"In 1859, European rabbits (Oryctolagus cuniculus) were introduced into the Australian wild so that they could be hunted. Thomas Austin, a wealthy settler who lived in Victoria, Australia, had 13 European wild rabbits sent to him from across the world, which he let roam free on his estate. From this one backyard sanctuary, it took only around 50 years for these invasive (meaning non-native to the land) rabbits to spread across the entire continent."

From National Geographic, "How European Rabbits took over Australia", accessed November 2023.

The quote above summarises the events that led to European rabbits having a huge impact on the Australian landscape. The estimate from the same source is that approximately 200 million feral rabbits live in Australia. They cause damage to crops, native habitats, and as a result of competing for food sources can also impact populations of herbivorous native animals.  

Because rabbits are able to adapt to different environments well, and populate so quickly, they have become a very difficult to manage invasive species in Australia.