There were no known sightings of this critically endangered animal outside Victoria. Now it’s in NSW

A critically endangered Leadbeater’s possum – previously thought to be extinct in NSW – has been discovered in Kosciuszko National Park, to the delight of ecologists.

The discovery of the sole possum near the Yarrangobilly Caves indicates the presence of a colony of the tiny creatures, which weigh just 125 grams.

The historic find was made last Monday during a review by threatened-species officers from the NSW environment department of almost 1 million images from wildlife cameras as they surveyed for the critically endangered smoky mouse.

The cameras had been in the field for a year, and the photos of the possum were taken last October.

Dr Fred Ford, the senior threatened-species officer who made the discovery, said: “It was amazing to see that distinctive bushy tail waving among the rows of images on the screen – it jumped right out at me.”

The find came after a ground and aerial culling program removed 9036 wild horses from Kosciuszko National Park between November 2021 and April 30 this year. It is the first NSW sighting recorded since European settlement.

Leadbeater’s possums, which are critically endangered, were thought in the 1940s and 1950s to be extinct in Victoria before a small population was discovered in mountain ash forest near Marysville in 1961.

Ecologist Professor David Lindenmayer from the Australian National University, who has spent decades studying the animals, said they favoured habitat with tall trees for nesting and wattle understorey for food sources.

“How exciting it is to live in a country where discoveries are being made,” Lindenmayer said. “This discovery highlights the importance of large national parks for biodiversity.”

Lindenmayer, a member of the Biodiversity Council, unsuccessfully searched for Leadbeater’s possums near the Yarrangobilly Caves in the 1980s, after identifying the habitat as attractive for the creatures, which are commonly called “forest fairies”.

He said it was likely the possum, which was discovered close to the area he had searched (before the advent of motion-sensor camera traps), was a separate subspecies that had been isolated for a long time.

NSW Environment Minister Penny Sharpe said it was extraordinary to discover a species previously thought to be extinct in the state.

“This special find in Kosciuszko National Park once again highlights why the Minns Labor government is taking action to remove invasive species to protect Australia’s only mainland alpine region, which spans the NSW and Victoria border.”

Critically endangered Leadbeater’s possums in Victoria.Credit: Justin Cally

Victorian Environment Minister Steve Dimopoulos said his government stood ready to offer expertise “to give the species hope for the future on both sides of the border”.

“The discovery of a new, separate population brings hope for the conservation of this species and reduces the risk to the species from single catastrophic events.”

The Biodiversity Council says the discovery highlighted the importance of conserving large areas of high-quality habitats, even if significant species had not previously been detected.

Threatened-species officers in NSW will now work to identify the size and extent of the Leadbeater’s colony in Kosciuszko. They will deploy cameras across mountain forests in the park, using methods developed in Victoria.

Partially fossilised records show Leadbeater’s possums also once lived near the Wombeyan Caves, outside Goulburn in southern NSW, and near Buchan Caves in north-eastern Victoria.

It is estimated that only 4000 Leadbeater’s possums remain in the wild in Victoria. There are two distinct genetic groups of Leadbeater’s possums in Victoria: highland and lowland, and there are thought to be as few as 40 lowland possums remaining in the wild.

It’s not known what subspecies the possum discovered in NSW belongs to.

A team from Zoos Victoria has released a male lowland possum named Mercury, and a female highland possum, Narvi, into protected bushland in the hope they will breed and form a new colony.

Lisa Stuart is a bushland ranger with Healesville Sanctuary’s Coranderrk Bushland Nature Conservation Reserve north-east of Melbourne. Stuart has dedicated nine years to restoring the swampy habitat into a “Goldilocks” ecological setting, with 140,000 trees densely planted in the eight-hectare floodplain.

“The mid-storey is vitally important because it creates connectivity that Leadbeater’s possums need to move around safely, and it provides access to tall eucalyptus where the possums can forage for sap and invertebrates,” Stuart said.

“I was a little bit teary when we put the nest box on a tree because I’ve been working on this for such a long time. To see the possums out there doing their thing, using the habitat we have created, it was a special thing for me.”

Lindenmayer said the NSW discovery underscored the importance of large and intact national parks, and called on the Victorian government to back the Great Forest National Park proposal, which would link a patchwork of national parks and state forests.

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