Key Threatening Processes
Under the Nature Conservation Act 2014, the Minister for the Environment and Heritage added the Loss of mature native trees (including hollow-bearing trees) and a lack of recruitment to the List of Key Threatening Processes, following advice from the Scientific Committee, on 27 September 2018.
A submission to the Scientific Committee was made on behalf of Conservation Council ACT Region; Friends of Grasslands; Australian Native Plant Society Canberra Region; Canberra Ornithologists Group; and Field Naturalists Association of Canberra.
Mature native trees, which have developed hollows within the trunk and branches, are an important form of habitat for mammals, reptiles, bats and birds, who use the hollows to nest, raise young and shelter from predators. Hollow formation is an incredibly slow process with most hollows forming in eucalypt trees after the tree reaches 120 years old. They are formed through weather damage, branch shedding, insect attack, and advanced through modification by strong-billed native parrots like cockatoos and galahs.
Since urbanisation and land clearing began in the ACT region, there has been a dramatic decline of mature aged trees. Competition for suitable nesting hollows is fierce, and birds such as superb parrots, that migrate to the ACT each year, must work extra hard to compete with our resident parrot community for nesting hollows. Superb parrots, like many other threatened Australian birds including swift parrots, brown treecreepers and glossy black-cockatoos, are unlikely to persist in the ACT without stronger protections of hollow-bearing trees.
A Conservation Advice accompanies the listing with the priority management objective to reduce the loss of mature native trees and its impact on threatened native species and to improve recruitment of native woodland tree species across the ACT. Conservation issues and proposed management actions include:
Actions to mitigate against the loss of mature native trees include:
- Restrict, as far as possible, clearing of: mature eucalypts over 50 cm diameter at breast height; mature native trees that contain nest hollows; and native trees (other than eucalypts) that have reached approximately 67% of their maximum diameter.
- Promote retention of standing dead trees wherever possible.
- Encourage retention of non‐mature native trees across urban and rural landscapes to ensure a future supply of mature trees and avoid lag times.
Conservation and management
Actions to promote improved health of mature native trees across the landscapes:
- Provide funding and support to encourage rural landholders to manage stock and control grazing to reduce compaction and accumulations of nutrients under trees to enhance recruitment and health of isolated trees.
- Maintain connectivity of woodland tree species at a range of temporal and spatial scales.
Actions to promote improved recruitment:
- Provide buffer plantings around isolated trees
- Fence off isolated remnants and trees to reduce grazing pressure
- Continue to fund tree replacement programs in urban areas and revegetation programs across the ACT.
Survey, Monitoring and Research
- Continue to specifically monitor loss of mature trees across the ACT’s landscapes.
- Continue research on Eucalypt dieback in the ACT and appropriate provenance for revegetation programs under climate change.
An Action Plan (threat abatement plan) will be prepared to outline measures to reduce the removal of mature native trees.