Rabbit population to explode: No new biocontrols as calicivirus resistance builds

A 2022 federal funding cut means there are no new viral strains to counter increased calicivirus resistance in a booming rabbit population.

Rabbit numbers are taking off in the wake of good seasons and growing resistance to calicivirus.

Australia’s rabbit population of 200 million is set to explode, triggered by rising immunity to calicivirus strains introduced eight years ago and no federal funding for alternatives.

Invasive Species Council interim chief executive Jack Gough said there were no new biocontrol agents on the horizon after federal funding for Australia’s Rabbit Biocontrol Pipeline Strategy was cut in 2022.

“We’re getting to the 10 year-point where the virus’ effectiveness drops off radically. At the same time we’ve had really good seasonal conditions and (rabbit) numbers are getting up.”

But he said the cupboard was bare when it came to identifying new strains of calicivirus, myxo or any other virus that might keep the pest population in check, following the federal cut.

Centre for Invasive Species Solutions chief executive Shauna Chadlowe said cutting the pipeline strategy, which had been operating since 2007, meant Australia was without a national biocontrol program for rabbits.

She said the Albanese Government had allocated funding in the 2025-26 budget towards gene-driver technology, but its value as a tool to control rabbits was at least 20 years away.

“First cab off the rank (in using the technology) is feral mouse control, which is 10 years away, then rats and after that rabbits,” Ms Chadlowe said.

She said rabbit populations were already starting to spike, with the Tasmanian Government already raising concerns.

Rabbit Free Australia chairman Craig Magnussen said “we’re hearing from all parts of Australia that numbers are up, which is exacerbating the drought in South Australia”.

“Given we’re what we’re hearing there’s real concern about the lack of funding for biocontrol,” Mr Magnussen said.

“When myxo came in (in 1950) they thought it was the silver bullet and then we saw resistance come back in. Then we thought calicivirus was the silver bullet.”

“We wonder whether we’re now staring down the barrel of a rabbit boom.”

Mr Gough said that when the federal department was asked in 2022 why the bid to extend the Rabbit Biocontrol Pipeline Strategy had failed, he was told it was not competitive against other bids.

“This shouldn’t be how it compares to other competing priorities,” Mr Gough said.

“This is and always will be a national priority.”