Deserts and semi-deserts: soil, climate, wildlife. Australia: natural areas Animals of tropical deserts and semi-deserts in Australia

Deserts and semi-deserts are waterless, dry regions of the planet, where no more than 25 cm of precipitation falls per year. The most important factor their formation is the wind. However, not all deserts experience hot weather; on the contrary, some of them are considered the coldest regions of the Earth. Representatives of flora and fauna have adapted to the harsh conditions of these areas in different ways.

How do deserts and semi-deserts arise?

There are many reasons for the formation of deserts. For example, there is little rainfall because it is located at the foot of the mountains, which, with their ridges, cover it from rain.

Ice deserts formed for other reasons. In Antarctica and the Arctic, the main snow mass falls on the coast; snow clouds practically do not reach the interior regions. Precipitation levels generally vary greatly, for one snowfall, for example, an annual norm can fall. Such snow drifts form over hundreds of years.

Hot deserts are distinguished by the most diverse relief. Only some of them are completely covered with sand. The surface of most is littered with pebbles, stones and other miscellaneous rocks. Deserts are almost completely open to weathering. Strong gusts of wind pick up fragments of small stones and hit them on the rocks.

In sandy deserts, the wind carries the sand across the area, creating undulating sediments, which are called dunes. The most common type of dunes are dunes. Sometimes their height can reach 30 meters. Ridge dunes can be up to 100 meters high and stretch for 100 km.

Temperature regime

The climate of deserts and semi-deserts is quite diverse. In some regions, daytime temperatures can reach up to 52 ° C. This phenomenon is due to the absence of clouds in the atmosphere, so nothing saves the surface from direct sunlight. At night, the temperature drops a lot, again due to the lack of clouds that can trap the heat radiated from the surface.

In hot deserts, rain is rare, but sometimes there are heavy downpours. After rain, water does not soak into the ground, but rapidly flows from the surface, washing away particles of soil and pebbles into dry channels, which are called wadis.

Location of deserts and semi-deserts

On the continents, which are located in the northern latitudes, there are deserts and semi-deserts of the subtropical and sometimes also tropical - in the Indo-Gangetic lowland, in Arabia, in Mexico, in the southwestern United States. In Eurasia, extratropical desert regions are located in the Central Asian and South Kazakh plains, in the basin Central Asia and in the Near Asian highlands. Central Asian desert formations are characterized by a sharp continental climate.

In the southern hemisphere, deserts and semi-deserts are less common. Here are located such desert and semi-desert formations as the Namib, Atacama, desert formations on the coast of Peru and Venezuela, Victoria, Kalahari, the Gibson Desert, Simpson, Gran Chaco, Patagonia, the Great Sandy Desert and the Karoo semi-desert in southwestern Africa.

Polar deserts are located on the continental islands of the near-glacial regions of Eurasia, on the islands of the Canadian archipelago, in the north of Greenland.

Animals

Animals of deserts and semi-deserts for many years of existence in such areas have managed to adapt to harsh climatic conditions. From cold and heat, they hide in underground burrows and feed mainly on underground parts of plants. Among the representatives of the fauna there are many types of carnivores: fennec fox, cougars, coyotes and even tigers. The climate of deserts and semi-deserts has contributed to the fact that many animals have perfectly developed a thermoregulation system. Some desert dwellers can withstand fluid loss of up to a third of their weight (for example, geckos, camels), and among invertebrates there are species that can lose water up to two thirds of their weight.

AT North America and Asia there are a lot of reptiles, especially a lot of lizards. Snakes are also quite common: ephs, various poisonous snakes, boas. Of the large animals, there are saiga, kulans, camels, pronghorn, it has recently disappeared (it can still be found in captivity).

The animals of the desert and semi-desert of Russia are a wide variety of unique representatives of the fauna. The desert regions of the country are inhabited by sandstone hares, hedgehogs, kulan, dzheyman, poisonous snakes. In the deserts that are located on the territory of Russia, you can also find 2 types of spiders - karakurt and tarantula.

They live in polar deserts polar bear, musk ox, arctic fox and some species of birds.

Vegetation

If we talk about vegetation, then in deserts and semi-deserts there are various cactus, hard-leaved grasses, psammophyte shrubs, ephedra, acacias, saxaul, soap palm, edible lichen and others.

Deserts and semi-deserts: soil

The soil, as a rule, is poorly developed, and water-soluble salts predominate in its composition. The ancient alluvial and loess-like deposits predominate, which are reworked by the winds. Gray-brown soil is inherent in elevated flat areas. Deserts are also characterized by solonchaks, that is, soils that contain about 1% of easily soluble salts. In addition to deserts, salt marshes are also found in steppes and semi-deserts. Groundwater, which contains salts, when it reaches the soil surface, is deposited in its upper layer, resulting in soil salinization.

Completely different are characteristic of such climatic zones like subtropical deserts and semi-deserts. The soil in these regions has a specific orange and brick red color. Noble for its shades, it received the appropriate name - red soil and yellow soil. In the subtropical zone in northern Africa and in South and North America there are deserts where gray soils have formed. Red-yellow soils have developed in some tropical desert formations.

Natural and semi-desert - a huge variety of landscapes, climatic conditions, flora and fauna. Despite the harsh and cruel nature of the deserts, these regions have become home to many species of plants and animals.

MINISTRY OF EDUCATION OF THE MOSCOW REGION MOSCOW STATE REGIONAL UNIVERSITY

GEOGRAPHICAL AND ENVIRONMENTAL FACULTY

EXTRAMURAL

SPECIALTY "GEOECOLOGY"

Course work

by subject

"General Ecology"

"Deserts of Australia"

Completed:

4th year student of group 42

Bubentsova O.A.

Moscow 2013

1.General physical and geographical description

The Commonwealth of Australia is the only state in the world that occupies the territory of an entire continent. The Australian continent is located entirely in the Southern Hemisphere, and its very name comes from the Latin Terra Australis Incognita (Unknown Southern Land) - this is how the ancient geographers called the mysterious southern continent, the place of which they did not know, but whose existence they assumed. The Australian continent is washed on all sides by oceans - Pacific, Indian and South.

The Commonwealth of Australia includes, in addition to its own mainland, the island of Tasmania and small islands located off the coast of the continent. Australia governs the so-called outer territories : islands and island groups in the Pacific and Indian Oceans.

The area of the Commonwealth of Australia - 7.7 million square meters. km. Its population is small - only 14 million people. At the same time, the vast majority of Australians live in cities, including almost half in the two largest cities: Sydney (over 3 million inhabitants) and Melbourne (about 3 million inhabitants). The capital of Australia is Canberra. Australia is one of the most urbanized countries in the world.

The relief of Australia is dominated by plains. About 95% of the surface does not exceed 600 m above sea level. Most of Australia lies in the tropics, the North - in the subequatorial latitudes, the South - in the subtropics. In Australia, the heights of the plains are small, which causes constantly high temperatures throughout the mainland. Australia lies almost entirely within the summer isotherms 20 °C - 28 °C, winter isotherms 12 °C - 20 °C.

The position of most of Australia in the continental sector of the tropical belt determines the dryness of the climate. Australia is the driest of the Earth's continents. 38% of Australia's area receives less than 250 mm of precipitation per year. About half of the territory of Australia is occupied by deserts and semi-deserts.

Australia is rich in a variety of minerals. New discoveries of mineral ores made on the continent over the past 10-15 years have pushed the country to one of the first places in the world in terms of reserves and extraction of such minerals as iron ore, bauxite, lead-zinc ores. The main deposits of metallic minerals and deposits will be discussed in the next section of the work. From non-metallic minerals, there are clays, sands, limestones, asbestos, and mica of various quality and industrial use.

The rivers flowing from the eastern slopes of the Great Dividing Range are short, in their upper reaches they flow in narrow gorges. Here they may well be used, and partly already used for the construction of hydroelectric power stations. When entering the coastal plain, the rivers slow down their flow, their depth increases. Many of them in the estuarine parts are even accessible to large ocean-going vessels.

On the western slopes of the Great Dividing Range, rivers originate, making their way along the interior plains. In the region of Mount Kosciuszko, the most abundant river in Australia, the Murray, begins. Food r. The Murray and its channels are mostly rainy and to a lesser extent snowy. Dams and dams have been built on almost all the rivers of the Murray system, near which reservoirs have been created, where flood waters are collected and used to irrigate fields, gardens and pastures.

The rivers of the northern and western coasts of Australia are shallow and relatively small. The longest of them - Flinders flows into the Gulf of Carpentaria. These rivers are fed by rain, and their water content varies greatly at different times of the year.

Rivers whose flow is directed to the interior of the mainland, such as Coopers Creek (Barkoo), Diamant-ina, and others, are deprived not only of a constant flow, but also of a permanent, distinctly expressed channel. In Australia, such temporary rivers are called screams. They fill with water only during short showers.

Most lakes in Australia, like rivers, are fed by rainwater. They have neither a constant level nor a runoff. In summer, the lakes dry up and are shallow saline depressions.

Since the Australian mainland for a long time, starting from the middle Cretaceous, was in isolation from other parts of the globe, his vegetable world very idiosyncratic. Of the 12 thousand species of higher plants, more than 9 thousand are endemic, i.e. grow only on the Australian continent. Among the endemics are many species of eucalyptus and acacia, the most typical plant families in Australia. At the same time, there are also plants that are inherent in South America(for example, southern beech), South Africa(representatives of the Proteaceae family) and the islands of the Malay Archipelago (ficus, pandanus, etc.). This indicates that many millions of years ago there were land connections between the continents.

Since the climate of most of Australia is characterized by severe aridity, its flora is dominated by dry-loving plants: special cereals, eucalyptus trees, umbrella acacias, succulent trees ( bottle tree and etc.). In the far north and northwest of the country, where it is hot and warm northwest monsoons bring moisture, tropical rainforests grow. Giant eucalyptus trees, ficuses, palm trees, pandanuses with narrow long leaves, etc. predominate in their woody composition. Bamboo thickets are found in some places on the coast itself. Where the shores are flat and muddy, mangrove vegetation develops. Rainforests in the form of narrow galleries stretch for relatively short distances inland along the river valleys.

The further south you go, the drier the climate becomes. The forest cover is gradually thinning. Eucalyptus and umbrella acacias are arranged in groups. This is a zone of wet savannahs, stretching in a latitudinal direction south of the zone rainforest. The central deserts of parts of the mainland, where it is very hot and dry, are characterized by dense, almost impenetrable thickets of thorny low-growing shrubs, consisting mainly of eucalyptus and acacia.

The eastern and southeastern slopes of the Great Dividing Range, where there is a lot of rainfall, are covered with dense tropical and subtropical evergreen forests. Most of all in these forests, as elsewhere in Australia, eucalyptus trees. Higher in the mountains, an admixture of damarr pines and beeches is noticeable. Shrub and grass covers in these forests are varied and dense. In less humid variants of these forests, grass trees form the second layer. On the island of Tasmania, in addition to eucalyptus trees, there are many evergreen beeches related to South American species. In the southwest of the mainland, forests cover the western slopes of the Darling Range, facing the sea. These forests consist almost entirely of eucalyptus trees, reaching considerable heights. The number of endemic species is especially high here. In addition to eucalyptus, bottle trees are widespread.

In general, Australia's forest resources are small. total area forests, including special plantations, consisting mainly of species with soft wood (mainly radiata pine), at the end of the 70s was only 5.6% of the country's territory.

In Australia, all soil types characteristic of tropical, subequatorial and subtropical are presented in a regular sequence. natural belts.

In the area of tropical rainforests in the north, red soils are common, changing towards the south with red-brown and brown soils in wet savannahs and gray-brown soils in dry savannahs. Red-brown and brown soils containing humus, a little phosphorus and potassium, are valuable for agricultural use. Within the zone of red-brown soils, the main wheat crops of Australia are located.

The Australian continent is located within the three main warm climatic zones of the southern hemisphere: subequatorial (in the north), tropical (in the central part), subtropical (in the south). Only a small part of Tasmania lies within the temperate zone.

Most of the country is dominated by a dry and hot continental climate of the tropical zone. The northern part of Australia is located in the subequatorial climatic zone - here all year round hot, the humidity is very high in summer and low in winter. The eastern coasts are hot and humid all year round. The subtropical zone, in which the southern part of Australia is located, is represented by a predominantly continental climate - hot and very dry summers and cool, wet winters. The southwest coast of Australia is dominated by a Mediterranean climate with hot dry summers and mild rainy winters. southeastern part Australia and northern Tasmania are affected monsoon climate with hot rainy summers and mild dry winters. The southernmost part of Tasmania is located in a temperate zone with a mild, humid climate.

The hot climate and insignificant and uneven precipitation over most of the mainland lead to the fact that almost 60% of its territory is deprived of runoff to the ocean and has only a rare network of temporary watercourses.

.Deserts of Australia

Australia is often called the continent of deserts, because. about 44% of its surface (3.8 million sq. km) is occupied by arid territories, of which 1.7 million sq. km. km - desert.

Even the rest is seasonally dry.

This allows us to say that Australia is the most arid continent on the globe.

The Deserts of Australia is a complex of desert regions located in Australia.

The deserts of Australia are located in two climatic zones - tropical and subtropical, with most of them occupied by the last zone.

Great Sandy Desert

Great Sandy Desert or Western desert- sandy-saline desert<#"justify">Great Victoria Desert

Great Victoria Desert - sandy-saline desert<#"justify">Gibson Desert

Gibson Desert - sandy desert<#"justify">Small Sandy Desert

Small Sandy Desert - sandy desert<#"justify">Simpson Desert

Simpson Desert - sandy desert<#"justify">The average temperature in January is 28-30 °С, in July - 12-15 °С.

In the northern part of precipitation less than 130 mm, dry creek beds<#"justify">Tanami

Tanami - rocky-sandy desert<#"justify">Desert Strzelecki

The Strzelecki Desert is located in the southeast of the mainland in the states of South Australia, New South Wales and Queensland. The desert area is 1% of the area of Australia. It was discovered by Europeans in 1845 and named after the Polish explorer Pavel Strzelecki. Also in Russian sources it is called the Streletsky Desert.

Stone Desert Sturt

The stone desert, which occupies 0.3% of the territory of Australia, is located in the state of South Australia and is an accumulation of sharp small stones. Local aborigines did not sharpen their arrows, but simply collected stone tips here. The desert got its name in honor of Charles Sturt, who in 1844 tried to reach the center of Australia.

Tirari Desert

This desert, located in the state of South Australia and occupying 0.2% of the mainland, has one of the harshest climatic conditions in Australia, due to high temperatures and almost no rain. There are several salt lakes in the Tirari Desert, including Lake Eyre.<#"justify">3.Animal world

The long isolation of Australia from other continents has led to the exceptional originality of the fauna of this continent, and in particular its desert region.

Species endemism is 90%, and the rest of the species are subendemic, that is, they go beyond the deserts in their distribution, but not beyond the mainland as a whole. Of the endemic groups, there are: marsupial moles, Australian wheatears, scale-foot lizards.

In Australia, there are no representatives of the orders of carnivores, ungulates, insectivores, and lagomorphs; the detachment of rodents is represented only by species of the mouse subfamily; from birds, there is no order of sandgrouse, families of pheasant, bee-eater, finches and a number of others. The fauna of reptiles has also become impoverished: species of the families of lizards of lacertids, snakes, vipers and pit snakes have not penetrated here. Due to the absence of the mentioned and a number of other animals, local, endemic families and genera, as a result of wide adaptive radiation, have mastered free ecological niches and developed a number of convergent forms in the process of evolution.

Among the aspid snakes, species have arisen that are morphologically and ecologically similar to the vipers, the lizards of the Scinnaidae family have successfully replaced the lacertids that are absent here, but especially many convergent forms are observed in marsupial mammals. They ecologically replace insectivores (marsupial shrews), jerboas (marsupial jerboas), large rodents (wombats or marsupial marmots), small predators(marsupial martens) and even largely ungulates (wallabies and kangaroos). Small mouse-like rodents widely inhabit all types of deserts (Australian mouse, jerboa mouse, and others). The role of large herbivores in the absence of ungulates is performed by marsupials from the kangaroo family: brush-tailed kangaroos live in the Gibson Desert; gigantic red kangaroo etc. Small predatory marsupials are similar in appearance and biology to the shrews of the Old World (crest-tailed marsupial shrew, fat-tailed marsupial shrew). Underground way of life are marsupial moles, inhabit sandy plains.

Marsupial badgers live in the Simpson Desert. The largest native predator in the deserts of Australia is the marsupial marten. About 10 thousand years ago, man entered the Australian continent and settled it. Together with a man, a dog also came here - a constant companion of a primitive hunter. Subsequently, feral dogs spread widely in the deserts of the mainland, forming a stable form called the dingo dog. The appearance of such a large predator caused the first significant damage to the native fauna, especially to various marsupials. However, the greatest damage to the local fauna was caused after Europeans appeared in Australia. Either deliberately or accidentally, they brought here a number of wild and domestic animals (the European rabbit - they quickly multiplied, settled in large colonies, destroyed the already meager vegetation cover). Widely settled throughout the center of Australia, the common fox and house mouse. In the central and northern regions, small herds of feral donkeys or solitary one-humped camels are often found.

Many birds (parrots, zebra finches, emblem finches, pink cockatoos, diamond turtledoves, emu birds) gather near temporary watering holes in the desert during the hot hours of the day. Insectivorous birds do not need a watering place and inhabit desert areas far from any sources of water (Australian wrens, Australian warblers). Since real larks did not penetrate the deserts of Australia, their ecological niche was occupied by representatives of the warbler family, which have adapted to a terrestrial lifestyle and are surprisingly similar in appearance to larks. Flat gravel and rocky plains, salt marshes with rare thickets of quinoa are inhabited by Australian wheatears. In the thickets of shrubby eucalyptus - a large eyed large-headed or weed chicken lives. In all desert habitats, black Australian crows can be seen. Reptiles in the Australian deserts are extremely diverse (families skink, gecko, agamus, aspid). Monitor lizards reach the greatest diversity in the deserts of Australia compared to other regions. A lot of snakes, insects (dark beetles, bombardier beetles and others).

.Vegetable world

All the deserts of Australia lie within the Central Australian region of the Australian floral kingdom. Although, in terms of species richness and level of endemism, the desert flora of Australia is significantly inferior to the flora of the western and northeastern regions of this continent, however, in comparison with other desert regions of the globe, it stands out both in the number of species (more than 2 thousand) and the abundance of endemics. Species endemism here reaches 90%: it has 85 endemic genera, of which 20 are in the Asteraceae family, 15 are haze and 12 are cruciferous.

Among the endemic genera there are also background desert grasses - Mitchell's grass and triodia. A large number of species are represented by the families of legumes, myrtle, protea and Compositae. Significant species diversity is demonstrated by the genera eucalyptus, acacia, protea - grevillea and hakeya. In the very center of the mainland, in the gorge of the McDonnell Desert Mountains, narrow-range endemics have been preserved: low-growing liviston palm and macrosamia from cycads.

Even some types of orchids settle in the deserts - ephemera, germinating and blooming only in short period after the rains. Sundews also penetrate here. The depressions between the ridges and the lower part of the slopes of the ridges are overgrown with clumps of prickly triodia grass. The upper part of the slopes and the crests of dune ridges are almost completely devoid of vegetation, only individual kurtiles of prickly grass Zygochloi settle on loose sand. In interdune depressions and on flat sandy plains, a sparse stand of casuarina, individual specimens of eucalyptus, and veinless acacia is formed. The shrub layer is formed by Proteaceae - these are Hakeya and several types of Grevillea.

Saltwort, ragodia, and euhylena appear in depressions in slightly saline areas. After the rains, the depressions between the ridges and the lower parts of the slopes are covered with colorful ephemera and ephemeroids. In the northern regions on the sands in the Simpson Desert and Bolshoy Peschanoy, the species composition of background grasses changes somewhat: other types of triodia, plectrachne and shuttle beard dominate there; becomes the diversity and species composition of acacias and other shrubs. Along the channels of temporary waters they form gallery forests of several species of large eucalyptus trees. The eastern fringes of the Great Victoria Desert are occupied by sclerophyllous shrubbery of scrub mom. In the south-west of the Great Victoria Desert, undersized eucalyptus trees dominate; the herbaceous layer is formed by kangaroo grass, feather grass species, and others.

The arid areas of Australia are very sparsely populated, but the vegetation is used for grazing.

Climate

In the tropical climatic zone, which occupies the territory between the 20th and 30th parallels in the desert zone, a tropical continental desert climate is formed. The subtropical continental climate is common in the southern part of Australia, adjacent to the Great Australian Bight. These are the outskirts of the Great Victoria Desert. Therefore, in the summer period, from December to February, the average temperatures reach 30 ° C, and sometimes even higher, and in the winter (July - August) they decrease to an average of 15-18 ° C. In some years, the entire summer period temperatures can reach 40 ° C, and winter nights in the neighborhood of the tropics drops to 0 ° C and below. The amount and territorial distribution of precipitation is determined by the direction and nature of the winds.

The main source of moisture is the "dry" southeast trade winds, since most of the moisture is retained by the mountain ranges of Eastern Australia. The central and western parts of the country, corresponding to about half of the area, receive an average of about 250-300 mm of precipitation per year. The Simpson Desert receives the least amount of precipitation, from 100 to 150 mm per year. The rainy season in the northern half of the continent, where the monsoon change of winds dominates, is confined to the summer period, and, in its southern part, arid conditions prevail during this period. It should be noted that the amount of winter precipitation in the southern half decreases as one moves inland, rarely reaching 28°S. In turn, summer precipitation in the northern half, having the same tendency, does not spread south of the tropic. Thus, in the zone between the tropic and 28°S. there is a dry zone.

Australia is characterized by excessive variability in average annual precipitation and uneven precipitation throughout the year. Long dry periods and high average annual temperatures, prevailing over a large part of the continent, cause high annual evaporation rates. In the central part of the mainland, they are 2000-2200 mm, decreasing towards its marginal parts. The surface waters of the mainland are extremely poor and extremely unevenly distributed over the territory. This is especially true for the desert western and central regions of Australia, which are practically drainless, but make up 50% of the continent's area.

Hydrography

australian desert fauna rainfall

The features of runoff in Australia and on islands close to it are well illustrated by the following figures: the runoff volume of the rivers of Australia, Tasmania, New Guinea and New Zealand is 1600 km3, the runoff layer is 184 mm, i.e. little more than in Africa. The runoff volume of Australia alone is only 440 km3, and the thickness of the runoff layer is only 57 mm, i.e., several times less than on all other continents. This is due to the fact that most of the mainland, unlike the islands, receives little rainfall and there are no high mountains and glaciers within it.

The area of internal runoff includes 60% of the surface of Australia. Approximately 10% of the territory has a drain into the Pacific Ocean, the rest belongs to the Indian Ocean basin. The main watershed of the mainland is the Great Dividing Range, from the slopes of which the largest and most full-flowing rivers flow. These rivers are almost exclusively fed by rain.

Since the eastern slope of the ridge is short and steep, short, fast, winding rivers flow towards the Coral and Tasman Seas. Receiving more or less uniform nutrition, they are the most deep rivers Australia with a clearly defined summer maximum. Crossing the ridges, some rivers form rapids and waterfalls. The length of the largest rivers (Fitzroy, Berdekin, Hunter) is several hundred kilometers. In the lower reaches, some of them are navigable for 100 km or more, and at the mouths are accessible to ocean-going vessels.

The rivers of Northern Australia flowing into the Arafura and Timor Seas are also full-flowing. The most significant are those that flow from the northern part of the Great Dividing Range. But the rivers of the north of Australia, due to the sharp difference in the amount of summer and winter precipitation, have a less uniform regime than the rivers of the east. They overflow with water and often overflow their banks during the summer monsoon rains. In winter, these are weak narrow watercourses, which dry up in places in the upper reaches. Most major rivers north - Flinders, Victoria and Ord - in the summer they are navigable in the lower reaches for several tens of kilometers.

There are also permanent streams in the southwest of the mainland. However, during the dry summer season, almost all of them turn into chains of shallow polluted reservoirs.

In desert and semi-desert internal parts Australia has no permanent streams. But there is a network of dry channels, which are the remnants of the former developed water network, formed under the conditions of the pluvial epoch. These dry channels are filled with water after rains for a very short time. Such intermittent streams are known in Australia as "creeks". They are especially numerous in the Central Plain and are directed towards the endorheic, drying up Lake Eyre. The Nullarbor karst plain is devoid of even periodic streams, but has an underground water network with a runoff towards the Great Australian Bight.

The soil. Landscape

The soil cover of deserts is peculiar. In the northern and central regions, red, red-brown and brown soils are distinguished (characteristic features of these soils are an acid reaction, coloring with iron oxides). AT southern parts In Australia, serozem-like soils are widespread. In western Australia, desert soils are found along the outskirts of drainless basins. The Great Sandy Desert and the Great Victoria Desert are characterized by red sandy desert soils. Salt marshes and solonetzes are widely developed in drainless internal depressions in the southwest of Australia and in the basin of Lake Eyre.

The Australian deserts are divided into many different types in terms of landscape, among which Australian scientists most often distinguish mountainous and foothill deserts, structural plains deserts, rocky deserts, sandy deserts, clay deserts, plains. Sandy deserts are the most common, occupying about 32% of the continent's area. Along with sandy deserts, stony deserts are also widespread (they occupy about 13% of the area of arid territories. Piedmont plains are an alternation of large-stony deserts with dry channels small rivers. This type of desert is the source of most of the country's desert streams and has always served as a habitat for the aborigines. Deserts of structural plains are found in the form of a plateau with a height of no more than 600 m above sea level. After sandy deserts they are the most developed, occupying 23% of the area of arid territories confined mainly to Western Australia.

Population

Australia is the least populated continent on Earth. About 19 million people live on its territory. Total population The population of the islands of Oceania is about 10 million people.

The population of Australia and Oceania is divided into two unequal groups of different origins - indigenous and alien. There are few indigenous people on the mainland, and on the islands of Oceania, with the exception of New Zealand, Hawaii and Fiji, they form the vast majority.

Scientific research in the field of anthropology and ethnography of the peoples of Australia and Oceania began in the second half of the 19th century. Russian scientist N. N. Miklukho-Maclay.

Like America, Australia could not have been inhabited by humans as a result of evolution, but only from outside. In the composition of its ancient and modern fauna, not only primates are absent, but in general all higher mammals.

So far, no traces of the early Paleolithic have been found within the mainland. All known finds of human fossil remains have features of Homo sapiens and belong to the Upper Paleolithic.

Indigenous people Australia has such pronounced anthropological features as: dark brown skin, wavy dark hair, significant beard growth, wide nose with low tolerance. The faces of Australians are distinguished by prognathism, as well as a massive eyebrow. These features bring the Australians closer to the Veddas of Sri Lanka and some tribes of Southeast Asia. In addition, the following fact deserves attention: the oldest human fossils found in Australia bear a close resemblance to the bone remains found on the island of Java. Tentatively they are attributed to the time coinciding with the last ice age.

Of great interest is the problem of the path along which the settlement of Australia and the islands close to it took place. Along with this, the question of the time of development of the mainland is being solved.

Undoubtedly, Australia could only be inhabited from the north, that is, from the side of Southeast Asia.

This is confirmed both by the anthropological features of modern Australians and by the paleoanthropological data discussed above. It is also obvious that a man of the modern type penetrated into Australia, i.e., the settlement of the mainland could not occur earlier than the second half of the last glacial period.

Australia has existed for a long time (obviously since the end of the Mesozoic) in isolation from all other continents. However, during the Quaternary, the landmass between Australia and Southeast Asia was for a time more extensive than it is at present. A continuous land "bridge" between the two continents, obviously, never existed, since, if there was one, the Asian fauna would have to penetrate Australia through it. In all likelihood, in the Late Quaternary, on the site of shallow basins separating Australia from New Guinea and the southern islands of the Sunda Archipelago (their modern depths do not exceed 40 m), there were vast areas of land formed as a result of repeated fluctuations in sea level and land uplifts. The Torres Strait, which separates Australia from New Guinea, may have formed very recently. The Sunda Islands could also be periodically interconnected by narrow strips of land or shoals. Most land animals could not overcome such an obstacle. People gradually, by land or overcoming shallow straits, penetrated through the Lesser Sunda Islands to New Guinea and to the Australian mainland. At the same time, the settlement of Australia could occur both directly from the Sunda Islands and the island of Timor, and through New Guinea. This process was very long, it probably stretched for whole millennia during the late Paleolithic and Mesolithic. At present, on the basis of archaeological finds on the mainland, it is assumed that a person first appeared there about 40 thousand years ago.

The spread of people across the mainland was also very slow. Settlement went along the western and eastern coasts, and in the east there were two ways: one - along the coast itself, the second - to the west of the Great Dividing Range. These two branches converged in the central part of the mainland in the area of Lake Eyre. In general, the Australians are distinguished by anthropological unity, which indicates the formation of their main features after the penetration into Australia.

Australian culture is very distinctive and primitive. The originality of culture, the originality and closeness to each other of the languages of various tribes testify to the long isolation of the Australians from other peoples and their autonomous historical development up to modern times.

By the beginning of European colonization, about 300 thousand Aborigines lived in Australia, divided into 500 tribes. They fairly evenly populated the entire mainland, especially its eastern part. Currently, the number of indigenous Australians has decreased to 270 thousand people. They make up approximately 18% of Australia's rural population and less than 2% of the urban population. A significant proportion of Aboriginal people live on reservations in the northern, central and western regions or work in mines and in pastoral farms. There are still tribes that continue to lead their former, semi-nomadic way of life and speak languages that are part of the Australian language family. Interestingly, in some unfavorable areas, Indigenous Australians make up the majority of the population.

The rest of Australia, that is, its most densely populated areas - the eastern third of the mainland and its southwest, is inhabited by Anglo-Australians, who make up 80% of the population of the Commonwealth of Australia, and people from other countries of Europe and Asia, although people with white skin are poorly adapted for life in tropical latitudes. By the end of the XX century. Australia has come out on top in the world in terms of skin cancer incidence. This is due to the fact that an “ozone hole” periodically forms over the mainland, and the white skin of the Caucasians is not as protected from ultraviolet radiation as the dark skin of the indigenous population of tropical countries.

In 2003, the population of Australia exceeded 20 million people. This is one of the most urbanized countries in the world - more than 90% are city dwellers. Despite the lowest population density compared to other continents and the presence of vast almost uninhabited and undeveloped territories, as well as the fact that the settlement of Australia by immigrants from Europe began only at the end of the 18th century and for a long time the basis of its economy was Agriculture, human impact on nature in Australia has very large and not always positive consequences. This is due to the vulnerability of the very nature of Australia: about half of the mainland is occupied by deserts and semi-deserts, and the areas adjacent to them periodically suffer from droughts. It is known that arid landscapes are one of the most vulnerable types of natural environment, easily destroyed by outside interference. Cutting down trees, fires, and overgrazing disturb the soil and vegetation cover, contribute to the drying up of water bodies and lead to complete degradation of landscapes. ancient and primitive organic world Australia cannot compete with more highly organized and viable introduced forms. This organic world, especially the fauna, also cannot resist a man - a hunter, fisherman, collector. The population of Australia, mainly living in cities, seeks to relax among nature, tourism is developing more and more, not only national, but also international.

.Agriculture

Agricultural map of Australia

Fishing

Cattle

Forestry

Gardening

pastures

vegetable growing

uncultivated land

animal husbandry

Aquaculture

Agriculture is one of the main branches of the Australian economy.<#"justify">1)crop production

) Vegetable growing

)Winemaking

)Livestock

1) Beef

2) Lamb

3) Pork

)dairy farming

)Fishing

)Wool

)Cotton

Australia manufactures a large number of fruits, nuts and vegetables. More than 300 tons of products are oranges<#"justify">10.Assessment of the state of natural systems and characteristics environmental protection measures in Australia

Based on the foregoing, it is possible to assess the state of natural systems and their capabilities to perform the following functions:

ensuring the conditions of human life;

providing a spatial basis for the development of productive forces;

provision of natural resources;

conservation of the gene pool of the biosphere.

Until recently, it was generally accepted that almost 1/3 of the territory of the continent is generally useless in terms of economic development. However, over the past three decades, huge deposits have been discovered in these desert places. iron ore, bauxites, hard coal, uranium and many other minerals, which made Australia one of the first places in the world in terms of mineral wealth (in particular, it accounts for about 1/3 of the bauxite reserves of the capitalist world, 1/5 of iron and uranium).

For a century it was said that Australia "rides on the back of a sheep" (the production and export of wool was the basis of its economic life). Now the country has largely “switched to the ore trolley”, becoming one of the largest producers and exporters of mineral raw materials. The Commonwealth of Australia is rich in various minerals, which, with a few exceptions, almost completely provide the development of the manufacturing industry with mineral raw materials.

The water resources of the continent itself are small, the most developed river network is on the island of Tasmania. The rivers there have a mixed rain and snow supply and are full-flowing throughout the year. They flow down from the mountains and therefore are stormy, rapids and have large reserves of hydropower. The latter is widely used for the construction of hydroelectric power plants. The availability of cheap electricity contributes to the development of energy-intensive industries in Tasmania, such as the smelting of pure electrolyte metals, the manufacture of cellulose, etc.

Australia's agricultural resources are also quite scarce, but this does not prevent the development of agriculture, although in limited areas.

Thus, all industry, manufacturing and much of agriculture is concentrated in small areas - the southeast and (to a lesser extent) the southwest. Technogenic load on natural complexes here is very high, which cannot but affect the ecological situation.

On the basis of the foregoing, it is possible to single out the main directions of environmental protection measures in the territory of the Commonwealth of Australia:

Protection and rational use of those resources with which the territory under consideration is poor: water resources, forest and soil resources.

Protection and rational use of resources that are actively used - mineral resources, recreational resources.

Protection and rational use of resources specific to the Australian region: protection of biota, development of a network of specially protected natural areas of a network of specially protected natural areas.

Protection of atmospheric air, especially in areas of high technogenic load.

It should be noted that the Environmental Policy in the Commonwealth of Australia is managed by a separate state body - the Ministry of the Environment, which suggests that very serious attention is paid to environmental problems here. The Ministry is developing economic and legal measures for environmental protection and rational nature management in industry, energy, agriculture, pays attention to areas with a high concentration of population and is developing a network of specially protected natural areas. The Ministry of Ecology interacts with international organizations in the field of environmental protection, other states and other state bodies of the Commonwealth.

The Commonwealth of Australia has established limits for the permissible impact on the components of the natural environment, standards for the use of natural resources, including water resources. Particular attention is paid to the protection of the continental shelf, water and forest resources. The special fauna and flora of the Commonwealth of Australia are legally protected, for which, among other things, nature reserves and other protected areas are created. Responsibility for violation of environmental legislation has been established.

The fact that the Commonwealth of Australia is one of the most environmentally prosperous countries can be called the result of the activities of state bodies and public organizations for environmental protection and rationalization of nature management.

.Environmental issues in Australia

Now more than 65% of the country's territory has been developed. As a result of economic activity, the nature of Australia was under the threat of human change to no lesser extent than in many densely populated countries of other continents. Disappearing catastrophically quickly woodlands <#"justify">Bibliography

1.Physical geography of continents and oceans: tutorial for stud. higher ped. textbook institutions / T.V. Vlasova, M.A. Arshinova, T.A. Kovalev. - M.: Publishing Center "Academy", 2007.

.Mikhailov N.I. Physical-geographical zoning. M.: Publishing House of Moscow State University, 1985.

.Markov K.K. Introduction to physical geography, Moscow: Higher school, 1978.

."The whole world", Encyclopedic reference book. - M., 2005

.Vazumovsky V.M. Physical-geographical and ecological-economic foundations of the territorial organization of society. - St. Petersburg, 1997.

.Working programm and guidelines for writing essays on the course "General ecology and nature management". - St. Petersburg, 2001.

.Petrov M.P. Deserts of the globe L.: Nauka, 1973

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Australia is often referred to as the desert continent. About 44% of the mainland's surface is occupied by desert and arid territories.
They are common on the Western Australian Plateau and on the plains of Central Australia.

In the driest regions of the center of the mainland, large areas are stony placers or shifting sands.
On the Western Australian Plateau, rocky deserts form on thick ferruginous crusts (a legacy of wet epochs). Their bare surface has a characteristic bright orange color.
On the Nullarbor Plain, composed of fissured limestones, the desert goes to the southern coast of the mainland.

Great Victoria Desert

The largest desert on the Australian continent.
Its size is about 424,400 km2.
The desert was first crossed by European explorer Ernest Giles in 1875 and named after Queen Victoria.
The average annual rainfall varies from 200 to 250 mm of rain. Thunderstorms are frequent (15-20 per year).
Daytime temperature in summer is 32-40 °C, in winter 18-23 °C.
It is generally accepted that the desert is an endless sand dunes or lifeless rocky plains. However, the Great Victoria Desert looks different. Huge variety of shrubs and small plants. After a rare rain, wild flowers and acacias contrasting on the red sand are an unforgettable sight.
Even without rain, the caves, rocks and gorges of the desert are mesmerizing.

Great Sandy Desert

The second largest after Victoria. The desert is located in the north of Western Australia, in the Kimberley region, east of the Pilbara. A small part of it lies in the Northern Territory.
The desert has an area of 360,000 km²
The Great Sandy Desert is the hottest region in Australia.
In the summer period from December to February, the average temperature reaches 35 ° C, in winter - up to 20 -15 ° C.
This is where the famous national park Kata Tjuta - Uluru (Ayers Rock), which attracts travelers from all over the world.

Tanami

The rocky and sandy desert is located northwest of the city of Alice Springs, in the Northern Territory of Australia.
The average annual rainfall in this area is more than 400 mm, that is, there are quite a lot of rainy days for the desert. But the location of Tanami is such that high temperature prevails, and with it a high rate of evaporation.
The average daily temperature in the summer months (October-March) is around 38°C, at night 22°C. Temperature in winter: daytime - about 25 °C, night - below 10 °C.
The main landforms are dunes and sandy plains, as well as shallow water basins the Lander rivers, in which there are pits with water, drying marshes and salt lakes.
There is gold mining in the desert. Tourism has developed in recent years.

Gibson Desert

Sandy desert in the center of Western Australia. It borders the Great Sandy Desert to the north and the Great Victoria Desert to the south.
One of the first explorers of the region described it as "a huge hilly desert of gravel."
Soils are sandy, rich in iron, strongly weathered. In places there are thickets of veinless acacia, quinoa and spinifex grass, which bloom with bright flowers after rare rains.
Annual rainfall in the Gibson Desert can range from 200 to 250 millimeters. The climate is typically hot, in the south temperatures in summer can rise above 40°C, in winter the maximum is around 18°C and the minimum is 6°C.

Desert Simpson

The Simpson Desert is the main part of the Uluru-Kata Tjuta National Park in Australia.
This desert is famous for the fact that its sands are bright red and like scarlet waves continuously roll over the desert.
The landscapes of this place amaze the imagination: between high dunes there are areas of smooth clay crust and rocky plains strewn with turned stones. Simpson is the driest desert
The average temperature in summer (January) is 28-30 °С, in winter - 12-15 °С. In the northern part of the precipitation is less than 130 mm.

Small Sandy Desert

The Little Sandy Desert is a piece of land in Western Australia, located south of the Great Sandy Desert, and in the east it merges into the Gibson Desert.

There are several lakes in the territory of the Little Sandy Desert, the largest of which is Lake Disapointment, and it is located in the north. Seyviori is main river passing through this region. It flows into Lake Disapointet.

The area of the region is 101 thousand km². The average annual precipitation, which falls mainly in the summer, is 150-200 mm.
Average summer temperatures range from 22 to 38.3° C, in winter this figure is 5.4-21.3° C

Tirari Desert

It occupies an area of 15 thousand square kilometers, and it is located in the eastern part of South Australia.

The desert contains salt lakes and large dunes of sand. There are quite severe conditions, high temperatures and very little precipitation, the average annual amount of which does not exceed 125 millimeters.

It is also part of the rocky ecoregion of Australia.

The Pinnacles

A small desert in the southwest of Western Australia. The name of the desert is translated as "desert of pointed rocks". The desert got its name for towering 1-5 meters separately standing stones in the middle of a sandy plain. The nearest settlement is the city of Cervantes, from which it is a 20-minute drive to the desert. Stones are rocks or peaks.

The Pinnacles is part of the Nambung National Park.
The landscapes in this part are exceptional, you might think that you are on another planet.
If you are a visitor to the Nambung National Park, do not miss the opportunity to see the beautiful nature of the Te Pinnacles desert.

Australia is located in the southern and eastern hemispheres of the planet. The world's smallest continent occupies only 5% of the Earth's land mass. The area of the continent with the islands is 7,692,024 km². The length from north to south is 3.7 thousand km, and from west to east - about 4 thousand km.

The coastline stretches for 35,877 km and is slightly indented. The waters of the Gulf of Carpentaria protrude into the territory of the northern coast of the continent, and the Cape York Peninsula protrudes noticeably against the background of the main coastline. The main bays are located in the southeast of Australia.

The most extreme points of the continent include:

in the north - Cape York, washed by the waters of the Coral and Arafura Seas;
in the south - Cape Saunt Point, washed by the waters of the Tasman Sea;
in the west - Cape Steep Point, washed by the waters of the Indian Ocean;
in the east - Cape Byron, washed by the waters of the Tasman Sea.

The largest island belonging to Australia is Tasmania. Its total area is 68,401 km². Off the northern coast are Groote Island, Melville and Bathurst, as well as the large Derk Hartog Islands to the west and Fraser Island to the east. Within the mainland shallows are the islands of Kangaroo, King and Flinders.

Big barrier reef is an invaluable natural monument located along the northeastern line of the continent. It includes clusters of small underwater and surface islands, as well as coral reefs. Its length will be more than 2000 km.

In the north, west and south, Australia is washed by the Indian Ocean, and in the east by the Pacific Ocean. In addition, the continent is washed by the waters of four seas: Timor or Orange, Arafura, Tasmanovo and Coral, which attract tourists from all over the world all year round.

Relief

Blue Mountains, Australia

The relief of Australia is dominated by flat areas. Mount Kosciuszko, 2228 m above sea level, is the highest point of the continent. The average height on the continent is 215 m. The Australian platform, which was once part of the ancient continent of Gondwana, is the foundation of the continent today. The basement area is covered by strata of marine and continental sedimentary rocks.

The modern relief includes the Western Australian Plateau, the Central Lowlands and the East Australian Mountains. As a result of the uplift and subsidence of the earth's crust, a trough filled with sedimentary rocks formed in the east of the Australian Platform. rocks. A large watershed range is located in the eastern part of the mainland. The mountains formed in have collapsed over time. Only the Australian Alps exceed the 2,000 mark. This is the only place on the continent where there is snow in places in shaded gorges.

There are no active volcanoes and earthquakes on the mainland. It is located in the center of the Australian plate, which saved it from seismically active faults at the boundaries of tectonic plates.

desert

Great Sandy Desert in Australia

Australia is the driest continent on earth. Desert zones make up 44% of the entire region. They are mainly located in the northwest of the continent. The largest deserts in Australia are listed below:

Great Victoria Desert

The largest area, which occupies 4% of the total area of the continent. Named after the British Queen. Part of the territory belongs to the natives. Agricultural activity is not possible due to lack of water.

Great sandy desert

It occupies an area equal to Japan. Due to the peculiarities of the climate, the sand forms high dunes. There is no permanent population. Precipitation does not fall every year, and there are no reservoirs.

Tanami Desert

A little-studied area in the north of the continent. There are shallow water basins, precipitation falls periodically. But due to high temperatures, moisture evaporates very quickly. There is gold mining in the desert.

Simpson Desert

The scarlet sands that roll over the area are famous among tourists. The region is named after an English geographer. In the 20th century, they searched for oil here to no avail. Today, the desert is popular with off-road enthusiasts.

Gibson Desert

Situated between the Great Sandy Desert and the Victorian Desert. There are several saline lakes on the territory. The state has created a reserve here for animals adapted to severe climatic conditions.

Small sandy desert

There are several lakes in the area. The biggest one is Disappointment. The water in it is unsuitable for drinking and household needs, although this did not prevent the natives from settling in the desert.

Desert Strzelecki

Named after the Polish explorer. Around the desert there are several villages whose population is engaged in agriculture. On the very territory there is a national park that offers entertainment for fans of extreme tourism.

Inland waters

The main river system on the continent is the Murray River and its tributaries: the Darling, the Murrumbidgee and the Goulburn. The total area is over 1 million km². Due to low rainfall, most rivers dry up. The springs originating in the mountains of Eastern Australia and the rivers of Tasmania have a permanent outflow.

The largest lakes: Eyre, Gairdner, Frome and Torrens are located in the south. Most of the time they are pits covered with salt-bearing clays. On the southeast coast there are numerous lagoons separated by shallows from the sea. Freshwater lakes are located on the island of Tasmania. Great Lake is exploited for hydrotechnical purposes.

Australia has large reserves of artesian water. The total reserves of freshwater underground sources are about 3240 thousand km². However, they are deep, warm and often saline. The water is suitable for watering livestock, but unsuitable for domestic use due to its high mineral content. The large Artesian basin occupies 1751.5 thousand km². The development of agriculture on the mainland depends on it.

Climate

The continent is located in three climatic zones:

Tasmania is in temperate climate. Since Australia is located south of the line, winter starts from June and summer from December. There are no sudden temperature changes or extreme weather conditions. From May to October it is always sunny, the air humidity is 30%. The average temperature in winter is usually not lower than 13º C. A cold winter is considered when the thermometer drops to zero. Summer is a period of cyclones and thunderstorms, the air warms up to 29º C. On the southeast coast, the climate resembles. The coldest region of Australia is Tasmania. In winter, frosts occur there. In the central regions of the continent, slight temperature differences are observed.

