Research shows there is a decline of up to 30 per cent in the numbers of the iconic platypus, with localised declines and extinctions being increasingly reported.
Scientists are concerned about the loss of the platypus following almost three years of data capture.
A national risk assessment was conducted by the Univerisity of New South Wales and funded by the Australian Research Council.
It used information obtained from the past two centuries on the whereabouts and population of platypus. This data was then combined with random capture surveys.
“We have great concerns about the future survival of this unique species,” project leader Professor Richard Kingsford, director of the UNSW Centre for Ecosystem Science, said.
Threats to the platypus populations include river regulation and flow disruption, increasing agricultural land use, pollution, and the capture of platypus in fishing and yabby nets.
“All of which are contributing to these declines across its range,” he said.
The national survey showed great variability in platypus numbers in eastern Australia.
UNSW researcher Dr Gilad Bino said “On degraded rivers, typically below dams and in regions of high agricultural land use, we generally see lower numbers of platypus, likely due to the impacts these threats have on bank erosion and availability of macroinvertebrate food sources,” he says.
Tahneal Hawke, a PhD candidate at UNSW said, “Previously we’ve had no information on historical platypus abundances and without this baseline reference we become misinformed about what a normal abundance is.
“This shift in our perception is particularly important for such a cryptic animal.
“Given sightings are rare, people perceive captures or sightings of just a few platypuses to be indicative of a healthy population, while historical records suggest numbers far exceeded our current observations.”