Chapter 1 Geography and ecological environment

1.1 Overview: An old continent and a unique environment

Australia is a continent situated on the Indo-Australian Plate.The geology of Australia includes virtually all known rock types.All geological time periods span over 3.8 billion years of the Earth's history.The evolution of Australian continent provides rich mineral resources, wonder landscapes, and unique ecological diversity.

1.1.1 Geographical features

Australia is located in Oceania, lying between the Indian and Pacific oceans, southeast of Asia.On the North, it is adjoined by the Timor Sea, the Arafura Sea, and the Torres Strait.The Coral Sea and the Tasman Sea border on the East.On the South it touches the Bass Strait and the Indian Ocean.On the West it is by the Indian Ocean. Neighboring countries include Indonesia, East Timor and Papua New Guinea to the north, the Solomon Islands, Vanuatu and the French dependency of New Caledonia to the northeast, and New Zealand to the southeast.

In area, Australia is the 6th largest nation after Russia, Canada, China, the United States and Brazil.It is the only nation that occupies an entire continent. Mainland Australia is the Earth's largest island but smallest continent.At the same time, it is one of the oldest landmasses and the flattest of the continents.The Australian landscape is distinctive and varied.It comprises three major structures: the Western Plateau, the Central Lowlands and the Eastern Highlands.

The Western Plateau is characterized by a series of plateax, which also take up nearly two-thirds of Australia.In fact the plateax have an average elevation between 300 and 600 meters, with ranges, basins, and rocks below.Much of the Western Plateau is relatively flat.Uluru (formerly known as Ayers Rock) is probably the best known.

The Central Lowlands consist mainly of great sedimentary basins lying to the east of the Western Plateau.Most of this area is flat and low-lying.Much of the Central Lowlands is occupied by the Great Artesian Basin, which is made up of sedimentary rocks.It is full of water that drains into the wetter Eastern Highlands.

The Eastern Highlands are shaped by a steep escarpment over much of their length on the coastal side.This escarpment is a series of high plateaus with more gentle slopes towards the interior.The coastal escarpment is more prominent along much of the New South Wales and southern Queensland coast, and along the more isolated ranges further north, such as those around Cairns.Australia's highest waterfalls occur where rivers flow over this escarpment.A coastal strip between the escarpment and the coast is flat but quite hilly in many places (Zhang Xianping,2007:4—6).

The Great Dividing Range, or Eastern Australian mountain range is Australia's most substantial mountain range and the 4th longest in the world.The Great Dividing Range separates rivers flowing to central Australia or the Murray-Darling Basin from those flowing to the Pacific Ocean or Bass Strait, and so it is one of the few areas of high land in Australia, which is otherwise dry, barren, flat, and sparsely populated. Because of the dry conditions of the central parts, Australia has one of the most urbanized and coast-dwelling populations in the world.More than 80 per cent of Australians live the coast.

1.1.2 Rivers and lakes

Australia's rivers form three groups: the coastal systems, the Murray Darling System and the internal drainage of central Australia.Many of the coastal rivers have long estuaries where the rising sea-level has penetrated far into the land.The Murray and Darling rivers are the two longest river systems and they form the Murray-Darling Basin, which covers more than one million square kilometers—14 per cent of the mainland.The Murray-Darling river system is 3370 kilometres long, about half the length of the world's longest river, the Nile.The central plains region known as the Channel Country is interlaced by a network of rivers.During the rainy season these rivers flood the low-lying countryside, but in dry months they become a series of water holes.

There are many lake types in Australia.The largest are salt lakes which are drainage sumps of internal rivers.For most of the time these lakes are beds of salt and dry mud.Lake Eyre is the largest of these lakes.It is famous for being the saltiest lake in Australia.Lake Eyre is on the border of South Australia.The lake protects an important desert wilderness.Some Australian animals drink the salty water without being harmed.

1.1.3 The climate

The climate of Australia, in general, is warm and dry.Winters are mild and summers warm to hot.Seasons are the reverse of those in the Northern Hemisphere. The island continent features a wide range of climate zones, from the tropical regions of the north, through the arid expanses of the interior, to the temperate regions of the south.Australia is the world's second-driest continent after Antarctica.In most parts of the country summers are hot.Winters are warm in the north and cooler in the south. Temperature differences between winter and summer vary the least in tropical Australia.All regions in Australia enjoy warm summers and relatively mild winters.

