Hidden populations of mountain pygmy possum found

By Aaron Smith 3 February 2011
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New populations of the critically endangered mountain pygmy possum have scientists excited.

NEW POPULATIONS OF one of Australia’s most endangered marsupials, the mountain pygmy-possum (Burramys parvus), have been discovered in Kosciuszko National Park.

Previously, scientists thought the tiny creatures, weighing about 45 g, only lived in four isolated populations, covering a total area of just 5 km sq. in southern NSW and the north-eastern Victorian Alps. 

But two pygmy possums were discovered by Australian Museum scientists conducting a routine fauna survey in December 2010 – in a surprising location, says biologist Dr Linda Broome from NSW’s Department of Environment Climate Change and Water, who has studied the species for 25 years.

The marsupials were found 30 km north of their other populations, at 1200 m and 1240 m above sea level – “much lower than that experienced in the southern sites, which are mostly above 1600 m but down to 1400 m,” Linda says.

“There are a lot of basalt boulder habitats in the region, similar to where we found this new population,” she says. “But what is exciting, is this new find is below 1600 metres and this opens up the possibility of discovering some more small populations at these lower elevations.” Linda has identified three small populations, capturing another 34 individuals in the same area.

However, even if more groups are discovered, the whole population of the species would still be fewer than 1,000 individuals, Linda adds.

Mountain pygmy possum under threat

Even with this new addition to the total population, the mountain pygmy possum is still in danger of becoming extinct within a generation. Nevertheless the find is exciting, Linda says. “This may mean they can hang on at low densities and at lower altitudes, which gives me confidence they can survive, but it still requires experimental work correlating temperature and breeding,” she says.

Previously only known in fossil form, the mountain pygmy-possum was thought to be extinct, until 1966 when one was spotted running around a ski lodge kitchen at Mount Hotham.

As the only marsupial known to hibernate under the snow, mountain pygmy possums are now under threat from climate change. Periods of short snow cover and early snow melt, as well as thinning snow cover, all disturb their hibernation. The little marsupials are also threatened by feral cats, foxes, urban development and shrinking supplies of Bogong moths, one of their major food sources.

Fossils found across Australia suggest that mountain pygmy possum relatives were once numerous and had a great geographic distribution. They are now restricted to what Linda calls a “tiny remnant population that could blink out anytime, unless we try to do something about it.”

Bold new strategy for endangered possum

Professor Mike Archer, a palaeobiologist at the University of New South Wales in Sydney warns that we can’t celebrate the long-term viability of the mountain pygmy possums just yet, but hopes a bold new captive breeding strategy could help save them.

Convinced the mountain pygmy possums followed encroaching rainforest up the mountain in a previous warming period, Mike thinks they then became trapped up there in the boulder fields when the rainforests disappeared. Unlike a conventional captive-breeding effort that is focussing on re-releasing animals to their ever-shrinking alpine habitats, the establishment of a colony in lowland rainforest, abundant in NSW and Victoria, could be an effective solution, Mike says.

Trevor Evans, the AG Society’s 2010 Conservationist of the Year, who founded the Secret Creek species conservation area in Lithgow, NSW, believes this new population is a prime candidate for a breeding program as it makes the adaptation to lower altitude a little bit easier.

“Given half a chance they could repopulate the Snowy [Mountains]. It’s preferred [that] they could do it by themselves, but we are planning on giving them a helping hand,” Trevor says.

A program to breed a population of the marsupials at Secret Creek is still in the planning stage, and Trevor is trying to raise funds to survey the site and analyse DNA samples of the animals. To ensure the future of this species, the captive breeding program will cost in excess of a million dollars. The Foundation for National Parks and Wildlife, Australian Geographic and the Paddy Pallin Foundation together have raised more than $63,000 since September last year.