Plants of the tropical deserts of Australia. Australia: natural areas. How do deserts and semi-deserts arise?

All Australian deserts lie within the Central Australian region of the Australian Floristic Kingdom. Although in terms of species richness and level of endemism desert flora Australia is significantly inferior to the flora of the western and northeastern regions of this continent, but compared to other desert regions globe it stands out both in the number of species (more than 2 thousand) and in the abundance of endemics. Species endemism here reaches 90%: there are 85 endemic genera, of which 20 are in the family Compositae, or Asteraceae, 15 - Chenopodiaceae and 12 - Cruciferae.

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, myrtaceae, proteaceae and asteraceae. Significant species diversity is demonstrated by the genera Eucalyptus, Acacia, Proteaceae - Grevillea and Hakea. In the very center of the continent, in the gorge of the deserted MacDonnell Mountains, narrow-area endemics have been preserved: the low-growing Liviston palm and Macrozamia from the cycads.

Even some types of orchids live in deserts - ephemerals that germinate and bloom 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 the prickly grass triodia. Top part The slopes and ridges of dune ridges are almost completely devoid of vegetation, only individual curls of the prickly grass Zygochloa settle on the loose sand. In interbarchan depressions and on flat sandy plains, a sparse tree stand of casuarina, individual specimens of eucalyptus, and veinless acacia is formed. The shrub layer is formed by Proteaceae - these are Hakea and several types of Grevillea.

In slightly saline areas in depressions, saltwort, ragodia and euhilena appear. After the rains, the interridge depressions and lower parts of the slopes are covered with colorful ephemerals and ephemeroids. In the northern regions on the sands of the Simpson and Great Sandy Deserts species composition the background grasses change somewhat: other species of triodia, plectrahne and shuttlebeard, dominate there; the diversity and species composition of acacias and other shrubs becomes greater. Along the channels of temporary waters, gallery forests of several species of large eucalyptus trees form. The eastern edges of the Great Victoria Desert are occupied by sclerophyllous mum scrub scrub. The southwestern Great Victoria Desert is dominated by low-growing eucalypts; The grass 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 climate zone, which occupies the territory between the 20th and 30th parallel in the desert zone, a tropical continental desert climate is formed. A subtropical continental climate is common in southern Australia adjacent to the Great Australian Bight. These are the marginal parts of the Great Victoria Desert. Therefore, in the summer, from December to February, average temperatures reach 30 ° C, and sometimes higher, and in winter (July - August) they drop to an average of 15-18 ° C. In some years, the entire summer period temperatures can reach 40° C, and winter nights in the vicinity of the tropics drop 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 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. Precipitation season in northern half The continent, where the monsoon change of winds dominates, is confined to the summer period, and, in its southern part, dry 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 trend, does not extend south of the tropic. Thus, in the zone between the tropics and 28° S. latitude. there is a belt of aridity.

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

Despite the fact that Australia is the smallest continent on the planet, it surprises with the diversity of its nature. The change in the balance of moisture and heat depends on the latitude of the area. This is manifested in the conditional division of the continent into territories with characteristic soil types, animals and plants - natural areas Australia.

Division of the continent into natural complexes

Australia is divided into four zones, which replace each other depending on the ratio of humidity and heat. The pronounced latitudinal zonation is due to the predominant flat terrain, which only in the east turns into mountain slopes.

The central position on the Australian continent is occupied by a zone of deserts and semi-deserts located in the tropical zone. It occupies half of all Australian lands.

Table Natural areas of Australia

A characteristic feature of Australia is the amazing originality of nature, which consists of a large number of endemic species, both among plants and among animals. Only on this continent can you find unusual representatives of flora and fauna that are not found anywhere else in the world.

Features of natural complexes

In Australia, the most impressive zone is the desert and semi-desert zone - it occupies largest territory and is located in the tropical zone.

