19 December 2023: Driven to extinction in the ACT, the green and golden bell frog may be poised for a return – thanks to a project led by University of Canberra researchers. If successful, reintroducing the frog species to the local ecosystem potentially holds a solution to the deadly chytrid fungus, which has devastated amphibian populations around the world.
Senior Research Fellow in Invasion Ecology Dr Simon Clulow and Centenary Professor Richard Duncan at the University’s Faculty of Science and Technology, along with Senior Lecturer Dr Ben Scheele from the Australian National University, are driving the Restoring amphibian populations in chytrid-impacted landscapes project.
The project was awarded over $900,000 in funding in the latest ARC Discovery Project round.
Spanning four years, the project involves collaboration with project partners including the ACT Healthy Waterways Program and Office of Nature Conservation under the ACT Government, Gininderry Conservation Trust, FrogWatch ACT, NSW Department of Planning and Environment, and Symbio Wildlife Park.
“The green and golden bell frog is a very charismatic little animal – its call sounds like a motorbike!” said Dr Clulow. “There was one isolated highlands population left at Captain’s Flat, near Canberra, but no one has seen this particular frog there in about two years.”
The species has been extinct in the ACT since 1979, thanks to the chytrid fungus – one of wildlife ecology’s most outstanding problems, this fungus has caused the largest extinction crisis in amphibians the world over.
The fungus attacks the skin of frogs, in areas containing keratin, the protein that forms the skin’s building blocks. Frogs breathe through their skin, making respiration difficult; the fungus also affects electrolyte transport, which can lead to heart attacks.
“Ben has published a paper showing that over 500 frog species have been affected by the chytrid fungus worldwide – in Australia alone, at least four species have already gone extinct,” Dr Clulow said.
“The chytrid fungus is also behind the decline of corroboree frogs, which have been bred in captivity – but the problem is that the fungus remains in the environment, and attacks any frogs released into the landscape. This is what has caused other attempts to bring the green and golden bell frog back, to fail.”
To overcome this problem, the project – the first landscape-level intervention for chytrid – will take a two-pronged approach.
The green and golden bell frogs will be bred in captivity, and then immunised against chytrid to build resistance before being released in the wild.
At the same time, the researchers will build habitat interventions across 25 wetlands in the ACT. These will include salted satellite ponds that help block infection, and structures designed to create natural hotspots and provide respite from the cold conditions that the fungus needs.
“The one-time vaccination will increase the frogs’ resistance,” said Dr Clulow. “It will not be passed on to the next generation – that’s why the other part of this intervention involves environmental manipulations that create conditions which are good for the frogs, but not good for the fungus.”
The salted satellite ponds and hotspot habitat structures will be set up in four pilot wetlands this summer; the work of breeding the frogs for release will then begin at Symbio Wildlife Park, and possibly the University.
“It will then be about a year and a half of work before we have all 25 wetlands set up and suitable for the reintroduction of the bell frogs,” Professor Duncan said.
Following release of the frogs, there are plans to build engagement with citizen scientists and community members, to look out for and record sightings of the frogs, and to take part in surveys with FrogWatch.
“From this project, we expect to see how relatively straightforward habitat manipulations might allow the frogs to co-exist with the pathogen,” Professor Duncan said.
And understanding the impact of such interventions for the green and golden bell frog will pave the way to save other amphibians around the world, anywhere they are impacted by chytrid.