Koala research

Koala response to harvesting in NSW north coast state forests

In 2018, the NSW Government tasked the Natural Resources Commission (the Commission) to deliver independent research to better understand how koalas are responding to harvesting in state forests on the NSW north coast.

This work is being undertaken as part of the whole-of-government NSW Koala Strategy 2018-21. The Strategy aims to stabilise and then increase koala numbers over the longer term.

With support from a panel with expertise in koala ecology and forest science, the Commission selected eminent scientific researchers and their research proposals from the Australian National University, Western Sydney University and the Department of Primary Industries Forest Science Unit to undertake the research. The researchers worked in collaboration to investigate koala movement, occupancy, density, diet and the nutritional quality of koala habitat on state forests.

The Commission has now delivered a final independent research report to the NSW Government. This synthesis report presents the findings of the Commission’s research program, implications for management and recommendations.

Evidence from this research program will inform the effectiveness of the NSW Government’s Coastal Integrated Forestry Operations Approval (Coastal IFOA), which sets out the rules for native timber harvesting in the State’s coastal state forests.

Final research report

Overall, the research findings suggest that the range of selective harvesting rates applied at the research sites consistent with the Coastal IFOA conditions and protocols did not adversely impact koala density.

The average nutritional quality of NSW north coast hinterland forests for koalas is relatively low compared to forests in other locations across the koala range from Queensland to South Australia, which restricts the landscape’s capacity to support koalas.

Other research insights include:

  • koala density was higher than anticipated in the surveyed forests and, as noted above was not reduced by selective harvesting
  • koala density was mostly similar between state forest and national park sites
  • selective harvesting at the treatment sites did not significantly change canopy tree species composition and, therefore, is not expected to impact on nutritional quality of koala habitat
  • tree species composition, not tree size, is the key determinant of habitat nutritional quality for koalas.

The emerging evidence to date also suggests intensive harvesting occurring in the past five to 10 years is unlikely to have impacted koala density, but more research is needed on the immediate responses.

To maintain widespread koala persistence in the north coast hinterland existing Coastal IFOA prescriptions should be maintained. The Commission considers no substantial changes to tree retention guidelines are required at this point in time. However, the final report outlines additional issues that could be considered to improve koala outcomes under the Coastal IFOA.

The report identifies opportunities to improve knowledge that will ensure forest management is delivering the best possible outcomes for koalas. For example, the Commission recommends the NSW Government extend this independent research program to investigate koala and habitat response to intensive harvesting on north coast state forests. The Commission also recommends further research on selective harvesting across both the North Coast and Northern Tablelands Koala Management Regions.

The research program is also using DNA and chemical analysis of koala faecal pellets to determine what tree species koalas are feeding on to inform target species for retention. However, the analysis has been delayed. The Commission will update this report when the analysis is complete later in 2021.

Published research

Researchers engaged under the Commission’s Koala Research Program will publish their research in peer-reviewed scientific journals.

The results on koala occupancy and density in response to harvesting were recently published in the science journal Nature titled Regulated timber harvesting does not reduce koala density in north-east forests of New South Wales.

Researchers will also submit research findings on habitat nutritional quality and koala diet to journals. Links to these articles will be provided here when they are published.

Research program update - February 2020

Research began in early 2019. However, the 2019/20 wildfire impacted significant areas of the NSW North Coast, including harvest areas in state forests. Due to these extensive fires, the Forestry Corporation of NSW postponed previously planned intensive harvesting operations including at the research sites. Instead, the Forestry Corporation of NSW will now apply a different type of harvesting – called selective harvesting – at the research sites.

In August 2020, the Environment, Energy and Science Koala Strategy Board asked the Commission to refocus the research program on koala response to selective harvesting in the North Coast state forests. Research will build on initial data collection and will be carried out within committed timeframes.

Researchers will also investigate the impact of wildfire on koala habitat and population in the North Coast state forests. This extension work is funded under the NSW Forest Monitoring and Improvement Program.

