A report released Thursday shows that fewer wild animals have been struck by vehicles in three states during shelter-in-place orders, with the number of mountain lions killed in Southern California and elsewhere in the state declining by more than 50%.
Researchers at the UC Davis Road Ecology Center determined that 56% fewer mountain lions were killed in California between the 10 weeks before the stay-at-home orders compared with the 10 weeks after, with the number of large wild animals being killed by vehicles falling 21% from 8.4 per day to 6.6 a day.
“The reduction in numbers of wildlife killed is surprising, and is a silver lining for both wildlife and people at this difficult time,” said Winston Vickers, who directs the California Mountain Lion Project, a program of the Karen C. Drayer Wildlife Health Center in the UC Davis School of Veterinary Medicine.
“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,” Vickers said.
The UC Davis researchers analyzed traffic and collision data collected from California, Idaho and Maine, which have advanced systems for tracking wildlife-vehicle conflict. The study provides the first evidence that wildlife-vehicle conflict decreased along with reduced vehicle travel during the response to the COVID-19 pandemic, said Road Ecology Center director Fraser Shilling.
“There is a statistically significant decline in wildlife deaths on highways in all three states following reductions in traffic this spring,” Shilling said. “This has not been the case for any of the previous five years for these three states. If anything, there is usually an increase in spring.”
If it continues, the respite could amount to about 5,700 to 13,000 fewer large mammals being killed each year in the three states, and 50 fewer mountain lion deaths per year in California, he said.
The positive impacts noted in the report “are likely to be just the tip of the iceberg of reduced deaths of wildlife on U.S. roads and highways,” given the under-reporting of large animals involved in collisions with vehicles and the lack of systematic reporting of smaller animals killed on roads, Shilling wrote.
He plans to continue to watch closely for impacts to wildlife given a two-to-three-fold increase in traffic in recent weeks as states reopen their economies.
Shilling noted “the clear link between traffic and rates of mountain lion death,” and said puma populations must be protected from traffic, especially in Southern California and the Bay Area, to reduce mountain lion mortality.
In a unanimous decision in April, the California Fish and Game Commission moved a step closer to protecting six struggling mountain lion populations, including those in the Santa Monica and Santa Ana mountains, under the state’s Endangered Species Act.
The commission’s decision cleared the way for a yearlong review on whether the six populations of mountain lions should be formally protected under the state act, with the act’s full protections applying during the yearlong candidacy period.
Supporters are seeking “threatened species protection” — which is designed to protect species that at risk of extinction in the foreseeable future without improved management — involving the “most imperiled populations” of mountain lions in California, according to Tiffany Yap, a biologist at the Center for Biological Diversity and primary author of the petition.
Researchers with the National Park Service, UC Davis and UCLA warn that if enough inbreeding occurs, the Santa Ana population could go extinct within 12 years, and the Santa Monica population within 15 years.
The state Department of Fish and Wildlife had recommended the move shortly after P-56, a male mountain lion in the critically endangered Santa Monica population, was killed in January under a state-issued depredation permit by a landowner who had lost livestock to the big cat.
Planning and fundraising is underway for a wildlife crossing over the 101 Freeway in the Liberty Canyon area of Agoura Hills that would provide a connection between the small population of mountain lions in the Santa Monica Mountains and the large and genetically diverse populations to the north.
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