Why are amphibians considered indicators of aquatic ecosystem health?
Many species of amphibians spend most of their lives in water and breathe at least partially through their skin making them highly sensitive to changes in their aquatic environments. Worldwide many species of amphibians including frogs, toads, and salamanders are declining. Scientists are working hard to find answers as to why many amphibian species are declining, even those that live in areas relatively untouched by humans. In California, several species are already listed under the Act, including the threatened California red-legged frog (Rana aurora draytonii) and the endangered arroyo toad (Bufo californicus). Q. Are other populations of mountain yellow-legged frog declining? Yes. In October 2000, the Service published a 90-day administrative finding on a petition to list the Sierra Nevada populations of mountain yellow-legged frog as endangered pursuant to the Act. The Service concluded that the petition provided substantial information and that listing of the Sierra Nevada popula
