Canberra researchers install clay burrows to save critically endangered grassland earless dragons

You would be lucky to spot a Canberra grassland earless dragon at the best of times, with an estimated 100 or fewer left in the wild. So saving this Canberra critter is critical.

University of Canberra PhD student Ryan Colley, who has been studying the species' genetics since 2020, said the dragons were "very hard to see" outside their burrows.

"You'll occasionally see one running around, but it's very rare," he said.

In a bid to help the tiny reptiles survive, researchers have now made their own dragon dens out of clay.

70 degrees and no shade

ACT Parks and Conservation dragon recovery coordinator Ben Croak said the grasslands could be brutal for an animal so small, being unable to survive temperatures above 40 degrees Celsius.

"The grasslands get incredibly hot in summer," Dr Croak said.

"In the middle of summer, we've recorded temperatures up to 70C on the ground, which is incredibly lethal to a little dragon like this."

The dragons usually shelter and nest in spider burrows, so the new terracotta tubes are designed to mimic them, dropping about 20 centimetres beneath the ground.

"The ground's pretty insulated, and having them around 20cm provides a thermal gradient for them to shuttle up and down," Dr Croak said.

"[That way] they can get to the sort of desired temperature they want to be at."

PVC tubes have previously been used to monitor the dragons, but Dr Croak said they were not suited to egg-laying.

Clay holds moisture, which the team hopes will buffer the impact of climate and help incubate eggs.

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Dr Croak said the trial would test the tubes ahead of an approaching hot summer.

"I think they're like most things, they'll take advantage of things that are there for them," Dr Croak said.

Early signs of promise

One hundred specially made dragon dens have been installed at two sites in Canberra to give the reptiles a variety of burrows to choose from.

"They've taken up the burrows quite quickly, which was a bit of a shock," Mr Colley said.

"Because these burrows mimic more of the natural burrows, it was good to see them use those over the PVC burrows."

Using an endoscope to peer into the burrows, Mr Colley has been closely monitoring how the new digs are being used.

"When you see them in the burrow, they're curled up at the bottom," he said.

A different sort of art installation

Finding someone to make the burrows was a challenge in itself.

Dr Croak said he rang around, but finding an artist or workshop interested in a commissioned work of 100 tubes, each 20cm long and "as thin as possible whilst maintaining structural integrity" did not stir the creative juices of everyone.

"The loss of artistic licence when it came to just making a clay tube was kind of a deterrent for some people," he said.

"Tom from Strathnairn Arts in North Canberra really embraced the idea and pumped them out for us really quickly.

"So it was really, really cool of those guys to do that."

Tom has joined the team in the field to see his artwork installed.

Dwindling gene pool

Providing shelter and nesting sites is only part of the challenge around the conservation of this critically endangered species.

Dragon populations in the ACT are small and isolated.

Mr Colley, who also works at the Office of Nature Conservation, said that was a major concern.

"These populations are becoming quite genetically isolated from each other even though they're within a short distance," he said.

He said the first step was translocating animals between sites in the hope of boosting genetic diversity.