The koala may receive more public affection than any of Australia’s other wildlife, yet complacency over its status, as well as habitat loss, predation and climate change, is putting this emblematic mammal at risk of extinction.
With an extremely wide range that encompasses much of eastern Australia, the koala has always been thought of as common. However, scientists are warning that numbers of this marsupial have dropped by up to 95 per cent since the 1990s, and there are believed to be just 43,000 individuals remaining. In southeast Queensland alone, the population of this tree-dwelling mammal has plummeted from 25,000 to 4,000 in a decade.
Demand for more active conservation
Alarmed by this decline, a Senate committee began gathering evidence in February on whether the koala should be listed as an endangered species. At present, the koala is not even classed as vulnerable in Australia.
Within three months, the committee received more than 80 submissions from individuals, government departments, local councils and researchers, with many demanding urgent action by the government to save remaining koala populations.
Scientists say that unless more energetic conservation measures are taken, the mammal’s future could be in doubt.
“This species is supposed to be common, yet it’s slipping to extinction under our noses,” said Christine Hosking, a nature conservationist at the University of Queensland.
Large-scale land clearing for urban development, industry and agriculture has progressively deprived the koala of much of its habitat. It has also fared badly in recent droughts and heat waves, which are expected to become more common in southern Australia as a result of climate change. To make matters worse, increased carbon dioxide in the atmosphere is reducing the nutrient content of eucalyptus leaves, the koala’s sole food source.
Ms Hosking’s research shows that temperatures above 37ºC are intolerable for the koala. “Once you get over 37 degrees, there’s zero probability of a koala,” she said. “As we get more of these extreme temperatures and protracted droughts, the koalas simply won’t be able to cope.”
The koala also faces challenges from an HIV-type retrovirus and Chlamydia, which renders half the marsupial’s population infertile. A 2009 report predicted that koalas would become extinct within 30 years because of this disease.
A draw for tourism
The image of the koala on tourist brochures attracts thousands of foreigners to Australia every year, and this cuddly critter is thought to be worth around $1 billion (£650 million) a year to the Australian economy. However, some senators have voiced concerns that protecting the koala could lead to conflicts with landowners who want to fell trees and develop their properties.
The decision on whether to list the koala as endangered ultimately lies with the federal Sustainability Minister, Tony Burke, who is waiting for a report from the parliamentary committee.
Listing the koala as endangered would be a first step towards developing a national action plan to safeguard its future. It would also facilitate conservation work, making it easier to protect remaining habitat and to find funding for research into a Chlamydia vaccine.
Without better protection, koala experts fear for the species. “They’ll just become more and more rare in the wild, found at increasingly low densities, and populations will become unviable,” said Dr McAlpine, landscape ecologist at the University of Queensland.
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Alex Royan, ARKive Species Text Author