According to a report in the Idyllwild Town Crier, mountain yellow-legged frogs released last summer at the NRS’s James San Jacinto Mountains Reserve made it through winter but are now succumbing to drought.
In early August, biologists from the San Diego Zoo’s Institute for Conservation Research surveyed two San Jacinto Mountain creeks that had received captive-bred tadpoles in 2013. Roughly 25 percent of the amphibians had survived, the scientists report. Despite the high mortality rate, there are still “a significant number of frogs that are healthy and growing,” according to institute research coordinator Frank Santana. The researchers intend to continue checking on the released frogs every three weeks throughout the summer.
Biologists suspect drought has made the frogs more susceptible to the Chytridiomycota fungus associated with mass amphibian deaths around the world. Known as the chytrid fungus, the pathogen is causing dieoffs of mountain yellow-legged frogs in Southern California’s San Gabriel Mountains this year. The San Gabriels and the rest of California are experiencing exceptionally dry conditions after three years of below-recorded-average rainfall.
The mountain yellow-legged frog (Rana muscosa) is considered among the most endangered amphibians in California. Though once plentiful in the San Gabriel, San Bernardino, and San Jacinto mountains, fewer than 200 frogs are believed to survive in the area.
The frogs were released as part of an effort to restore the species that dates back to 2010. Program partners include the San Diego Zoo, the U.S. Geological Survey, U.S. Forest Service, U.S. Fish and Wildlife Service, California Department of Fish and Wildlife, and the University of California.