A SURVEY of Australian koala numbers carried out by CSIRO has concluded that there are significantly more animals in the wild than earlier estimates carried out by the Australian Koala Foundation.

CSIRO’s 2024 National Koala Population Estimates indicate a population of between 224,000 and 524,000 animals in the wild. The result is a slight amendment from a preliminary report issued a year earlier.

The numbers contrast strongly with Australian Koala Foundation estimates made in 2021, which suggested koala numbers were in a range from 32,000 to 58,000. Another AKF estimate made three years earlier suggested a range from 45,000 to 82,000. Land clearing was often cited as a key cause.

CSIRO has applied new modelling in its latest 2024 assessment, under the National Koala Monitoring Program. Using datasets collected over the past ten years, the NKMP modelling approach is developed to enable the integration of all available data sources to provide the best possible, national-scale estimates of koala population and distribution.

The latest estimate is based on both the listed (Queensland, New South Wales and the Australian Capital Territory) and the unlisted (Victoria and South Australia) koala populations, alongside mapping of the current estimated distributions for these areas.

In February 2022, the koala was up-listed to ‘Endangered’ under the Federal Government’s Environment Protection and Biodiversity Conservation Act. Previous estimates had relied on more qualitative approaches such as expert elicitation to fill gaps.

In contrast, the National Koala Monitoring Program provides a robust, data-driven approach to deriving koala population estimates, CSIRO says.

“The program is achieving this by designing and implementing an inclusive monitoring and modelling approach which enables the integration of multiple different sources of data and knowledge into processes which are established to ensure a long-lasting and robust monitoring program,” the CSIRO report said.

While solely data-driven estimates have challenges, including limited and fragmented data, CSIRO said it had made two distinct advances over past estimates:

• A concerted effort to collate koala presence, absence, and abundance data from a wide range of sources (individuals, research organisations, community groups, local governments, and state governments). This effort had been neglected up until this point, and
• An analytical framework combining all these disparate sources and data types. This methodology was, and still is, right at the forefront of statistical ecology, CSIRO said.

The CSIRO report presented a snapshot of on-going efforts to refine the population estimates after last year’s preliminary exercise. These included:

• New data collected by the NKMP and its partners
• Refined data handling procedures
• Furthering intuitive understanding of the likely sources of non-koala variation (ie patterns induced by piecemeal data collection)
• Improvements and refactoring of the statistical model and the associated analysis code, and
• Establishment of a broader community of koala modellers.

“All these advances lead to a better understanding of the data and the patterns that they describe,” CSIRO said.

“As the National Koala Monitoring Program is deployed we will be able to update these estimates of the current state of the population with increasing confidence,” it said.

The NKMP modelling team plans to produce a new update in September this year.

Click here to view the CSIRO report