Animal pests

Foxes, rabbits, pigs, rodents, deer, goats, cats, wild horses, cane toads and dogs cost the Australian economy more than $720 million each year.

Pets

Domestic pets, particularly cats, are among the greatest of threats to our wildlife. The number of native animals killed by dogs and cats nationally each year is estimated to be in the millions - with the highest published estimates at 18 million native animals a year.

One domestic cat that is allowed to roam freely will kill an average of 30 native birds and animals a year, including feathertail gliders, sugar gliders, pigmy possums, ringtail possums, baby brush tail possums, bandicoots, small bats, birds, lizards, snakes, skinks, geckos, frogs, bats, rats and marsupial mice.

Cats are most active at night, dusk and dawn when much of our native wildlife is also active. Because of their natural hunting instinct—cats hunt for pleasure as well as for food—even well fed cats will prey on wildlife.

Dogs have been responsible for the mauling and death of many different species of native animals including cassowaries, tree kangaroos and possums. Dogs are also the main culprits in the spread of hydatids, a common but largely ignored disease in Australia that can kill people, livestock and wildlife.

Dog faeces are a health risk, particularly if they are allowed to get into waterways.

Cats can be trained to live permanently indoors, and should always be kept indoors at night. Domestic cats that aren't allowed to roam are also more likely to be healthier and live longer, because they don't get into fights or get injured by vehicles.

For more information:

Native Animal Network Association http://www.nana.asn.au/n2-domestic.htm

Feral cats and dogs

An even greater threat to wildlife is that posed by feral cats and dogs.

By day feral cats rest in hollow logs, clumps of grass or debris and by night they prowl bushland and backyards, preying on native Australian animals. The average feral cat needs 300g of flesh daily to survive. Cats’ mouths can carry bacteria to which wildlife has little resistance, and wildlife that has been injured by cats usually dies - if not from injuries, then from infection.

Wild dogs in Australia include:

• Dingoes, which originated from the wolves of Asia and the Middle East and arrived in Australia about 4000 years ago;
• Feral dogs – domestic dogs living in the wild;

According to the NSW National Parks and Wildlife Service, wild dogs mainly occur along the Great Dividing Range, coastal hinterlands, and in north-western NSW. Wild dogs cause substantial losses of livestock for sheep graziers: up to 30 per cent in some areas. They prey on native mammals and birds and may also compete with native predators, such as quolls, for food and other resources.

Rabbits

The feral European rabbit is one of the most widely distributed and abundant mammals in Australia. It causes severe damage to the natural environment and to agriculture. Feral rabbit control is complicated because of welfare and harvesting issues, and because both native and introduced predators feed on feral rabbits in many parts of Australia.

Domesticated rabbits arrived in Australia with the First Fleet. Thomas Austin freed about a dozen on his property near Geelong, Victoria, in 1859. From there they spread, reaching the Queensland - New South Wales border by 1886 and covering most of their present range by 1910.

Today, feral rabbits occur in many different habitats across Australia, ranging from deserts to coastal plains — wherever there is suitable soil for digging warrens. Feral rabbits compete with native wildlife, damage vegetation and degrade the land. They ringbark trees and shrubs, and prevent regeneration by eating seeds and seedlings. Their impact often increases during drought and immediately after fire, when food is scarce and they eat whatever they can.

Feral rabbits may have caused the extinction of several small (up to 5.5 kilograms) ground-dwelling mammals of Australia's arid lands, and have contributed to the decline in numbers of many native plants and animals. In the Norfolk Island group, feral rabbits and goats reduced Philip Island to bedrock, leaving at least two plants locally extinct. Feral rabbits even threaten colonies of seabirds such as Gould's petrel.

Reference

http://www.environment.gov.au/biodiversity/invasive/publications/rabbit/index.html

Cane toads

Cane Toads were introduced to Australia to eat French's Cane Beetle and the Greyback Cane Beetle. The 'whitegrub' larvae of these beetles eat the roots of sugar cane and kill or stunt the plants. The Australian Bureau of Sugar Experimental Stations imported about 100 toads from Hawaii to the Meringa Experimental Station near Cairns. The toads bred quickly and more than 3000 were released in the sugar cane plantations of north Queensland in July 1935.

Cane Toads have since spread south and west across the continent and now occur in Queensland, Northern Territory and New South Wales. During the early 1960s, the Cane Toad was recorded in north-eastern New South Wales and is now considered to occur on the north coast of New South Wales as far south as the Clarence River/Yamba. A breeding colony was confirmed at Lake Innes, near Port Macquarie, in 2003 after being introduced at Byron Bay in about 1965.

The cane toad continues to expand its range southwards at about 1.3 kilometres a year, and is also spreading across the tropical north towards Western Australia. The toads can be accidentally transported to new locations, for example in pot plants or loads of timber. Toads can be excluded from garden ponds and dams by a 50 cm high barrier such as a thick hedge or a wire mesh fence.

All stages of the Cane Toad's life-cycle are poisonous. The venom produced by the parotoid glands acts principally on the heart. No humans have died in Australia from Cane Toad poison but overseas, people have died after eating toads and even soup made from boiled toad eggs.

Australian native fauna that have been killed by eating or mouthing Cane Toads include goannas, Freshwater Crocodile, Tiger Snake, Red-bellied Black Snake, Death Adder, Dingo and Western Quoll. The Brown Snake, however appears to be immune.

Cane Toads poison many native animals whose diet includes frogs, tadpoles and frogs' eggs, and compete for food with vertebrate insectivores such as small skinks. They also may carry diseases that can be transmitted to native frogs and fishes.

Cane toad drawing and map: Department of Environment and Water Resources. Map shows distribution of Cane Toads in Australia Adapted from: Clarke GM et al (2000). Environmental Pest Species in Australia.

References:
http://www.amonline.net.au/factsheets/canetoad.htm

http://www.frogwatch.org.au/canetoads/default.cfm

http://www.environment.gov.au/biodiversity/invasive/publications/cane-toad/index.html