Rare yellow-legged frogs are returned to drought-hammered San Gabriel Mountains
By the end of March and April, the orange-and-yellow frogs at the bottom of Lake Cachuma near Interstate 5 will have returned, having been released from the San Gabriel Mountains in the aftermath of the first spring rain in 30 years.
For most of the past two decades, all the frogs were presumed to have been lost. In recent years, most of the San Gabriel Mountains have seen some of their most damaging storms, including several that have dropped more than a foot of rain in the span of a few days. And in one spring, the rains, combined with a drought, turned the mountains so dry that many of the frogs were all but impossible to find.
But this year, the frogs returned in numbers, and now scientists think they might be safe for the next 20 or 30 years.
“The frogs have been missing for two generations,” said Robert Wood Johnson, a professor of science and ecology at the University of Southern California. “And the climate is not expected to change much, so we really don’t expect long-term problems.”
In the spring, the frogs had to be released under very strict conditions, such as a temperature of 70 degrees at night and a safe depth of six inches, said Robert Shuster, director of the San Gabriel Mountains Science Center, or SGMSC. The frogs were placed in a special cage that had been lined with insulation and gravel.
After the frogs were released to begin living outdoors, they started to breed in a special area of the lake. In some cages, the breeding was successful, and many babies were born. In others, the eggs were still developing and sometimes the babies died. Then, after the new babies were released alive, the scientists determined which babies had survived and which had not.
These babies were then released in another cage with more insulation and gravel to keep the weather out, and the process was repeated.
The frogs were released on March 24, the first day of the official beginning of the rainy season. By April 11, they would all have been released.
The first rain came on April 12. Shuster said the day was
