INVASIVE SPECIES

An invasive species is a non-indigenous species, occurring as a result of human activity, with an adverse impact on the habitats that it invades. Invasive species include feral animals, marine pests, non-native insects, other invertebrates, diseases, parasites, and weeds (weeds are discussed separately). Some invasive animals were deliberately brought into Australia while others were accidentally imported.

Invasive species are a threat to the environment, but they also have an impact on social and economic activities such as the agriculture industry. They can threaten native species, contribute to land degradation (through soil erosion) and reduce agricultural productivity. The damage they cause can be detrimental to the environment (threatening our unique biodiversity) and a high cost to the Australian economy. For instance in Australia, the annual cost, in terms of control and production loss estimates, of 11 types of feral animals has been estimated at around $720 million (CRC 2004).

The cane toad is an example of a deliberately introduced feral animal. It was brought to Australia to control the cane beetles that destroy sugar cane crops. Cane toads failed to control the cane beetle and instead became a pest themselves, eating and poisoning various other insects, mammals and snakes. They continue to spread across Australia.