A rabbit invasion has residents of Phillip Island on edge, with the situation reaching what locals describe as 'plague proportions'. Every day, Peter Bradley and his wife Vicki face a battle against these furry invaders, as they try to protect their home from the relentless burrowing of rabbits.
'It's a constant struggle,' Bradley shares. 'No matter how many times I patch up the holes, they keep coming back. It's like a never-ending game of whack-a-mole.'
This issue is not unique to the Bradleys; it's a shared struggle across the beautiful Bass Coast region. Harold Jackson, a resident of Phillip Island for 27 years, has seen the rabbit problem escalate to unprecedented levels. The damage to his garden in Cowes has cost him nearly $20,000, and it's only getting worse.
'It's an ongoing battle,' Jackson laments. 'They dig holes everywhere, even in my rose garden, destroying the roots.'
Last month, the Bass Coast shire council took a unanimous decision to develop a new plan to tackle this issue, acknowledging that previous efforts and investments have failed to make a significant impact.
Dr. Brian Cooke, an expert on rabbits, believes the surge in coastal rabbit populations may be due to environmental factors that counteract Australia's biological control program. With almost 60 years of experience studying these animals, Cooke has worked on successful eradication programs, including on Macquarie Island. He suggests that a benign virus, RCV-A1, might be protecting rabbits from Australia's main biological weapon, calicivirus.
'The distribution of this non-pathogenic virus is primarily coastal,' Cooke explains. 'It thrives in high-rainfall areas and doesn't reach the drier inland regions.'
Cooke further elaborates that RCV-A1 provides cross-immunity, making rabbits immune to the deadly rabbit haemorrhagic disease virus (RHDV), also known as calicivirus. In coastal environments, where green grass is abundant year-round, the exposure to RCV-A1 is higher.
Dr. Tanja Strive, a senior principal research scientist at CSIRO who has extensively studied RCV-A1, confirms that lab testing has shown 'some cross protection' from calicivirus in rabbits previously infected with the benign virus. She adds that it has long been observed that control measures are less effective in coastal areas.
'When the first calicivirus spread from Wardang Island, it decimated over 90% of rabbit populations across Australia, except in some temperate and coastal areas,' Strive says.
The combination of natural coastal conditions and suburban development in the Bass Coast creates what Strive calls an 'upward spiral' for rabbit immunity. 'In coastal areas, higher rainfall supports year-round breeding, and in peri-urban areas, irrigation provides a constant food source without the need for rain,' she explains. 'Once the population becomes dense, it further facilitates the transmission and spread of the benign virus, increasing their immunity.'
For residents like Carola Adolf, who has lived on her Bass property for 35 years, the rabbit explosion has made daily life hazardous. While mowing her property, her ride-on mower unexpectedly fell into a hidden rabbit hole, causing her to bite her tongue and bleed profusely.
'It's not just the holes,' Adolf says. 'They undermine everything, including fences and the root systems of trees. My horses are at constant risk of breaking their legs if they step into one of these burrows.'
Tackling this problem requires coordination across different government bodies, but so far, such collaboration has been lacking.
'We're desperately seeking new ideas because what we've tried in the past hasn't worked,' says Councillor Mat Morgan, who seconded the motion to develop a new eradication plan. 'It's not something we can tackle alone. We have multiple land managers involved, including DEECA, Phillip Island Nature Parks, and various local councils.'
Jack Harris, the coordinator of the Bass Coast Landcare Network's rabbit project, highlights the variability in rabbit management practices among landholders. 'You might have one landholder doing an excellent job controlling rabbits, while their neighbor isn't interested at all,' he says. 'This creates a patchwork of properties, some rabbit-free and some not, making it difficult to get a handle on the problem.'
Community resistance to common anti-rabbit strategies, such as baiting, adds another layer of complexity, Cooke notes. 'Some people worry about their pets being poisoned, which is a valid concern.'
The need to protect endangered eastern barred bandicoots, reintroduced to Phillip Island, further complicates control efforts. Baiting cannot be used in areas where bandicoots are known to be present.
However, Cooke emphasizes the ecological implications of a large rabbit population. 'It supports a high volume of feral predators like foxes and cats, which also prey on native fauna. Additionally, rabbits cause significant damage to native plants.'
Morgan believes that controlling the rabbit population is crucial for the region's environmental reputation. 'Bass Coast and Phillip Island have the potential to become a haven for endangered wildlife,' he says. 'We've seen various endangered species find refuge on the island. By controlling the rabbit populations, we can further enhance our biodiversity and create an extraordinary opportunity.'
For now, the council is working on a report outlining eradication options. Cooke warns that time is of the essence. 'It's better to act now rather than wait another five years, when the problem and the cost will have doubled.'
He adds that Australia has lost some institutional knowledge about rabbit control due to the success of biological control measures in the past. 'Most people under 50 have never experienced high rabbit numbers, so they don't fully understand the extent of the problem. It's time to remind everyone that rabbits are not just cute creatures from children's stories; they are a major ecological concern.'
This issue is a complex puzzle, and finding a solution requires collaboration, innovation, and a deep understanding of the ecological dynamics at play.