Flora and fauna:

Vegetable world

The flora is quite peculiar and endemic, since Australia is located at a considerable distance from the rest of the continents. The climate is characterized by a sharp aridity, because of this, exceptionally viable plants dominate in nature. Trees have a powerful root system, which is adapted to suck water from a depth of up to 30 meters. In some plant species, the leaves are hard, leathery and turn away from the sun to avoid excessive evaporation. Eucalyptus, bottle tree, palms and ficuses dominate.

Represented by acacia and soddy cereals. In places where there is a lot of precipitation, the same eucalyptus trees grow, but accompanied by horsetails and ferns, as well as other plants characteristic of the Mediterranean climate. continents are small. The total area of green areas is 5% of the territory of Australia, including artificial plantations of pine and other softwoods. The colonists brought in European species of trees, herbs and shrubs. Grapes and cotton have taken root well, as well as fruit trees and vegetables. Corn, rye, oats, wheat and barley grow well on Australian soil.

Animal world

Since Australia was discovered later than other continents and developed separately, it is home to animals that are unique and are not found anywhere else in the world. There are practically no ruminants, ungulates and monkeys on the mainland. But there are a lot of representatives of marsupials: kangaroo; marsupial squirrel; ant-eater; Tasmanian devil; marsupial mouse. In total there are about 250 species. There are many bizarre animals: echidna, koala, platypus, frilled lizards. Among the unusual birds include lyrebirds and emus. By the number of dangerous representatives of the fauna of Australia, you can give the palm. It is better to stay away from the wild dog Dingo, cassowary, reptiles and spiders. The most dangerous animal, oddly enough, is considered a mosquito from the genus Kusaki. He is a carrier of dangerous diseases. Marine animals are also dangerous. Species of sharks, jellyfish and octopuses can pose a serious threat to people resting on the coast.

Minerals

The main wealth of the continent is considered, the potential of which is 20% higher than in the rest of the world. Australia has a lot of bauxite. Since the second half of the XX century. began mining iron ore. In the west are deposits of polymetals. Gold is mined in the southwest of the mainland. Scientists have established that there are deposits of natural gas and oil in the bowels. Research is currently underway.

Ecological situation

The country's economy is kept in high positions due to the extraction of minerals. Mining depletes the subsoil and destroys the topsoil. Because of this, the area under agriculture is shrinking. Chronic water shortages have forced the government to create a series of bans. At certain times of the year, people are not allowed to water lawns, wash cars, or fill swimming pools.
During the Cold War, there were nuclear tests. This negatively affected the radiation situation. Maraling, the area where the tests were carried out, is still considered contaminated.

Modern uranium springs are located close to Spencer Gulf and Kakadu National Park. This worries the public: the precedent, when dirty water was poured into the reserve, has already been created. Aboriginal life depends on natural factors. As a result of the desertification of the continent, they have to leave their inhabited settlements forever. State and world famous public organizations make every effort to preserve the unique Australia and its. New nature reserves and national parks are being created.

Population

The first generation of colonists arrived on the mainland in 1788. At that time, Australia was a place of exile for lawbreakers. The number of the first settlers was just over a thousand people. As a result of forced immigration, the number of people has increased significantly. Australia ceased to be a place of exile for convicts in 1868. The influx of voluntary colonialists is associated with the development of cattle breeding and the discovery of mines.

Modern society does not remind of the difficult years of development and formation of the country. The population is 24.5 million people. In terms of population, the country ranks 50th in the world. The number of aborigines is 2.7%. Migrants most often have British, German, New Zealand, Italian and Filipino roots. There are a large number of confessions in the country. official language considered Australian English. It is used by 80% of the population.

Population density differ in different regions. On average, no more than three people live per square kilometer. The southeastern coast of the mainland is most densely populated. Australia has a high life expectancy of the population, on average about eighty years. The process of rapid aging due to low birth rates, as in Europe, is not observed. Australians are still among the young nations.

About 3.8 million sq. km of the surface of Australia (44%) is occupied by arid territories, of which 1.7 million square meters. km - desert. This allows us to say that Australia is the most arid continent on the globe.

The deserts of Australia are confined to ancient structural elevated plains. The climatic conditions of Australia are determined by its geographical location, orographic features, the vast Pacific Ocean and the proximity of the Asian mainland. Of the three climatic zones of the southern hemisphere, the deserts of Australia are located in two: tropical and subtropical, with most of them occupied by the latter zone.

Australia is characterized by excessive variability in average annual precipitation and uneven precipitation throughout the year. The presence of long dry periods and high average annual temperatures prevailing over a large part of the continent cause high annual evaporation rates. In the central part of the mainland, they are 2000-2200 mm, decreasing towards its marginal parts. The surface waters of the mainland are extremely poor and extremely unevenly distributed over the territory. This is especially true for the desert western and central regions of Australia, which are practically drainless, but make up 50% of the continent's area.

The hydrographic network of Australia is represented by temporary drying watercourses (creeks). The drainage of the rivers of the deserts of Australia belongs partly to the basin of the Indian Ocean and the basin of Lake Eyre. The hydrographic network of the mainland is supplemented by lakes, of which there are about 800, and a significant part of them are located in deserts. The largest lakes - Eyre, Torrens, Carnegie and others - are salt marshes or dried-up basins covered with a powerful layer of salts. The lack of surface water is compensated by wealth groundwater. A number of large artesian basins stand out here (Desert Artesian Basin, Northwest Basin, Northern Murray Basin and part of Australia's largest groundwater basin, the Great Artesian Basin).

The soil cover of deserts is very peculiar. In the northern and central regions, red, red-brown and brown soils are distinguished (characteristic features of these soils are an acid reaction, coloring with iron oxides). Serozem-like soils are widespread in the southern parts of Australia. In western Australia, desert soils are found along the outskirts of drainless basins. The Great Sandy Desert and the Great Victoria Desert are characterized by red sandy desert soils. Salt marshes and solonetzes are widely developed in drainless internal depressions in the southwest of Australia and in the basin of Lake Eyre.

The Australian deserts are divided into many different types in terms of landscape, among which Australian scientists most often distinguish mountainous and foothill deserts, structural plains deserts, rocky deserts, sandy deserts, clay deserts, plains. Sandy deserts are the most common, occupying about 32% of the continent's area. Along with sandy deserts, rocky deserts are also widespread (they occupy about 13% of the area of arid territories. Piedmont plains are an alternation of large-stony deserts with dry channels of small rivers. This type of desert is the source of most of the country's desert watercourses and always serves as a habitat for aborigines. Deserts Structural plains are found in the form of a plateau with a height of no more than 600 m above sea level.After sandy deserts, they are the most developed, occupying 23% of the area of arid territories, confined mainly to Western Australia.