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Fungus Contributes to Arizona Amphibian Deaths
Date Posted: May 24, 2000A chytrid fungal infection has been identified as the cause of death in a rare species of leopard frog. The Ramsey Canyon leopard frog (Rana subaquavocalis) is confirmed in only two Arizona locations. This is potentially really bad news for the species, and it may explain the winter die-offs and loss of all adult frogs in Ramsey Canyon over the last two years. Chytridiomycosis has been receiving a lot of attention in the amphibian literature of late. Mass mortality and apparent extinctions of frogs and toads in Australia and Central America have been attributed to this same fungal disease. Investigators are finding the fungus in other parts of the world now, including Arizona, where it has been found in lowland leopard frogs, Chiricahua leopard frogs (Rana chiricahuensis), and Rio Grande leopard frogs (Rana berlandieri). Two of the four Tarahumara frogs (Rana tarahumarae), formerly found in Arizona but which are now extinct, captured in the Sierra el Tigre, Sonora, Mexico, and placed in Tucson’s Arizona Sonora Desert Museum in October 1999, also died of chytridiomycosis. Herpetologists have recently found the fungus on seemingly healthy frogs and tadpoles, possibly indicating that additional stressors may trigger the mass die-offs. Stressors may include such things as environmental contaminants, increased UV radiation, habitat destruction or alteration, and introduction of predators and competitors.