EPIDEMIC DISEASE AND THE CATASTROPHIC DECLINE OF AUSTRALIAN RAIN-FOREST FROGS

In the montane rain forests of eastern Australia at least 14 species o f endemic, stream-dwelling frogs have disappeared or declined sharply (by more than 90%) during the past 15 years. We review available infor mation on these declines and present eight lines of evidence that coll ectively suggest that a rapidly spreading, epidemic disease is the mos t likely responsible agent. The extreme virulence of the putative frog pathogen suggests it is likely exotic to Australian rain forests. We propose that exotic pathogens may be responsible for some recent decli nes of amphibian populations on other continents and that the intercon tinental spread of such pathogens is greatly facilitated by human acti vities such as the thriving international trade in aquarium fish. Our hypothesis may help explain why some amphibian populations in seemingl y pristine environments have mysteriously declined.