Dissertation
Recovery responses of koala habitat after fire
University of the Sunshine Coast, Queensland
Doctor of Philosophy, University of the Sunshine Coast, Queensland
2025
DOI:
https://doi.org/10.25907/00904
Abstract
The koala (Phascolarctos cinereus) is Endangered, at risk of extinction in the wild from ongoing habitat loss due to clearing, drought and fire. In late 2019 and in 2020 Australia experienced widespread severe wildfires and many threatened species were adversely affected. I surveyed a 230 hectare forested property with known koala habitat near Crows Nest, Queensland, Australia, after wildfire in November 2019, to assess impact, and then for three years to assess recovery of koala habitat. The most fire-resilient tree species and forest types were identified for koala habitat. Koala preference for tree species and forest type was also assessed. Fire severity and subsequent recovery were classified using field characters. Remote sensing data (Sentinel-2, dNBR) was ground-truthed within the property to assess burn severity at the local scale and then extrapolated to assess regional impacts of fire on koala habitat forest types across 12,000 km2. A series of annual ground surveys on the property aligned field data with the remote sensing data to test how well these remote sensing techniques assess recovery of koala habitat, as impacted by burn extent and severity. The regional study used a large koala sighting dataset to determine if areas with koalas tend to burn; if koalas are selective for forest type, terrain, tree species and tree size; if koala populations recover after fire. Fire promoted epicormic shooting along tree stems, but at extreme fire severity, coppicing was the dominant response. High fire severity was tolerated by most preferred koala tree species, but tree mortality increased significantly with extreme fire severity. From five koala habitat forest types studied, one upland type burnt significantly more severely and extensively than the others, but recovered. The dNBR measured foliar recovery, but not specifically epicormic shooting and coppicing, which would go on to form canopy. Koalas did not occur in areas that burnt any more than unburnt areas. Koalas preferred certain tree species and forest types. Koala presence decreased after the first year of fire recovery, but increased slightly in the fourth year. Koalas used two-thirds of 120 Regional Ecosystems in the region, but notably preferred two REs, with negative mean dNBR, thus unburnt. This suggests koalas might prefer unburnt REs. Koalas preferred flatter, lower elevations and southern and eastern aspects, and are selective for forest type, tree species and tree size. We found koala population recovery after fire can take years, not months, and may be due to time taken for tree recovery, but modified koala movement behaviour and koala deaths may also be factors.
Details
- Title
- Recovery responses of koala habitat after fire
- Authors
- Derek Johnson - University of the Sunshine Coast, Queensland, School of Science, Technology and Engineering
- Contributors
- Alison Shapcott (Principal Supervisor) - University of the Sunshine Coast, Queensland, Centre for BioinnovationSanjeev Kumar Srivastava (Co-Supervisor) - University of the Sunshine Coast, Queensland, Sustainability Research Cluster
- Awarding institution
- University of the Sunshine Coast, Queensland
- Degree awarded
- Doctor of Philosophy
- Publisher
- University of the Sunshine Coast, Queensland
- DOI
- 10.25907/00904
- Organisation Unit
- School of Science, Technology and Engineering; Centre for Bioinnovation
- Language
- English
- Record Identifier
- 991107746102621
- Output Type
- Dissertation
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