Yosemite toads (Bufo canorus) are endemic to the Sierra Nevada, California, from Ebbetts Pass, Alpine County to the Spanish Mountain area, Fresno County (Karlstrom 1962, 1973;
Stebbins 1966; unpublished Sierra National
Forest survey data, 1995, 2002). Sites occur
from 1,950–3,444 m elevation, with the
majority of sites between 2,590–3,048 m
(Karlstrom, 1962). Jennings and Hayes
(1994a) estimate that populations have
disappeared from 50% of historically reported
sites, although the overall range of the species
may have only contracted in the far north and
in western Fresno County. Disappearances
have been concentrated at lower elevation sites
on the western edge of the range, with greater
persistence at higher elevation sites (Davidson
et al., 2002).