History
The European rabbit (Oryctolagus cuniculus) was first introduced to Australia by the First Fleet in 1788. They were bred as food animals, most likely in cages. In the first decades, they do not appear to have been numerous, judging from their absence from archaeological collections of early colonial food remains. The first feral rabbit population was reported in Tasmania as early as 1827. In the 1840s, rabbit-keeping became even more common, with examples of the theft of rabbits from ordinary peoples' houses appearing in court records and rabbits entering the diets of ordinary people.
In 1859, a man named Thomas Austin imported 24 wild rabbits from England and released them into the wild for hunting purposes on his property, Barwon Park, near Winchelsea, Victoria. Within a number of years, the original number of 24 rabbits multiplied into millions. By the 1920s, less than 70-years since its introduction, the rabbit population in Australia ballooned to an estimated 10 billion, reproducing at a rate of 18 to 30 per single female rabbit per year. The rabbits started to migrate across Australia at a rate of 80 miles a year. After destroying two million acres of Victoria's floral lands, they traversed across the states of New South Wales, South Australia, and Queensland.
They reached the Queensland – New South Wales border by 1886 and covered most of their present range by 1910. This was despite the Western Australian Government’s 1700 kilometre rabbit-proof fence, built between 1901 and 1907. By 1890, rabbits were spotted all way in Western Australia.
Australia is an ideal location for the prolific rabbit. The winters are mild so they are able to breed nearly year-round. There is an abundance of land with limited industrial development. Natural low vegetation provides them with shelter and food, and years of geographic isolation has left the continent with no natural predator for this new invasive species.
Although the rabbit is a notorious pest, it proved useful to many people during the depressions of the 1890s and 1930s and during wartime. Trapping rabbits helped farmers, stockmen, and stationhands by providing food and extra income, and in some cases helped pay off farming debts. Rabbits were fed to working dogs and boiled to be fed to poultry. Later, frozen rabbit carcasses were traded locally and exported. Pelts, too, were used in the fur trade and are still used in the felt-hat industry.
Currently, the rabbit inhabits around 2.5 million square miles of Australia with an estimated population of over 200 million, occurring throughout Australia, except in the northernmost areas.
In 1859, a man named Thomas Austin imported 24 wild rabbits from England and released them into the wild for hunting purposes on his property, Barwon Park, near Winchelsea, Victoria. Within a number of years, the original number of 24 rabbits multiplied into millions. By the 1920s, less than 70-years since its introduction, the rabbit population in Australia ballooned to an estimated 10 billion, reproducing at a rate of 18 to 30 per single female rabbit per year. The rabbits started to migrate across Australia at a rate of 80 miles a year. After destroying two million acres of Victoria's floral lands, they traversed across the states of New South Wales, South Australia, and Queensland.
They reached the Queensland – New South Wales border by 1886 and covered most of their present range by 1910. This was despite the Western Australian Government’s 1700 kilometre rabbit-proof fence, built between 1901 and 1907. By 1890, rabbits were spotted all way in Western Australia.
Australia is an ideal location for the prolific rabbit. The winters are mild so they are able to breed nearly year-round. There is an abundance of land with limited industrial development. Natural low vegetation provides them with shelter and food, and years of geographic isolation has left the continent with no natural predator for this new invasive species.
Although the rabbit is a notorious pest, it proved useful to many people during the depressions of the 1890s and 1930s and during wartime. Trapping rabbits helped farmers, stockmen, and stationhands by providing food and extra income, and in some cases helped pay off farming debts. Rabbits were fed to working dogs and boiled to be fed to poultry. Later, frozen rabbit carcasses were traded locally and exported. Pelts, too, were used in the fur trade and are still used in the felt-hat industry.
Currently, the rabbit inhabits around 2.5 million square miles of Australia with an estimated population of over 200 million, occurring throughout Australia, except in the northernmost areas.
