Greater Glider population recovery efforts

Questions with Greening Australia and Landcare Victoria on the Greater Glider population recovery project.

1. How are the populations measured after events such as the 2019-2020 Black Summer Bushfires? 

• It’s challenging to assess the impact on populations immediately after a natural disaster and even now, two years after the 2019/2020 bushfires began, we still don’t know the full extent of the impact of these devastating fires on Greater Glider populations. 
• We do know that the fires had a significant effect on Greater Glider populations and their habitat in East Gippsland. Research by Deakin University also found that across Australia, almost 30 per cent of Greater Glider habitat was burnt in the 2019/2020 fires.

2. What makes the Greater Glider such a unique animal and why is it so important to protect? 

• Greater Gliders are Australia’s largest gliding mammal. They have large fluffy ears and a long, furry prehensile tails. Greater Gliders can glide up to 100m in a single glide and can change direction at a 90-degree angle mid-flight.
• Greater Gliders play significant ecological and functional roles in ecosystems; they are an important part of forest food webs and their disappearance / population decline risks disrupting the delicate balances that exist in the natural world. Additionally, taking action before Greater Gliders disappear entirely from the wild is crucial as strategies such as captive breeding and reintroduction programs are costly conservation interventions and can have increased risks of failure. 
• Australia is home to an incredibly rich diversity of wildlife and many species are found nowhere else in the world – including Greater Gliders. It’s critical that we take action to protect and conserve this unique species before it is too late.

3. What is a conservation intervention? 

• A conservation intervention is an action we take to manage, protect, enhance or restore biodiversity or ecosystem services. 

4. Will cameras be installed within the glider nest boxes to monitor their use?  

• The nest boxes we are installing will be monitored for occupancy (by any species e.g. Greater Gliders, Sugar Gliders etc.) using a thermal monocular and thermal drone fly overs approximately two months after the boxes have been installed.
• Using a thermal monocular, Greening Australia has previously observed Greater Gliders using our nest boxes at other sites in Victoria.
• The measure of success will come several years later when we survey the area (using thermal drones and on-ground surveys) to ascertain if the population is stable or has increased against baseline data.

5. Does their tendency to inhabit small, isolated home ranges also have an impact on genetic diversity? 

• Although there is currently little understanding about the genetic relationships between Greater Glider populations, there is a concern that habitat loss and fragmentation is placing the species at further risk of the effects of low genetic diversity.
• Greater Gliders are unable to move effectively or safely through cleared land to access new habitat or other Glider populations, which means that gene flow between populations – genetic exchange via breeding – can be virtually non-existent. This can create low genetic diversity in small and isolated populations.
• Populations with low genetic diversity can have a negative impact on population health, including by limiting the ability to adapt to environmental change and increasing the risk of extinction.

 
6. Are there any future plans to develop similar responses in other bushfire affected areas?  

• For now the scope of this project is limited to our actions in Hartland State Forest. However an exciting component of this project is the development of a new suite of Greater Glider genetic markers from scat testing, which will provide environmental practitioners with a powerful tool to better understand, map, plan, monitor and protect populations in the future.
• The nest box design and implementation process we are using for this project can also be applied in other locations where Greater Glider populations live to support this vulnerable species recover.
• Additionally, an important component of the Gliding to Recovery project has been involving local Landcare networks and community members. In partnership with Far East Victoria Landcare Network, Greening Australia is delivering community engagement and training events that focus on educating and building the awareness and capacity of locals to assist in conservation efforts.

 
7. When was it decided that the ‘Gliding to Recovery’ project was necessary? 

• Five years ago survey data highlighted a rapid decline in Greater Glider population in their stronghold areas including the Southern Highlands of Victoria. Taking action on the ground to address some of the threats facing this species became even more urgent than it already was.
• Additionally, the bushfires of 2019/2020 destroyed close to 30 per cent of Greater Glider habitat. The impact of these fires was catastrophic for this already vulnerable species, diminishing suitable hollows and causing drastic habitat fragmentation, so our Gliding to Recovery project provides much needed shelter in unburnt pockets of land. 

8. Besides natural disasters, what are some of the other main threats on this species? 

• Greater Gliders’ reliance on forest habitat and large hollow-bearing trees means that habitat loss and fragmentation from land clearing and bushfires pose a major threat to this species.
• Habitat fragmentation and population isolation also impact on the ability of Greater Gliders to move through landscapes, recolonise suitable habitat and reduces genetic exchange between sub-populations. As populations decline and become more isolated, they are also more prone to the effects of small population size and potentially genetic decline.
• It is well documented that Greater Gliders also have poor dispersal abilities, occupy very small home ranges (approximately 1-4 hectares) and generally do not breed every year, so population growth is slow. These factors contribute to making the Greater Glider extremely vulnerable to wildfire and other threats such as hyper-predation by owls.
• Climate change also poses a severe threat for this species. Hotter, drier climates predicted may cause heat stress and increased mortality for Greater Gliders, while more frequent and intense bushfires will continue to contribute to habitat loss and population decline.

9. So far, what have been the highlights of the project (first-hand accounts of what you have experienced out in the field)? 

• The enthusiasm and dedication of the project team has been truly inspirational. Spending time immersed in the habitat of Greater Gliders has given us a greater understanding and appreciation of their preferred glide pathways and feed trees.
• Conventional spotlighting to survey Greater Glider presence has always been a challenging, so our ability to use thermal drones to confirm Greater Glider presence in areas has been a massive highlight. This technique has allowed us to better map the distribution of Greater Gliders throughout the forest.

10. Why are there a lack of naturally formed tree hollows? 

• Greater Gliders prefer to inhabit old growth forests and the hollows they use for shelter and nesting can take hundreds of years to form. The progressive loss of large hollow-bearing trees due to land clearing is happening at a much faster rate than these hollows are formed naturally, leading to a significant lack of hollows for Greater Gliders. 

11. How are you installing the boxes within the trees? 

• We work with a team of expert arborists to install the nest boxes at heights where we know the Greater Gliders are moving about in the forest. This can be up to 20-30m in the canopy. Each arborist climbs up the trunk of the tree to install the nest box and is supported by someone on the ground to hoist the boxes and other necessary tools up into the canopy using ropes.

 
12. How many people are working on the project in total? 

• This is an exciting Greening Australia project which involves a number of our team directly, but also incorporates work with project partners including local Landcare networks and community members, four people from Federation University, and eight contractors including two arborists. 

13. How do Greater Gliders contribute to their eco-system? 

• Greater Gliders play significant ecological and functional roles in ecosystems; they are an important part of forest food webs and their disappearance / population decline risks disrupting the delicate balances that exist in the natural world.

 
14. Where do you expect the population to be after a few years of the installation of the boxes? 

• By implementing 300 nest boxes we are aiming to enhance critical habitat refugia for Greater Gliders and prevent further population decline in our target area – Hartland State Forest. Because Greater Gliders are slow to reproduce (producing only one young roughly every two years) population growth will inevitably be gradual. However, we hope that through targeted, proactive and science-based interventions such as the Gliding to Recovery project, over time we can reverse the decline of Greater Gliders and support this unique animal to thrive.

If you enjoyed this story on Greater glider population recovery efforts, then click here to see what else is being done to save our endangered species.