NSW DCCEEW researchers discover critically endangered Leadbeater's possum in Kosciuszko National Park, Australia

Tuesday, June 3, 2025

Last week, the NSW Department of Climate Change, Energy, the Environment and Water (DCCEEW) research team - more specifically, Martin Shultz and Fred Ford - have discovered seven photographs of the Leadbeater's possum near Yarrangobilly Caves, amidst the footage taken in October in Kosciuszko National Park, NSW, Australia, as they were going through nearly 1 million photos from trail cameras set up to conduct a survey of the smoky mouse. While both species are critically endangered in Australia, Leadbeater's possum was previously thought to be extinct in NSW, with the only known current populations being observed in Victoria, where the species is the mammal emblem of the state since 1971. The NSW Government has started the application for an expedited conservation listing of the Leadbeater's possum with the NSW Threatened Species Scientific Committee. The finding has been confirmed by the Healesville Sanctuary and the Australian National University (ANU).

Biodiversity Council member Professor David Lindenmayer from ANU has previously, 35 years ago, while pursuing a PhD, spent a few months around Yarrangobilly looking for the signs of presence of the Leadbeater's possum, due to the prediction of a climate model that the species may be found at that location, but "never saw one in the park". In his own words, "With so little high-quality habitat left in Australia, we should do our utmost to protect remaining areas; hopefully, there will be many more wonderful discoveries ahead, especially as detection techniques improve." He further indicated that large parks like the "iconic" Kosciuszko National Park and the other major reserves in Australia should be provided for as necessary, as they are critical for biodiversity conservation.

Dr Dan Harley, a Senior Ecologist at Healesville Sanctuary, noted that the NSW discovery, despite its unexpectedness, "in no way" changes the species' Critically Endangered status for the moment. Nevertheless, it has become a promising development for the future of the species that has been very close to extinction, as he noted past developments relating to the rediscovery of the species in 1961 and the discovery of its lowland and subalpine populations in 1986 and the 1990s respectively, which give rise to hope that the recent Black Summer bushfires might not have entirely destroyed the possibility of a remnant population of the species remaining in Victoria's northeast. Further, he said: "The discovery of the species further north in NSW was completely unexpected, and is a remarkable turn of events. Within Victoria there is strong genetic differentiation between highland and lowland Leadbeater’s possums over a small distance. On this basis, and given the large distance between the Victorian populations in the Central Highlands and the NSW discovery site, it is highly probable that the NSW population is genetically distinct from populations in Victoria. Once the genetic results are in, I expect that we will have Northern Leadbeater’s possums in NSW and Southern Leadbeater’s possums in Victoria, each with distinctive management requirements."

Adult Leadbeater's possum, also known as fairy possum due to difficulty of observing one in the wild, is approximately 40cm long and 125g in weight. There are two varieties of them found in Victoria, as described above, and there are less than 40 lowland Leadbeater's possums left. Healesville Sanctuary has established a captive breeding program with another variety of the Leadbeater's possums, the highland ones, successfully raising Narvi, a female highland possum who has been released at the predator-free Coranderrk Bushland Nature together with a lowland possum, Mercury, with the goal of establishing a new colony. Healesville field officer Arabella Eyre stated that cross-population breeding would hopefully improve genetic diversity in the wild populations: "The lowland population is so small, there are fewer than 40 individuals left in the wild," she said. "That's nine breeding pairs, and that can only hold on for so long. Without being able to bring in genetic diversity, we expect that they will be extinct within the next 15 years." Which is why this first attempt for the sanctuary to match a mixed pairing is so important. Healesville Sanctuary's threatened species keeper Amie Hindson explained that there was immediate rapport between them from night one, expressing that "They're a really special love story for us."

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Sources

Alasdair McDonald. Endangered Leadbeater's possum found in Kosciuszko National Park — ABC, June 1, 2025
Hello Possum! Species thought extinct in NSW found in Kosciuszko National Park — Lismore App, June 1, 2025
Kamilia Palu. Trail camera captures extinct animal in iconic Aussie national park: 'Extraordinary' — Yahoo! News, June 1, 2025
First Leadbeater’s possum detection in NSW shows importance of protecting big conservation areas — Biodiversity Council, May 31, 2025
Invasive Species Council. 🥰💚Some good news! A critically endangered Leadbeater’s possum – previously thought to be extinct in NSW – has been discovered in Kosciuszko National Park!! — Facebook, June 1, 2025
Danielle Pope. Breeding program launched in Victoria for critically endangered Leadbeater's possums — ABC, May 31, 2025

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