Farmers and invasive species experts are hoping looming El Niño conditions will finally provide an opportunity to control a rabbit population that has surged across Australia during recent wet years.
Despite parts of the country receiving record-breaking rainfall in recent weeks, Australia’s overall outlook will be dry.
The Bureau of Meteorology (BOM) has predicted El Niño will continue into 2024 with the potential for higher-than-average temperatures and lower-than-average rainfall in some areas.
The La Niñas of previous years meant an explosion in rabbit populations with an increase in vegetation.
The situation was further exacerbated by a lack of opportunity to release biocontrols, allowing rabbits to continuously breed.
Centre for Invasive Species Solutions chief executive Andreas Glanznig said the change in weather patterns provided a chance to bring rabbit numbers back.
“Rabbit numbers are up due to La Niña and good times, and also just because a lot of land managers haven’t been able to use rabbit biocontrol agents like K5,” Mr Glanznig said.
“[Those] agents can generally only be released when there’s no young rabbits around.”
He said rabbits under 10 weeks of age generally were not killed by calicivirus — the most effective rabbit biocontrol agent.
Mr Glanznig said rabbits could breed 12 times a year and caused around $217 million in damage annually to pastures and crops, as well as native wildlife and ecosystems.
“Even though that’s a staggering cost, it’s still only 10 per cent of what the cost would be if myxomatosis and calicivirus had never been released,” he said.
Lesley Loxton has been struggling to control increasing rabbit populations on her property at Compton in South Australia’s south-east.
“I’ve always had some rabbits, but I think they get worse every year and it’s unmanageable now because they’re just so destructive,” Ms Loxton said.
Mr Glanznig urged landholders wanting to control rabbits to follow the guidelines, with early autumn providing better conditions for baiting.
“A national survey undertaken a couple of years ago came up with a staggering result — that three-quarters of land managers didn’t follow the release guidelines for rabbit calicivirus,” Mr Glanznig said.
Mr Glanznig said the agents were suppressing rabbit numbers by about 90 per cent, but their impact did wane over time.
“Rabbit biocontrol agents aren’t silver bullets. They need to be used as part of an integrated approach which includes chemical control, warren ripping, and so on if you’re going to have a sustained impact and control of rabbits over time,” he said.
(ABC)
