These iconic animals aren’t dying outMinden Pictures/Alamy
By Michael Le PageWho has said koalas are “functionally extinct”?
The Australian Koala Foundation, which lobbies for the animals’ protection, has put out a press release stating that it “believes koalas may be functionally extinct in the entire landscape of Australia”. The release triggered a flurry of worried headlines.
So are they?
No, although many populations of koalas are falling sharply due to habitat loss and global warming.
Could they go extinct?
There is no danger of koalas going extinct in Australia overall, says biologist Christine Adams-Hosking of the University of Queensland, who has studied the marsupials’ plight. “But at the rate of habitat clearing that is going on, we are going to see increased local population extinctions,” she says.
Why has the AKF made this claim now?
The claim was made on the eve of elections in Australia in which environmental issues such as climate change have become a big issue. The AFK has called on politicians to act. “There’s a lot of politics going on, and somehow the koala gets involved,” says Adams-Hosking.
What does functionally extinct even mean?
The term is used in several different senses. It can mean that a species has declined to a point where it can no longer plays the role it once did in a ecosystem, with significant effects on that ecosystem. Some define it even more narrowly, saying a species is functionally extinct when its decline leads to the extinction of other species. That’s not what we’re talking about here.
There are more meanings?
Yes. Others use it – arguably incorrectly – to describe a species that is probably extinct but we can’t be sure. For instance, when researchers failed to find any river dolphins in China in 2006, they declared the baiji “functionally extinct”.
Surely this isn’t what the AKF meant?
No. The term is also used to describe a species where there are still many surviving individuals but the species is thought to be doomed in the long-term because, say, of the loss of genetic diversity. This is the sense of functionally extinct meant by the AKF. “This is a scientific term to describe ‘beyond the point of recovery’,” wrote the head of the AKF, Deborah Tabart, in a blog post.
But koalas haven’t passed this point?
Some local populations of koalas are indeed heading towards functional extinction, says Adams-Hosking. “But Australia is a big country, there are koalas all over the place and some of them are doing fine,” she says. “You can’t just make that statement broad-brush.” Adams-Hoskins also questions the AKF’s claim that just 80,000 koalas remain. In 2016, she and colleagues estimated that there are around 300,000.
That sounds better…
No one knows for sure how many are left. What we do know is that koala numbers are falling as the eucalyptus forests they live in and feed on are cut down to make way for cities and farms. Habitat loss is the biggest threat, as it is to most wildlife.
What about climate change?
It is already having a big impact, says Adams-Hosking, causing some populations to decline 80 per cent. Koalas can’t cope with day after day of temperatures above 36°C, as has been happening in the west of the country during the many recent heatwaves. Extreme droughts are also harming the eucalyptus trees they feed on.
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