Less driving means less roadkill, and safer mountain lions, during pandemic

California’s mountain lions are key beneficiaries of the coronavirus pandemic, with lighter-than-usual traffic resulting in a 58% reduction in the state’s lion roadkill in the 10 weeks following stay-at-home orders, according to a report released Thursday, June 25, by the UC Davis Road Ecology Center.

The study found that large wildlife killed by vehicles in the three states surveyed — California, Idaho and Maine — were all down substantially. But the findings are particularly significant for several endangered local populations of California’s mountain lions, including those in the Santa Ana and Santa Monica mountains.

In both ranges, motor vehicle strikes are a primary source of death for the big cats.

“For Southern California mountain lions, even one lion making it across a road instead of being killed can be very significant for populations like the ones in the Santa Monica or Santa Ana mountain ranges,” said Winston Vickers, who directs the California Mountain Lion Project at UC Davis.

The reduced roadkill is among several silver linings to the devastating COVID-19 pandemic, with the reduced traffic also credited for fewer vehicle crashes and for reduced greenhouse gas emissions.

During the period studied by UC Davis, traffic was down 71 percent in California. While there’s been a three-fold increase in traffic since then, that’s still about half the normal number of vehicles on the road, according to the study.

While the current increase of coronavirus cases is bad news for humans, wildlife could continue to benefit.

“Traffic may stay depressed,” said Fraser Shilling, director of the UC Davis Road Ecology Center.

At the lower rate of roadkill documented during the period studied, there would be a statewide reduction in motor-vehicle deaths to mountain lions of about 50 a year. For all large wildlife — including deer, moose, elk, black bear and coyotes, as well as lions — the report offers an estimate of 5,700 animals whose lives could be spared in California over the course of a year.

Shrinking populations

For the lions of the Santa Ana and Santa Monica mountains, historical roadkill and population numbers tell a dire story.

In the Santa Monica Mountains west of the 405 Freeway and south of the 101 Freeway, the adult population is estimated to be six — with just one known male. Another male was killed trying to cross the 101 in Camarillo in March and a third male was killed trying to cross the 405 in the Sepulveda Pass in September.

In the Santa Ana Mountains, there are an estimated 16 adults — five males and 11 females. Since 2015 at least four lions have been killed trying to cross Interstate 15. And since 1990, 57 were killed by vehicles on roadways on the west side of I-15 and 64 on the east side, Vickers said.

Compounding the problem is inbreeding, which means the lions in both ranges have a moderate to almost certain chance of local extinction in the next 50 years, according to a 2019 study.

Fundraising is underway for an $85 million wildlife overpass on the 101, which would help the Santa Monica Mountains’ cats mingle with those in the much larger ranges north of the freeway. And a just-completed study offers less expensive crossing options for the I-15, which would help the Santa Ana Mountain wildlife access fresh genes by breeding with those east of the freeway.

While mountain lions are not endangered statewide or worldwide, there’s growing concern about the longevity of several local populations. In April, the state Fish and Game Commission awarded temporary protective status to the animals in six areas, including the Santa Ana, Santa Monica, San Gabriel and San Bernardino mountains. The decision also triggers a year-long study to determine whether those populations merit permanent protection.

Shilling said about 75 to 100 mountain lions are reported killed by vehicles in the state each year, although the true number of such deaths could be twice that number because many go unreported. In the 10 weeks before stay-at-home orders, 19 mountain lions were reported killed by vehicles. That dropped to 8 lions in the 10 weeks after, a reduction not accountable to seasonal changes.

“If anything, there’s usually an increase in spring,” Shilling said.

Source: Orange County Register