Land Relief In its northern and western regions, the landscape of Western Australia consists primarily of broad plateaus articulated by several mountain ranges; to the east lie immense deserts. The Kimberley region in the far north is a multisectioned plateau. The coastline is rugged and dangerous, with strong currents and a tidal range that may reach 39 feet 12 metres , while the rolling inland areas are sparsely wooded and scattered with bristly grasses.
The limestone King Leopold Ranges rise from the southern part of the region. The Fitzroy and Ord rivers delineate the southern and eastern border of the Kimberley.
Although the main period of dune formation ended about 10, years ago, the dune crests are still active shifting. Gibson Desert, in the centre of Western Australia. On the coast proper, limestone ranges and gorges make up the arid Cape Range on the peninsula to the west of Exmouth Gulf. Ningaloo Reef and Exmouth Gulf are nearby. Unlike the Canadian Shield, however, the Western Australian craton has been subjected to weathering processes for some million years.
The gently undulating, weathered plateau of the Yilgarn block lies between 1, and 2, feet and metres above sea level. It is bounded to the east by the flat, waterless, treeless, marine limestone of the Nullarbor Plain , which terminates at the Southern Ocean in an unbroken line of spectacular coastal cliffs.
To the west, the scarp of the Darling Range runs north-south for some miles km , separating the Yilgarn block from the coastal plain of the Perth Basin. In the extreme south, the block rises to an elevation of 3, feet 1, metres in the Stirling Range and then drops abruptly into the ocean, resulting in a rugged granite coastline with clean, white sandy bays. Archipelagoes of granite islands occur offshore.
Lake Argyle near Kununurra, Western Australia. Usually dry, these rivers become raging torrents during the cyclone season. To the east of the Pilbara flows the Rudall River, which drains inland to the saline and usually dry Lake Dora. Indeed, inland drainage is characteristic of most of Western Australia, and the great majority of the lakes shown on any map of the state are saline playas dried-up lake beds , not bodies of fresh water except after major rainfall events. The dry, rough country lying to the south of the Pilbara is drained by the Gascoyne River.
However, the largest rivers of the region, including the Swan , Blackwood, and Frankland, have their headwaters in the Wheatbelt—an extensive area cleared for agriculture—and are consequently saline. Perth and the Swan River estuary, southwestern Western Australia. Deep sands and loamy earths, both mostly red, are also common in the Pilbara region. Similarly, soils in the eastern deserts are red, but they are generally sandy. In the central southern region and the Nullarbor plain, calcareous loams and stony soils predominate.
The region has deeply weathered up to about feet [50 metres] , kaolinized, gravelly and sandy soils, from which most nutrients have long been leached. Much of the indigenous vegetation of the Yilgarn area has been cleared for agricultural purposes, rendering virtually all the streams and rivers saline and unfit for human consumption. A portion of the previously productive soils can no longer support crops, owing to excessive concentrations of soluble salts, mostly sodium chloride , which have accumulated in the soils since clearing.
Climate The northern and southern parts of Western Australia have entirely contrasting climates; the north is tropical, with summer rainfall, while the south has a Mediterranean climate. The major determinant of the weather is the movement of an anticyclone that produces winds in an east-west direction across the continent for about half the year.
In winter this system moves to the north and is responsible for clear skies, sunny days, and easterly winds in the tropics. The anticyclonic belt has moved so far south by the summer that its axis is off the southern coast. Easterly winds prevail over most of the state, but in the far north a depression develops, bringing westerly monsoon wet-dry wind patterns to the coastal districts northeast of Onslow and to parts of the Kimberley.
Several tropical cyclones known elsewhere as hurricanes or typhoons develop offshore during the northern wet season, which lasts from about December to March. They frequently move inland between Broome and Onslow, although occasionally they have traveled south of Perth before curving inland. Tropical cyclones can be highly destructive, but they are also beneficial , bringing widespread rain to otherwise parched inland areas.
The highest annual precipitation occurs in the extreme north, on the Mitchell Plateau in the Kimberley, and in the extreme southwest, between Pemberton and Walpole in the karri Eucalyptus diversicolor country. In both locations mean annual rainfall is more than 55 inches 1, mm.
Precipitation decreases south and north from both locations and with increasing distance inland from the coast. The driest areas receive less than 8 inches mm annually, and possibly less than 6 inches mm. July is the coldest month. Frosts may be widespread over the southern part of the state and occasionally extend into the tropical zone but are not generally troublesome. They are most frequent in July and August. Snow is rare, and only in southern areas, especially in the Stirling Range, does it occasionally lie on the ground for a few hours.
More than 10, species of vascular plants have been documented in the state, and some one-third of these, including many carnivorous varieties, are endemic to the area.
The Kimberley region is sparsely wooded, primarily with eucalypts , but also with the distinctive, moisture-storing boab which has close affinities to the Indian and African baobabs. Spinifex grass is ubiquitous , as is generally the case throughout the portion of the state that lies north of the Tropic of Capricorn. In the Pilbara area mulga and acacia shrublands are interspersed with eucalypt woodlands and spinifex grasslands. In the southeast the Nullarbor Plain is textured with bluebush and saltbush shrubs, acacias, eucalypts, and mallee scrubland.
