Australia is an island continent which is geographically isolated from the rest of the world. This has resulted in the evolution of many unique plants and animals and the development of a very fragile ecosystem. This ecosystem has been influenced by human immigration for many thousands of years. The original immigrants were the Aborigines who are thought to have migrated to Australia from Asia between 50 and 100 thousand years ago. These primitive people learned to live in the inhospitable environment of Australia with very little effect. Their major environmental impact was from the use of ontrolled burning of the land.
Over the years they had learned the benefit of periodic fires to control pests and to clear debris before it accumulated and led to large uncontrolled disastrous fires. This also returned nutrients to the soil which helped to grow back new vegetation. Unlike those who followed, the Aborigines had very little impact on the environment. Following the Aborigines, Asian seafarers are believed to have traveled to Australia to trade on the north shores. Experts are not sure, but they believe that these seafarers are the ones who first introduced the dingo into Australia almost 3,500 years ago.
The dingo rapidly became the top predator and is probably the cause of the disappearance of the Tasmanian wolf and the Tasmanian devil from Australia. They will hunt down almost anything but they are not known to attack humans. They will attack kangaroos, wombats, rabbits, and even lizards. After the settlers arrived and the sheep were brought in, the dingo started to hunt the sheep. The sheep were much easier for them to get. As a result of this the sheep grazers built a 3,307 mile long fence to separate the sheep from the dingo. A $20 US bounty is now placed on the pelt of each ingo.
European immigrants did not come to Australia until after April 29, 1770 when captain James Cook landed in Botany Bay and made the first claim for England on the eastern part of the island. He called it New South Wales. In 1787, England started their first colony in Australia which was a penal colony since England’s prisons were very overcrowded. That year, on May 13, eleven ships carrying almost 1,500 people, 800 of them convicts, left England for the new colony. The ships first landed in Botany Bay on January 18, 1788 but found it unsuitable for a colony. They then moved north to Port
Jackson, one of the world’s best natural harbors. The settlement was started on January 26 which is now celebrated every year as Australia day. The settlement was later named Sydney after Britain’s secretary, Lord Sydney. Lord Sydney was responsible for the entire colony. The first European immigrants brought with them their livestock, plants, and traditional ways. Much of this was not suitable for Australian conditions. They also brought with them cultural beliefs including the Christian belief that man was superior to the rest of creation and had the God given right to exploit nature.
The Europeans believed that the Aborigines were inferior and refused to use the knowledge that they had acquired about the environment. They began a campaign of genocide with bullets, diseases, and even poison. With few Aborigine survivors the practice of periodic burning came to an end. This led to many of the plants and animals which had become dependent on this regular burning to die off. Sheep ranching quickly became a major agricultural practice in Australia. By 1860 over 20,000,000 sheep were grazing and by 1890 there were over 100,000,000 spread over the entire continent.
Sheep graze in large herds and their hooves destroy the fragile soil by trampling it down so hard that roots and water can not easily get through it. Over grazing quickly led to soil erosion turning pastures into dust bowls. This also led to the overgrowth of tougher plants, some of which were poisonous. Destruction of the grazing land also effected many of the small native animals such as bandicoots which had depended on it for food and cover. The European rabbit has also been able to thrive in Australia at the expense of the environment. They were first introduced by a squatter named
Thomas Austin who had 24 rabbits sent to him in 1859. He used them for breeding and also released some to hunt. The rabbits found that there was plenty of good food and liked the sandy soil for burrowing. They reproduced rapidly and quickly took over and replaced other native animal species. Large stretches of the country became scarred from the burrowing and barren from the rabbits eating the vegetation in sight. The water buffalo is another non-native animal which has caused several problems. They were introduced by the Australian Army in the far north during the early 1800’s.
Originally there were only about 100 in Australia but by 1981 there were nearly 300,000 roaming the wet-lands. When they were introduced into Australia they brought the blood sucking fly with them. When the fly sucks the blood from animals it releases a chemical that can kill them. These flies breed in the dung of the buffalo and have been able to breed freely because the Australian dung beetle cannot get rid of the large patties left by the buffalo. The Australian dung beetle is only use to the small pellets left by the sheep.
The buffalo also tear up the ground which has led to severe soil erosion and heir wallowing turns the wetlands into muddy bogs harming breeding grounds of many small water-living plants and animals. The unpredictable Australian weather, particularly the droughts led the immigrants to develop reservoirs and irrigation systems. Unfortunately, life along these rivers had adapted to the periodic floods and droughts. Many of these native plants, deprived of this natural cycle, have suffered and are in danger of extinction. The cooling effects of the dams, due to water drawn off the bottom, has made many rivers too cold for native fish to spawn.
The European immigrants had specific ideas regarding the beauty of nature. The Australian landscape did not fit these standards of beauty. They therefore began to landscape by first clearing native plants and replacing them with imported ones. The list of these plants grew year after year. Some failed while others thrived and overcrowded the native plants. One of these plants is the Prickly pear. It was originally imported as a hedge plant but eventually took over 120,000 square miles of land. The effects of immigration on the Australian environment over the last ew centuries has been devastating.
The original European immigrants could not foresee the major impact their transplants and traditions would have on the environment. Even if they had, conquering the land was necessary for their survival. In many areas the environmental degradation may have past the point where it can be restored and is now beyond repair. However, with greater understanding and knowledge of the Australian ecosystem it is hoped that further degradation can be stopped or even reversed. What is needed now is the commitment of people and resources to make it happen.
