A new study commissioned by the World Wide Fund for Nature-Australia found the bushfire crisis took a toll on platypus populations, which were already in decline.
Researchers from the University of New South Wales surveyed for platypuses in the Mid North Coast region of NSW in July and August 2020, seven months after a severe drought and bushfire impacted the area.
The study compared platypus numbers in a burnt river catchment, Dingo Creek (and tributaries Bobin and Bulga Creeks) to an unburnt catchment – the nearby Thone River.
In the burnt sections of Dingo, Bobin and Bulga Creeks, researchers managed to trap only two platypuses. In the unburnt downstream section of Dingo Creek, they trapped three platypuses.
In contrast, in the nearby Thone River, which escaped the fires but was similarly impacted by the drought, they caught seven platypuses.
Both river catchments were impacted by the recent extreme drought. Dingo Creek ceased to flow between November and December 2019 and the Thone River nearly ceased to flow during the same period.
Dr Gilad Bino, from the University of New South Wales, said the platypus is a species in trouble.
“We know that during the drought platypuses were found dead or in need of veterinary care.
“Our study suggests that wildfires pose another largely unrecognised and significant threat to this iconic species. Particularly when conditions leading up to bushfires are poor.
“Seven months after the fires, we found significantly fewer platypuses in burnt waterways compared to unburnt ones,” he said.
Dr Bino said bushfires can impact platypuses both directly and indirectly.
“As waterways dry up, platypuses can perish in fires as they attempt to travel to deep pools for refuge.
“Then with vegetation incinerated, the first post-fire rains wash silt and nutrients into rivers degrading water quality and driving declines in macroinvertebrates, the prey of platypus,” Dr Bino said.
Dr Kita Ashman, WWF-Australia Threatened Species and Climate Adaptation Ecologist, said the increased frequency and severity of fires and droughts will further strain the viability of platypus populations but there are actions that can help the species survive.
“We must protect the deep pools where platypuses take refuge during droughts, revegetate river banks to reduce sedimentation, stop the unsustainable diversion of water, and ensure good habitat connectivity so that the species can move along waterways.
“It’s crucial that platypuses can move across barriers including dams and other in-stream structures. This ensures safe haven deep pools can be reached, populations are not fragmented, and recolonisation is easier following droughts and fires,” Dr Ashman said.
WWF-Australia has launched the largest wildlife and nature regeneration program in the nation’s history.
To learn how to support WWF’s Regenerate Australia program, visit www.wwf.org.au/RegenerateAustralia
The impact of the 2019-2020 fires on platypus populations in the MidCoast region