A battle to save a critically endangered possum is being fought on many fronts and multiple timelines.
Victoria’s Leadbeater’s possum, known as “forest fairies” for their elusiveness, were thought to be extinct when they were rediscovered near Marysville in 1961.
The state’s faunal emblem, with its big eyes and bushy tail, relies on dense, damp areas in old growth forest and nests in hollows that take over 150 years to form.
Less than 40 of the lowland subspecies exist today in a tract of the Yellingbo Forest, east of Melbourne, after most of its habitat was lost to logging and development.
But a project spearheaded by state-owned statutory authority Melbourne Water aims to grow the creature’s future habitat through a climate-modelled seed bank.
The seeds have been collected from areas with climatic conditions similar to what is expected for the Yarra Valley in the next 25 to 65 years.
The sources span from forests in Gippsland, in Victoria’s southeast, to Wyong, north of Sydney.
“We know that to save the lowland Leadbeater’s possum from extinction, we need to protect and expand its habitat by growing forests that will be resilient to hotter, drier climates,” Melbourne Water partnership coordinator Kacie Melfi said.
Six species of native trees were shortlisted to help shore-up future habitat for the Leadbeater’s possum.
Melbourne Water is working with Zoos Victoria and Victoria’s Department of Energy, Environment and Climate Action to identify land that could provide future habitat for the species.
A collaboration between Zoos Victoria and Monash University focuses on the creature’s gene pool to assure its survival.
The organisations have successfully bred a hybrid of the highland Leadbeater’s subspecies with its lowland counterpart in captivity, to help stem the inbreeding depression in the latter variety.
“We’ve got 39 (lowland) individuals left in the wild; that’s just nine breeding pairs,” Zoos Victoria field officer Arabella Eyre told AAP.
“We’re really excited that we’ve recently produced our first hybrid joey.”
Previous attempts to move the highland Leadbeater’s possums from their ash forest and sub-alpine woodlands habitat in Victoria’s Central Highlands into lowlands populations haven’t been successful.
“That’s why testing in captivity and having the ability to test that mixing in a controlled environment is really important for us,” Ms Eyre said.
Another key feature of the conservation program is to temporarily house juveniles, who can be lost to predators like cats or by wandering into unsuitable habitat.
“The problem being a possum is when you hit your teenage years and it’s time to go find a mate, there’s not that many options left in the wild,” Ms Eyre said.
“We’re able to collect those sub adults just before they disperse, take them back to Healesville sanctuary and kind of play possum matchmaker and then re-release them into the wild.”
Habitat loss remains a major challenge.
“We’ve cleared over 90 per cent of lowland Leadbeater’s habitat; they were originally distributed all the way down to Koo Wee Rup and the Bass River, and now only in this single reserve,” Ms Eyre said.
“The story of the possum’s decline is really a story of the loss of habitat.”
While Victoria’s environment department was a partner in conservation efforts like the seed bank project, its Forest Fire Management Victoria branch was levelling thousands of hectares for strategic fire breaks, forest ecology expert David Lindenmayer said.
“This is in complete conflict with other really important, direct things that we could do right now, like not knock the animals’ nest trees down that are 300 or 400 years old, that are going to take centuries to regrow,” he told AAP.
“One part of the department is not talking to the other part of the department.”
Victoria banned commercial native logging in January but a dead endangered greater glider possum found near fire break works in the Yarra Ranges National Park in May reignited debate over the state’s forests.
“The reality is there’s 18,000 hectares of forest that hasn’t regenerated (after commercial logging), and we’re knocking down 300 year old trees for firebreaks that don’t work,” Professor Lindenmayer said.
He said research had shown for more than a decade that logged forests became more fire-prone.
But the department argues fuel breaks retained far more trees and couldn’t be compared to disused logging coupes.
According to Forest Fire Management Victoria, asset protection fire breaks protect towns and public assets, while landscape protection breaks give firefighters access to blazes in the bush and to back-burn.
The organisation has established 1447km of fuel breaks, between 20m and 40m wide across Victoria, and has funding to extend to 6000km of breaks by 2030.
Forest Fire Management Victoria chief fire officer Chris Hardman said regeneration and fire breaks were a proven and effective tool against bushfires.
“In the Upper Yarra catchment, fuel breaks help us keep bushfires small and therefore protect communities, assets such as Melbourne’s main water supply, and the environment – including protecting the habitat of the vulnerable population of Leadbeater’s possum from bushfires,” Mr Hardman said in a statement.
Forest Fire Management Victoria maps show no new strategic breaks are planned within 34 kilometres of Yellingbo Forest, and no felling is occurring on seed bank sites in the Yarra Valley.
Prof Lindenmayer felt his warnings about the Leadbeater’s possum habitat, which went back to his doctoral thesis in 1989, were falling on deaf ears.
“We’re knocking down 300 year old trees,” he said.
“It’s going to be the year 2300 by the time we get them back again.”
Adrian Black
(Australian Associated Press)