Effects on Australia's ecology
Since their introduction from Europe in the 19th century, the effect of rabbits on the ecology of Australia has been devastating. They are suspected of being the most significant known factor in species loss in Australia. Feral rabbits compete with native wildlife, damage vegetation and degrade the land. They ringbark trees and shrubs, and prevent regeneration by eating seeds and seedlings. Their impact often increases during drought and immediately after a fire, when food is scarce and they eat whatever they can. Feral rabbits have caused the extinction of several small (up to 5.5 kilograms) ground-dwelling mammals of Australia’s arid lands, and have contributed to the decline in numbers of many native plants and animals.
Rabbits are also responsible for serious erosion problems, as they eat native plants, leaving the topsoil exposed and vulnerable to sheet, gully, and wind erosion. The removal of this topsoil is devastating to the land, as it takes many hundreds of years to regenerate thus, interfering with the food production.
The introduction of the rabbit has also strained the native wildlife of Australia. Rabbits have been blamed for the destruction of the eremophila plant and various species of trees. Because rabbits will feed on seedlings, many trees are never able to reproduce, leading to local extinction. Additionally, due to direct competition for food and habitat, the population of many native animals such as the greater bilby and the pig-footed bandicoot has declined dramatically.
Competition and land degradation by rabbits is listed as a key threatening process in Australia. Rabbits can cause damage by:
Low-density rabbit populations can still cause significant damage to native plants and pastures, suggesting there might be no ‘safe’ level of rabbit density. It takes less than one rabbit per hectare to prevent the successful regeneration of many native trees and shrubs, which are vital for biodiversity and farm productivity. Removal or loss of vegetation makes soils prone to wind and water erosion, which on farms can lead to reduced soil fertility and siltation of dams.
With declining populations of many small Australian mammal species over the past 200 years, it is possible that rabbits have partially filled an ecological niche. Rabbit warrens provide refuge for some native species such as echidnas and large reptiles. However, cats and foxes also use rabbit warrens for shelter and dens for their young, thus helping these predators to persist in hot, arid areas. Rabbits also eat and disperse viable native plant seeds, performing an important function in the ecosystem. However, they can also spread weeds and permanently damage native seedlings in the process.
Rabbits are also responsible for serious erosion problems, as they eat native plants, leaving the topsoil exposed and vulnerable to sheet, gully, and wind erosion. The removal of this topsoil is devastating to the land, as it takes many hundreds of years to regenerate thus, interfering with the food production.
The introduction of the rabbit has also strained the native wildlife of Australia. Rabbits have been blamed for the destruction of the eremophila plant and various species of trees. Because rabbits will feed on seedlings, many trees are never able to reproduce, leading to local extinction. Additionally, due to direct competition for food and habitat, the population of many native animals such as the greater bilby and the pig-footed bandicoot has declined dramatically.
Competition and land degradation by rabbits is listed as a key threatening process in Australia. Rabbits can cause damage by:
- overgrazing native and sown pastures, leading to loss of plant biodiversity and reduced crop yields
- competing with native animals and domestic livestock for food and shelter, increasing grazing pressure and lowering the land’s carrying capacity
- building warrens, causing land degradation and erosion (figure 1)
- preventing or inhibiting the regeneration of native shrubs and trees by grazing (figure 2)
- increasing and spreading invasive weeds (figure 1)
- acting as a food source for introduced predators, which can lead to increased lamb losses and disease prevalence, and a decrease in small mammal diversity (figure 3)
Low-density rabbit populations can still cause significant damage to native plants and pastures, suggesting there might be no ‘safe’ level of rabbit density. It takes less than one rabbit per hectare to prevent the successful regeneration of many native trees and shrubs, which are vital for biodiversity and farm productivity. Removal or loss of vegetation makes soils prone to wind and water erosion, which on farms can lead to reduced soil fertility and siltation of dams.
