This week, for the first time, the platypus was added to Victoria’s threatened species list and classified as “vulnerable” in the state. Human population growth, urban sprawl and droughts have taken a toll on the waterways they live in and this is expected to worsen with climate change.
According to scientists, not enough is known about where platypuses live or how many are spread throughout the state. To help address this lack of knowledge, they are calling on Victorians to take part in a citizen science survey called the “Great Victorian Platypus Search”. Volunteers would take samples from local waterways to test for the presence of platypus DNA, a process known as environmental DNA sampling.
“It’s all very well declaring it as threatened, but currently we have only a very patchy understanding of where they exist and in what numbers,” said Mr Griffiths, who works at EnviroDNA, a small research consultancy, and has been researching the monotremes for two decades.
Environmental not-for-profit organisation Odonata, in partnership with EnviroDNA and Aboriginal-led organisation Outback Academy Australia, want to map the entire distribution of platypuses throughout Victoria’s waterways to inform any attempt to reverse the decline in numbers.
For many species in freshwater ecosystems, this data has previously been too difficult and costly to collect, said Odonata founder Nigel Sharp.
“Before we can develop a plan to reverse their decline, we first have to fill a critical gap in our current understanding of the species populations,” he said. “This could potentially reveal platypus occurrence in new areas where no previous records exist.”
The project will ask citizen scientists around Victoria to collect water samples from about 2000 designated sites during the breeding season for platypuses (August to October) and share the samples with EnviroDNA’s laboratory to be screened for platypus DNA.
Victorians will also be encouraged to submit their platypus sightings online at platypusSPOT, or via an app of the same name, with the results to be shared online in real-time for the public to see.
A wealth of new research on platypuses has shown how extraordinary these animals are. In a recent study published in the journal Mammalia, scientists found that when illuminated by ultraviolet light – a spectrum of light not visible to human eyes – the pelts of platypuses give off a blue-green glow.
And genetic research also shows platypuses share milk genes with mammals, and some egg-laying genes with birds and reptiles.
Platypus declines aren’t limited to Victoria. Five creeks surrounding Brisbane have lost their platypus populations, and researchers in NSW said platypuses in north-east NSW seem to have disappeared due to the drought and the impact of feral pests and livestock.
The Melbourne platypus population has been monitored through trapping surveys and more recently through DNA monitoring. During the millennium drought they stopped breeding and disappeared from many local creeks, but numbers have slowly increased, said Mr Griffiths.
When the Victorian Government announced the platypus would be listed as a threatened species it also said $250,000 would go immediately towards restoration works at key habitat sites, and $50,000 would be used to develop a long-term plan.
Miki Perkins is a senior journalist and Environment Reporter at The Age.