For this natural complex characterized by very scanty precipitation, which evaporates very quickly in hot climates. It is not surprising that Australia is often called the desert continent, because there are 5 large desert areas:

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• Victoria - the largest desert on the Australian continent, occupies 424 thousand square meters. km.
• sandy desert - the second largest wasteland. Here is the famous Australian national park Ayres Rock, which attracts tourists from all over the world.
• Tanami - unlike most deserts, it is characterized by a sufficient number of rainy days. However, due to the intense heat, precipitation evaporates very quickly. Gold mining is underway in the desert.
• Gibson Desert - its soils are highly weathered and very rich in iron.
• Desert Simpson - the driest Australian desert, which is famous for its bright red sands

Rice. 1. Red Sands of the Simpson Desert

The vegetation of this zone is very poor, but here you can also find drought-resistant cereals and herbs, and salt-tolerant varieties of trees.

Desert animals were able to adapt to life in harsh conditions. Some of them, hiding from the heat, burrow into the soil: marsupial species of rats, moles, and jerboas. Reptiles hide in rocks and rock crevices. Such large mammals, like the Dingo dog and the kangaroo, they run vast distances in search of moisture and food.

With advancement to the east the zone tropical deserts gives way to the savannah zone. The flora of this natural complex is already somewhat richer, but here too there is still an insufficient amount of moisture.

There are three types of Australian savannas, which replace each other as humidity decreases:

• deserted;
• typical;
• wet.

The Australian savanna is a large flat area with grasses, thorny bushes and isolated trees or groves of acacias, eucalyptus, and casuarinas.

Rice. 2. Casuarina - a plant typical of Australia

Typical representatives of the Australian savannah are all kinds of marsupials and wombats. Birds are represented by bustards, emus, and budgerigars. There are a lot of termites.

In the wild of Australia you will not find herbivorous ungulates. They were “replaced” by kangaroos, numbering more than 60 species. These animals are record holders for speed running and jumping. The kangaroo, like the emu, is the national symbol of Australia.

Rice. 3. Australian Kangaroo

In the east of the continent there is a mountain system - the Great Watershed Range, on the slopes of which there are two forest zones:

• evergreen forests;
• permanently wet forests.

Palm trees, ferns, ficus, and eucalyptus trees grow here in great abundance. The fauna of these zones is somewhat richer and represented small predators, various species of reptiles, koala, platypus, echidna.

What have we learned?

We learned which natural zone is dominant on the mainland - tropical deserts and semi-deserts. It gives way to savannas and open forests, which smoothly transform into the zone of evergreen and constantly wet forests. Characteristic nature of Australia - the presence of a large number of endemic plants and animals.

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Australia is located in the Southern and Eastern hemispheres of the planet. The world's smallest continent occupies only 5% of the Earth's landmass. The area of ​​the continent with 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 extends for 35,877 km and is slightly indented. The waters of the Gulf of Carpentaria jut into the northern coast of the continent, and the Cape York Peninsula protrudes prominently against the background of the main coastline. The main bays are located in the southeast of Australia.

The most extreme points continent include:

• in the north - Cape York, washed by the waters of the Coral and Arafura seas;
• in the south - Cape South Point, washed by the waters of the Tasman Sea;
• in the west - Cape Steep Point, washed by the waters Indian Ocean;
• in the east is 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 the islands of Groot Island, Melville and Bathurst, as well as the large islands of Derk Hartog in the west and Fraser in the east. Within the mainland shallows are Kangaroo, King and Flinders Islands.

The Great Barrier Reef is an invaluable natural monument located along the north-eastern line of the continent. It includes clusters of small underwater and surface islands, as well as Coral reefs. Its length is more than 2000 km.

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

Relief

Blue Mountains, Australia

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

Modern relief includes the Western Australian Tablelands, the Central Lowlands and the East Australian Mountains. As a result of rising and falling earth's crust, a trough filled with sedimentary rocks formed in the east of the Australian Platform. The Great Dividing Range is located in the eastern part of the continent. The mountains formed in the area collapsed over time. Only the Australian Alps exceed the two thousand mark. This is the only place on the continent where snow lies in places in the shaded gorges.

