In 2013 Australia’s governments decided they would not attempt to eradicate smooth newts, which had recently established in waterways in Melbourne’s south-eastern waterways, probably after being abandoned as an illegal pet.
In failing to take action, our governments were embarking on a dangerous ecological experiment – allowing salamanders, a completely new order of amphibians to this country, to remain in the wild and spread.
Because smooth newts are so different from anything Australian species have encountered before, the potential impacts are hard to predict. But the fact that smooth newts are prolific breeders, have a broad diet and can inhabit many types of habitats is a great cause for concern. They are likely to compete for food and habitat with native frogs and fish, and are potentially carriers of chytrid fungus, which has decimated frog populations in Australia.
Given the ecological risks, the Invasive Species Council, with pro-bono assistance from ecological consultancy, Ecology Australia, undertook surveys in the spring 2016 breeding season to determine if the smooth newt is persisting in Melbourne. Bait traps, dip netting, electrofishing and e-DNA analysis were used.
The surveys confirmed the smooth newt was still persisting and breeding in suburban waterways, but had not yet spread widely. There was still time to act to eradicate the newt, but first more information was needed to confirm the full extent of the infestation.
With funding from the Lord Mayor’s Charitable Foundation, the Helen Macpherson Smith Charitable Trusts and Melbourne Water, in 2019 we teamed up with Monash University to conduct a full environmental DNA survey of the waterways over a large area to narrow down the area occupied by the smooth newt.
This work confirmed that the newt’s spread has been limited. They occupy an area of only about 6 km2 and eradication may still be possible. The Monash team is now undertaking a small-scale trial of control methods to work out how best to achieve eradication.
We are now seeking funds to expand and complete the eradication trial. If the eradication methods are shown to be viable, a case for full eradication will be presented to the Victorian Government.