Environmental issues

Pests and weeds

Pest animals

Since colonisation, many species of animal have been introduced into Australia from other countries. They include cane toads, goats, foxes, deer, rabbits, pigs, cats, dogs and horses.

Introduced predators, such as foxes and feral cats, can decimate prey populations and are believed to have caused the extinction of many native species. Many other native animals face the threat of extinction if the impacts of introduced predators are not controlled. Introduced herbivores can cause extensive damage to native vegetation and soils through grazing, trampling and digging. They may also compete with native herbivores for food, and further degrade the environment by providing an abundant food source for other pests. For example, rabbits can support high densities of feral cats and foxes, which in turn suppress native prey.

Some species have been listed as key threatening processes under the Threatened Species Conservation Act.

As well as damaging the natural environment, pest animals can degrade sites of cultural significance such as Aboriginal rock art sites or historically significant structures. In addition, pest animals can pose a major threat to agriculture, for example by killing, harassing or competing with livestock, spreading disease and contributing to soil erosion. Pest animals can affect aquatic as well as terrestrial ecosystems.

The Invasive Animals CRC estimates that pest animals cost Australia approximately $720 million per year, but could be much more. Within New South Wales, more than 350 species, populations and communities are considered to be threatened by the impacts of pest animals.

Significant pest animals

Cane toads

The infamous cane toad was introduced to Queensland in 1935, and it's been spreading ever since. While cane toads are established on the North Coast, most of NSW is still free of this pest. Help us stop them spread any further.

Feral bees

Introduced honeybees can have various impacts on native plants and animals. Feral honeybees have been listed as a key threatening process in NSW.

Feral deer

Find out how deer can damage native environments. Download the deer management plan for Sydney's Royal National Park.

Feral cats

Feral cats get all their food from the wild. They will hunt many types of native birds , mammals, reptiles and frogs. Find out more.

Feral goats

Grazing and browsing by feral goats are a major threat to soils and plants in NSW, particularly in the Western Division. Goats also compete for food and shelter with native animals, damage Aboriginal heritage sites and are potential vectors of livestock diseases. Find out about NPWS programs to control these pests.

Feral horses

NPWS tries to control wild horses in parks and reserves across the state. Find out more about our horse management programs, and download independent reports about them.

Feral pigs

Feral pigs eat native plants and animals, foul water sources, and cause soil erosion. They're also an agricultural pest. Find out about NPWS pig control programs.


Foxes have spread throughout much of Australia, contributing to declines and regional extinctions of a range of native fauna, particularly among medium-sized ground-dwelling and semi-arboreal mammals, ground-nesting birds and freshwater turtles. They have been declared a key threatening process in NSW, and a threat abatement plan is now in place to limit the impact of this pest.

Introduced ants

Fire ants and other exotic ant species can have a big impact on biodiversity. In the case of fire ants, they can also greatly disrupt human activities. Find out more.

Introduced rats

Ship rats have caused much damage to the native ecosystems of Lord Howe Island since they were introduced in 1918. They have been declared a key threatening process on the island.

Plague minnows

These introduced fish have devastated populations of native frogs and other animals. They have been declared a key threatening process in NSW and NPWS has prepared a threat abatement plan to tackle the species.


Rabbits are widespread across the southern two-thirds of Australia. They have been declared a key threatening process in NSW because of their huge impact on some native plants and animals.

Wild dogs

Wild dogs, including dingoes, can cause substantial losses of livestock especially sheep, goats and cattle. They also prey on native species such as kangaroos, wallabies and terrestrial wetland birds. Find out about NPWS programs to control these pests.

Information on vertebrate pest animal species in Australia and New Zealand


The Invasive Animals Cooperative Research Centre is counteracting the impact of invasive animals through the development and application of new technologies and by integrating approaches across agencies and jurisdictions.

The NSW Department of Primary Industries Vertebrate Pest Research Unit undertakes research which addresses industry priorities in relation to vertebrate pest management and, increasingly, the management of environmental pests. The aim is to improve agricultural production and enhance conservation values through the reduced impact of vertebrate pests.


Page last updated: 05 August 2015