To understand these declines, we must document the current distribution of these species over their entire historical range to learn where they have disappeared. In 1988 the California Department of Fish and Game commissioned the California Academy of Sciences to conduct a 6-year study on the status of the state's amphibians and reptiles not currently protected by the Endangered Species Act. This article describes the distribution and status of all native true frogs in California as determined by the California Fish and Game study. The species have also been affected by the widespread introduction of vertebrate and invertebrate aquatic predators. It is not in danger of extinction in the state.
Dots indicate locality records based on verified museum specimens.
Red dots and green squares denote localities where native frogs are extant. Gold dots and blue squares indicate where native frogs are presumed extinct. No habitat loss hypothesis adequately explains why this frog survived with current land-use practices for over 50 years before its decline. It is still abundant in California only in the northern third of its range on lands under federal ownership. Most populations were apparently healthy until the mid-1970's, when a population crash occurred in southern California and the Sierra Nevada foothills after several years of severe floods and drought, which may have been responsible for the declines, although it is not certain.