Why Australia’s 200m wild rabbit population could soon explode

Australia has waged a long and successful war against destructive wild rabbits, but the Albanese government is being accused of giving up on the 75-year-long fight as funding runs dry to develop the next killer virus to cut the now booming population.

Rabbits came to Australia on the first fleet in 1788, but spread prolifically after grazier Thomas Austin introduced them to south-west Victoria in 1859 for hunting. They quickly spread out of control and the population peaked at 10 billion in 1920.

Feral rabbits are a hungry and damaging pest that cause desertification of the landscape, as seen here in outback South Australia near the NSW border.Credit: Glen Schulz/Rabbit Free Australia.

Australian scientists at the CSIRO released the myxomatosis virus in 1950 and decimated the rabbit population. But the resilient pest adapted and bounced back. Several new viruses have been introduced since then with similar results.

The population is now estimated at 200 million and surging after several years of above-average rain across the eastern seaboard. Experts say the next deadly disease is needed now.

Invasive Species Council advocacy director Jack Gough said Australia had been investing in national, coordinated programs to develop viruses, or biocontrols, for pests like rabbits “but the funding has now run out”.

“Not having an ongoing coordinated national focus to develop the next breakthroughs on biocontrol for rabbits is giving up the fight,” Gough said.

“A national research program is the only way we’re going to get game-changing solutions like myxomatosis and calicivirus were in the past.”

Experts say a new virus is needed around every 10 years to remain effective, as the rabbit population adapts to the disease and death rates decline.

Australia’s top science agency the CSIRO released the world’s first vertebrate pest biocontrol in 1950, in a desperate bid to quell the rabbit plague. The virus, known as myxomatosis or myxo, killed around 99.8 per cent of infected rabbits.

But the prolific breeders bounced back and within three decades the rabbit population was estimated at more than 300 million.

In 1995, a new viral disease escaped from a South Australian testing station and spread across the country. Rabbit haemorrhagic disease virus, known as calicivirus, killed up to 98 per cent of rabbits in arid areas.

Once again, rabbits bounced back and another strain of calicivirus was released in 2017, which reduced populations by more than a third.

Experts say the next virus will soon be needed. But funding for Australia’s Rabbit Biocontrol Pipeline Strategy ceased in 2022, while financial support for the Investment in Genetic Biocontrol of Vertebrate Pests program ended this year. The Albanese government has not renewed funding for the ongoing work needed to develop a new virus.

Rabbits reached plague proportions yet again in the 1990s, as seen here, as the population bounced back from myxomatosis.

Australia’s State of the Environment report lists rabbits as the most damaging pest species, endangering the most threatened native plants and animals. Rabbits are listed as impacting more than 300 threatened species, double the number affected by foxes and cats.

Centre for Invasive Species Solutions national rabbit coordinator Heidi Kleinert said rabbits are popping up in more and more new locations.

“There’s a boom and bust cycle with rabbits, and they’ve definitely had a great boom cycle for the last couple of years and people will be seeing them in new places, not only in rural areas, but encroaching into peri-urban areas as well.”

Kleinert said rabbits are a dominant and damaging species in the landscape.

“They graze on all the native plant species, taking away food from our native fauna. Each year new species are added to the threatened species list and if we do nothing they will just disappear off the face of the earth.”

Federal Agriculture Minister Julie Collins was asked about the expert warnings over the lack of investment in new viruses and if Australia had given up the fight against rabbits.

A spokesperson for the Department of Agriculture listed financial contributions made by the federal government, including more than $3 million in programs to reduce rabbit numbers including co-funding state programs for activities like poison baiting and destroying warrens.

ABC television’s Eat the Invaders has revived the debate about human consumption of pests as part of eradication efforts, but Gough says “we can’t cook our way out of the problem”.

He argued that the community would not consume enough to make a serious dent in the rabbit population, but the creation of a rabbit meat industry could have perverse outcomes.

“Australians were eating 20 to 30 million rabbits per year in the 1940s and it had no impact on the population, which can increase by about 90 per cent per year,” he said.

“It was the rabbit meat and fur industry that actively campaigned to stop the introduction of calicivirus in the 1980s.

“Promoting ferals as a resource motivates people to spread them further or keep them in the landscape, it creates an interest group opposed to effective control, and it gives governments an excuse to avoid funding real action.”

Australian Farm Institute executive director Katie McRobert said rabbits delivered a more than $200 million annual hit to the agriculture sector, eating crops and eating feed for livestock.

“In such a vast country, biocontrol is a critical tool in managing invasive pests like rabbits,” McRobert said. “The quiet defunding of biocontrol programs should concern all Australians. This is the way the biosecurity battle ends – not with a bang but with an unremarked whimper.”