Temecula’s proposed Altair development just west of the 15 Freeway has been blocked by a Superior Court judge, who ruled the 270-acre proposal did not adequately address the habitat of mountain lions and other wildlife in the area.

Judge Daniel Ottolia’s decision preserves areas traveled by the mountain lions when crossing over or under the freeway. While such crossings are rare, biologists say they’re vital to maintaining the species’ genetic diversity in the Santa Ana Mountains and avoiding local extinction.

“The judge threw a lifeline to these highly imperiled cats, who need all the help they can get,” said J.P. Rose, attorney for the Center for Biological Diversity, which was among environmental groups that filed the lawsuit.

He said the 1,750-home development as proposed “could be a death knell for local mountain lions.” The lawsuit also cited concerns that the plan would threaten the rare western pond turtle and the endangered San Diego ambrosia.

It’s uncertain if the city of Temecula, the principal defendant, or the developer, Ambient Communities, will appeal, but some type of development in the area is still likely to be pursued.

“Ambient remains committed to the project and whether that’s an appeal or fixing the (environmental report) hasn’t been determined,” said Christian Marsh, an attorney for the developer.

If there is no appeal, Rose anticipates the city and developer will “go back to the drawing board” to come up with a smaller plan.

However, Marsh said shrinking the project is just one alternative — that the developer could stick with the current plan and resubmit it with additional environmental analysis.

Ottolia’s ruling, received by Rose on Friday, April 3, affirms a tentative decision the judge issued in November. While the tentative decision allowed the city and developer time to address his concerns, Ottolia said in the final ruling that the defendants’ response failed to resolve concerns that the Environmental Impact Report and proposed mitigations were inadequate.

Future crossings

Mountain lions are regularly photographed by trail cameras in the area of the proposed development and the project is adjacent to an existing underpass that can allow the animals to travel between the Santa Ana Mountains west of the freeway and the much larger Eastern Peninsular ranges east of the freeway.

Largely hemmed in by development and freeways, Santa Ana Mountain cats face the threat of being unable to reproduce because of inbreeding. A 2019 study determined that they could become extinct in the area in the next few decades and that better access to the Eastern Peninsular ranges would greatly improve their odds.

An underpass at the south end of the proposed development, at the Santa Margarita River, is potentially a prime crossing area for mountain lions, although it is unknown if they have ever used it.

Winston Vickers, a UC Davis veterinarian who researches mountain lions in the area, documented seven male lions crossing the freeway from 2001 to 2016, but six of those trips were verified by genetic analysis and it’s not known exactly where they crossed. The sole lion tracked crossing the freeway while wearing a GPS collar made the trip at the Gopher Canyon Road underpass nearly 20 miles to the south.

At least four more lions were killed from 2013 to 2018 trying to cross on the freeway itself.

But Vickers’ cameras have caught lions approaching the Santa Margarita River underpass. He said a variety of factors currently deter the animals from continuing through to the other side, including homeless people living in the tunnel and pedestrian traffic, dense brush, and noise and light from the freeway.

The underpass “is critical to mountain lion movement between the Santa Ana Mountains and the Palomar Mountains east of Interstate 15,” according to Vickers and fellow mountain lion expert Kathy Zeller in a letter critical of the environmental report.

A Cal Poly Pomona report detailed potential sites for wildlife crossings — a project initiated by Vickers — and produced a $570,000 plan for improving the river underpass to make it more attractive to mountain lions.

City’s defense

The environmentalists’ lawsuit said human activity around the underpass is likely to increase with a nearby subdivision and new trails, further deterring lions. The city countered that the developer would make its own improvements so the tunnel is more inviting to lions, including the erection of barriers to discourage foot traffic.

The city and developer also argued that “the Project’s impacts on mountain lions could be reduced to less than significant” if the proposed 450,000-square-foot “civic” building at the southern end was reduced to the 20,000-square-foot nature center.

Concerns about the western pond turtle and San Diego ambrosia were also dismissed by the defendants, with the city’s brief saying the impact on them would be “less than significant.”

The city noted that mitigation for environmental damage included an estimated $23 million for conservation efforts over the next hundred years. It also says that the project’s footprint has been significantly reduced by rerouting a planned four-lane road known as the Western Bypass.

“From the very outset, Ambient sought to realign the Western Bypass to lessen impacts on the hillside escarpment, wildlife movement and conservation areas,” the city said in a court filing.

However, Ottolia wrote in his ruling that the city’s claims that the development would allow adequate linkage for mountain lion crossing was “not supported by substantial evidence.”