The animal kingdom is so diverse that there is no one-size-fits-all solution for conservation. Sometimes, a unique situation pops up that makes conservation particularly challenging. An example hails from a region in Australia, in which globally endangered koalas have high local population densities. Addressing the issue of overabundant koalas in South Australia requires a humane, targeted, and cost-effective conservation strategy.

Current Status of the Koalas

Koalas are currently listed as ‘Endangered’ under the Commonwealth Environment Protection and Biodiversity Conservation Act and as ‘Vulnerable’ by the International Union for the Conservation of Nature (IUCN). While these classifications reflect the status of koala populations globally and in eastern Australia, koalas in South Australia do not hold a specific conservation status. This is largely because their population has grown beyond sustainable levels in that region.

Research indicates that koala distribution is influenced by a combination of rainfall and temperature. As koalas are not well adapted to extreme climates, access to suitable habitat is essential for their survival. So, in the summer, more rainfall can enhance habitat quality by reducing the impacts of rising temperatures and increased fire risk. The Mount Lofty Ranges in South Australia are one such area. These mountains support between 22,000 to 26,000 koalas in estimate, representing approximately 10% of Australia’s total koala population. 

However, the South Australian government has identified a maximum sustainable density of around 70 koalas per square kilometer. This means the current population levels in the region have already exceeded this threshold. Furthermore, population modelling suggests that the number of koalas in South Australia could increase by an additional 17-25% over the next 25 years.

Addressing the Overabundance of Koalas in South Australia

Koalas have a complex conservation history shaped by both biological and socio-political factors. Because of their exceptionally high local densities, these marsupials can significantly alter vegetation structure and composition through intense grazing pressure for their feeding. While population control is ecologically vital, lethal culling remains entirely unfeasible due to public opposition. Therefore, rather than culling, conservation strategies for overabundant koalas in South Australia tend to focus on preventing further environmental degradation and promoting ecosystem recovery.

Although costly and controversial, artificial fertility control is currently one of the most viable alternatives to manage this problem. To do this, veterinary professionals target female koalas for sterilization. They then perform a non-surgical procedure using reversible subcutaneous hormone implants. These hormone implants would allow reproductive capacity to be restored if regional population dynamics shift in the future.

Multi-stakeholder Knowledge Sharing and Participation

The unique situation of koalas in South Australia requires further research and close monitoring. Climate change may impact koala habitats across the continent, changing the population composition of the species with it. Therefore, support for further research on conservation strategies that include ecosystem adaptation and overpopulation is essential.

Additionally, the role of Indigenous people and local communities in koala conservation must not be overlooked, especially for close monitoring and land stewardship. The perspectives of Indigenous people have gained increasing recognition in koala conservation across Australia, particularly in Queensland, New South Wales, and the Australian Capital Territory, where koala populations have declined as a result of bushfires and habitat loss. However, Indigenous involvement in the management of overabundant koala populations, especially in South Australia, remains limited, with room for exploration and knowledge sharing.

Editor:Nazalea Kusuma

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