By Anthony Brown
In the mountainous rainforests of Australia, something terrible is happening. Scientists first noticed the phenomenon in 1979. Since then, it has stuck ruthlessly. Its victims simply vanish, either totally or from certain locations. Whatever it is, scientists are worried. Australia's frogs are under threat from an unknown enemy.
Six species of frog have disappeared, and another five are suffering from drastic declines in population, threatening them with extinction.
The declines are happening in areas that are protected as nature reserves and are thus not linked to any overt environmental degradation, such as logging or mining.
Between 1979 and 1986 four species, the southern and northern platypus frogs and the southern and Eungella day frogs, disappeared for no apparent reason. The platypus frog is famous for its remarkable ability to carry its newborn young in its stomach.
To add to the mystery, researchers in South and Central America are also reporting disappearances and massive declines.
Dr Glen Ingram, curator of amphibians at the Queensland Museum in Brisbane, said scientists were befuddled at what was happening and at this stage could only guess at the cause.
Dr Ingram said there were two competing theories to explain what was happening. One is that, because frogs are hypersensitive to changes in their environment, their disappearances may be an early indication of the greenhouse effect.
"If you look at the data, it's not as concrete as you would like. But the thing that seemed to have changed is that we do seem to be having an increase in temperature. We have a very big increase in ultraviolet radiation in Queensland and the rain doesn't seem to be falling as heavily as it used to [much of Queensland is experiencing the longest drought on record]. It tends to spread out over a large time frame, and when it does fall heavily, it tends to fall in the cooler months and, of course, in the cooler months is when frogs don't breed."
He said if the greenhouse effect is the cause, then human beings should worry.
"It just basically means that our atmosphere might be becoming poisonous around us. If frogs are the first indication, we really have got a big trouble in the sense that it would take many years for us to cause the changes to stop and go back to where we were. In that time, humans are going to have a bad time of it, just like any animal."
Dr Ingram said the other theory was that it could be an unknown disease. Researchers were looking at both theories seriously.
Dr Ingram is president of the Australian Frog Trust, established by the Wildlife Preservation Society of Queensland to raise funds for research into why frogs are disappearing. To contact the Australian Frog Trust to help with fundraising and/or publicity, ring (07) 221 0194.