Ecologists are warning platypus populations could be in trouble in New South Wales, but say they have no way of knowing because there is no state monitoring system.
Conservation ecologist Gilad Bino from the University of NSW said researchers have relied on reports of opportunistic sightings and data from citizen scientists to make the case for the animal to be put on the threatened species list.
Last year, researchers at UNSW appealed to the Threatened Species Scientific Committee to list the platypus as a nationally threatened species under the Environment Protection and Biodiversity Conservation Act 1999.
The case was rejected, largely due to a lack of baseline data.
The decision means researchers are stuck, both needing the species to be put on the threatened species list to trigger monitoring, and needing the monitoring to be able to get it on the list in the first place.
"It's a catch-22," Dr Bino said.
"It's not on any listing in New South Wales or Queensland, so it's not being monitored or considered at all."
Fate uncertain after Black Summer fires
In bushfire-affected areas of South East NSW, next to no baseline data exists.
Dr Bino is worried that local extinctions are going unrecorded.
"We really don't want to be in the same position as with the koalas where we wake up a bit too late, to all of a sudden realise that the species is in danger," he said.
Researchers have also drawn comparisons with places such as Kangaroo Island, which was also affected by the Black Summer bushfires of 2019–20 and for which baseline data was available.
"What we saw there was that definitely both the drought and the bushfires have had a significant impact on the [platypus] population," Dr Bino said.
The UNSW team has found platypuses can survive extreme weather events, but only if their natural habitats were in good condition.
Healthy rivers and creeks are critical for the animals, which are dependant on stable earthen banks to dig burrows.
"In degraded systems where there is bank erosion and things like that, extreme conditions can push platypuses populations beyond their ability to cope," Dr Bino said.
'We've dropped the ball'
Antia Brademann is part of a group of citizen scientists who spend hours quietly observing rivers in the Upper Murrumbidgee every August and September.
They are looking for signs of the normally shy platypus, which are extra active this time of year as the species prepares for the breeding season.
The Waterwatch group has been monitoring two sites along a stretch of the river for seven consecutive years. This will be their eighth.
"We don't have any other surveys being carried out in the area, so these surveys are giving us really important information to know what is going on," Ms Bradermann said.
The survey data collected by the group is showing that so far, numbers of platypuses — although small — are steady.
But more volunteers are needed.
"It involves groups of volunteers standing along a bank and recording platypus activity for an hour," Ms Bradermann said.
"People's feedback is that it's always a wonderful time, just to sit by the river and soak it all in."
Dr Bino said the work of groups such as Waterwatch was vital to understanding how the iconic Australian animals were faring.
"There are whole swathes of areas in their range where platypuses have never been seen, or haven't been seen in 20 or 30 years," he said.
The Platy Project, an online citizen scientist mapping platform built in partnership with the Australian Conservation Foundation, has already helped researchers fill these gaps.
"They're really hard to monitor, but that kind of information is vital," Dr Bino said.
"Those devastating bushfires have had a huge impact. We know they've had a huge impact on platypuses as well.
"We've dropped the ball."
