Feral Rabbits in Australia

History

Rabbits were first introduced to Australia by the First Fleet in 1788. They were brought on the trip to help feed the people who intended to colonise in Australia. There was not too many rabbits in the decade or so but by 1827 in Tasmania there were many. In some large estates it was believed that there was thousands. In the 1840s rabbit-keeping became very common. There were even examples of rabbit thefts appearing in court records as well as many people eating the rabbits to sustain themselves.

The current invasion of rabbits has appeared to have originated when Thomas Austin released 24 wild rabbits on his property. His property, Barwon Park, was near Winchelsea in Victoria. The rabbits were released in October 1859 for hunting reasons. Austin spent a lot of his time in England hunting. When he arrived in Australia he found no native rabbit population. So he asked his nephew to bring him some animals over from England to hunt with. Many other farms released rabbits into the wild after Austin.

The rabbits spread quickly across the southern parts of Australia. The country had perfect conditions for the rabbit population. With mild winters the rabbits succeeded in breeding all year around. Combined with widespread farming many scrub or woodland areas have been transformed into vast areas full of low vegetation.

Within ten years of their release there were so many rabbits that two million could be shot or trapped without having any noticeable effect on the population. It was the fastest spread ever recorded of any mammal anywhere in the world showing the capabilities of introduced animals. Rabbits are very common in the southern and central areas of Australia with dotted populations in the northern deserts.

The rabbit is proved an infamous pest but in the 1890s and 1930s depressions it helped many people. It helped provide something to eat and to gather some extra income. They did this by selling things like their pelts and meat for money.

Effect on Australia’s environment

Since the introduction of rabbits their effect on Australia’s ecology has been overwhelming. They are suspected of being the one of or the most significant factor in species loss in the country. It is unknown the loss of plant species during this time. Rabbits are also known to kill young trees by ringbarking them. This is a process where the barks is peeled off the tree which means the tree is no longer protected and can be killed easily.

The species is also known for causing serious erosion problems because they eat the native plants which leaves the topsoil exposed. It leaves it vulnerable to sheet, gully and wind erosion. This is devastating because it takes hundreds of years to regenerate.

Control measures

By 1887 the damage caused by the rabbits was so substantial the New South Wales Government offered an award for a new method of exterminating rabbits. One idea thought of using a disease to help control the population. The disease proposed was not proved practical but caused the introduction of microbiology into Australia.

After being released into Australia they bred rapidly. Their species caused millions of dollars of damage to farmers’ crops. One of the conventional ways to control rabbits was to shoot them. This successfully helped to control low level population areas. It also helps provide food for people and pets.

Poisoning is probably the most used conventional technique for killing rabbits because it requires the least effort. The problem with this technique is that it renders the rabbits unable to be eaten by humans or pets. Two commonly used poisons for killing rabbits are sodium fluoroacetate and pindone.

Another ways is to use ferrets. The ferrets chase the rabbits out of their burrows to make them run into traps. This is more of a hunting activity then an effective control method.

They is also ploughing, blasting, and fumigating, just destroying them and their homes using various methods.

In 1907 the rabbit-proof-fence was built in Western Australia between Cape Keraudren and Esperance to try to prevent the rabbits spreading. European rabbits can jump very high and burrow underground. So the fence was unlikely to be a success due to all the possible problems with it. Such as holes in the fence or farmers leaving gates open.

Releasing rabbit-borne diseases has proven somewhat successful in hampering the population of rabbits in Australia. In 1950 the Myxoma virus was deliberately released into the rabbit population, which caused it to drop from an estimated 600 million to somewhere around 100 million. Due to genetic resistance in the surviving rabbits the population recovered to about a couple hundred million by 1991.

To combat this resistance in the rabbits they released a second virus, rabbit haemorrhagic disease (RHD). The virus escaped from Wardang Island, South Australia and by late October 1995 the virus was found in rabbits at Yunta and Gum Creek, in north-eastern South Australia. By winter the next year the virus was well establish in many parts of Australia. The virus was more successful in the hooter parts of Australia. This was due to the fact that another calicivirus in the cold, wet parts of Australia and it was immunising rabbits against the more deadly form.

There is a vaccine for RHD but no cure for it or myxomatosis. The pets affected are euthanized as it is incurable.

Bibliography

http://en.wikipedia.org/wiki/Rabbits_in_Australia

Feral Rabbits In Australia

Rabbit Map 2006/7

By Riley Goldsworthy