It was widely distributed in high elevation water bodies from southern Plumas County to southern Tulare County. Recent surveys found that the species has disappeared from 70 to 90 percent of its historic localities. Remaining frog populations are widely scattered and consist of few breeding adults. What was recently thought to be one of the largest remaining populations, containing over 2000 adult frogs in 1996, has completely collapsed - only two frogs were found in the same area in 1999. The Yosemite toad was historically common in the high country of the central Sierra Nevada, from Fresno to Alpine Counties.
Recent surveys report that it has disappeared from a majority of historic sites.
Declines have been especially alarming in Yosemite National Park, with studies at Tioga Pass documenting wholesale population crashes. Both amphibian species and their habitats have been adversely impacted by introduced fish, pesticides, ozone depletion, pathogens, and cattle grazing. This is particularly true of the Sierra Nevada, where over half of the native amphibians are in decline or warrant some type of formal protection. Yet the federal government's new Framework Plan for managing Sierra national forests contains virtually no enforceable protections for amphibians. Pollutants cause direct mortality and delay, alter, or reduce breeding and feeding activity and larval development.