PRESS-ENTERPRISE (Riverside, California) 20 November 06 Scientists step in to save endangered tadpoles - Mountain yellow-legged frogs are one of the Inland region's most imperiled animal species. (Jennifer Bowles)
Biologists, worried that an endangered frog species could slip even closer to extinction, snatched dozens of tadpoles facing certain death in the San Jacinto Mountains so they could be raised in captivity and returned to the wild.
Mountain yellow-legged frogs are one of the Inland region's most endangered species. Adam Backlin, a U.S. Geological Survey ecologist, estimated that 100 to 150 frogs remain across the San Bernardino, San Jacinto and San Gabriel mountain ranges.
When the 2003 wildfires tore through the southern face of the San Bernardino Mountains, the flames burned the trees and shrubs around one of the frogs' strongholds, worrying biologists that an impending flood could wipe them out.
Eleven of the frogs were rescued back then and taken to the Los Angeles Zoo. Seven that survived later died of a bacterial infection after they were transferred to the San Diego Zoo's center for Conservation and Research for Endangered Species in Escondido.
In the latest rescue, Backlin and other federal scientists noticed in August that pools in a tributary of the north fork of the San Jacinto River northwest of Idyllwild were dangerously low. They used nets to scoop 82 tadpoles into disposable plastic containers and took them in coolers to the zoo's research facility in Escondido.
"When (the population) gets that low, we just have to step in and do whatever we have to do to keep them alive," said Jeff Lemm, the facility's research animal coordinator.
"They were all going to die," he said. "It was pretty much guaranteed."
Backlin said there was no suitable habitat into which to relocate the tadpoles. Other tadpoles upstream were left behind, because the pools appeared stable, he said.
Of those rescued, five tadpoles died shortly after arriving at the zoo's facility, Lemm said.
So far, 10 tadpoles have metamorphosed into froglets, and the rest are in good condition, feasting on fish food, zucchini, spinach, romaine lettuce and the algae that builds up on the 55-gallon tanks, Lemm said.
None show signs of a fungus associated with the frogs that died previously, said Allan Pessier, veterinary pathologist.
Lemm said he will feel more comfortable about their survival once they have reached adulthood, probably in the spring. At that point, he said, a decision will be made by federal and state wildlife agencies and the U.S. Forest Service on how many to return to the wild.
Others will stay at the facility to establish a captive-breeding program, Lemm said.
Lemm and Backlin said frogs, because they live in water and on the ground, are strong indicators of environmental health; when they aren't doing well, something could be wrong with the streams that provide drinking water for humans.
"Once they start dropping out, it should throw up some red flags that the ecosystem is having some problems," Backlin said. "They're declining worldwide, and it's a real indication that we should be looking at ways to improve the environment for our own sake."
Scientists step in to save endangered tadpoles