Science

Australian Experts Announce Koalas Are ‘Functionally Extinct’

Last week, the Australian Koala Foundation shocked the world with their announcement that they believe, “There are no more than 80,000 koalas in Australia, making the species functionally extinct”. While this count is much lower than the most recent academic estimates, there are little doubt koala numbers in many places are in sharp decline.

The exact number of koalas still remaining in Queensland, New South Wales, Victoria, South Australia, and the Australian Capital Territory is not known, but they are highly susceptible to threats like deforestation, disease and the adverse effects of climate change. Once a koala population falls below a critical point, it can no longer recover its count subsequently leading to extinction.

The term “functionally extinct” describes a perilous situation where the population of a species has declined to such a low count that it can no longer play a substantial role in their ecosystem. For millions of years, koalas have significantly contributed to the health of our eucalyptus forests by eating its upper leaves and providing essential nutrient recycling on the forest floor with their droppings. Koalas are even speculated as a possible food source for megafauna carnivores as their known fossil records date back around 30 million years.

Functionally extinct can also refer to a population that is no longer viable or such a small population that, in spite of breeding, suffers from inbreeding complications that threaten its future viability. At least some urban areas populations of the koala are known to suffer in this way. Genetic studies on the Koala Coast, located 20kms south-east of Brisbane, reveal that the resident koala population is suffering from reduced genetic variation. In some areas of South East Queensland, koalas have experienced catastrophic declines. Koala populations in certain inland regions of Queensland and New South Wales declined by as much as 80 % due to effects by climate extremes like severe droughts and heatwaves.

Exhaustive multi-disciplinary koala research is engaged in concentrated effort to find ways of protecting wild koala populations and safeguarding that they remain viable now and into the future. Some key areas under study are habitat loss, population dynamics, genetics, disease, diet and climate change.
Koala researchers admit that finding the exact number of koalas in the wild is a little hard to say as they are usually difficult to spot, are not stationary and are sporadically distributed throughout an extremely wide range encompassing urban and rural areas in four states and one territory. Determining whether each population of koalas dispersed across eastern Australia is functionally extinct would entail a huge effort.

A 2016 attempt to determine population trends for the koala in the four states of Queensland, New South Wales, Victoria, and South Australia, had a panel of 15 koala experts using a structured, four-step questionnaire to estimate bioregional population sizes of koalas, and changes in those estimates. They found:
• The estimated percentage of koala population loss in Queensland, New South Wales, Victoria, and South Australia was 53 %, 26 %, 14 %, and 3 %, respectively.
• The estimated overall count of koalas in Australia was pinned at 329,000 within a range of 144,000–605,000 and an estimated average decline of 24 % covering three generations in the past and future.

Koalas have been listed as ‘vulnerable’ in Queensland, New South Wales and the Australian Capital Territory since May 2012 as their populations in these regions have declined substantially or are at risk of doing so. Koala populations inhabiting the southern states of Victoria and South Australia vary widely from abundant to low or locally extinct. Even though these koalas are not currently listed as vulnerable, they are also experiencing a range of serious threats like low genetic diversity.

Unfortunately, the current “vulnerable” listing has not achieved any noteworthy positive results for koala populations in Queensland and New South Wales till date. In fact, recent research consistently shows the opposite as the key threats such as habitat loss remain and are even increasing. Koala’s typical habitat of eucalyptus woodlands and forests continue to rapidly diminish, and unless they are protected, restored, and expanded as a priority, the future of wild koala populations seems to be bleak.

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