Rare Frogs Return to San Bernardino

Interim Editor, Southern Sierran

In September 2005, biologists from the U.S. Geological Survey found 11 endangered mountain yellow-legged frogs in City Creek in San Bernardino County. The species had disappeared from the area more than two years earlier.

Photo courtesy Adam Backlin, U.S. Geological Survey The adult mountain yellow-legged frog can measure 1.5 to 3 inches long. Their bodies are a mix of brown and yellow with dark spots, white or yellow throat, and bellies, and undersides and legs ranging from pale to intense yellow.

In 2003, a fire blackened the watershed and caused flooding that buried the frogs' habitat under 10 feet of sediment. All of the frogs in the area disappeared and biologists expected that the population in the area would not rebound naturally.

But thanks to heavy rainfall in the winter of 2004, the creek was flooded once again, clearing out the sediment and recreating the pools that are essential to sustaining the frog's habitat.

Scientists are still unsure of how the frogs managed to return to the creek, but test results should be released this month to answer that question. USGS Adam Backlin said it is possible that the frogs survived as tadpoles in smaller tributaries in the area, returning to City Creek upon reaching maturity.

'What we hope to learn now is if these new mountain yellow-legged frogs are related to the previous residents in City Creek, and if they are infected with chytrid fungus, a fungi that has been implicated in playing a major role in the decline of this and many other amphibian species globally,' Backlin said.

Photos courtesy Adam Backlin, U.S. Geological Survey Left: City Creek habitat in 2004 after the 2003 fire and debris flows. Right: City Creek habitat in 2005 after 2004-2005 flooding. City Creek is the only creek occupied by the frogs in the San Bernardino Mountains and is one of the locations of Proposed Critical Habitat Designation by the U.S. Fish and Wildlife Service.