More extreme weather caused by climate change will put more pressure on koala populations.(ABC News: Rachel Carbonell)
First of all: are koalas really at risk of extinction or is that a beat-up?
We don’t know exactly how many koalas were in Australia when Europeans arrived.
But to get an idea of how many were in Australia in the mid to late 1800s, records from the koala fur trade tell a shocking story.
In Queensland alone, 500,000 skins were collected in the 31 days of the last open season in 1927.
Australia wide, as many as 8 million koalas were killed for their pelts during the late 1800s and early 1900s, according to the Australian Koala Foundation.
Most of those were sent to Europe, the UK and the US to be turned into coats, gloves and hats, according to koala ecologist Frank Carrick from the University of Queensland (UQ).
“There was a huge fur trade to Europe and principally to the UK in the late 1800s. There are millions [of export skins] recorded,” Professor Carrick said.
“When the public became a bit sensitive to this, they were exported as wombat skins.”
Millions of koalas were killed for their skins during the late 1800s and early 1900s.(Supplied: Australian Koala Foundation)
Today, our best estimate of the current number of koalas comes from a 2012 study by Christine Hosking from UQ, and her peers.
They calculated that there are around 330,000 koalas left in Australia, though given the difficulty of counting them, the error margin ranges from 144,000 to 605,000.
Dr Hosking and colleagues found that in the 21 years prior to 2012 and projected over the next 21 years, Queensland’s koala population will more than halve, and in New South Wales it will drop by 26 per cent.
Victoria, South Australia and the ACT will see significant, but smaller declines.
So is it fair to say koalas are at risk of extinction? Koala expert and zoologist Bill Ellis from the University of Queensland says in many parts of Australia, especially Queensland and New South Wales, it is:
“The short answer is yeah, we should be particularly worried,” Dr Ellis said.
“We’ve been doing surveys … up on coastal central Queensland and you talk to people who remember koalas, and there are records, but they’re not there anymore. That’s ringing alarm bells.”
Professor Carrick agrees: “They’re in dire straits, [but] it’s not a lost cause,” he said.
So how do we stop the decline of koalas?
Priority number one
Koala researchers say habitat destruction needs to stop if we’re going to keep koalas from going extinct.(ABC News: Stephanie Zillman)
It helps to think of the actions needed to preserve koalas as a hierarchy.
At the very top — priority number one — is stopping habitat loss, according to koala microbiologist Peter Timms from the University of the Sunshine Coast.
That includes restoring degraded habitat and creating connectivity between patches.
“Habitat [loss] is the number one threat. If they haven’t got a tree, nothing else matters,” Professor Timms said.
Researchers have outlined several approaches to this problem, depending on whether we’re talking about rural or urban environments.
In urban environments, where the key threats are housing, industrial infrastructure and roads, preserving koala habitats needs to be made a priority above development, according to Dr Hosking.
That means putting a dollar value on koalas and a healthy environment.
“There’s constant pressure from development so [governments are] making concessions that just aren’t good enough,” she said.
“It’s not too late [to re-establish wildlife corridors] but it really does come back to political will. Until governments are willing to say, ‘no you can’t clear there, but we’ll pay you to reforest’ … it’s not going to happen.”
Re-establishing wildlife corridors can help koalas and other wildlife move safely between food patches.(ABC News: Kerrin Thomas)
In rural areas, pressure on koalas comes mostly from land clearing for agriculture and mining.
In many instances, regrowth is cleared to make pasture for cattle. For a farmer to let that regrowth regenerate to forest means lost grazing area and income.
A large-scale solution being put forward by many koala ecologists like Dr Ellis is to pay farmers to restore and maintain koala habitats.
“The real future here could be making incentives for people to incorporate koala habitat on their land,” he said.
“There’s a lot of good agricultural land, but you don’t want to bankrupt [farmers]. You want to make it worth their while to have koala habitat on their country.”
He said farmers are worried about having their land locked up and being “driven to the wall”.
And Dr Hosking agrees: “Money talks. [Farmers] have got to have a reason to do it. If there was a dollar value in [standing] trees, they’d stop pushing them over.”
Priorities 2, 3, 4, 5…
Bushfires are an increasing threat to koalas, especially in southern states. But habitat connectivity allows areas to be repopulated after fire.(Supplied: WIRES)
The reason habitat loss is priority number one is because almost all other threats are made worse by it.
Koalas are more likely to be hit by cars if their habitat is fragmented by roads and they’re forced to travel between patches for food.
They’re more likely to encounter dogs when the urban environment encroaches on their space.
And they’re more susceptible to diseases like chlamydia when they’re stressed.
Climate change and more intense bushfire and drought are another cause of koala decline, especially in inland areas where summer temperatures are becoming more severe, Dr Hosking said.
“As soon as you get days over 40 degrees [Celsius] successively, the koalas just seem to fall out of trees — they can’t thermoregulate,” she said.
Expanding habitat and connectivity provides resilience against bushfire and means populations can re-establish from unburnt patches.
And though it can only go a small way to combating climate change, more trees also means more carbon drawdown.
While addressing climate change is a long-term challenge, there is some more promising news when it comes to addressing chlamydia.
Chlamydia is a disease that causes a range of problems in koalas, including infertility and blindness.(ABC: Matt Wordsworth)
Although chlamydia was already in the koala population when Europeans arrived, we’ve probably made it worse, according to Professor Timms.
“The chlamydia that’s in koalas is very similar to the chlamydia that’s in sheep and cattle,” he said.
“There’s a bit of science to suggest that we might have made it worse by bringing in [livestock].”
But at least one vaccine is almost ready to be rolled out, according to Professor Timms.
His lab at USC has developed a single shot vaccine over the past 10 years, with “very promising” results.
“We did a trial where we gave the vaccine to animals already with the disease. In six out of seven koalas it actually reversed the disease and they could be released back into the wild without using antibiotics, which can have serious side effects,” he said.
It also appears to prevent disease in infected animals before they start showing symptoms, he added.
“We’re at the stage now where we think that 90 per cent of the basic research work is done. I’m pretty keen now to move this out of the lab and into the real world,” Professor Timms said.
While restoring and protecting habitat is essential to the long-term survival of koalas, a vaccine could help buy us time.
“If you can stop these populations going infertile then their reproduction rates should start going back up,” he said.
Watch Catalyst’s Are We Killing Our Koalas? on iview now.