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

Deserts

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 region, which occupies 4% of the total area of ​​the continent. Named after the British Queen. Part of the territory belongs to the aborigines. Agricultural activities are impossible due to lack of water.

Great Sandy Desert

Occupies an area equal to Japan. Due to the climate, sand forms high dunes. There is no permanent population. Precipitation does not occur every year, and there are no bodies of water.

Tanami Desert

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

Simpson Desert

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

Gibson Desert

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

Small Sandy Desert

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

Strzelecki Desert

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

Inland waters

Home river system on the continent is the Murray River and its tributaries: the Darling, Murrumbidgee and Goulburn. The total area is more than 1 million km². Due to low rainfall, most rivers dry up. Springs originating in the mountains of Eastern Australia and the rivers of Tasmania have constant water 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 southeastern coast there are numerous lagoons, separated from the sea by shallows. Freshwater lakes are located on the island of Tasmania. Great Lake is exploited for hydraulic 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 salty. The water is suitable for watering livestock, but is unsuitable for use on the farm due to its high mineral content. The Great 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 begins in June and summer begins in December. Sudden temperature changes or extreme weather conditions not visible. From May to October it is always sunny, air humidity is 30%. average temperature in winter it 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 the island of Tasmania. In winter there are frosts. In the central regions of the continent, minor temperature changes are observed.

Flora and fauna:

Vegetable world

The flora is quite unique and endemic, since Australia is located at a considerable distance from the rest of the continents. The climate is characterized by severe aridity, because of this, only resilient plants dominate in nature. The trees have a powerful root system, which is adapted to suck water from a depth of up to 30 meters. Some plant species have hard, leathery leaves that are turned away from the sun to avoid excessive evaporation. Eucalyptus, bottle tree, palms and ficus trees dominate.

Represented by acacia and turf grasses. In places where there is a lot of rainfall, 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 Australia's territory, including artificial plantations of pine and other soft tree species. The colonists brought European species of trees, grasses and shrubs. Grapes and cotton have taken root well, as well fruit trees and vegetables. Corn, rye, oats, wheat and barley grow well on Australian soil.

Animal world

Because Australia was discovered later than other continents and developed separately, it is home to animals that are unique and not found anywhere else in the world. There are practically no ruminants, ungulates or monkeys on the mainland. But there are a lot of representatives of marsupials: kangaroos; marsupial squirrel; ant-eater; Tasmanian devil; marsupial mouse. There are about 250 species in total. There are many bizarre animals: echidna, koala, platypus, frilled lizards. Unusual birds include lyrebirds and emus. By number dangerous representatives The fauna of Australia can be given 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 to be 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 vacationing on the coast.

Minerals

The main wealth of the continent is considered to be, the potential of which is 20% higher than in the rest of the world. Australia has a lot of bauxite. From the second half of the 20th century. development has begun iron ore. In the west there are deposits of polymetals. Gold is mined in the southwest of the mainland. Scientists have found that there are deposits in the depths natural gas and oil. On this moment Research is underway.

Ecological situation

The country's economy is maintained in high positions due to the extraction of mineral resources. Mining development depletes the subsoil and destroys the top layer of soil. Because of this, areas under Agriculture. Chronic water shortages forced the government to create a series of bans. At certain times of the year, people should not water their lawns, wash their cars, or fill their swimming pools.
During times cold war were held on the territory of the country nuclear tests. This had a negative impact on 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 national park Cockatoo. This worries the public: a precedent has already been created when dirty water was poured into the reserve. The life of the aborigines depends on natural factors. As a result of desertification of the continent, they have to leave their settled settlements forever. The state and world-famous public organizations are making every effort to preserve the uniqueness of Australia and its country. New 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 increased significantly. Australia ceased to be a place of exile for convicts in 1868. The influx of voluntary colonizers was associated with the development of cattle breeding and the opening of mines.

