Instead, the team explored the possibility that the arrival of specific genetic traits acted as the trigger for the invasion, something which would help to explain the overwhelming genetic evidence for a single introduction. The study's genetic findings and the failure of pre-1859 rabbits to become invasive undermined this possibility. The researchers point out that if the trigger for the invasion had been environmental change, such as the development of large pastoral areas by human settlers, then multiple local rabbit populations would likely have expanded.

The new findings suggest that the genetic composition of those animals can be just, if not more, influential. Previous studies have suggested that several factors contribute to biological invasions, including the number of individuals, the number of introductions, and environmental change. The researchers found that as the rabbits moved further away from Barwon Park, genetic diversity declined and rare genetic variants which occur in rapidly growing populations became more frequent.ĭespite the construction of rabbit-proof fences, the deliberate introduction of the myxoma virus and other measures, rabbits remain one of the major invasive species in Australia threatening native flora and fauna and costing the agricultural sector an estimated $200 million per year. 'Our findings show that despite the numerous introductions across Australia, it was a single batch of English rabbits that triggered this devastating biological invasion, the effects of which are still being felt today.' 'We managed to trace the ancestry of Australia's invasive population right back to the South-West of England, where Austin's family collected the rabbits in 1859. Joel Alves, who is currently a researcher at the University of Oxford and CIBIO Institute said: However, they did not sample ancestral European and domestic populations, which was crucial to disentangle the source of Australia's rabbits. Recent studies disputed the single-origin hypothesis, instead arguing that invasive rabbits arose from several independent introductions.

The researchers studied historical records alongside new genetic data collected from 187 European rabbits-mostly wild-caught across Australia, Tasmania, New Zealand, Britain and France between 18-to establish where Australia's invasive rabbits originated from whether the invasion arose from a single or multiple introductions how they spread across the country and whether there was a genetic explanation for their success compared to that of other imported rabbit populations.

Within three years, 'Austin rabbits' had multiplied into thousands, according to a local newspaper report and Austin himself.

On Christmas Day, 24 rabbits arrived in Melbourne and were dispatched to Barwon Park. On 6 October 1859, Austin's brother, William, sent a consignment of wild rabbits-caught on the family's land in Baltonsborough in Somerset-together with some domestic rabbits, on the ship Lightning. In a study published today in PNAS, an international team led by the University of Cambridge and CIBIO Institute in Portugal finally provides genetic proof for this version of events and settles a debate about whether the invasion arose from a single or several independent introductions. Historians and the Australian public have long assumed that the country's 'rabbit plague' began at Barwon Park, the estate of Thomas Austin, near Geelong in Victoria.

Puzzle maker at discovery education com