A NATIVE invader is threatening the long-term survival of the endemic Manning River turtle, which is only found in the freshwater creeks and rivers of the Manning River system.
This ancient, unique creature is at risk of extinction because of its limited population size and a range of other threats.
Of all the pressures on this species, a new threat is emerging.
It is called hybridisation, and it is likely to occur because of another native Australian turtle, the Macquarie River turtle.
The Macquarie River turtle is not native to the Manning River system and is thought to have been introduced via the release of unwanted aquarium turtles, or escapes from farm dams and ponds during floods.
The native Manning River turtle and the invading Macquarie River turtle are likely to interbreed.
Interbreeding creates hybrid offspring, and in extreme cases, the genetics of an entire population is at-risk, and unique animals, like the Manning River turtle, can be swamped with these hybrid genes.
The Macquarie River turtle was first noticed in the Manning River around 2007.
Since 2013, surveys have found increasing numbers of this native invader.
It has been found in parts of the Manning River, Gloucester River, Nowendoc River and Dingo Creek, which are all of these are the prime habitats of the Manning River turtle.
The risk of hybridisation between these two species has been examined by university student Elise Rourke, who has been working with MidCoast Council.
“When we think of the impacts of feral pest animals we think about overseas predators like cane toads or foxes,” said Ms Rourke.
“We don’t tend to think that a native species can be introduced and can cause problems.”
Mat Bell, Senior Ecologist with MidCoast Council, said detailed knowledge of the species is key to its protection.
“To deal with this, there will need to be greater understanding of where Macquarie River turtles occur, and how their wild population can be managed,” said Mr Bell.
“The community will need to be engaged to never release unwanted aquarium turtles or stock Macquarie River turtles in ponds or dams, and we need to engage with river users to report sightings of turtles, especially Macquarie River turtles, to organisations like 1 Million Turtles.”
By John WATTS
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