Modern society does not remind us 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 fiftieth in the world. The number of Aboriginal people is 2.7%. Migrants most often have British, German, New Zealand, Italian and Filipino roots. On the territory of the country there is a large number of denominations. Official language considered Australian English. It is used by 80% of the population.

Population density differs 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, with an average of about eighty years. The process of rapid aging due to low birth rates, as in Europe, is not observed. Australians are still considered a young nation.

Australia is often called the desert continent 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 suggests that Australia is the driest continent on the globe.

Deserts of Australia are 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 occupying the latter zone.

Great Sandy Desert

The Great Sandy Desert or Western Desert is a sandy-salt desert in the north-west of Australia (Western Australia).

The desert has an area of ​​360,000 km² and is located approximately within the boundaries of the Canning sedimentary basin. It extends 900 km from west to east from Eighty Mile Beach on the Indian Ocean deep into the Northern Territories to the Tanami Desert, as well as 600 km from north to south from the Kimberley region to the Tropic of Capricorn, passing into the Gibson Desert.

It gradually decreases to the north and west, the average height in the southern part is 400-500 m, in the north - 300 m. The predominant relief is ridges of sand dunes, the average height of which is 10-12 m, the maximum is up to 30 m Ridges up to 50 km long are elongated in the latitudinal direction, which is determined by the direction of the prevailing trade winds. The region is home to numerous salt marsh lakes that occasionally fill with water: Disappointment in the south, Mackay in the east, Gregory in the north, which is fed by the Sturt Creek River.

The Great Sandy Desert is the hottest region of Australia. In the summer from December to February, the average temperature reaches 35 °C, in winter - up to 20--15 °C. Precipitation is rare and irregular, mainly brought by the summer equatorial monsoons. In the northern part, about 450 mm of precipitation falls, in the southern part - up to 200 mm, most of it evaporates and seeps into the sand.

The desert is covered with red sands; the dunes are predominantly inhabited by prickly xerophytic grasses (spinifex, etc.). The dune ridges are separated by clay-salt plains, on which acacia shrubs (in the south) and low-growing eucalyptus trees (in the north) grow.

There is almost no permanent population in the desert, with the exception of several Aboriginal groups, including the Karadjeri and Nygina tribes. It is assumed that the interior of the desert may contain minerals. In the central part of the region is Rudall River National Park, in the far south is the listed World Heritage Uluru-Kata Tjuta National Park.

Europeans first crossed the desert (from east to west) and described it in 1873 under the leadership of Major P. Warburton. The Canning Stock Route, 1,600 km long, runs through the desert region in a northeasterly direction from the town of Wiluna through Disappointment Lake to Halls Creek. Wolf Creek Crater is located in the northeastern part of the desert.

Great Desert Victoria

The Great Victoria Desert is a sandy-salt desert in Australia (the states of Western Australia and South Australia).

The name in honor of Queen Victoria was given by the British explorer of Australia Ernest Giles, who in 1875 was the first European to cross the desert.

The area is 424,400 km², while the length from east to west is more than 700 km. To the north of the desert is the Gibson Desert, to the south is the Nullarbor Plain. Due to unfavorable climatic conditions(arid climate) there is no agricultural activity in the desert. It is a protected area in Western Australia.

In the state of South Australia in the desert there is a protected area called Mamungari, one of 12 biosphere reserves Australia.

Average annual precipitation varies from 200 to 250 mm of rain. Thunderstorms occur frequently (15-20 per year). Daytime temperatures in summer are 32--40 °C, in winter 18--23 °C. Snow never falls in the desert.

The Great Victoria Desert is inhabited by several Aboriginal Australian groups, including the Kogarah and Mirning peoples.

Gibson Desert

The Gibson Desert is a sandy desert in Australia (in the center of Western Australia), located south of the Tropic of Capricorn, between the Great sandy desert in the north and the Great Victoria Desert in the south.

