Cryptic Declines in a Widespread Australian Frog Complex

(Bd). Occupancy declined sharply with elevation, from 71% at low elevations to 28% in upland areas, with counts of calling males showing a similar pattern. Bd prevalence increased from 6.7% at low elevations to 29.2% in upland sites, with the highest infection intensities also recorded at higher elevations. These findings implicate Bd as a potential contributor to upland declines, possibly alongside other environmental pressures. Our results demonstrate that common species can undergo substantial, unrecognized contractions in the absence of targeted monitoring and provide an example of time-lagged declines potentially associated with chytrid fungus.