Koalas are one of Australia’s most recognized and unique marsupials, found across the eucalypt forests of the eastern and southern coasts. While their conservation status is complex and geographically varied, the combined populations in the country’s most populous regions face a severe threat. In February 2022, the Australian federal government officially up-listed the koala populations of Queensland, New South Wales (NSW), and the Australian Capital Territory (ACT) to the Endangered classification. This official change reflects a significant and continuing decline in the species’ numbers across a large portion of its range.
The Official Conservation Status
The koala’s formal protection status is governed by the national Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act). This legislation defines the level of threat a species faces, providing a framework for conservation efforts and environmental planning. The listing of koalas in the three eastern jurisdictions as Endangered signifies that they are facing a very high risk of extinction in the wild in the near future.
This Endangered status was an uplisting from the previous Vulnerable classification, which the populations held since 2012, highlighting the rapid acceleration of threats. The designation requires all new development projects in these areas to undergo much stricter environmental impact assessments. Any action likely to have a significant impact on koala habitat must now be referred for approval under national environmental law. This contrasts with populations in Victoria and South Australia, which are currently considered stable and are not listed under the EPBC Act.
Primary Drivers of Population Decline
The primary reason for the koala’s designation as Endangered is the relentless loss and fragmentation of their habitat. Habitat is cleared predominantly for agriculture and urban expansion, particularly in Queensland and NSW. This destruction forces koalas to cross increasingly dangerous, fragmented landscapes, leading to higher rates of mortality from vehicle strikes and dog attacks.
Disease is another major factor severely limiting population recovery, particularly the combination of Chlamydia pecorum and Koala Retrovirus (KoRV). Chlamydia causes severe conditions like blindness and urinary tract infections, known as “wet bottom.” More critically, it causes reproductive tract disease in females, resulting in infertility due to cystic lesions. Koala Retrovirus (KoRV) is linked to an immune deficiency that makes the animals far more susceptible to contracting and suffering from Chlamydia and cancers like lymphoma.
The unprecedented 2019–2020 Black Summer bushfires delivered a catastrophic blow to already fragile eastern populations. These mega-fires impacted an estimated 61,000 koalas and destroyed or severely degraded an estimated 25% of their habitat in NSW. Koalas that survived the flames often suffered burns to their paws and faces, smoke inhalation, and dehydration, with many succumbing later due to the loss of their food source and shelter. The cumulative effect of habitat loss, chronic disease, and acute fire events creates a cycle of decline that threatens the species’ long-term survival.
Geographic Nuance in Koala Populations
The koala’s conservation challenge is complicated by dramatic variations in population health across the continent. While the northern and eastern populations are declining rapidly and federally listed as Endangered, the koalas in parts of Victoria and South Australia are considered secure and are not listed. Some southern populations, which were historically reintroduced, sometimes experience localized overabundance.
These dense populations can exceed the carrying capacity of their habitat. This leads to severe overbrowsing, where the koalas consume eucalypt foliage faster than the trees can regenerate, causing habitat degradation and, ultimately, starvation. Management in these areas often focuses on non-lethal population control. This contrasts sharply with the challenges in the north, where the entire focus is on preventing population collapse.
Conservation and Recovery Efforts
The recovery of the endangered koala populations in Queensland, NSW, and the ACT is guided by a National Recovery Plan published in 2022. The plan establishes a ten-year pathway with the goal of stopping the decline and increasing the extent, quality, and connectivity of occupied habitat. A major focus is on strategic habitat restoration, which involves creating wildlife corridors to link fragmented patches of forest.
On-ground efforts include large-scale tree planting projects, often involving local landholders, to establish new koala food trees along river systems and in areas previously cleared for agriculture. Additionally, the construction of fauna connectivity structures, such as underpasses and rope bridges over major highways, is aimed at reducing mortality from vehicle strikes in high-risk areas.
A significant breakthrough in disease management is the recent approval of the world’s first koala chlamydia vaccine. This single-dose shot was shown to reduce mortality from the disease by at least 65% in wild koalas during trials. This vaccine is now approved for use in wildlife hospitals and in the field, offering a powerful tool to address the disease that has severely impacted reproductive success and population viability across the eastern states.