The Gibson Desert has an area of ​​155,530 km² and is located within a plateau that is composed of Precambrian rocks and covered with rubble resulting from the destruction of an ancient ferruginous shell. An early explorer of the region described it as “a vast, rolling gravel desert.” The average height of the desert is 411 m; in the eastern part there are remnant ridges up to 762 m high, composed of granites and sandstone. The desert is bordered on the west by the Hamersley Range. In Western and eastern parts consists of long parallel sandy ridges, but in the central part the relief levels out. In the western part lie several salt marsh lakes, including the 330 km² Disappointment Lake, which borders the Great Sandy Desert.

Precipitation is extremely irregular, its amount does not exceed 250 mm per year. The soils are sandy, rich in iron, and highly weathered. In some places there are thickets of veinless acacia, quinoa and spinifex grass, which bloom with bright colors after rare rains.

In 1977, a reserve (Gibson Desert Nature Reserve) was organized on the territory of the Gibson Desert, the area of ​​which is 1,859,286 hectares. The reserve is home to many desert animals, such as great bilbies (threatened with extinction), red kangaroos, emus, Australian duckweed, striped grass wren and moloch. Birds flock to Disappointment Lake and neighboring lakes, which appear after rare rains, in search of protection from the dry climate.

Populated primarily by Australian Aborigines, the desert area is used for extensive grazing. The desert was discovered in 1873 (or 1874) by the English expedition of Ernest Giles, who crossed it in 1876. The desert received its name in honor of expedition member Alfred Gibson, who died in it while searching for water.

Small Sandy Desert

The Little Sandy Desert is a sandy desert in western Australia (Western Australia).

Located south of the Great Sandy Desert, in the east it becomes the Gibson Desert. The name of the desert is due to the fact that it is located next to the Great Sandy Desert, but has a much smaller size. According to the characteristics of the relief, fauna and flora, the Small Sandy Desert is similar to its large “sister”.

The area of ​​the region is 101 thousand km². The average annual precipitation, which falls mainly in summer, is 150-200 mm, the average annual evaporation is 3600-4000 mm. Average summer temperatures range from 22 to 38.3 ° C, in winter this figure is 5.4-21.3 ° C. The internal flow, the main watercourse is Savory Creek, flows into Disappointment Lake, located in the northern part of the region. There are also several small lakes in the south. The headwaters of the Rudall and Cotton rivers are located near the northern borders of the region. Spinifex grass grows in red sand soils.

Since 1997, several fires have been recorded in the region, the most significant was in 2000, when 18.5% of the region's area was damaged. About 4.6% of the bioregion's territory has conservation status.

There are no large settlements within the desert. Most of the land belongs to the Aborigines, their largest settlement is Parnngurr. Crossing the desert to the northeast is the 1,600 km long Canning Cattle Trail, the only route through the desert running from the town of Wiluna through Disappointment Lake to Halls Creek.

Simpson Desert

Simpson Desert is a sandy desert in the center of Australia. for the most part located in the south-eastern corner of the Northern Territory, and a small part in the states of Queensland and South Australia.

It has an area of ​​143 thousand km², bounded from the west by the Finke River, from the north by the MacDonnell Range and the Plenty River, from the east by the Mulligan and Diamantina rivers, and from the south by the large salt Lake Eyre.

The desert was discovered by Charles Sturt in 1845 and was named Arunta in Griffith Taylor's 1926 drawing. After surveying the area from the air in 1929, geologist Cecil Medigen named the desert after Allen Simpson, president of the South Australian Branch of the Royal Geographical Society Australasia. It is believed that the first European to cross the desert was Medigen in 1939 (on camels), but in 1936 it was done by the expedition of Edmund Albert Colson.

In the 1960s-80s, oil was searched unsuccessfully in the Simpson Desert. At the end of the 20th century, the desert became popular among tourists; excursions in four-wheel drive vehicles are of particular interest.

The soils are predominantly sandy with parallel ridges of dunes, sandy-pebble in the south-eastern part, and clayey near the shores of Lake Eyre. Sand dunes 20-37 m high stretch from northwest to southeast over distances of up to 160 km. In the valleys between them (450 m wide) the spinifex grass grows, fixing sandy soils. There are also xerophytic shrubby acacias (veinless acacia) and eucalyptus trees.