These consist of eucalypts, and there is an extremely rich understory. The dominant trees are jarrah E. These forests are protected in vast state reserves and in surface-water catchments. Western Australia is host to some species of mammals and several hundred species of birds and reptiles. Common marsupials include kangaroos, wallabies, wombats, possums, and bandicoots. Dugongs, dolphins, and whales are found in coastal waters. Many of the offshore islands have seal and penguin populations. Waterbirds, including ducks, plovers, terns, egrets, herons, and others, are abundant in the wetlands of the southwest.
Eagles and other raptors are prominent inland, as are cuckoos, nearly two dozen types of parrots, and a spectrum of smaller birds such as finches, wrens, honeyeaters, and flycatchers. Dozens of species of geckoes, other lizards, and amphibians have also been recorded. Freshwater and marine turtles live in coastal and inland waters. Hundreds of species of plants are rare or threatened, and many have become extinct.
More than half of the medium-sized mammals have disappeared from the Wheatbelt since European settlement, and many of their populations have also disappeared or declined drastically from the arid pastoral lands and from the central, sandy deserts. People Ethnic groups When the first permanent European settlers arrived at Perth in , they encountered an Aboriginal population that had occupied the lands of Western Australia for tens of thousands of years.
As European settlements spread across the colony, however, the Aboriginal communities were decimated by shooting, poisoning, starvation, and disease. The largest—and growing—single concentration of Aboriginal peoples is in the Greater Perth area. There are also significant communities of Scottish, Irish, and Italian ancestry, as well as a sizeable combined community of German and Dutch heritage. A small but notable Chinese population lives primarily in or near Perth.
English is the only language spoken in the vast majority of households in Western Australia. The next largest language communities, each constituting a tiny portion of the population, are Chinese and Italian. Australian Aboriginal languages are spoken by an even smaller fraction of the population. Christianity is the dominant religion in Western Australia, with Christians constituting about three-fifths of the population.
Numbers of Roman Catholics and Anglicans are roughly equivalent and together constitute about three-fourths of the Christian community. Buddhists and Muslims are the next largest religious groups, but each accounts for only a tiny portion of the population.
A sizable minority of Western Australians do not identify with a particular religion; mirroring a national trend, this proportion has been growing. Located on the Swan Coastal Plain , Perth and its port city-suburb, Fremantle , are situated around the estuary of the Swan and Canning rivers and are surrounded by intensive gardening and horticultural areas.
The next largest cities include Mandurah , Bunbury , Geraldton , and Kalgoorlie -Boulder, all of which are a mere fraction of the size of Perth. Skyline of Perth, the state capital of Western Australia. The Wheatbelt is characterized by massive farms, spanning thousands of acres, each with its owner-occupied homestead complex.
The region is served by the ports of Geraldton, Bunbury, and Albany , in addition to the major port of Fremantle and the adjacent Cockburn Sound. Manjimup is a significant timber town in the far southwest, while the coastal towns of Busselton , Margaret River, and Augusta serve a growing tourist market. Photographic Library of Australia Beyond the Wheatbelt is a sparsely populated pastoral country, with its huge leasehold properties, or stations. The coastal towns of Port Hedland and Karratha provide port and service facilities for the mining industry.
Other larger coastal towns include Carnarvon, noted for its irrigated fruit and vegetables, and the former U. Navy communications station of Exmouth. Broome , on the northwestern coast, is a prime tourist destination, and, along with Derby in King Sound , is also a centre for beef export.
The Aboriginal community is generally youthful, with roughly half of its population—compared to about one-third of all other residents—under age Since natural increase the excess of births over deaths has barely been sufficient to replace the population, growth has been achieved largely through immigration. Of these, more than one-third had been born in the United Kingdom specifically, in England and Scotland , about one-tenth in New Zealand , and smaller but nonetheless significant proportions in Italy, South Africa , and Malaysia.
Immigration from Britain and Europe has been declining slowly since the late 20th century, while that from eastern Asian countries and South Africa has been on a rise. The value of agricultural production and exports increased in total but decreased proportionately in the latter half of the 20th century, while the value of mineral including petroleum and natural gas extraction and export increased.
The main form of agriculture is extensive grain and sheep farming in the southwestern region. The major products are wheat, barley, and other grains; meat and animals especially sheep and cattle ; wool; and, increasingly, crops such as lupines and oilseeds.
Irrigation supports dairying on the coastal plain south of Perth, vegetables and tropical-fruit growing at Carnarvon, and crop experimentation at Kununurra.
Fine wool from Merino sheep is the main product from the extensive pastoral areas, and beef is the primary output from the far north.
Wine is produced in the Swan River valley adjacent to Perth, as well as in newer grape-growing areas in the Margaret River and Mount Barker districts of the southwestern region. The southwest also produces beef, apples, and citrus fruits. Although felling trees in uncut old-growth forests was banned in , jarrah and karri forests that are interspersed with secondary growth have continued to be logged. Fishing, especially whaling abandoned in the s , also was an early mainstay of the Western Australian economy.
Rock lobsters the most important commercial marine resource , prawns shrimp , and scallops are caught primarily off the west coast, and abalones, Australian salmon, and herring are caught off the southwest and south coasts.