Global Warming could kill Mountain Pygmy Possum

February 18, 2007

Australia's mountain pygmy possum could be extinct within a decade, with climate change already pushing numbers to record critical lows, new research shows. The tiny possums are facing starvation, as warming temperatures disrupt their winter hibernation, waking them before the arrival of their main food source - the bogong moth. Last year, Australia's warmest spring on record rapidly melted high-altitude snow in Kosciuszko National Park by the first week of September, waking the possums more than a month before the arrival of the bogongs.

NSW National Parks wildlife ecologist Dr Linda Broome said, ''The situation is looking quite desperate, because normally the possums wake up in October or as late as November, when there are already plenty of moths about. ''... Without a plentiful supply of this rich source of fat and protein to replenish their winter fat reserves, the possums can die from stress or starvation.

''They're also more vulnerable to predation by feral cats and foxes because they're forced to move out from their shelters in the cracks and crevices of boulders to look for seeds and berries.'' When the annual mass migration of bogong moths arrived in the Australian Alps in 2006, numbers were well down on previous years due to the severity of the drought in Queensland and western NSW where the moth larvae feed on grasses and crops, Dr Broome said. ''There isn't much food about for the possums this year, so it's quite worrying. The situation is becoming steadily worse and we could lose them within 10 years if these warming trends continue. It's terribly disheartening.''

Trapping surveys last December in Kosciuszko National Park failed to locate any possums at Mount Townsend and only four males were recorded at Charlotte Pass. At Mount Blue Cow, the number of females recorded during field surveys had plummeted from 31 to two females, with only MountKosciuszko offering a glimmer of hope for the survival of the species, with 60 possums recorded. ''It looks like there's one population hanging in there, but they were obviously very hungry because they were quite skinny and ate all the walnuts in the traps. That's never happened before.'' The possums usually hibernate around May, doubling their body weight in late summer and autumn. During hibernation, they reduce their body temperatures from 36degrees to about 2 degrees. Air temperature strongly affects the duration and efficiency of hibernation, with warmer temperatures causing more frequent waking and loss of energy and fat reserves.

''If they wake up too often, it uses an enormous amount of energy and really weakens their systems.'' Increased fire frequency and drought linked to climate change was also destroying the possum's secondary food source, the slow- growing mountain plum pine. DrBroome said after the 2003 fires burnt 80 per cent of possum habitat at Mount Blue Cow, volunteers planted 500 mountain plum pine seedlings, but drought killed about 50 per cent of these. ''We raised another 400 from cuttings to replace them, but it was far too dry last spring to plant them out,'' she said.

Dr Broome, who has studied the critically endangered possums for more than 20 years, said ''desperate measures'' were being discussed, such as supplementary feeding with seeds and nuts to stop the possums starving. ''You could scatter seeds and walnuts to keep them going, but how long can you realistically do that for? There's also a risk that it could bring disease into the population.'' At first the 40g possums, which date back 20,000 years, were only known from fossil remains discovered in 1895 and were presumed extinct. A live animal was found in 1966. *Canberra Times