THE MERCURY (Hobart, Australia) 29 October 08 Disease wiping out frogs (Helen Kempton)
Fungal disease, not climate change, is pushing frog populations to the brink of extinction, a scientist has argued.
However, University of Tasmania Professor Hamish McCallum said more research was needed to gauge what dangers chytridiomycosis posed to Tasmania's frog populations.
The fungal disease, which already has wiped out 67 species of frogs, including four in Queensland, was first reported in Tasmania in 2004. Since then it has been found on the fringe of the South-West Wilderness World Heritage Area.
A $400,000 monitoring program is under way through Natural Resource Management North to see where the disease may have spread in Tasmania and what species were most susceptible to it.
Department of Primary Industry and Water zoologist Mike Driessen said facilities would also be set up so samples could be analysed in Tasmania.
Mr Driessen said at this stage it appeared the fungal disease was spread through human activity.
More than 32 per cent of amphibians worldwide are now under threat and Prof McCallum joined academics from the University of Florida and Penn State University to co-author a paper on frog population decline.
The paper asserts climate change was not speeding up the spread of disease.
The paper, Evaluating the links between climate, disease spread and amphibian decline, was published in US publication Proceedings of the National Academy of Sciences.
While scientists had known the disease was decimating frog populations -- particularly in Australia's tropics and in Central and South America -- there was also a suggestion global warming had sped up its passage.
Prof. McCallum said sophisticated statistical techniques were used to evaluate two competing hypotheses -- one that the disease was introduced recently and the pattern of extinctions was consistent with the spread of an invasive disease and the second that global warming had caused increased cloud cover leading to warmer night and cooler daytime temperatures which meant the fungus was able to grow faster.
When the scientists looked at the specific climate variables which might affect the growth of pathogens, they found no evidence that observed climate changes were associated with increased growth of the fungus.
Disease wiping out frogs