Exotic Animals - Herbivores
The European Rabbit - Oryctolagus Cuniculus
Wild rabbits of English stock were introduced to Australia in 1859 at 'Barwon Park' near Geelong. They soon began to colonise the surrounding bush. Rabbits probably reached the Northern Territory in 1894 by natural spread.
In the Northern Territory, rabbits are patchily distributed in arid areas south of a line extending east-west across the Territory 100 km north of the tropic of Capricorn. A few isolated populations have been recorded further north.
Rabbits have a very high reproductive potential. Rabbit densities are rarely known precisely and fluctuate according to seasonal conditions and disease outbreaks. High densities of rabbits (more than 50/ha) have been recorded historically in some parts of the Northern Territory.
Rabbits are said to be Australia's worst vertebrate pest. They compete with domestic stock for food, they damage soils thus contributing to erosion problems and cause profound damage to native plants. In the arid areas of Australia including the southern Northern Territory, rabbits overgraze pasture plants and reduce trees and shrubs by killing mature plants and suppressing the recruitment of seedlings.
Rabbits may also have a deleterious impact on native fauna which may be direct through competition for food or shelter, or indirect through environmental modification.
Australia wide, biological control has had a significant impact on rabbits. Myxomatosis was introduced into Australia in the early 1950s. It spread to the Northern Territory naturally in 1951 and has been present ever since. In 1993 the arid adapted Spanish rabbit flea was introduced to the Northern Territory to help spread myxomatosis.
The most recent biological control for rabbits is the Rabbit Haemorrhagic Disease. Since its accidental release in 1995, the disease has spread naturally over most of Australia where rabbits are found. As a result rabbit numbers across much of arid Australia including the Northern Territory have dropped by over 80%.
A cost effective non-biological way of reducing rabbit numbers over large areas is by ripping warrens. Ripping involves using a bulldozer towing a plough to collapse the warrens. Other methods used to control rabbits include poisoning, shooting, trapping and fumigation. These methods can be effective in controlling rabbits but only over small areas.
