Australian Pests

Pest Animals in Australia- Results of European Immigration

Australia -what a beautiful country. Many people dream of going to Australia to start a new life far away from home. And indeed Australia’s history is a history of immigration. Since England sent their first convicts to Australia 1788, immigration was the essential part of building up Australia’s white population.

But only a minority of people are aware of the negative consequences of immigration. Except of chasing away aboriginal people and forcing them into exile, the introduction of exotic animals is a serious result Australia has to face today.

The main pest animals are brought by European settlers for different reasons. For transport (horses, camels), wool, leather, food (goats, cows, sheep, pigs), sport (foxes, rabbits), “pest control” (cane toads) or because it made the settlers feel more at home with familiar animals around (cats, dogs, birds). And not all today’s pests have brought liberally. For example mouses and rats introduced to Australian main land by accident or domestic animals escaped domestication living in the wild now.

There are many wherefores why exotic animals are part of Australia’s wildlife today. What impacts those animals have varies from animal to animal. There some which are just minor or moderate pests. These animals are not especially a problem or at least not most of the time. Examples for those pests are feral hoses, donkeys, camels or cows.

Others are a serious problem and have great influence on native wildlife and livestock, like rabbits, goats, pigs, foxes, dingos, cats, mice, starlings, cane toads and more. The main impacts those animals have on valued resources can be divided into groups: Grazing Impacts, Crop Impacts, Predator Impacts, Infrastructure Damage, Environmental Impacts, Disease Risks and Social Costs.


Grazing Impacts

The competition between pest animals, like rabbits and goats, and livestock for pasture contains the danger of over-grazing especially in drought seasons. Long term damage like soil erosion or changes in plants is very likely.


Crop Impacts

Crops are damaged by a wide range of pests. Birds, feral pigs and rodents can reduce the yields of grain, sugarcane, fruit and vegetables. The impact might be only sporadic but occasionally high damage has been reported over the years.


Predator Impacts

Introduces carnivores are a serious threat to livestock. Wild dogs, foxes and even feral pigs have a major impact on cattle and sheep. Without natural predators and food resources they try to survive by attacking domestic stock and native animals.


Infrastructure Damages

Destruction of fences caused by feral horses, feral donkeys, camels and feral pigs or rodents damaging electrical and other equipment on farms and houses, are impacts on properties that can easily run the cost into several thousands of dollars.


Environmental Impacts

Native animals threatened by introduced predators and pest herbivores competing for food, shelter and water resulted in extinction of many native animals. Australia has to report half of the world’s mammal extinction over the last 200 years. And not only animals are affected by exotic pests. Feral pigs are responsible for a huge damage of wetlands and rainforest by rooting up soil.


Disease Risk

The ability to move between different areas makes pest animals to an enormous risk of spreading diseases. Deer is discussed to have an impact on spreading Bovine Johne’s Disease between properties. Wild dogs could spread hyadatids which could affect humans and live stock. But not only is the spread of diseases a big concern. Bringing new diseases into the country is also a realistic worry.


Social Cost

This group is often overlooked but must not be underestimated. It usually is the end-product of economic costs. Enterprises in some areas may be affected as well as personal impacts on farms and/or families. Pest animals may even have effects on cultural values by predation on totemic native species and more.
Although there are many approaches to reduce pest animals technical, economic and social factors make it quite difficult to obtain results. The lack of time, techniques, money and difficulties in coordination are serious impediments to reduction of pests.

In summary, it can be said, that immigration is an important point in building an interesting and colourful society. But the negative impacts must not be underestimated. Imported animals, if legally, illegally or accidently, always bear the danger of changing the native environment and wildlife. The results of these changes cannot be foreseen.

Alexandra Mellert