The Simpson Desert is the last refuge for some of Australia's rare desert animals, including the comb-tailed marsupial. Vast parts of the desert received the status protected areas:

· Simpson Desert National Park, western Queensland, organized in 1967, occupies 10,120 km²

· Simpson Desert conservation park, South Australia, 1967, 6927 km²

· regional reserve Simpson Desert, South Australia, 1988, 29,642 km²

· Wijira National Park, northern South Australia, 1985 7770 km²

In the northern part, precipitation is less than 130 mm, dry creek beds are lost in the sand.

The Todd, Plenty, Hale, and Hay rivers flow through the Simpson Desert; in the southern part there are many drying up salt lakes.

Small settlements that raise livestock draw water from the Great Artesian Basin.

Australian desert fauna precipitation

Tanami is a rocky sandy desert in northern Australia. Area -- 292,194 km². There was a desert the last frontier Northern Territory and was little explored by Europeans until the 20th century.

The Tanami Desert occupies the central part of Australia's Northern Territory and a small area of ​​north-eastern Western Australia. To the southeast of the desert is the settlement of Alice Springs, and to the west is the Great Sandy Desert.

The desert is a typical central regions Australia is a desert steppe with vast sandy plains that are covered with grasses of the genus Triodia. The main landforms are dunes and sand plains, as well as shallow water basins of the Lander River, which contain water holes, dry marshes and salt lakes.

The climate in the desert is semi-desert. 75--80% of precipitation falls in summer months(October-March). The average annual rainfall in the Tanami region is 429.7 mm, which is high for a desert area. But due to high temperatures, the rain that falls quickly evaporates, so the local climate is very dry. The average daily evaporation rate is 7.6 mm. The average daytime temperature in the summer months (October-March) is about 36--38 °C, night temperature is 20--22 °C. The temperature in the winter months is much lower: daytime is about 25 °C, nighttime is below 10 °C.

In April 2007, the Northern Tanami Aboriginal Protected Area was created in the desert, covering an area of ​​about 4 million hectares. It is home to a large number of vulnerable native flora and fauna.

The first European to reach the desert was explorer Geoffrey Ryan in 1856. However, the first European to explore the Tanami was Allan Davidson. During his expedition in 1900, he discovered and mapped local gold deposits. The area has a small population due to unfavorable climatic conditions. The traditional inhabitants of the Tanami are the Australian Aborigines, namely the Walrpiri and Gurindji tribes, who are the land owners of much of the desert. The largest settlements are Tennant Creek and Wauchope.

Gold mining is carried out in the desert. IN Lately tourism is developing.

Strzelecki Desert

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 makes up 1% of Australia. It was discovered by Europeans in 1845 and named after the Polish explorer Pawel Strzelecki. Also in Russian sources it is called the Streletsky Desert.

Stone Desert of Sturt

The rock desert, which occupies 0.3% of Australia's territory, is located in the state of South Australia and is a collection of sharp small stones. Local aborigines did not sharpen their arrows, but simply dialed 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's area, has some of the harshest climatic conditions in Australia, due to high temperatures and virtually no rain. The Tirari Desert is home to several salt lakes, including Lake Eyre. The desert was discovered by Europeans in 1866.

The exceptional originality and antiquity of the flora and fauna of Australia is explained by its long isolation. Most plant (75%) and animal (90%) species in Australia are endemic, i.e. they are not found anywhere else in the world. Among the animals there are few mammals, but species extinct on other continents have survived, including marsupials (about 160 species) (see Fig. 66 on p. 140). Typical representatives of the Australian flora are eucalyptus (600 species), acacia (490 species) and casuarina. The mainland has not given the world valuable cultivated plants.

