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Australia’s Rabbits: How a Farmer Caused the Plague – Knowledge

On Christmas Day 1859, 24 rabbits from England arrived in Melbourne, Australia. The rabbits were a gift from Thomas Austin, a wealthy English settler who wanted to establish a colony of these animals on his Australian plantation. He did that – and more.

Three years later, thousands of European hares (Oryctolagus cuniculus) were roaming around. In 1865, Austin boasted to a local newspaper that he had killed about 20,000 rabbits on his estate, where he hosted rabbit hunting parties for English aristocrats such as Prince Alfred, son of Queen Victoria.

Austin wasn’t the first to down rabbits. Five animals were among the first British naval vessels to reach Sydney in 1788. It was the first of about 90 rabbits introduced to Australia’s east coast over the next 70 years. However, it was Austin’s rabbits who ultimately ruled the continent. A new study shows. Today, about 200 million rabbits wreak havoc on fields and native plants, causing $200 million in agricultural damage annually. Almost all of them, the researchers conclude, can be traced back to the fateful ship Austin received in 1859.

Austin’s brother also sent wild rabbits

To find out how the rabbit plague came about, Francis Jiggins, a geneticist at the University of Cambridge, and his colleagues analyzed the DNA of 187 rabbits collected from across Australia. They examined potential parent populations in England and France, as well as a few rabbits from Tasmania and New Zealand.

Like the team in Proceedings of the National Academy of Sciences With the exception of two local populations near Sydney, most Australian rabbits share a common ancestry. Genetics of rabbits showed the origin of the invasion to be near the Austin estate in Victoria. As the rabbits spread from this location, the genetic diversity of the population decreased and a homogenous herd of rabbits formed. Additionally, the researchers found many genetic similarities between Australian rabbits and rabbits from southwest England, where Austin’s family first collected rabbits to bring to Australia. The researchers conclude that Australia’s current rabbit infestation began when Austin released the first batch of 24 rabbits on his garden.

Genetics also provides clues as to why these populations are prime for invasion. Reports of early Australian rabbits mention floppy ears and brightly colored fur, two characteristics common to domesticated rabbits, suggesting that they were too tame to adapt to Australia’s wild landscape. However, genetic analysis revealed that the Australian rabbits descended from Austin’s litter share a large proportion of wild ancestry.

Historical records confirm this. Austen family letters and stories indicate that in addition to domesticated rabbits, Austen’s brother also sent many wild-caught rabbits to Australia. During the 80-day journey, the rabbits began to multiply.

Australia’s landscape is still grappling with the aftermath of the event

Austin’s rabbits had another advantage over their predecessors: they came from a more forgiving Australian environment. When earlier rabbit newcomers entered the bush, they encountered strange vegetation and an array of carnivorous reptiles, marsupials and dingoes. But by the mid-1800s, the outback had been converted to grazing land, and hunters were hunted to protect livestock. “It’s like a perfect storm,” says Joel Alves, an evolutionary geneticist at the University of Oxford.

Australia’s landmass is still struggling after the storm. Once the rabbits left Austin’s garden, they spread more than 100 kilometers a year, despite the creation of fences and smallpox-like viruses to eradicate them. In just 50 years, the animals colonized an area roughly 13 times larger than their original European range—faster than any other introduced mammal, including pigs and cats.

And they keep multiplying. “It’s like a broken brake on a car,” says Alves.

However, not all scientists blame Austin alone for the rabbit plague in Australia. David Peacock, an ecologist at the University of Adelaide, says other rabbits, like Austin’s animals, were introduced to the continent. In 2018, Peacock co-authored a study that found rabbit invasions were fueled by introducing too many rabbits.

However, he applauds efforts to understand the origins of Australian rabbits because they could help develop more targeted pathogens to control and eradicate rabbit populations. “The better we understand the origins, distribution and genetics, the better we can deal with Australia’s most problematic pests.”

This post From the journal Science Science. This is not an official translation Science– Editorial staff. In case of doubt, the English original published by AAAS applies. German editing: Weiss