The Environment, Energy and Science Koala Strategy Board will reconsider the original research question – i.e. intensive harvesting – when the NSW Koala Strategy is reviewed in 2021.

Research program update - July 2019

Nutritional value of koala habitat led by researchers at the Australian National University

  • Researchers have commenced analysis of the nutritional composition of leaf samples. Leaf samples will continue to be collected and analysed until November 2019.
  • Researchers are collecting samples from sites with different harvesting prescriptions, species compositions and time since harvest to determine and compare the value of habitats for koalas.

Next steps:

  • Field work and leaf analysis is expected to be completed by May 2020.
  • Statistical modelling is expected to be completed by July 2020.

Koala diet and its links to habitat quality led by researchers at Western Sydney University

  • Researchers are collecting koala scats and reference plant material. This will continue to September 2019.
  • DNA extraction of plant material has commenced and will continue to October 2019. Researchers will analyse DNA from scats to compare with plant reference material. This will identify the plant species in the diets of koalas.

Next steps:

  • Sample collection and DNA extraction is expected to be completed by October 2019.
  • Diet composition and nutritional analysis will continue to the end of 2020.

Koala population density using acoustic sensors and DNA led by researchers at the Forest Science Unit in the NSW Department of Primary Industries

  • Researchers are now selecting sites to establish acoustic sensor arrays to record koala calls.
  • Calls will be recorded and screened from August 2019. Data will be used to estimate koala density and describe their movements at sites before and after regeneration harvesting, and at other sites 5-10 years after heavy harvesting.

Next steps:

  • Pre-harvest field sampling, call screening, genetic analysis and spatial count modelling will be completed by December 2019.
  • Post-harvest field sampling, call screening, genetic analysis and spatial count modelling will begin in August 2020.

Research program

In 2018, the Commission selected three research projects to investigate how koalas are responding to regeneration harvesting in state forests on the NSW North Coast.

The Commission has revised the program to investigate koala response to selective harvesting. The same research projects will continue.

The research teams will lead complementary but distinct projects that will focus on:

  • Nutritional value of koala habitat led by researchers at the Australian National University
  • Koala diet and its links to habitat quality led by researchers at the Western Sydney University
  • Koala population density using acoustic sensors and DNA led by researchers at the Forest Science Unit in the NSW Department of Primary Industries.

The Commission’s revised research program plan explains the projects in more detail.

The Commission will provide a final report of findings to the Premier and the Minister for Environment in mid-2021. In addition to the final report, the Commission will annually report on the progress of the research projects.

Expert panel

The Commission established an expert panel comprising koala and forestry experts to support delivering a robust, and scientifically credible research program.

The expert panel members include:

  • Dr Desley Whisson
    Senior Lecturer in Wildlife and Conservation, Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin University
    Dr Whisson is a terrestrial ecologist with 15 years’ experience in conducting applied research on koala ecology and management. She is particularly interested in the spatial ecology of koalas including their habitat use and movements in modified landscapes.

  • Dr Alistair Melzer
    Adjunct Research Fellow, Koala Research CQ, School of Medical and Applied Sciences and research program leader for koala research, Central Queensland University
    Dr Melzer, a field ecologist, has worked on koalas and their habitat for over 20 years. Most recently, he was a member of the Queensland Government Koala Expert Panel, providing advice on the most appropriate actions to reverse declining populations and ensure long-term persistence of south east Queensland’s koalas.

  • Professor Patrick Baker
    Professor of Silviculture and Forest Ecology, School of Ecosystem and Forest Sciences, University of Melbourne
    Professor Baker studies forest dynamics and has 25 years of experience working in temperate and tropical forests studying the impacts of past disturbances and climate variability on current structure and composition. Professor Baker was an Australian Research Council Future Fellow from 2012 to 2017 focussing on developing silvicultural systems to make south-eastern Australian forests more resilient to climate change.

Stay informed

The Commission will be updating this webpage as the project is implemented. If you would like to receive updates regarding this work, you can sign up to our mailing list.