Using historical and genetic data, scientists have traced the origins of what they call “the fastest rate of colonization for an introduced mammal ever recorded.” New research, published in the Proceedings of the National Academy of Sciences, has confirmed what historians have long suspected: that the country’s rabbit infestation originated at Barwon Park, the estate of Thomas Austin, near Geelong in Victoria. The European rabbit, Oryctolagus cuniculus, was first introduced to mainland Australia with the First Fleet in 1788, when five domestic rabbits were brought to Sydney. However, despite at least 90 subsequent introductions, populations only exploded in the second half of the 19th century – rabbits spread across the Australian continent within 50 years, at a rate of 100 km per year. In 1859, Austin received a shipment of 24 wild and domestic rabbits from his brother in Baltonsborough, southwest England. Within three years, the animals had multiplied into the thousands. Scientists now say that the continent-wide invasion of rabbits resulted from this single introduction rather than earlier multiple introductions. In addition to historical records, they analyzed genetic material from 187 European rabbits caught in mainland Australia, Tasmania, New Zealand, Great Britain and France between 1865 and 2018. The researchers found that mainland Australian rabbits were more genetically similar to populations found in south-west England, near Boltonsborough. The prevalence of rare gene variants in Australian rabbits also increased with distance from Barwon Park, a process known to occur in geographically expanding populations. The researchers traced DNA found in the cells’ mitochondria – which was inherited from the mother – and estimated that “the Australian mainland rabbits in our data set trace their maternal ancestry to five females introduced from Europe.” The analysis also found evidence of other rabbit introductions that resulted in surviving populations, but without wide geographic spread. Two groups of rabbits – one in Sydney and one in Cattai National Park, northwest of the city – had separate origins, the study showed. The researchers hypothesize that the Barwon Park rabbits were likely more successful at spreading because of their wild origins. Many previous imports were of domesticated rabbits, with reports of “dawning, showy coat colors and floppy ears” as characteristics. Study co-author Professor Mike Letnic, of the University of New South Wales, said the wild rabbits introduced to Barwon Park may have had genetic traits that made them more likely to survive in the Australian desert. Subscribe to Guardian Australia’s Morning Mail Our Australian morning news email breaks down the key national and international stories of the day and why they matter Privacy Notice: Newsletters may contain information about charities, online advertising and content sponsored by external parties. For more information, see our Privacy Policy. We use Google reCaptcha to protect our website and Google’s Privacy Policy and Terms of Service apply. “If animals are bred for domestication, one of the things they’re missing is predators,” he said. “Anti-predator behavior is learned and evolved … the genes you carry that might make you nervous or jumpy end up being junk and are lost in domestication.” Barwon Park rabbits had “invaded many different environments across the country”, Letnic said. “There are rabbits that live in relatively cool and relatively wet areas of Australia, and then there are rabbits that live in the middle of the desert.” The damage caused by rabbits to agricultural crops is estimated at 200 million dollars annually. An invaluable impact of the parasites is that they have enhanced predator pressures across the continent, Letnic said. “The numbers of foxes, cats and dingoes tend to be much higher in areas where there are lots of rabbits, and that means it makes life difficult for other animals because there are more predators.” “It highlights that whatever we do, we must avoid…bringing [wild animals] in this country and escape them”. In Tasmania and New Zealand, rabbits also became a pest decades after their introduction. The researchers found that Tasmanian rabbits had mixed ancestry from domestic British and mainland Australia, while New Zealand rabbits had a mix of wild and domesticated British and mainland Australia.
