A year on from Black Summer fires, drones enlisted to help save koalas

For an animal that's culturally ubiquitous, koalas are remarkably hard to spot in the wild.

As a result, it's difficult for scientists and conservationists to know just how many koalas are out there.

In New South Wales the population could be around 36,000, but last year's NSW parliamentary inquiry heard those figures are "outdated and unreliable" and the real number could be half that.

The same inquiry recommended exploring the use of drones to gain a more accurate head-count.

Happily, researchers from the University of Newcastle were already testing drones in collaboration with the NSW Department of Planning, Industry and Environment.

Their study, published in the journal PLOS One, suggests that it works.

Drones found koalas 'every two hours'

A team with a drone was able to spot koalas more effectively and cheaply than a team using more traditional methods, such as studying the forest floor for traces of koala scat, or shining spotlights into trees at night to catch a glimmer of eye-shine.

"For our sample area in Port Stephens, koalas can be located with the drones every two hours," lead author Dr Ryan Witt said.

"This is very different to spotlighting, which we found was one every five to seven hours.

"And with the scat samples it was one every 43 hours."

Dr Witt and his team flew drones in the night-time hours before dawn.

In the infra-red images, the koalas appear like fuzzy white blobs, sometimes almost indistinguishable from the canopy in which they perch.

To visually confirm that the blobs were in fact koalas, the researchers flew the drone back at first light to check.

Though the grainy black-and-white images may not seem like much, Dr Witt believes they could herald an important change - and not just for koala conservation.

Ultimately, he envisions airborne fleets equipped with AI to scan and sift through a landscape, automatically cataloguing the animals below.

This would mean that for the first time accurate population data may be gathered for many species - from flying foxes to brush-tailed possums.

That AI technology already exists, but does not yet work in real-time.

Last year, QUT researchers flew AI-enabled drones over forests burnt in the Black Summer fires to estimate the number of koalas that had survived.

By teaching the AI to distinguish possum from koala, researchers are building the foundations of a "dataset for biodiversity", Dr Witt said.

"I think that we're really at the start of what might be a new tool that revolutionises the way that we monitor biodiversity on a regular, longitudinal basis," he said.

Current spotting methods 'labour intensive'

A common traditional technique to count koalas is for a team of six to spend several nights walking through an area of bush along parallel straight lines, shining spotlights into the trees.

"That method is really labour intensive," said Dr Witt.

Because spotting is slow and expensive, estimates of koala populations vary wildly.

In 2016, a panel of 15 experts estimated there were over 300,000 koalas in Australia, though they admitted it was hard to say for sure. Their estimate had a sizable margin of error: from 600,000 to 144,000.

Three years later, the Australian Koala Foundation produced its own figure: as few as 43,000 koalas remained in the country.

The Black Summer bushfires have confused this picture even more.

A report commissioned by WWF estimated over 60,000 koalas in four states had been killed, injured or displaced as a result of the Black Summer fires.

This loss, combined with land-clearing, feral animals, and disease, has led to predictions that the koala is fast going extinct.

In Queensland, New South Wales and the ACT, koalas are listed as 'vulnerable' under national environmental law and may be upgraded to 'endangered' this year.

Need for 'baseline data'

Last year's NSW parliamentary inquiry concluded the tree-dwelling marsupial could vanish from NSW forests "well before" 2050.

A few months later, in November, Federal Environment Minister Sussan Ley announced $A2 million ($NZ2.14m) for a national koala population census.

This would provide "baseline data" on how many koalas were out there, she said.

"I have been so frustrated that no one could give me the data I needed ... it's just not there - only in patches," Ley said.

The $2m set aside for a national koala audit will have to stretch far to cover the vast national distribution of the species.

In fact, dividing the funding figure by the distribution one leaves $1.40 to survey each square kilometre.

Deploying drones may help, but the drones themselves are expensive - the one used for the research would cost about $20,000 to buy today.

Even so, Dr Witt believes drone-mounted AI systems are the future of biodiversity monitoring.

"The greatest challenge will be to get this drone system working in real time so that you don't have to rely on someone looking at a screen and going that could be a koala that might not be," he said.

And this fine-tuning, he said, will require old-fashioned boots on the ground.

"You can start to teach the AI to decide that's a koala, that's a rock, that's a possum, that's a wallaby, and so on," he said.

- ABC