This week’s assignment of ‘endangered’ status to the greater glider may surprise many Australians, but for experts it’s hardly unexpected.
On Tuesday, Australia’s environment minister Tanya Plibersek accepted advice from the government’s threatened species scientific committee to ‘uplist’ the conservation status of the southern and central greater glider (Petauroides volans), a large marsupial that calls forests along Australia’s east coast home.
It’s the largest of eastern Australia’s gliding possums (at least another eight are found here), known for its furry body, teddy bear-esque ears, and a canopy-like membrane that allows it to slide through the air. Individuals typically reside in ‘dens’ provided by old eucalyptus tree hollows. Some eucalypts provide the leaves that serve as their primary source of food.
But the destruction of vital habitat during the catastrophic Black Summer bushfires in 2019-20 has pushed glider populations of the species to the brink.
Extended family: greater gliders are separate species and are all likely under threat
The greater glider was first listed as vulnerable in 2016, and was considered one species – P. volans. But since 2020, experts consider the glider to be at least three distinct species.
P. volans inhabits forests from Proserpine in the Whitsunday region of Queensland down the continent’s east coast to the forested areas surrounding Melbourne, Victoria. P. minor occupies the wet-dry tropical region near Townsville and Cairns north-eastern Australia, and has been now added to the threatened species list as ‘vulnerable’.
A third species – P. armillatus – is considered vulnerable by Queensland’s government, and likely faces the same pressures as the others.
“The taxonomy of the gliders is not completely resolved as yet,” explains Professor David Lindenmayer of the Australian National University, Canberra. “There may be up to five species of greater gliders, and it’s unlikely that any of them will be secure in number.
“We’re going to have to work hard to make sure that we can conserve all of those species because it’s all an important part of Australia’s natural heritage.”
There is encouraging language from the Australian government, with environment minister Plibersek publicly backing efforts to help gliders recover from the Black Summer bushfires. But while those fires had a devastating effect on numerous plant and animal populations, other factors like climate change, habitat clearing and fragmentation and timber harvesting pose existential threats to glider survival.
“All these various threats and factors interacting in different ways ultimately increase the risk of extinction,” says Luke Emerson, a researcher at Deakin University’s Centre for Integrative Ecology who specialises in the ecology of arboreal marsupials like the glider.
“Rising temperatures, increasing fire severity, shorter fire intervals, logging on top of that, conversion and fragmentation of habitat… all these things are interacting to put greater pressure on arboreal marsupials.
“These multiple threats are interacting in ways that we can predict, but there’s probably ways that we can’t predict that are going to negatively impact them as well.”
The bad list: more Australian icons added or re-graded in 2022
The greater glider isn’t alone in being uplisted on the nation’s threatened species register in 2022.
Populations of the iconic koala (Phascolarctos cinereus) living in Queensland, New South Wales and the Australian Capital Territory were notably transferred from vulnerable to endangered status earlier this year. The yellow-bellied glider (Petaurus australis australis) and long-nosed potoroo (Potorous tridactylus trisulcatus) were listed as vulnerable in March.
And many species other than mammals have been added to the list in 2022.
Watson’s (Litoria watsoni) and Littlejohn’s tree frog (L. littlejohni), the gang-gang cockatoo (Callocephalon fimbriatum) and the South Australian Bassian thrush (Zoothera lunulata halmaturina) have been either added or uplisted to endangered, while the pilotbird (Pycnoptilus floccosus) was added as vulnerable.
The work to protect animal species from spiraling further towards extinction is a difficult business at the best of times. Triumphs are rare.
One of note is Zoos Victoria’s 33-year-old captive breeding program for eastern barred bandicoots (Perameles gunnii), which was retired in 2021 when the species – previously extinct in the wild – was downlisted to endangered. The species is now regenerating itself in specially fenced, predator free release sites across Victoria.
For Zoos Victoria reproductive biologist Dr Marissa Parrot, the success of the bandicoot program was a career high point. But alongside these all-too-rare moments of success are declines in other species.
“It’s such an amazing feeling to know that you’ve made a difference to a species… but it’s just one of thousands that do need help,” Parrott says. “When an animal is added to the endangered species list, they’re going to hopefully get more focus and more funding, and they need that long-term care.
“But it also means that they’ve got to the point where they need to be added to an endangered list, and that’s quite devastating.”
Parrott believes that improving public knowledge of both the existence of species and the threats that exist in the wild may improve outcomes for many animals.
That knowledge-building can extend to people taking individual action – such as providing suitable food trees to support endangered animals that lose habitat, participation in citizen science programs or even turning outdoor lights off to support threatened moths.
While the uplisting of species like the greater glider is a troubling event, Parrott say it can serve to draw people’s attention to the challenges confronting lesser-known animals.
“Animals like the greater glider are beautiful, and they’re fluffy, and they can really grab people’s attention,” she says. “It’s great that they’re getting that attention, but we also have many species no one’s ever heard of, like the pookila (New Holland mouse), and the bogong moth, which is also a tiny little animal, but an amazing species.
“Just last week I’ve seen gang gang cockatoos and grey-headed flying foxes in my own suburb – showing that these endangered species that are in trouble are actually around us [is important].”
Common causes and solutions for endangerment
The challenges confronting greater gliders are shared by these other, less prominent animals.
While addressing climate change requires largescale transformation across society, there are other actions that can be implemented to provide more immediate relief for native species.
Government conservation advice provided for all animals added or uplisted so far in 2022 notes land and vegetation clearing as a survival threat. For gliders, it poses a catastrophic risk.
That’s why moving the forestry industry to an entirely plantation-based sector is a critical solution Lindenmayer believes needs to be implemented, and soon.
“It’s time to exit native forest logging,” he says. “The Western Australians have done this: on the 31st of December 2023, [WA] will no longer be logging native forests.
“Victoria needs to do that at the same time, so does New South Wales. It’s really important that we tackle that issue, which renders huge areas of forest unsuitable for animals like greater gliders, either permanently or for periods of up to 200 years.”
Lindenmayer also points to non-forestry land clearing and coal mine construction in the eastern states as adding pressure to threatened forest-dwellers. But he also wants to see the government to take biodiversity seriously.
“The federal minister can actually get involved in this seriously and not unravel, but improve, environmental laws, to make sure that more biodiversity is not lost. That’s critical.”
Australia accounts for 35% of global modern mammal extinctions. Over the past 200 years, about 10% of our terrestrial endemic mammals have gone extinct.