Deserts and semi-deserts of Australia. natural areas. Australia - the mainland of tropical deserts Natural zones of Australia - deserts and semi-deserts

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 vipers, lizards of the Scinnaaceae 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; giant red kangaroo, etc. Small predatory marsupials are similar in appearance and biology to Old World shrews (crest-tailed marsupial shrew, thick-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 intentionally 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 scarce vegetation cover). The common fox and the house mouse are widely settled throughout the center of Australia. 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).

The exceptional originality and antiquity of the flora and fauna of Australia is explained by its long isolation. Most plant species (75%) and animals (90%) of Australia are endemic, that is, they are not found anywhere else in the world. There are few mammals among the animals, however, species extinct on other continents, including marsupials (about 160 species), have survived. Characteristic representatives of the Australian flora are eucalyptus (600 species), acacia (490 species) and casuarina. The mainland did not give the world valuable cultivated plants.

Australia is located in four geographical zones - from subequatorial to temperate. The change in natural zones is due to changes in temperature and precipitation patterns. The flat nature of the relief contributes to a well-defined, disturbed 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 mainland, have received the greatest development.

The central parts of the mainland in two geographical zones (tropical and subtropical) are occupied by deserts and semi-deserts. Australia is rightly called the continent of deserts (Great Sandy, Great Victoria Desert, Gibson Desert, etc.). Tropical deserts and semi-deserts dominate the Western Australian Plateau in a tropical continental climate. In stony and sandy riverbeds, thin forests of casuarinas stretch along the riverbeds. In the hollows of clayey semi-deserts, there are thickets of quinoa and salt-tolerant species of acacia and eucalyptus. Deserts are characterized by "pillows" of bushy cereal spinifex. Soils of semi-deserts are gray soils, deserts are primitive stony, 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 in a subtropical continental climate on brown semi-desert and gray-brown soils. Against the background of dry rare cereals, wormwood and saltwort are found, tree and shrub vegetation is absent.

The shortage problem is the most acute in Australia. Previously, it was solved by pumping groundwater from numerous wells. But at present, a decrease in the water level in artesian basins has been recorded. The depletion of underground water reserves, along with a decrease in the full flow of rivers, has exacerbated the shortage of water in Australia, forcing the implementation of programs to conserve it.

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

The Great Barrier Reef has the largest variety of corals on the planet (up to 500 species). The threat, in addition to pollution of coastal waters and poaching, is the polyp-eating starfish crown of thorns. Rising ocean temperatures due to global warming are causing coral bleaching and death.

The main feature of the animal and plant world of Australia is the predominance of endemics. Australia is the most deserted continent. Global, depletion of water resources, depletion of flora and fauna pose a threat to the nature of the mainland. Specially protected natural areas occupy 11% of the continent's area.

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 position, orographic features, the vast water area of the 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.

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. 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 the richness of groundwater. A number of large artesian basins stand out here (Desert Artesian Basin, Northwest Basin, Northern Murray River 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 rocky 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.

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

The division of the mainland into natural complexes

Australia is divided into four zones, which replace each other depending on the ratio of humidity and heat. The pronounced latitudinal zonality is due to the prevailing flat relief, 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 is she who occupies half of all Australian land.

Table Natural areas of Australia

*natural areas*	*Climate type*	*Typical representatives of the flora*	*Typical representatives of the fauna*
Permanently wet forests	tropical monsoon	eucalyptus ferns	tiger cat
Evergreen hardwood forests	Subtropical (Mediterranean)	stunted eucalyptus trees	dingo dog various types of lizards and snakes
Savannahs and woodlands	Subequatorial and tropical	casuarina	ostrich Emu
Deserts and semi-deserts	Tropical (continental)	cereals and herbs blackbeard	snakes and lizards ostrich Emu

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

Features of natural complexes

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

This natural complex is characterized by very scarce precipitation, which evaporates very quickly in a hot climate. It is not surprising that Australia is often called the continent of deserts, because there are 5 large desert territories here:

What have we learned?

We learned which natural zone is dominant on the mainland - these are tropical deserts and semi-deserts. It is replaced by savannahs and light forests, which smoothly pass into the zone of evergreen and constantly wet forests. A characteristic feature of the nature of Australia is the presence of a large number of endemics among plants and animals.

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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 eras). 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.
It is here that the famous Kata Tjuta National Park - Uluru (Ayers Rock) is located, 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 of the Lander River, in which there are water pits, 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 the main river that runs through this area. 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 harsh 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 standing stones rising 1-5 meters 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.