With declining populations of many small Australian mammal species over the past 200 years, it is possible that rabbits have partially filled an ecological niche. Rabbit warrens provide refuge for some native species such as echidnas and large reptiles. However, cats and foxes also use rabbit warrens for shelter and dens for their young, thus helping these predators to persist in hot, arid areas. Rabbits also eat and disperse viable native plant seeds, performing an important function in the ecosystem. However, they can also spread weeds and permanently damage native seedlings in the process.
hover the mouse above the photos to view more information
Feral rabbits can be found in many different habitats across Australia, ranging from deserts to coastal plains — wherever there is suitable soil for digging warrens. They are scarce in areas with clay soils and abundant where soils are deep and sandy, such as in the north-east of South Australia. In arid areas, feral rabbits need access to water, but elsewhere they can often obtain enough moisture from their food.
proposed action by goverment
By 1887, losses from rabbit damage compelled the New South Wales Government to offer a £25,000 reward for "any method of success not previously known in the Colony for the effectual extermination of rabbits". The Commission received 1456 suggestions, including several schemes involving biological controls, but none was found both safe and effective.
A Royal Commission was held to investigate the situation in 1901. Once the problem was understood, various control methods were tried to limit or reduce the population of rabbits in Australia. These methods had limited success until the introduction of biological control methods in the latter half of the 20th century.
Current techniques available for controlling rabbits can be categorised broadly as biological and conventional (chemical+ mechanical). Biological control for rabbits has been particularly effective.
A Royal Commission was held to investigate the situation in 1901. Once the problem was understood, various control methods were tried to limit or reduce the population of rabbits in Australia. These methods had limited success until the introduction of biological control methods in the latter half of the 20th century.
Current techniques available for controlling rabbits can be categorised broadly as biological and conventional (chemical+ mechanical). Biological control for rabbits has been particularly effective.
conventional control measures
For much of the 19th century, the most common methods of feral rabbit control have been trapping and shooting as it can successfully be used to keep the rabbit population in check whilst providing food for people or pets. However, large scale eradication requires different means.
Another method was the destruction of warrens and above-ground harbours through ripping, ploughing, blasting and fumigating. The sandy soil in many parts of Australia makes ripping and ploughing a viable method of control, and both tractors and bulldozers are used for this operation.
Poisoning is probably the most widely used of the conventional techniques, as it requires the least effort. Two commonly used poisons for rabbit control are sodium fluoroacetate (1080)and pindone. Pressure fumigation or diffusion fumigation using toxins are used to kill rabbits while they are in their warrens.
Another technique is hunting using ferrets, wherein ferrets are deployed to chase the rabbits out to be shot or into nets set over the burrows. Since the number of rabbits ferrets can kill is limited, this is more a hunting activity than a serious control method. Historically, trapping was also frequently used; steel-jawed leg-holding traps were banned in most states in the 1980s on animal cruelty grounds, though trapping continues at a lower level using rubber-jawed traps. All of these techniques are limited to working only in settled areas and are quite labour-intensive.
However, conventional controls are labour intensive and time consuming and, faced with the rate at which rabbits breed, cannot hold down numbers on their own.
Another method was the destruction of warrens and above-ground harbours through ripping, ploughing, blasting and fumigating. The sandy soil in many parts of Australia makes ripping and ploughing a viable method of control, and both tractors and bulldozers are used for this operation.
Poisoning is probably the most widely used of the conventional techniques, as it requires the least effort. Two commonly used poisons for rabbit control are sodium fluoroacetate (1080)and pindone. Pressure fumigation or diffusion fumigation using toxins are used to kill rabbits while they are in their warrens.
Another technique is hunting using ferrets, wherein ferrets are deployed to chase the rabbits out to be shot or into nets set over the burrows. Since the number of rabbits ferrets can kill is limited, this is more a hunting activity than a serious control method. Historically, trapping was also frequently used; steel-jawed leg-holding traps were banned in most states in the 1980s on animal cruelty grounds, though trapping continues at a lower level using rubber-jawed traps. All of these techniques are limited to working only in settled areas and are quite labour-intensive.
