Biological control of pests
If you have been to some of the islands off Tasmania where rabbits and foxes have not been introduced, the first thing you notice is the diverse birdlife flitting freely in the grasslands. It's a stark reminder of the impact of introduced species on the mainland.
One application of biotechnology is biological control – attempting to eradicate introduced plant or animal pests (such as prickly pear and rabbits), or to reduce the harm they do to the environment. Being an island continent makes such an exercise conceivable, but what can we do to re-establish diversity? Which year should we take as the starting point for measuring diversity?
In Australia, our native plants and animals have adapted to life on an isolated continent over millions of years. However, particularly since European settlement, our native animals have had to compete with a range of introduced animals for food, habitat and shelter.
Some of our native species have also had to face new predators. Rapid changes in land usage, such as increased crop growing areas, have also affected our soils and waterways.
Feral animals
Invasive Animals Cooperative Research Centre
Feral animals in Australia are either domestic animals that have gone wild, or those that were introduced for pest control or for recreational use.
Feral animals causing most public concern are: rabbits, foxes, cats, pigs, goats, donkeys, horses, camels, water buffalo, introduced fish, the northern Pacific seastar (Asterias amurensis), the Indian mynah and cane toads.
These species have few natural predators or fatal diseases in Australia and some have high reproductive rates. As a result, their populations can multiply rapidly if conditions are favourable. Drought is the main factor controlling their populations, as numbers drop quickly when food and water are limited.
Some feral animals prey on native animals and compete with them for food, shelter and habitat. Some feral animals may compete with livestock for food, or prey on our livestock. They can also cause damage to the land and waterways used by farmers and native animals.
Domestic rabbits were first introduced to Australia with the first fleet in 1788. However, they did not become established in the wild until Thomas Austin brought 24 wild rabbits from England in 1859, and released them for hunting on his property in southern Victoria. They bred so well that by 1866, only seven years later, 14,253 rabbits were recorded as being shot for sport on the property.