Australia’s most skilled aerial mammal, the yellow-bellied glider, is on an “inexorable slide” to extinction as global heating creates more extreme bushfires that are robbing the species of the food and tree hollows it relies on to survive.
Thanks to large parachutes of skin stretching from their wrists to their ankles, yellow-bellied gliders can travel up to 140 metres in a single jump, the furthest of any Australian mammal, including the larger and better known endangered greater glider.
Scientists studying the species said its characteristics – including a diet of tree sap, nectar and insects, reliance on old trees with hollows for shelter and nesting, and a tendency to live across a large “home range” – make it especially vulnerable to the climate crisis.
They said fragmentation of the glider’s forest habitat, logged and cleared for development, had already put pressure on “yellow-bellies” before the black summer bushfires of 2019-20 scorched 41% of their habitat and pushed them on to the national threatened species list in 2022.
Prof John Woinarski, an ecologist at Charles Darwin University and a leading threatened species expert, said the glider was “sliding inexorably towards extinction”.
“They need hollows to rest in during the day, but across Australia the number of these old trees is declining rapidly through logging and fire,” he said. “Many hollow-bearing species are in trouble – and the yellow-bellied gliders’ [decline is] more pronounced than the others.”
Shrieking and gurgling
Yellow-bellied gliders live for about six years, are about the size of a small cat and live in family groups of up to six animals in a home range of between 25 and 85 hectares (62 and 210 acres) – a much larger area than is typically relied on by greater gliders.
They are nocturnal, notoriously hard to spot and one of the loudest marsupials in Australia. Their distinctive shrieking and gurgling calls can be heard from as much as 500 metres away. One researcher said the sound was “like a satanic pig going through an exorcism”.
The glider has two sub-species. One is restricted to the wet tropics of north Queensland and is considered endangered.
The other sub-species lives between south-east Queensland and south-east South Australia. It is listed as vulnerable in Queensland, New South Wales and Victoria, and endangered in South Australia. It is feared it could already be extinct in the latter.
There is no reliable estimate of how many yellow-bellied gliders are left. The national threatened species scientific committee said it was likely there were more than 10,000 but fewer than 100,000. It estimated the population across the south-east had fallen by at least 30% over 12 to 15 years.
Research in three areas of NSW after the black summer fires found between 13% and 66% fewer gliders in burnt areas.
“Climate change is going to make conservation of any forest-dwelling species much harder,” Woinarski said. “It’s the loss of hollow-bearing trees that is exacerbated by repeated fires. Recurrent fires are a recipe for doom.”
Dr Rod Kavanagh, a forest ecologist and adjunct professor at Southern Cross University, began researching the gliders in the late 1970s. He said the species was “under-studied” and more research and data were needed to understand how it was affected by the climate crisis.
He said he had visited known glider habitat in northern coastal NSW after the black summer and had found no gliders in severely burnt areas. Gliders were also absent from unburnt areas, he said, but there were no notable declines on the south coast.
How to help
Woinarski said land clearing and native forest logging in NSW and Queensland continued to put pressure on the gliders but the biggest issue was that “we need to get serious about climate change and reducing emissions”.
“In 20 years, it is going to be far harder to help them,” he said. “We need greater public awareness … It is such an endearing and fascinating creature and we all need to appreciate what a wonderful animal it is.”
Desley Whisson, an associate professor and ecologist at Deakin University who coordinates glider research, called for greater support for projects that planted vegetation in cleared areas and connected fragmented forest areas that the species relied on. She said greater public awareness of where gliders live and their plight would also help them survive.
“I think fire is one of the biggest risks,” she said. “I try to stay optimistic and I think we can all do something positive.
“I would hate to think of a world that doesn’t have yellow-bellied gliders in it.”
