Saving the species: this tiny two-year-old is the right possum for the job
May 22, 2012 Bridie Smith
ONE of the country’s rarest mammals and Victoria’s faunal emblem will be the subject of a captive breeding program – the first major breeding and release program for Leadbeater’s possums – as scientists intervene to build up the wild population and establish an insurance population in captivity.
The precarious state of the endangered possum – numbering less than 2000 in the wild – prompted Zoos Victoria to embark on the project after the Black Saturday bushfires destroyed 45 per cent of its habitat and roughly halved the wild population.
Last week Healesville Sanctuary’s threatened species biologist, Dan Harley, identified the ”male founder” of the program, which has passed health checks and had a microchip the size of a grain of rice inserted between his shoulder blades.
The tiny two-year-old, weighing in last Wednesday at 131 grams, hails from the Yellingbo Nature Conservation Reserve, 50 kilometres east of Melbourne. It’s here in the swampy forest – no more than four kilometres long and 120 metres wide – that the only population of lowland Leadbeater’s possums live. In the past eight years there has been a 40 per cent decline in population, with fewer than than 70 individuals remaining.
The animals are genetically distinct from their central highland cousins after thousands of years of isolation. But their low numbers mean the Yellingbo Leadbeater’s possums are considered most at risk of extinction. ”A single fire could wipe them out,” Dr Harley said.
This fragile existence has made them prime candidates for captive breeding and Dr Harley is now scouring the reserve for a suitable female mate. The task is easier said than done – the animals breed for life, so researchers have to be careful which they remove. And the breeding animals selected not only have to be single and healthy, they need a fair dollop of ”street cred” as well.
”An animal that has been able to cut it in the wild for a few years is far more valuable to us than a young animal just out of the pouch,” Dr Harley said.
Two breeding pairs a year will join the captive breeding program over the next three years, with scientists monitoring the genetic diversity and health of their offspring as they climb towards their target of 150 wild animals.
Melanie Lancaster, assistant curator for threatened species, said infrared cameras would monitor the founding animals in their enclosure, allowing researchers to ensure they retained key behaviours vital for their survival in the wild post-release.