Red Legged Frogs ‘Annihiliated’ By Woolsey Fire

The Woolsey Fire wiped out almost all of a program aimed at reintroducing the California red-legged frog into the Santa Monica Mountains.

Hundreds of frogs perished.

Their creeks have been scorched … then filled with choking mud and ash.

Biologists had been very happy with the program that started five years ago

In the weeks prior to the fire, the rare amphibians were flourishing, happily eating insects, and reproducing on their own in two of the four streams spread throughout the mountains. Then the fire struck and burned up much of their habitat. This was immediately followed by a season of heavy rainfall, which caused debris flows that filled the streams with silt and mud.

Three of the four creeks in the Santa Monica Mountains were “annihilated,” according to Katy Delaney, a National Park Service ecologist who has been leading the project for more than five years. She is now contending with essentially starting over with her study.  

There were frogs living in each of these streams – from tadpoles to grown adults. After the fire, she saw one lone frog straggling in one of the reintroduction streams. Another biologist witnessed another single frog post fire and post debris flow from the rains at another site.

“If there is a frog here and there, that’s great but there are no breeding pools left,” Delaney said. “They are all filled in with debris.”

The amphibians are listed as threatened under the Endangered Species Act. A population discovered north of the 101 Freeway in the nearby Simi Hills in 1999 has been used to replenish the species in four spots in the mountains for the past five years. The idea was that translocated populations would eventually mature, mate, and reproduce on their own.

The silver lining to the otherwise doomed project seems to be the source population in the Simi Hills. Although that location was also burned in the fire, it’s located at a lower gradient, which means the canyon is not as steep and the debris flow is minimal in comparison to the sites in the Santa Monica Mountains. The frogs there seem to have survived relatively unscathed.

During a night survey that was done in December of that particular area, biologists found 90 frogs in the charred landscape. Delaney even danced a jig as she and another biologist kept counting the frogs as they walked beneath blackened trees and brushed past sooty branches. This proved to be a happy surprise during what was otherwise a generally gloomy period for Santa Monica Mountains National Recreation Area, of which 88% of the National Park Service land burned in the fire.