Yellow-bellied glider (northern subspecies)
Common name: Yellow-bellied glider (northern subspecies)
Other names: Fluffy glider
Scientific name: Petaurus australis unnamed subspecies
Family: Petauridae (striped possum and wrist-winged gliders)
Conservation status: This Wet Tropics population of the yellow-bellied glider is an unnamed subspecies and is listed as Vulnerable in Queensland (Nature Conservation Act 1992) and nationally (Environment Protection and Biodiversity Conservation Act 1999). It is ranked as a critical priority for conservation under the department’s Back on Track species prioritisation framework.
The yellow-bellied glider is a medium sized gliding marsupial. Its head and body length is around 300mm with the fluffy tail 450mm in length. Males are slightly larger than females with males weighing 470–725g and females weighing 435–660g. This Wet Tropics population is smaller and lighter in weight than the more widespread southeast populations; males 470–567g and females 420–520g.
The yellow-bellied glider has a greyish brown body colour with a distinct black stripe running down their back from forehead to the base of the tail. The belly is a distinctive off-white which may acquire a yellowish tinge in older individuals, but less so than those in more southerly populations. The gliding membrane has a black margin and there is a black stripe on the outer side of the hind limb to the paw and lower limbs are black. Ears are pale coloured and bare.
Habitat and distribution
The yellow-bellied glider occurs in eastern Australia from north Queensland (west of Mossman) to the south-eastcorner of South Australia. This northern subspecies is the most northern population and occurs along the western margin of the of the Wet Tropics bioregion from the Mt Windsor Tableland, west of Mossman, in the north to the Herbert River Gorge, west of Ingham, in the south. It is isolated by a 400km gap to the next population which is on the Clark Ranges inland from Proserpine. This Wet Tropics population is restricted to altitudes above 600m. It is subdivided by natural gaps in their habitat into three subpopulations: the Mt Windsor Tableland, the Mt Carbine Tableland and the Cardwell Range.
The glider’s habitat is very tall (25–40m) wet eucalypt open forest. The presence of two eucalypt species is essential, red mahogany Eucalyptus resinifera (tapped for its sap) and large rose gums Eucalyptus grandis (used as the main den tree). Its habitat is restricted to a narrow band about 0.25–5.0km wide which is an ecotone between rainforest and drier woodland ecosystems. Available habitat for the three sub-populations is estimated to be 2,290–2,471ha at Mt Windosor Tableland, 7,240–7,370ha at Mt Carbine Tableland and 33,395–39,605ha at Cardwell Range. In 1997 glider numbers in each subpopulation were estimated to be 160–346 at Mt Windsor Tableland, 507–1,032 at Mt Carbine Tableland and 3,540–4,138 at Cardwell Range.
Life history and behaviour
The yellow-bellied glider is a nocturnal and arboreal gliding marsupial. Glides of over 100m by adults have been recorded, but are usually much less. The yellow-bellied glider is one of the most vocal marsupials and has a variety of calls that include loud distinctive shrieks, gurgling chatters and soft moans.
During the day the gliders shelter in den trees which are predominantly very large rose gums that have hollows large enough to accommodate family groups. Gliders live in family groups of 2–6 individuals, each group defends a home range of about 25–120ha. Individuals may travel up to one kilometre between the den and feed trees.
The diet is varied and includes pollen, invertebrates, nectar, honeydew and manna when seasonally available. Sap from the red mahogany tree, the only tree to be tapped for its sap by the Wet Tropics glider population, is a major item particularly when other sources are limited.
Births occur throughout the year with a single young spending around 100 days in the pouch. After a further 50 days in the den they move outside initially by climbing on trees and branches as opposed to gliding.
Threats to the yellow-bellied glider are predominantly associated with habitat alteration and fragmentation, threats include:
- the loss of habitat through rainforest encroachment which is thought to be the main threat to the glider, particularly where rainforest encroachment has reached an irreversible state of a denser closed forest with eucalyptus emergents. Changed fire regimes are thought to be the main contributing factor to rainforest expansion and long-term climate change is also having an effect.
- clearing and fragmentation of habitats. In the past, the wet eucalypt open forests of the Wet Tropics were subjected to clearing and disturbance for forestry and agriculture, especially in the Herberton–Ravenshoe area.
- habitat modification with less clear impacts on the gliders include grazing by cattle affecting forest ground cover and understorey structure, and timber harvesting affecting forest canopy structure and reducing nectar volume.
- barbed wire fencing impacts on the gliders by causing injury, or entanglement and resulting in a loss of individuals.
- feral cat predation on gliders when feeding low on red mahogany trees.
- climate change is likely to influence the distribution of habitat, through the migration of bioclimates that support habitat, and by influencing fire regimes.
A national recovery plan for the yellow-bellied glider (Wet Tropics) Petaurus australis unnamed subspecies has been developed. The recovery plan identifies management actions to recover the species. These include:
- Conduct habitat planning, including defining essential habitat distribution.
- Implement fire regimes to maintain essential habitat.
- Protect and manage habitat outside of the protected area estates.
- Research the impacts of cattle grazing on glider habitat.
- Collect and analyse glider and barbed wire incident data to establish level of impact and identify potential hotspot locations for targeted management.
- Undertake monitoring programs for yellow-bellied glider populations.
- Improve understanding of climate change impacts.
- Assessing predation by feral cats is recommended.
Since 2010 the department previously with the Tablelands National Park Volunteers and currently with the Tree Kangaroo and Mammal Group has an active program gathering data on the occurrence, foraging and habitat of the yellow-bellied glider (northern subspecies). The project is progressively documenting the occurrence of the yellow-bellied glider between Atherton and Ravenshoe, and mapping essential habitat trees (red mahogany trees tapped for sap and large rose gums as potential den trees).
A biennial census of the yellow-bellied glider is conducted by Queensland Parks and Wildlife Service in the upper reaches of the Daintree River on the Mt Carbine Tableland.