Global warming and amphibian extinctions in eastern Australia

Pounds et al. recently argued that the dramatic, fungal pathogen-linked extinctions of numerous harlequin frogs (Atelopus spp.) in upland rainforests of South America mostly occurred immediately following exceptionally warm years, implicating global warming as a likely trigger for these extinctions. I tested this hypothesis using temperature data for eastern Australia, where at least 14 upland-rainforest frog species have also experienced extinctions or striking population declines attributed to the same fungal pathogen, and where temperatures have also risen significantly in recent decades. My analyses provide little direct support for the warm-year hypothesis of Pounds et al., although my statistical power to detect effects of small (0.5 degrees C) temperature increases was limited. However, I found stronger support for a modified version of the warm-year hypothesis, whereby frog declines were likely to occur following three consecutive years of unusually warm weather. This trend was apparent only at tropical latitudes, where rising minimum temperatures were greatest. Although much remains uncertain, my findings appear consistent with the notion that global warming could predispose some upland amphibian populations to virulent pathogens.