Australia’s rabbit plague began with the importation of just 24 rabbits, a new study confirms.
The paper, published in The Proceedings of the National Academy of Sciences (PNAS) used genomic data and historical DNA to trace the genealogy of Australia’s rabbits to the southwest of England, where their ancestors were collected by the family of Thomas Austin in 1859.
Within three years of importing wild rabbits from his family’s land in Somerset in the UK, the “Austin rabbits” had multiplied to thousands. Within the next 50 years, rabbits would spread to all corners of the country at a rate of 100km per year – the fastest colonisation rate for an introduced mammal recorded.
By the beginning of the 20th century, the “grey blanket” had well and truly spread to all corners of the country.
Previous research had disputed the “single-origin hypothesis”, pointing to historical evidence there were at least 90 rabbit introductions prior to 1859.
However, rabbits introduced to Australia before 1859 were often described as tame, with fancy coat colours and floppy ears – traits associated with domestic breeds but usually absent in wild animals.
Co-author professor Mike Letnic said while there were other distinct rabbit populations in Australia, they had not been nearly as successful as the wild Austin rabbits.
“Rabbits first introduced in Sydney haven’t spread beyond, partly because of their domestic origins, whereas wild rabbits are found all over the country,” he said.
“The time lag from the initial introduction of rabbits into Australia, and the lack of success before the arrival of the wild genotype in 1859 suggests it is specific genetic traits which acted as the trigger for the invasion.”
Despite population-control measures such as the construction of rabbit-proof fences, the deliberate introduction of the myxoma virus, and more, rabbits remain a major threat to native flora and fauna, costing the Australian agricultural sector an estimated $200 million per year.
Lead author Dr Joel Alves says their study serves as a reminder that the actions of just one person, or a few people, can have a devastating environmental impact.
“These findings matter because biological invasions are a major threat to global biodiversity, and if you want to prevent them, you need to understand what makes them succeed,” he said.
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