Disturbance from logging and fire has drastically altered forest distribution and composition in south-eastern Australia, leading to widespread loss of ecological function and biodiversity. In Victoria alone, 115,000 ha of known or likely threatened species habitat was logged from 2005-2020. Silvertop Ash (Eucalyptus sieberi) is a disturbance-adapted native eucalypt species that is increasingly dominating these areas. Unfortunately, Silvertop has high levels of herbivore deterring toxins and is a poor-quality food source for Australia’s most iconic eucalyptus leaf-eating mammals, greater gliders (Petauroides volans) and koalas (Phascolarctos cinereus). In addition to decreasing the nutritional quality of forests for these animals, disturbance-related proliferation of Silvertop Ash is causing substantial reductions in overall biodiversity and landscape resilience. 

In 2021, Envite partnered with the Australian National University (ANU) on an ambitious project aiming to reverse the cumulative impacts of logging and fire on eucalyptus tree species diversity in East Gippsland forests, with a focus on restoring and improving greater glider habitat. Together, we established a series of forty 0.25 ha experimental plots (10 ha in total) to develop and refine methods for future upscaling across the landscape, using a previously logged (~3 years prior) Immediate Protection Area that burned in the 2019/20 bushfires as a case study.  

The methods being trialed include: 

• Ecological thinning of Silvertop Ash; 
• Silvertop thinning plus supplementary seeding of more diverse, locally appropriate eucalyptus tree species with a focus on improving the nutritional landscape for greater gliders; 
• Thinning and supplementary planting of the same, locally-appropriate eucalyptus tree species; and
• Control sites with no intervention, used to assess the efficacy of our actions against ‘business as usual’. 

This novel restoration work will create the conditions needed for greater gliders to exist in forests that would otherwise remain uninhabitable due to disturbance–related changes in tree species composition and nutritional quality. Monitoring of eucalyptus tree species recruitment and diversity at trial sites will be used to inform best-practice methods for restoring habitat for greater gliders and broader biodiversity across the landscape, including by managing Silvertop Ash proliferation following disturbance. 

Envite’s role in this project has been funded by a Landcare Led Bushfire Recovery Program Grant, supported by the Australian Government’s Bushfire Recovery Program for Wildlife and their Habitat. 

Related links: 

Project website

Project video