Newt troublemakers settle in

An entirely new order of invasive amphibians has set up residence in Australia, with populations of newts thriving on the outskirts of Melbourne.

Two smooth newts (click to embiggen)
Smooth newts, Lissotriton vulgaris, look a bit like skinks, and the worry is that native predators may make the same mistake (Photo: Museum Victoria)

The smooth newt, Lissotriton vulgaris, is native to Europe, but the similar climate in south-eastern Australia appears to have helped it establish breeding populations at at least four sites around Melbourne (Tingley R, Weeks AR, Smart AS, van Rooyen AR, Woolnough AP & McCarthy MA 2014, “European newts establish in Australia, marking the arrival of a new amphibian order”, Biological Invasions, DOI: 10.1007/s10530-014-0716-z).

This is a big deal, because there are no newts native to Australia. In fact, the only indigenous amphibians are frogs, many of which—like the Baw Baw Frog—are endangered due to an infectious disease caused by chytrid fungus.

However, newts were imported as pets up until 1997, when the Victorian government declared it a “controlled pest animal.” It’s likely that the current populations originally came from escaped or released pets.

Being a relative newt-comer, it’s not yet known how bad an impact they will have. The newts eat invertebrates, crustaceans, and the eggs and hatchlings of frogs and fish, so it’s likely that they will compete with and even prey on native species.

It’s possible they could also transmit the frog-killing chytrid fungus. But the researchers are also concerned about a toxin they produce. So far it’s looking like the toxin is at too low levels to do any harm, but there is still a worry that they could poison other native species that may prey on them.

Fortunately, it still seems to be early days for the newt invasion, so there is some hope that quick intervention could get them under control.

Anyone who encounters a newt is encouraged to report them to the Department of Environment and Primary Industries (DEPI).

Beth spoke to researcher Dr Reid Tingley about the newts on our show on 10 July 2014. You can listen to the podcast.

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