said. However, that cat lived only a few more weeks and did not establish a territory.

Vickers’ team gathers information on attempted crossings from GPS collars that track movements.

The collar is a key tool for a study launched in 2001 in Riverside, Orange and San Diego counties that has targeted more than 80 cougars. Since then, Vickers said, almost half have died. He said 10 are being tracked now.

A week ago, Vickers set a trap on the Santa Rosa Plateau, in a bid to place a new collar on a female cougar his team tracked for two years. But she didn’t take the bait. Collars are programmed to fall off after a year, and hers was about to do just that.

Of those killed on I-15, four were hit at points between Temecula and Rainbow. The fifth was run over south of Highway 76, tracking maps show.

Other cougars walked to edges of I-15 but didn’t cross. Their zigzag movements were tracked to where I-15 bridges Temecula Creek, which flows into the protected Santa Margarita River.

“We’ve had several mountain lions approach that crossing from the west and then just turn around and go back,” Vickers said.

Vickers said lions in the Santa Anas prey most often on deer, bobcats, coyotes and raccoons. Half of animals tracked in the early 2000s occasionally killed domestic animals, he said, “but none focused on them as a substantial food source.”

A recent experiment by the Western Riverside County Regional Conservation Authority echoed his team’s finding about I-15 crossings.

The agency set up remotely operated cameras at both ends of the Temecula Creek bridge, for most of 2012, in hopes of documenting a cougar passing underneath, said Laurie Correa, director of reserve management and monitoring.

Correa said the temporary cameras snapped mugs of bobcats, coyotes, weasels, skunks and deer — and even people hiking down the creek.

“We have gotten lots of good camera data, just not from the mountain lions,” she said.

Although it is an intimidating barrier, Beier said, “We can make that freeway more friendly to animal crossings.”

Vickers said one way would be to construct a “wildlife bridge” covered with dirt and native plants to provide safe passage. Those have rarely been used in this country.

“However, they are widely used in Europe and in Canada, and are starting to be planned and built much more often in the U.S. in recent years,” he said.

Another idea is to retrofit culverts and freeway bridges, Vickers said.

Solutions are expensive and financing them could prove daunting. But the alternative is costly, too, in terms of environmental damage.

Vickers said a cougar collapse could spark an explosion in the deer population, which in turn would pressure plants that support a variety of birds.

“You would harm the ecology of the region by removing the top predator,” he said.

Contact David Downey at 951-368-9699 or ddowney@pe.com.