Foundation ‘get together’ raises funds to
save endangered Corroboree Frogs
Edwina Priest

Southern Corroboree Frog Photo Arthur White

These tiny yet striking frogs, which grow to only 25 millimetres as adults, sport bright yellow stripes across their jet black bodies. They are unique to a very small sub-alpine area (about 400 square kilometres) of snow gum woodlands and spongy sphagnum moss bogs in Kosciuszko National Park in New South Wales - one of the coldest parts of the Australian mainland. The frogs are found only at altitudes above 1300 metres in the Snowy Mountains.

Healthy indicators

Frogs are often described as indicators of a healthy ecosystem and have a vital role in providing important information about the state of the environment. As they are highly sensitive to changes in their environment, their disappearance clearly marks and imbalance in the greater ecosystem. Thinning of the ozone layer, global warming, air and water pollution, as well as the spread of disease are all contributing factors.

“Frog populations have been in decline both in Australia and around the world for some time now, which tells us we are in trouble,” said Rod Pietsch, Threatened Species Officer, Department of Environment and Conservation (DEC).

“Within two decades, previously secure species such as the Corroboree Frog have become critically endangered, while other species have even become extinct altogether. What’s very worrying is that these extinctions have occurred in areas that are only slightly disturbed such as remote rainforest habitats and alpine areas,” he said.

Wild Population Declines

The Southern Corroboree Frog suffered a drastic population decline and a significant range contraction in the early 1980s, which has resulted in less than a few hundred adult frogs left in the wild today. Scientists have assumed that a range of factors including climate change and introduced fungal diseases such as the highly infectious chytridiomycosis have caused the frog population to diminish at an alarming rate.

While it remains unclear to scientists as to whether climatic change has contributed to the frog population’s decline, research indicates that Corroboree Frog eggs and tadpoles are susceptible to changes in rainfall patterns and temperatures that can lead to early pool drying.

“Corroboree Frogs have adapted to living in colder climates, however some winters may now not be long, cold or wet enough for them to breed effectively,” said Rod.

He also added that very little is known about mortality in the population once juvenile frogs leave the pools for the surrounding non-breeding habitat where they remain for two years before returning as breeding adults.

Southern Corroboree Frog breeding tanks Photo Amphibian Research Centre Victoria

Captive breeding program

In 2001, the Foundation directed funds from its Endangered Species Appeal towards a long-term captive breeding program conducted by DEC to re-establish Corroboree Frogs. Scientists decided that as a last resort active intervention was necessary to save the species from becoming extinct.

Eggs were delicately gathered from the wild and taken to the Amphibian Research Centre (ARC) in Melbourne where they were raised under strict quarantine to avoid them becoming infected with the chytrid fungus, which is believed to be largely responsible for their demise.

Release to the wild

In December 2005, DEC scientists will release several hundred sexually mature three year old frogs back in to Kosciuszko National Park where it is hoped they will bolster the wild population and breed.

“This is an exciting phase in the recovery of the endangered Corroboree Frog and we’re hoping that our efforts will reverse the imminent threat of extinction. Of course there’s no guarantee that the Corroboree Frog will be saved but we, along with the Foundation, have to at least make the effort,” said Rod.

As a precaution, not all frogs raised in captivity will be released back into the wild. Many will remain in captivity as insurance against extinction, as well as to produce more offspring for subsequent releases.

“The newly released frogs will be carefully monitored in the months and years ahead to see just how successful the release might have been,” concluded Rod.

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