1.1.4 States and territories

Australia consists of six states and two territories.

Australia also administers Ashmore and Cartier Islands, Christmas Island, the Cocos (or Keeling) Islands, the Coral Sea Islands, Heard and McDonald Islands, Norfolk Island and the Australian Antarctic Territory as external territories (Wang Zhijin,2004:10).

1.1.5 Ecological environment

Australia's geological history has made for a wide range of landscapes, climate, plants and animals found on earth and Australia contains the world's most bio-diverse ecosystems.A richly diverse geology provides a wide range of minerals such as bauxite, coal, iron, ore, copper, tin, gold, silver, uranium, nickel, tungsten, mineral sands, lead, zinc, diamonds, natural gas, and petroleum.These natural resources are what the economic development depends on.

1.1.5.1 Plants

Australia has been isolated for thousands of years and plants have been able to develop independently to suit the harsh and arid natural conditions.There are four types of vegetation in Australia: open and closed forests; woodland and grassland;scrub, and deserts as well.Evergreen, vegetation ranges from the dense bushland and eucalyptus forests of the coast to the mulga and mallee scrub and saltbush of the inland plains.In general, the plants can be divided into two types: one is the unique flora as the result of long period of isolation and the other is the tropical plants originating in Asia which arrived in the continent vias land bridges.The native flora of Australia is the most diverse and varied in the world, growing in tropical, rainforest, stony inland deserts, and sandy heath lands.Golden wattles are Australian's national flowers.

1.1.5.2 Animals

Forty million years of isolation from other major landmasses have given Australia a collection of flora and fauna that is unique to the rest of the world.The diverse conditions of the region have contributed to the evolution of creatures and mammals with rare characteristics.Australia has rich types of animals.

The native groups include marsupials and monotremes.There are more than 140 species of marsupials, such as kangaroo and the koala.Kangaroos are the typical of the marsupials, for most of them are herbivorous.The koala is a tree-dwelling marsupial. It spends most of its life in trees.The monotremes are egg-laying mammals.The most distinctive is the platypus and echidna.They inhabit Australia's eastern watercourses where they can find food in the water and mud.

Exotic groups were introduced to Australia by British people for game purposes and for curiosity's sake, for example, rabbits.Now some of new animals have created new industries, like sheep, and others came to live in the rural country.

In Australia, more than 700 birds including endemic and exotic ones are known. Besides, reptiles, amphibians and insects are rich and unique in this country.

1.1.5.3 Heritages

According to the Department of Foreign Affairs and Trade of Australian government, there are 17 Australian properties on the World Heritage List, which is administered by the United Nations Educational, Scientific, and Cultural Organization.

The ten properties for their outstanding natural universal values are as follows:

(1) The Great Barrier Reef,

(2) The Lord Howe Island Group,

(3) Central Eastern Rainforest Reserves of Australia,

(4) The Wet Tropics of Queensland,

(5) Shark Bay,

(6) Fraser Island,

(7) The Australian Fossil Mammal Sites (Riversleigh/Naracoorte),

(8) Macquarie Island,

(9) The Greater Blue Mountains Area,

(10) Heard and Mcdonald Islands.

The two following properties are known for their cultural values:

(1) The Royal Exhibition Building,

(2) The Sydney Opera House.

The five following properties are famous for both outstanding cultural and natural universal values:

(1) Kakadu National Park,

(2) The Willandra Lakes Region,

(3) The Tasmanian Wilderness,

(4) Uluru-Kata Tjuta National Park,

(5) Purnululu National Park.

(World heritage properties, May 2008)

Australia ensures high quality management of its World Heritage areas through national legislation to protect these values involving strict environmental assessment process and a very high level of community and Indigenous involvement in management.

1.1.5.4 Environmental challenges

Australia is the driest continent and this presents a major challenge to its fragile environment and directly impacts on its biodiversity.The following issues are regarded as environmental challenges which Australia is facing.

First, climate change poses a particular threat to specific areas-such as Australia' s mountain regions, the Great Barrier Reef, tropical rainforests, and wetland systems. Australia's economy and environment are highly susceptible to the impact of climate change.Australia's approach to climate change is based on reducing Australia's greenhouse gas emissions and adapting to the climate change that we cannot avoid.