However, conventional controls are labour intensive and time consuming and, faced with the rate at which rabbits breed, cannot hold down numbers on their own.
fence
Between 1901 and 1907, the Australian government went with a national approach by building three rabbit-proof fences to protect the pastoral lands of Western Australia.
Despite the enormity of the project, the fence was deemed unsuccessful, since many rabbits traversed over to the protected side during the construction period. Additionally, many have dug their way through the fence, as well.
- The first fence stretched 1,138 miles vertically down the entire western side of the continent, starting from a point near Cape Keravdren in the north and ending in Starvation Harbor in the south. It is considered to be the world's longest continuous standing fence.
- The second fence was built roughly parallel to the first, 55 - 100 miles further west, branching off from the original to the southern coast, stretching 724 miles.
- The final fence extends 160 miles horizontally from the second to the western coast of the country.
Despite the enormity of the project, the fence was deemed unsuccessful, since many rabbits traversed over to the protected side during the construction period. Additionally, many have dug their way through the fence, as well.
Biological measures
The Australian government also experimented with biological methods to control the feral rabbit population.
Biological methods used to combat the European rabbit include:
The release of the Myxoma virus in 1950 was highly successful, as an estimated 90% - 99% of the rabbit population in Australia was wiped out. This virus, found in South America, only affects rabbits. Unfortunately, because mosquitoes and fleas do not inhabit arid areas, many rabbits living in the continent's interior were not affected. A small percentage of the rabbit population also developed a natural genetic immunity to the virus and continued to reproduce. Today, only about 40% of rabbits are still susceptible to this disease.
To combat the reduced effectiveness of myxoma, flies carrying a rabbit haemorrhagic disease (RHD), was released in Australia in 1995. Unlike myxoma, RHD is able to infiltrate the arid areas. The disease helped reduced rabbit populations by 90% in arid zones. However, like myxomatosis, RHD is still limited by geography. Since its host is a fly, this disease has very little impact on the cooler, higher rainfall regions of coastal Australia where flies are less prevalent. Moreover, rabbits are beginning to develop resistance to this disease, as well.
Biological methods used to combat the European rabbit include:
- Myxoma virus, which causes myxomatosis, (introduced in the 1920s but early testing was unsuccessful), spread through Australia’s rabbit populations in the 1950s and is spread by mosquitoes, two imported species of rabbit fleas or close contact with another infected rabbit.
- Rabbit haemorrhagic disease virus, which causes RHD, spread initially from Wardang Island in 1996 and then across Australia and is transmitted by flies and direct contact between rabbits.
The release of the Myxoma virus in 1950 was highly successful, as an estimated 90% - 99% of the rabbit population in Australia was wiped out. This virus, found in South America, only affects rabbits. Unfortunately, because mosquitoes and fleas do not inhabit arid areas, many rabbits living in the continent's interior were not affected. A small percentage of the rabbit population also developed a natural genetic immunity to the virus and continued to reproduce. Today, only about 40% of rabbits are still susceptible to this disease.
To combat the reduced effectiveness of myxoma, flies carrying a rabbit haemorrhagic disease (RHD), was released in Australia in 1995. Unlike myxoma, RHD is able to infiltrate the arid areas. The disease helped reduced rabbit populations by 90% in arid zones. However, like myxomatosis, RHD is still limited by geography. Since its host is a fly, this disease has very little impact on the cooler, higher rainfall regions of coastal Australia where flies are less prevalent. Moreover, rabbits are beginning to develop resistance to this disease, as well.
Today, many farmers still use conventional means of eradicating rabbits from their land. Although the rabbit population is a fraction of what it was in the early 1920s, it still continues to burden the country's eco- and agricultural systems. They have lived on Australia for over 150-years and until a perfect virus can be found, they'll probably be there for several hundred more.