Rabbits: An introduced species in Australia
...nywhere in the world” Source: www.http://rubens.anu.edu.au/student.projects/rabbits /history.html#Introduction%20and%20Establishment IMPACT - “The rabbit is one of the greatest pests of the pastoral industry in Australia, and has fundamentally altered ecosystems” Source: The Rabbit- An Introduced species, by Smith, Jeremy. Rabbits are one of Australia's foremost environmental pests. They have been one of the main causes of habitat destruction, native flora and fauna extinction, land degradation and crop destruction. The rabbit impacts greatly upon: · Native wildlife By directly competing for food and habitat the rabbit has displaced many small to medium size marsupials such as the greater bilby, (now an endangered species), and the burrowing bettong. Due to selective grazing the rabbit has changed ecosystem composition radically. When an ecosystem is changed, the dependant fauna are displaced by a depletion in their required food source and breeding grounds. In its spread across Australia, the rabbit took advantage of pre-existing burrows and evicted various burrowing mammals such as the rufous hare-wallaby, the bilby and the burrowing bettong from their burrows. Wildlife was often killed by poison and traps set for rabbits. Rat-kangaroos, tiger cats and magpies were some of the species inadvertently affected. Goannas, wombats and bandicoots were often directly poisoned, as they were perceived as a menace to the farmer. · Soil In the semi-arid and arid zones the rabbit continues to degrade the soil by destroying the stability of the soil by the removal of vegetation cover. By denuding the landscape, as rabbits will in droughts, it is leaving the soil highly susceptible to various forms of erosion and loss of fertility. · Vegetation During drought, rabbits will kill trees and shrubs by ring barking and digging to eat the roots in search of moisture. Hence, rabbits not only control species germination, but the species composition of mature plants thus effecting biodiversity. BIOLOGICAL CONTROL There are 3 major biological control methods: Myxomatosis: Myxomatosis is a benign disease of the American cottontail rabbits transmitted by fleas and mosquitos. It is specific to leporids and is caused by the myxoma poxvirus. Myxomatosis was first field tested in 1938 and successfully released in Australia in 1950 and resulted in a estimated 99% mortality rate. In the first two years it reduced the rabbit population from 600 million to less than 100 million. Although rabbits began to build up a resistance soon after. The innate resistance of rabbits to myxomatosis increased rapidly in the first few years after its release and the rabbits with a genetic resistance to the disease became more common. Immunocontraception: Immunocontraception is a new and exciting CRC research project that is taking bold steps in genetic manipulation. The aim is to manipulate the fertility of rabbits through gene insertions on the myxoma virus, rendering the infected rabbit (Oryctolagus cuniculus) infertile. This project is ...