Tjaltjraak rangers using environmental DNA analysis to monitor country

Aunty Donna Beach feels she is tracing the footprints left by her ancestors whenever she walks on Tjaltjraak Boodja country near Esperance. 

Soon, the senior cultural ranger at the Esperance Tjaltjraak Native Title Aboriginal Corporation (ETNTAC) hopes footprints of a different variety will be used to measure the country’s biodiversity through a process known as environmental DNA, or eDNA, analysis.

Rupert McDonald, an honours student from Curtin University, said the process involved collecting a sample of water, soil, air, or ice from the environment which would naturally contain biological material like hair, blood, mucus, saliva, or skin.

The sample is then taken to a laboratory where DNA from that material is extracted, isolated, and analysed.

That should show exactly what plants, animals, fungi, and bacteria had recently been in the area. 

Measuring biodiversity can also be done through species counts, but that can be a painstaking and expensive process, and could exclude shy and inconspicuous species.

Mr McDonald said environmental DNA analysis was a fairly new technology, but believed it held a lot of potential for ranger groups like those in Esperance.

“It’s just a matter of … working out how it can be potentially put in the pocket of guys like the Tjaltjraak who can just go out there and sample some water and by the afternoon be able to tell all the animals that have been drinking out of that water source,” he said.

He said it could also be used to measure the success of projects like wild dog fences.

“If you’ve got DNA from dogs or dingoes on the wrong side of the fence it would go to show the fence doesn’t really work,” Mr McDonald said.

Showing ‘what we need to protect’

This week, Tjaltjraak rangers and Mr McDonald travelled around Esperance collecting environmental DNA samples which would soon be tested in a laboratory.

Ranger Lachlan Adamson said the technique had cultural benefits because to care for country they needed to know what was there.

“We’re going to areas that are really remote in the bush and not too many people know about. We know these DNA samples are from the most uncontaminated water sources out there.”

Mr McDonald said contamination could cause problems for environmental DNA analysis as it may skew the results. 

“[For example] if you have a dog at home or a cat at home [DNA fragments from it] might end up in your sample which would then come up in the analysis to say that there’s cats and dogs drinking out of that water source,” he said.

But Mr Adamson believed it could also compliment other tools frequently used by the rangers like patrols, surveys, and motion-sensor cameras.

For example, if a test picked up the DNA of a rare species from a water hole, a motion sensor camera could be put there to try and see it on camera.

Mr Adamson also hoped the technique could help crack a recent case — where a strange-looking bird was photographed but it was blurry and in black and white.

“It’s a weird figure I’ve never seen before. Some sort of bird, it might be a ground parrot,” Lachlan said.

Hopefully, the environmental DNA analysis will shed some light when the lab results come back, which Mr McDonald said would likely take about two months.