Environment Matters Spring/Summer 2019

Platypus populations plotted with DNA

It’s dawn in the middle of winter and you’re sitting still beside the murky water of a small creek.

You hear a plop and see some ripples in the water – maybe it was a platypus! Or maybe it was a water dragon or water rat. It’s hard to tell. Until recently, labour-intensive surveys like this involving multiple volunteers were the only way to record the elusive platypus. Now science has made it as simple as a water test to uncover vital information. Ipswich City Council and Wildlife Queensland have been working together to build a picture of our local platypus population with annual environmental DNA surveys since 2016. Water samples are taken at locations with anecdotal platypus sightings or good habitat. The efficient technology allows a number of waterways to be tested each year – in 2019 there were

Mr Cecil said the pattern of positive results over the four years of surveys showed the current Ipswich platypus population was small and vulnerable, probably transient, and their creeks low on water with the drought. Mr Cecil said actions that cared for our waterways also benefits platypus, such as limiting chemicals and rubbish pollution, removing weeds and preventing sediment. The platypus was identified as a priority species in council’s Nature Conservation Strategy 2015 . This DNA data will help council make informed decisions about future conservation strategies to improve platypus populations in our region. If you spot a platypus report it to platypus@wildlife.org.au

25 sites across the region sampled within two days. Those samples are sent to a Melbourne lab that has coded platypus DNA – shed through biological material such as skin or fluid – and can detect it in the water samples. A positive result is a strong confirmation that a platypus has been there recently. Wildlife Queensland project manager, Matt Cecil, said there had been some surprises. “(On) Goodna Creek and the Bremer River there are lovely spots with water flowing and beautiful habitat and there

are no platypus there,” he said. “Where we are seeing them, we

wouldn’t consider those to be excellent conditions – low water flow, degraded by weeds.”

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