July 25, 2009

Endangered Frogs Found In California

Scientists have discovered evidence of a practically extinct mountain yellow-legged frog in Southern California, where the amphibian has not been spotted in a half-century.

Like other amphibians whose populations continue to decline, the frog was thought to have only about 122 adults in the San Gabriel, San Bernardino and San Jacinto mountain ranges.

In June, U.S. Geological Survey biologists and a research team from the San Diego Natural History Museum separately discovered a mountain yellow-legged frog at places that were 2 1/2 miles apart from each other in the Tahquitz and Willow creeks area of the San Jacintos.

The USGS team was only trying to test the area for the idea of reviving the species, ecologist Adam Backlin said Friday to AP News.

In 10 years of developing the species, 300 areas had been reviewed in the mountain ranges without any large amounts being found, Backlin said. The first frog was discovered on June 10 in Tahquitz Creek.

"We were just blown away," he said.

Scientists were aware that the frogs had a habitat there around 50 years ago because museums have specimens from the region, Backlin said. The historic record notes that the frogs thrived in every region that had a water elevation of 1,200 feet.

"Between 1968, the 1970s, they just disappeared off the map," he said. "We're trying to figure out now what happened. So anything that is still currently out there has probably persisted since that time."

The frogs are shy and hard to find. They typically do not travel much, so the large distance between the newly found frogs is a sign of a large population.

"And if there's a large population, there may be more frogs in that one creek than we know of across the entire range of the species," Backlin said.

The finds follows the San Diego Zoo's first-ever achievement in the proliferation a mountain yellow-legged frog bred in captivity. Tadpoles were taken from a stream in the San Bernardino National Forest and sent to the zoo. One frog completely grew and matured.

"Historically, scientists have had great difficulty breeding frogs in captivity," said Jeff Lemm, an animal research coordinator for the San Diego Zoo. "We are excited by this success and cautiously optimistic we will have more eggs soon."

Backlin noted that captive breeding is tricky because replicating conditions like the chill of winter, when the frogs hibernate, is not an easy thing to do.

"The hope is that we'll get a lot of animals from that captive population this spring and use those to start developing new populations," he said.

"The emergency slope reconstruction project had the dual benefit of opening a road that was about to fail as well as helping to ensure that the last known population of the mountain yellow-legged frog in the San Bernardino Mountains had a program in place to aid the frog's recovery," said Craig Wentworth, a senior environmental planner/biologist with Caltrans, who funded the frog recovery.

Jim Bartel, the field supervisor for the Fish and Wildlife Service office in Carlsbad, stated that his agency is happy to be involved in trying to rescue the mountain yellow-legged frog and save its habitat.

"We look forward to reintroducing the species to its native habitat," Bartel said.

Image Courtesy Adam Backlin, U.S. Geological Survey


On the Net: