By Julie Miller
New technology using environmental DNA has revealed that one of Australia’s most beloved icons, the platypus, is thriving in Blue Mountains waterways.
In the time of the Dreaming, an adventurous and disobedient duck named Gagar wandered away from her family on Narran Lake near Walgett, and was kidnapped by the malevolent water rat, Bigun. After escaping from her captor, Gagar later gave birth to three strange babies, who had four webbed feet and a duck bill, and were covered in fur. Banished by the other ducks, Gagar and her odd little family swam downstream to the colder waters of the Central Tablelands, where the fur-covered babies thrived and had children of their own, coming to be known as Biladurang – the platypus. This creature then continued to move east towards the Blue Mountains, its story flowed on through the waterways…
It’s fitting that this Wiradjuri creation story has its finale in the Greater Blue Mountains region – for it is here that the platypus, according to recent studies, continues to thrive.
After the devastating bushfires of 2020, however, there were concerns that the platypus may have been impacted by ash and silt, with anecdotal data unclear of their status. With funding provided by a Commonwealth grant, an ongoing study coordinated by the Department of Planning and Environment shows reassuring results, with platypus detected in 29 waterways on Wiradjuri, Darug and Gundungurra country.
The key to this groundbreaking study is the use of new technology, detecting the presence of the otherwise elusive creature through environmental DNA.
“This is a reasonably new technique that’s only really emerged for non-scientists in the last couple of years, but it’s a really easy way to get a picture of what’s going on,” says Alison Foster, Technical Officer for Conservation Bushfire Recovery with the National Parks and Wildlife Service.
In a nutshell, the technique detects small traces of platypus skin cells or body secretions in the waterways. It simply involves taking a sample of water, passing it through a filter, adding a preservative, then sending the sample off for a PCR test. Certain markers indicate the presence of different species, including platypus, with the results then sent back to the research team.
“One of the advantages of this technique is that citizen scientists or land managers can go out and collect these samples and get these samples analysed, and get information about where platypus are,” Ms Foster says. “It gives us a snapshot that helps form a bigger picture across the landscape on how platypus are going, and how they are affected by broad-scale events such as drought or bushfire.”
Focusing on seasons when platypus are most active – during the breeding season of Spring, and juvenile dispersal in Autumn – the study will involve samples taken from 100 waterways across the region.
“From the spring period (2021), we had 29 sites [from a total of 67] return positive DNA results; there were another nine sites that had equivocal results which means they contained only trace amounts of DNA, so they’re not conclusive,” Ms Foster explains. “So there’s some areas we’d like to go back to, and a couple of gaps in our sampling locations we couldn’t get to last Spring.”
Waterways where platypus have been detected so far include those in the Blue Mountains, Kanangra-Boyd, Nattai, Mount Royal, Turon and Marangaroo national parks, Bangadilly and the Upper Nepean State Conservation Areas.
“This is data we would like to share, especially with other researchers to get a bigger picture across the landscape,” Ms Foster says. “All this information we’ll make available through NSW Bionet so it can be used for any reason platypus information can be of use.”
There is also potential for Blue Mountains’ residents to become involved in future “citizen science” studies of the platypus, further cementing the region’s connection to this endearing creature.
For information on citizen science projects run by the Department of Planning and Environment, visit https://www.environment.nsw.gov.au/research-and-publications/your-research/citizen-science
*To hear the creation story of Biladurang, a Wiradjuri Creation Story, see https://youtu.be/4IVp3m4hTHw
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