Australia is located in four geographical zones- from subequatorial to moderate. The change in natural zones is due to changes in temperatures and precipitation patterns. The flat nature of the relief contributes to a well-defined latitudinal zonality, which is disrupted only in the east. The main part of the continent lies in tropical latitudes Therefore, tropical deserts and semi-deserts, occupying half the area of ​​the continent, have received the greatest development.

Rice. 66. Endemic animals of Australia: 1 - kangaroo; 2 - frilled lizard; 3 - emu; 4 - koalas; 5 - platypus; 6 - echidna

Natural areas

In the subequatorial and tropical geographical zones, significant territories are occupied by savannah And woodlands . The zone arcs across the Carpentarian Plain and the Central Lowland. There are wet, typical and desert savannas, developing respectively on red, red-brown and red-brown soils. In subequatorial latitudes they replace each other from north to south, and in tropical latitudes - from east to west as moisture decreases. The Australian savanna is an open space of grassy cover of bearded vulture, alang-alang, with individual trees or groves of eucalyptus, acacia, casuarina and moisture-storing baobab Gregory ("bottle tree"). In the interior regions, thickets of low-growing thorny bushes with small leathery foliage appear - scrubs, consisting of drought-resistant species of acacias, eucalyptus and casuarinas (Fig. 67).

An integral part of the Australian savannas are marsupials - kangaroos (red, gray, hare, wallaby), wombats. Large ones are typical flightless birds- emu, cassowary, Australian bustard. Budgerigars breed their chicks in eucalyptus woodlands. Termite buildings - termite mounds - are ubiquitous.

There are a total of 60 species of kangaroos in Australia. In nature, they “replace” absent herbivorous ungulates. Baby kangaroos are born tiny and immediately move into their mother's pouch - skin fold on her stomach, where they spend the next 6-8 months, feeding on milk. The weight of an adult kangaroo can reach 90 kg with a height of up to 1.6 m. Kangaroos are record holders in jumping: the length of their jumps reaches 10-12 m, and they can reach speeds of up to 50 km/h. The kangaroo, along with the emu, are depicted as national symbols on the coat of arms of the Commonwealth of Australia.

Rice. 67. Acacia scrub Fig. 68. Spinifex desert brown soils

The central parts of the continent in two geographical zones (tropical and subtropical) occupy deserts and semi-deserts . Australia is rightly called the continent of deserts(Great Sandy Desert, Great Victoria Desert, Gibson Desert, etc.). On the Western Australian Plateau, in a tropical continental climate, tropical deserts and semi-deserts dominate. In rocky and sandy semi-deserts, light forests of casuarinas stretch along river beds. In the depressions of clayey semi-deserts there are thickets of quinoa and salt-tolerant species of acacias and eucalyptus trees. Deserts are characterized by “cushions” of the spinifex bushy grass (Fig. 68). The soils of semi-deserts are gray soils; desert soils are primitive rocky, clayey or sandy.

In the south of the mainland in the subtropics, deserts and semi-deserts occupy the Nullarbor Plain (“treeless”) and the Murray-Darling Lowland. They are formed under subtropical continental climate conditions on brown semi-desert and gray-brown soils. Against the background of dry rare grasses there is wormwood and solyanka; there is no tree and shrub vegetation.

Animals of deserts and semi-deserts are adapted to life in conditions of high temperatures and low amounts of moisture. Some burrow underground like a marsupial mole, marsupial jerboa, kangaroo rat. Others, like the kangaroo and the dingo, are able to travel long distances in search of food and water. Lizards (moloch, frilled lizard) and the most poisonous land snake, the taipan, hide from the heat in the crevices of the rocks.

On the windward wet slopes of the Bolshoi Watershed Ridge in four geographical zones (subequatorial, tropical, subtropical, temperate) zones were formed variable-humid forests . The northeastern edge of the continent in a monsoon climate is occupied by subequatorial variable-humid forests. Palm trees, pandanus, ficus, and tree ferns grow in them on red-yellow ferrallite soils.

