New sightings of the critically endangered Leadbeater’s possum are no insurance against extinction
Researchers have recorded five new sightings of the critically endangered Leadbeater’s possum, but their location close to existing habitats means the species remains at risk of extinction – particularly from bushfire.
The 2009 Kinglake-Marysville fires burnt an area of approximately 68 000ha within Leadbeater’s possum’s known range, including 45 per cent of the permanent reserve system established to protect the species. The risk of catastrophic fires is expected to increase in the future due to climate change.
Leadbeater’s possum is a cryptic species that is difficult to detect, as it typically nests in large old trees and only emerges under the cover of night. The species was thought to be extinct for more than 50 years until its rediscovery in 1961.
University of Melbourne Masters student Arabella Eyre has spent the past 18 months searching for Leadbeater’s possums at sites outside its known range in the Central Highlands.
“Use of motion sensor cameras has really improved our ability to reliably survey for the species, and so we’ve found more records of them within their core distribution,” Ms Eyre said.
“We were hoping that by using these technologies, along with expert advice and extensive habitat mapping we would find undiscovered populations farther afield.”
However, after deploying more than 150 cameras in remote areas of north-east Victoria beyond Mansfield, Dinner Plain and Omeo, the only new observations of the species occurred within 15km of known habitat, confirming recent sightings in the area by VicForests.
These results come as the possum’s ‘critically endangered’ status finishes its public review period on 16 August.
The national review is seeking public comments on the eligibility of Leadbeater’s possum to be listed as critically endangered and the necessary conservation actions for the species.
Ms Eyre said while it was rewarding to record five new sightings after months of fieldwork with no sign of the possum, it was disappointing not to find any more distant populations.
“Ideally, we were hoping to find a large undiscovered population that was far enough from the Central Highlands to provide some insurance for the species against another devastating fire like those seen in 2009,” Ms Eyre said.
She said as these new records lie only 15km outside the species’ known distribution, they don’t provide a safeguard for the species against future fires.
University of Melbourne researcher Pia Lentini believes the survey results are an important step forward in our understanding of where this cryptic species does and doesn’t occur.
“There has been a bit of rhetoric in recent years that the possum could be much more widespread than previously thought, and so far Arabella’s research indicates that this isn’t the case,” Dr Lentini said.
“These results show that the possum still needs a lot of support.”
Zoos Victoria collaborator on the project Dan Harley said “it’s unclear how many possums this handful of records represents, but it’s certainly not a game changer for the species and in no way changes the conservation predicament”.
“Arabella’s research has identified little high-quality habitat beyond the Central Highlands and no distant populations, which really reinforces the importance of the core habitat for the possum within the Central Highlands," Dr Harley said.
Conservation prescriptions require that new verified detections of Leadbeater’s possums within the Central Highlands are protected with a 200m radius timber harvesting exclusion zone. Though these records fall outside of the Central Highlands, they will be protected with 200m buffers.
A draft consultation paper on the national conservation status of the Leadbeater’s possum is open for public consultation until 16 August. The research team will be submitting these new sightings and the survey areas where the species was not sighted as part of this process.
The project is part of an ongoing collaboration between scientists and students from the University of Melbourne, Zoos Victoria and the Arthur Rylah Institute, Department of Environment, Land, Water and Planning who are using innovative approaches to help conserve the possum under an uncertain future.