Wildfires are an added challenge for LA mountain lions

This article was originally presented on High Country News.

On November 8, 2018, faulty electrical equipment in California’s Woolsey Valley sparked a wildfire that engulfed the Santa Monica Mountains. The Woolsey Fire burned nearly 100,000 acres of land in the western edge of the greater Los Angeles area, destroying more than 1,600 buildings and killing three people.

This mountainous landscape is home to Los Angeles’ legendary mountain lions, which have persisted here despite urbanization and habitat fragmentation. But the fire eliminates half of their remaining habitats, including 88% of the land of the National Park in the National Recreation Zone of Santa Monica Mountains. Rachel blends, now a professor at Cal Poly Pomona, lived in LA during the fire and began to wonder how the lions were affected.

“I was a really big Mountain Lions fan in L.A., as most Angelenos are,” Blakey said. “And I thought, God, what happened? How did this forest fire affect them after they already have this type of surrounded area? “

The results of the study by Blakey and her co-authors were published in Current Biology on October 20. Using GPS tracking to map the lions’ travels and accelerometer data to record their activity, she and her collaborators compared the animals’ behavior during the 15 months before and after the fire.

Two lions died in the fire, but many others struggled to survive in the following years. Blakey describes the charred landscape as a “moonscape” without the vegetation and cover the cats need to ambush their preferred prey, deer. Lions avoided burned areas and took greater risks in search of better habitat, crossing busy highways. When they entered the territories of the dominant males, interspecies conflict ensued.

Researcher Jeff Sikich, who has studied the Santa Monica population for more than two decades and worked on the study with Blakey, said in an interview that more mountain lions are killed by cars than by any other cause. If the fire forces them to cross the roads more often, even more deaths are likely.

A young man known as P-61 survived the fire, but in search of a more suitable habitat, he then became an indirect victim of the fire. He was the first collared mountain lion recorded to cross the 405, a major highway with heavy traffic. His initial passage was successful, but he inadvertently entered the territory of another male, who attacked and chased him away. He was later recorded as considering a second crossing. But this time his luck ran out and he was hit and killed by a vehicle.

After the fire, some residents expressed fears that the mountain lions would move to more urbanized areas, researchers said. But their monitoring showed that cats only slightly increase their time in such areas. Cats have a “strong tendency to avoid these urban areas,” Sikic said, and that remained true even after the fire. On average, they spend only 5% of their time in urban areas, with even the bravest spending no more than 15% of their time there. When a mountain lion, known as the P-64, was caught between a burned area and a lively urban space, he chose the smoldering vegetation over the chance of human contact. He was severely burned and, unable to hunt, died.

Winston Vickers, a veterinarian and a wildlife researcher at UC Davis, works with a similar isolated population of mountain lions in Santa Anna Mountains in the eastern Los Angeles. He has also seen cases where animals prefer to risk a fire than to reach for human spaces. “We are becoming more and more (isolated populations), especially in places like coastal California,” Vickers said. He said the study was important to help researchers understand how a fire could affect isolated populations.