New population of mountain yellow-legged frog (Rana muscosa) discovered

For the first time in nearly 50 years, a population of a nearly extinct frog has been re-discovered in the San Bernardino National Forest’s San Jacinto Wilderness. Biologists from the U.S. Geological Survey (USGS) assessing suitability of sites tore-establish frogs and scientists from the San Diego Natural History Museum retracing a 1908 natural history expedition both rediscovered the rare Mountain Yellow-legged Frog (Rana muscosa) in the San Jacinto Wilderness near Idyllwild, California.

The precarious persistence of the Endangered Sierra Madre yellow-legged frog Rana muscosa in southern California, USA

We conducted surveys for the Endangered Sierra Madre yellow-legged frog Rana muscosa throughout southern California to evaluate the current distribution and status of the species. Surveys were conducted during 2000–2009 at 150 unique streams and lakes within the San Gabriel, San Bernardino, San Jacinto, and Palomar mountains of southern California. Only nine small, geographically isolated populations were detected across the four mountain ranges, and all tested positive for the amphibian chytrid fungus Batrachochytrium dendrobatidis. Our data show that when R. muscosa is known to be present it is easily detectable (89%) in a single visit during the frog's active season. We estimate that only 166 adult frogs remained in the wild in 2009. Our research indicates that R. muscosa populations in southern California are threatened by natural and stochastic events and may become extirpated in the near future unless there is some intervention to save them.