Australia's+Environment

=Environment of Australia= toc Occupying an entire continent of some 7.6 million square kilometers, Australia is the sixth largest country in the world. Its ocean territory is the world’s third largest, spanning three oceans and covering around 12 million square kilometers. Nearly seven million square kilometers, or 91 per cent of Australia, is covered by native vegetation. Although this figure may seem high, many of Australia’s desert landscapes are covered by native plants such as salt bush, albeit sparsely. There are 17 Australian properties on the World Heritage List. The Great Barrier Reef, the Tasmanian Wilderness, the Wet Tropics of Queensland and Shark Bay meet all four World Heritage criteria for natural heritage, with Kakadu National Park, Uluru–Kata Tjuta National Park, Purnululu National Park, Willandra Lakes region and the Tasmanian Wilderness listed for both natural and cultural criteria. The Australian Fossil Mammal Sites (Naracoorte/Riversleigh), Lord Howe Island Group, Central Eastern Rainforest Reserves (Australia), Fraser Island, Macquarie Island, Heard Island and McDonald Islands and the Greater Blue Mountains Area are listed under the World Heritage criteria for natural heritage. For tens of thousands of years, the lives and sense of cultural identity of Indigenous Australians were inextricably linked to the land, its forms, flora and fauna. Today, the identity of all Australians is shaped by a relationship with the natural environment. Australia is one of the most urbanized and coast-dwelling populations in the world. More than 80 per cent of Australians live within 100 kilometers of the coast.

Protected areas
Australia is the driest inhabited continent in the world and was part of Gondwana, the giant landmass that once connected the southern continents of Africa, Antarctica, Australia, India and South America and broke up more than 100 million years ago. Recognizing the need to protect and conserve the natural heritage arising from this historic connection, Australia set up a nationwide network of parks and reserves called the National Reserve System. It conserves examples of Australia’s natural landscapes and native plants and animals for future generations. Many Australian species date back to Gondwanan times—the Wet Tropics of Queensland, for example, contain 13 of the 19 families of the most ancient flowering plants known to survive from the days of Gondwana. The Wet Tropics are one of Australia’s 15 World Heritage properties listed for their natural values by the United Nations. Australia’s evolving National Reserve System aims to include samples of all ecosystems at an appropriate regional scale. At early 2008, the National Reserve System included over 9000 parks and reserves covering almost 900 000 square kilometers, or more than 11 per cent of Australia’s continental land area. In addition to those on the mainland and in Tasmania, there are protected areas located on Australia’s oceanic islands and external territories, comprising Norfolk Island (6.5 square kilometers), Lord Howe Island (12.47 square kilometers), Christmas Island (87 square kilometers), Macquarie Island (131.82 square kilometers), Heard Island and McDonald Islands (370 square kilometers) and Antarctic Specially Protected/Managed Areas (80.15 square kilometers) in the Australian Antarctic Territory.

Land
10.5 per cent of mainland Australia’s natural environment is protected by national environmental legislation. Australia has some of the oldest land surface on earth and while rich in biodiversity its soils and seas are among the most nutrient poor and unproductive in the world. This is due mainly to the country’s geological stability, which is a major feature of the Australian land mass, and is characterized by, among other things, a lack of significant seismic activity. Only six per cent of the Australian landmass is arable. Large volumes of water are required from both surface and groundwater supplies. Australian soils are highly dependent upon vegetation cover to generate nutrients and for stability. Land clearing, water extraction and poor soil conservation are all causes of a decline in the quality of Australia’s soils.

[[image:13_sediment_loads_fig-b.jpg width="300" height="258" align="left"]]Water
Australia is the driest inhabited continent on earth, with the least amount of water in rivers, the lowest run-off and the smallest area of permanent wetlands of all the continents. One third of the continent produces almost no run-off at all and Australia’s rainfall and stream-flow are the most variable in the world. Human activity continues to exert pressure on marine environments. Pollution is the most serious problem and the vast majority of marine pollution is caused by land based activities—soil erosion, fertilizer use, intensive animal production, sewage and other urban industrial discharges. Australia currently has 65 Ramsar (an international convention that provides the framework for conservation of wetlands) listed wetlands covering 7.5 million hectares and more than 850 of national importance. Australia’s marine environment is home to 4000 fish species, 500 coral species in the northern reefs alone, 50 types of marine mammal and a wide range of seabirds. It is estimated that as many as 80 per cent of marine species found in southern Australian waters occur nowhere else. Around seven per cent of Australia’s marine jurisdiction is identified marine protected areas.

Biodiversity
Australia is one of the most biologically diverse countries on the planet. It is home to more than one million species of plants and animals, many of which are found nowhere else in the world, and less than half have been described scientifically. About 85 per cent of flowering plants, 84 per cent of mammals, more than 45 per cent of birds, and 89 per cent of inshore, freshwater fish are unique to Australia. Australia is richly endowed with marsupials— there are more than 140 species. At least 18 exotic mammals have established feral populations in Australia, with cats and foxes responsible for the decline and extinction of several native animals. At least 2700 non-native (introduced) plants have established populations in Australia. Sixty-eight per cent of these introduced plants are considered a problem for natural ecosystems.

[[image:kangaroo_.jpg_tudruw.jpg width="240" height="180" align="left"]]Climate change
Australia is one of the world’s least densely populated countries (after Mongolia and Namibia), with fewer than three people per square kilometer, but the effects of climate change have been felt across the continent. From 1910 to 2004, average temperatures in Australia rose 0.9°C. The country has experienced more heat waves and fewer frosts. Since 1950, annual rainfall has declined on the eastern seaboard and in the south of the continent, but increased in the northwest. Droughts have become more intense and extreme rainfall events have increased in the northeast and southwest since the early 1970s.