Secondly, Australia's soils are among the most nutrient-poor and unproductive in the world.Only around 6 percent of the Australian landmass is considered arable. Australian soils are highly dependent on vegetation cover to generate nutrients and provide stability.Water extraction and poor soil conservation are all causes of a decline in the quality of Australia's soils.

Lastly, introduced plants as biological invasion cause substantial damage to native vegetation and habitats.For one thing, cactus was introduced to Australia as an ornamental plant and was maintained in gardens for some time.Then it escaped cultivation and became established in the wild, where it found ideal physical conditions for its growth and reproduction.That formed a big headache to Australians.For another, in the past 200 years about 17 different Australian mammals have become extinct.Some Australian animals depend on a specific food or habitat, and if these disappear, the animals will not survive.Other introduced animals such as cattle, rabbits and deer eat the food needed by native animals and this has also reduced the numbers (Australian Endangered Animals,1999).

In spite of facing these difficulties, the unique environment in Australia has shown something that Australians are proud of.Meanwhile, the government is trying every possible means to resolve environmental problems.

Australia is one of the world's oldest landmasses and has been populated by human beings for an estimated 60,000 years.This old continent contains the world's most ancient flowering plants and is among the world's most bio-diverse ecosystems. The importance of the natural environment tells people how the spirit of the land has infused the national character of Australian people(Xiao Yuehe &Li Youwen,2008:3).

New words

geology n．地质学

span v．横跨

Oceania n．大洋洲

adjoin v．邻接

border v．接近

landmass n．大陆

plateau n．高原

basin n．盆地

sedimentary a．沉积的

steep a．陡峭的

escarpment n．悬崖

slope n．斜坡

waterfall n．瀑布

strip n．条，带

substantial a．坚固的

barren a．贫瘠的

sparsely ad．稀少地

urbanized a．都市化的

estuary n．河口

penetrate v．渗透

the Nile n．尼罗河

interlace v．交错

reverse a．相反的

tropical a．热带的

arid a．干旱的

expanse n．宽阔的地区

temperate a．气候温和的

territory n．行政区，地域

ecosystem n．生态系统

bauxite n．矾土

ore n．矿石

copper n．铜

tin n．锡

uranium n．铀

nickel n．镍

tungsten n．钨

zinc n．锌

harsh a．粗糙的

vegetation n．植被

scrub n．灌木丛

dense a．密集的

eucalyptus n．桉树

mallee n. (澳大利亚南部生长的)小桉树

plain n．平原

flora n．植物群

heath n．石南树

wattle n. (澳大利亚)金合欢树

rainforest n．雨林

fauna n．动物群

mammal n．哺乳动物

marsupial n．有袋动物

monotreme n．单孔类动物

kangaroo n．袋鼠

koala n．树熊

herbivorous a．食草的

platypus n．鸭嘴兽

echidna n．针鼹

watercourse n．水道

exotic a．外来的

endemic a．地方的

reptile n．爬虫，爬行动物

amphibian n．两栖动物

property n．财产

assessment n．评估

fragile a．脆弱的

biodiversity n．生物多样性

pose v．造成

susceptible a．易受影响的

emission n．散发

arable a．可耕种的

extraction n．抽出

habitat n．栖息地

cactus n．仙人掌

ornamental a．观赏性的

reproduction n．繁殖

extinct a．灭绝的

infuse v．灌输

Exercises

1．Explain terms.

(1) Uluru (Ayers Rock)

(2) the Great Dividing Ranging

(3) the Great Barrier Reef

(4) the Murray-Darling Basin

(5) Lake Eyre

(6) Kangaroo

2．Answer questions.

(1) What is the geographical structure of Australia?

(2) What kind of climate does Australia have?

(3) What are the most common native plants and animals in Australia?

(4) What environment challenges Australia is facing now?

3．Questions for further consideration.

(1) What are the factors and causes that affect Australia's climate?

(2) Why do Australian people prefer to live in a coastal city or town?

(3) What aspects of Australia's location, landforms and climate have aided the development of tourism in Australia?

(4) How isthe natural environment of Australia different from that of Asian countries?