The parts of Australia where platypuses are found has shrunk by at least 22% or about 200,000 km² – an area almost three times the size of Tasmania – in the past 30 years, new research led by UNSW Sydney reveals.
The research concludes the platypus is now likely to meet the criteria for listing as a threatened species under Australia’s national environmental law.
The UNSW researchers, along with the Australian Conservation Foundation, WWF-Australia and Humane Society International Australia, today nominated the platypus to be listed as a threatened species under Commonwealth and NSW processes.
The research found the decline in platypus observations was most severe in NSW (32% reduction) and Queensland (27%). Although Victoria recorded a statewide decline of 7%, there have been reductions of 18-65% in some Melbourne catchments since 1995.
Declines in platypus observations were worst in places where natural river systems and water flows have been most heavily modified, such as the Murray-Darling Basin.
New dams, the over-extraction of water from rivers, land clearing, attacks by foxes and dogs, pollution and suburban sprawl are the main factors driving the decline.
Platypuses also drown in closed freshwater traps designed to catch yabbies and fish, which are still legally sold in NSW and Queensland.
The changing climate also presents a serious new threat to platypuses, with more severe droughts, reduced rainfall and intense fires drying out rivers and river vegetation.
“Protecting the platypus and the rivers it relies on must be a national priority for one of the world’s most iconic animals,” said Professor Richard Kingsford, a lead author of the report and the Director of the Centre for Ecosystem Science at UNSW.
“There is a real concern that platypus populations will disappear from some of our rivers without returning, if rivers keep degrading with droughts and dams.
“We have a national and international responsibility to look after this unique animal and the signs are not good. Platypus are declining and we need to do something about threats to the species before it is too late,” Professor Kingsford said.
“While our national environmental laws should be much stronger, listing the platypus as a threatened species is a critical first step towards conserving this iconic Australian species and putting it on a path to recovery,” said Dr Paul Sinclair, Campaigns Director at the Australian Conservation Foundation, which commissioned the research.
“The platypus is one of the most unique and archaic mammal species in existence, and this research along with recent advice to list the species as vulnerable in Victoria makes it abundantly clear there’s no time to waste in increasing their protection,” said Evan Quartermain, Head of Programs at Humane Society International Australia.
“Platypuses are to rivers what koalas are to forests,” said Dr Stuart Blanch, Senior Manager, Land Clearing and Restoration at WWF-Australia.
“These days a sighting of just a few platypuses is often associated with a healthy population, but historical records suggest today’s numbers are only a fraction of what they once were. This alarming decline is the wakeup call we need to better protect our rivers and creeks.”
Platypuses need healthy rivers and streams where they can swim and forage for food around riverbeds and riverbanks. They have traditionally been found from tropical north Queensland all the way down the east coast to Victoria and across most of Tasmania.
The research was led by Dr Tahneal Hawke, Dr Gilad Bino and Professor Richard Kingsford of UNSW Sydney.