South of 20°S w. they are replaced by rich evergreens rainforests on red soils and yellow soils, formed in a humid tropical climate. In addition to evergreen trees intertwined with vines and epiphytes (ficus, palm trees, southern beeches, silver tree), conifers appear - Australian cedar and Australian araucaria.

In the southeast of the mainland and the north of the island. Tasmania they are being replaced by subtropical variable-humid forests. On mountain brown forest soils, mixed forests of eucalyptus, southern beech, podocarpus, agathis and araucaria grow. On the dry leeward slopes of the Great Dividing Range they give way to eucalyptus open forests. Forests temperate zone occupy only the extreme south of the island. Tasmania.

Eucalyptus is one of the symbols of the Australian continent. Its leaves, positioned edge-on to the sunlight, form a shadow-free crown. The powerful root system of the tree is capable of drawing water from a depth of 30 m, so eucalyptus trees are planted to drain waterlogged areas all over the world. The fast-growing eucalyptus is used not only in woodworking, but also in medicine thanks to its essential oils.

In the extreme southwest of the continent, in a Mediterranean climate, the zone is widespread dry hard-leaved forests and shrubs . Eucalyptus forests with xanthorea (“grass tree”) grow on yellow soils and red soils; towards the center of the continent they are replaced by scrubs.

The fauna of Australian forests is richer. This is the kingdom of marsupials: tree kangaroo, marsupial squirrel, marsupial bear(koala), marsupial marten (cuscus). “Living fossils” found refuge in the forests - the platypus and the echidna. The world of forest birds is diverse: lyrebird, Paradise Bird, cockatoo parrots, weed chickens, kookaburras. Lots of snakes and lizards (methyst python, giant monitor lizard). Narrow-snouted crocodiles lie in wait for prey in rivers. In the 20th century The marsupial wolf was completely exterminated.

Ecological problems

During colonization in Australia, about 40% of all forests were cleared, with tropical rainforests suffering the most. Deforestation has resulted in depletion of vegetation cover, soil degradation and changes in animal habitats. Rabbits brought by the colonists also caused damage to the local fauna. As a result, more than 800 species of animals have become extinct over the past 500 years.

All greater influence global warming is affecting the nature of the continent. Due to decreased rainfall, droughts and forest fires have become more frequent. Rivers with a constant flow have become shallow, and rivers that are drying up have ceased to fill even during the rainy season. This has led to the encroachment of deserts onto savannas - desertification, aggravated by overgrazing, which affects 90 million hectares of land. In the areas of the “wheat-sheep belt”, land use is difficult due to salinization and soil erosion.

The most acute problem in Australia is the scarcity of water resources. Previously, it was solved by pumping out groundwater from numerous wells. But currently a decrease in water level has been recorded in artesian pools. The depletion of groundwater reserves, along with a decrease in river flows, has exacerbated water shortages in Australia, forcing the implementation of water conservation programs.

One of the ways to preserve nature is to create specially protected natural areas. They occupy 11% of the continent's area. One of the most visited national parks is Kosciuszko in the Australian Alps. In the north there is one of the world's largest parks - Kakadu, where not only wetlands that serve as habitat for many endemic birds are protected, but also caves with Aboriginal rock art. The Blue Mountains Park protects stunning mountain landscapes with a variety of eucalyptus forests. The nature of deserts (parks) is also taken under protection Great Victoria Desert, Simpson-Desert). The giant red sandstone monolith Ayers Rock, sacred to the Aboriginal people, is recognized as a UNESCO World Heritage Site in Uluru-Katayuta Park (Fig. 69). The fabulous world of corals is protected in an underwater park Great Barrier Reef.

In big barrier reef there is the greatest diversity of corals on the planet (up to 500 species). In addition to coastal pollution and poaching, the threat is posed by the polyp-eating crown-of-thorns starfish. Rising ocean temperatures due to global warming are causing coral bleaching and death.

Bibliography

1. Geography 8th grade. Textbook for the 8th grade of general secondary education institutions with Russian as the language of instruction / Edited by Professor P. S. Lopukh - Minsk “People's Asveta” 2014