Scientist return to cane toads to solve pest problem

 

NOT deterred by history, researchers trying to save endangered loggerhead turtle nests from rampant goannas are turning to Australia's biggest pest: the cane toad.

But nearly 85 years after they were introduced and caused ecological disaster across Queensland, the cane toads in this experiment won't be spreading.

This is because researchers involved in the trial on Wreck Rock Beach at Agnes Water are only interested in the "roadkill" variety.

A goanna caught eating a loggerhead turtle egg on sensor camera at Wreck Rock beach. Picture: David Booth/University of Queensland
A goanna caught eating a loggerhead turtle egg on sensor camera at Wreck Rock beach. Picture: David Booth/University of Queensland

They hope the poisonous scent released when the toads are under threat will be enough to scare off goannas that have been invading loggerhead turtle eggs along the beach and feasting on the eggs.

The move to enlist cane toads to protect the east coast's second largest nesting population of the critically endangered turtles comes after a study published in international conservation journal Oryx found a trial of aluminium mesh covered nets did not provide a long-term solution.

The paper's lead author and World Wide Fund for Nature-Australia marine species project manager Christine Madden Hof said the nets were time consuming to construct and dig into position.

"With so many nests to protect along a 23km stretch of beach, and limited numbers of volunteers, they are not cost effective," she said.

Christine Hof, Saranne Giudice and Nev McLachlan demonstrating the time consuming work required to install protective netting on just one loggerhead turtle nest to protect it from rampant goannas on Wreck Rock Beach.
Christine Hof, Saranne Giudice and Nev McLachlan demonstrating the time consuming work required to install protective netting on just one loggerhead turtle nest to protect it from rampant goannas on Wreck Rock Beach.

Conservationists including long-term volunteers Nev and Bev McLachlan from Turtle Care have had some success recently with placing roadkill cane toads on the nests.

They believe that in decades since toads were introduced to Australia, goannas have learnt to avoid the poison. Under the supervision of University of Queensland senior lecturer David Booth the team plans to trial the scent on the turtle nests this summer, hoping to have more success than the effort to control scarab beetles in sugar cane in 1935.

CQ Turtle Team volunteer Jodi Jones was hopeful the cane toad trial would be a success, given goannas were the biggest threat to the turtle nesting population at Wreck Rock.

"(The cane toads) will be a useful resource against the threat of goannas ... it'll be really interesting to see how this trial goes," she said.

Ms Jones said other trials were being conducted to ward off foxes which are one of the biggest threats to turtle nests at Facing Island, Boyne Island and Tannum Sands.

In October the Fitzroy Basin Association launched a fox control program by bringing a Sunshine Coast specialist with a fox-detecting dog to the area.

She said volunteers would monitor nests across the region in coming months to determine whether the control program was a success.

Another threat to the Wreck Rock turtle nesting population was a cyclone that hit the beach in 2014.

The researchers said the cyclone combined with the predators had led to more than 90 per cent of nests being destroyed.