The first landscape-scale study of the impact of bushfires on platypuses estimates a 14 per cent to 18 per cent decline in populations in fire affected areas in the nine months after last summer's devastating fires.
The study by Cesar Australia for the Australian Conservation Foundation found the fires burnt a large area of the best remaining platypus habitat in south-eastern Australia, affecting 13.6 per cent of the species' total range.
Thousands of hectares were burnt out in the Scenic Rim last summer, including rainforest.
The analysis estimates that 2 per cent of the total population of the species could have been killed.
With UNSW researchers estimating there are up to 317,500 platypuses left in the wild, this means as many as 6350 platypuses may have been killed.
Such a large death toll would have consequences for the platypus' national conservation status, supporting calls for the species to be listed as vulnerable.
"Platypuses have been under stress in other areas of their range from things like changing river flows and land clearing," said ecologist Josh Griffiths from Cesar Australia. "To see these bushfires impact so much of their best remaining habitat is devastating."
Researchers studied 142 sites pre-fires and post-fires. Forty-eight of the 142 sites were impacted.
Before the 2019/20 bushfires, platypuses were detected in 40 of the 48 fire-affected sites. After the fires, platypuses were detected at just 33 sites, a 14 per cent reduction.
"Last summer's bushfires razed the vegetation along numerous riverbanks where platypuses build their burrows, while ash and sediment clogged up the creeks they feed in and severely reduced their food sources," said ACF's nature program manager Basha Stasak.
"These unique Australian creatures have been badly affected by dams and the over-extraction of water from rivers, land clearing, attacks by foxes and dogs, pollution and suburban sprawl - and last summer they were hit hard by bushfires.
"Listing the platypus as a threatened species would be an important first step towards putting this much-loved Australian on the path to recovery," she said.