Rumours of Australian possum's death were greatly exaggerated

Rachel Nowak, New Scientist 31 Mar 09;

Last December, the Australian lemuroid ringtail possum was widely reported as the first possible extinction casualty of climate changeMovie Camera.

But last week it rose from the dead with ecologists reporting the discovery of three of the creatures and declaring that the species was never feared extinct. But its future is far from certain.

"They have a very limited range – most likely due to an inability to tolerate high temperatures – so they are at risk from future temperature extremes," says ecophysiologist Andrew Krockenberger of James Cook University in Cairns, Australia.

Stephen Williams of James Cook University in Townsville agrees. "There has been a massive decline in one population. One more hot summer could wipe [that population] out."
Media confusion

Last December, the story took on a life of its own when Williams made an off-the-cuff remark to a local journalist that the possums may already be extinct from the Carbine plateau in the Daintree National Park in northern Queensland. With no sightings in three years, the fear was that the population had been wiped out by record temperatures in 2005.

However, there is a second population of lemuroid ringtail possums (Hemibelideus lemuroides) living on the Atherton tablelands, roughly 100 kilometres south. This population remains in relatively good health.

The story became further confused because roughly 40% of lemuroid ringtail possums living on the Carbine plateau are white, the rest brown – many reports equated the different colours with different species.

These points became irrelevant two weeks ago, though, when, during a last ditch attempt to find whether any of the Carbine plateau population had survived, Williams spotted three of the possums.

"They're hanging in there. But we are completely certain that the species has severely declined – this is not a false alarm," Williams says.
Rapid decline?

Last year the lemuroid ringtail possum was declared not to be at high risk of extinction by the Red List, an influential although recently criticised barometer of extinction risk.

Although the Red List assessment was published in 2008, it "was done in 2006, or very early 2007", so could now be out of date, agrees Scott Burnett of the University of the Sunshine Coast in Queensland, one of the Red List assessors.

He cautions, however, that a road built in the late 1980s through the region occupied by the Carbine plateau population may have made it temporarily easier to count the animals, and that could be a "confounding factor".

Possums are usually counted by shining spotlights from the road into the rainforest, so sightings may have become less frequent as the forest canopy grows back, he says.