Deserts and semi-deserts of Russia and the world: names, species, where they are on the map, how they look, description of animals and plants, soil, climate, local residents. Deserts and semi-deserts - climate, wildlife and vegetation, interesting facts Natural conditions floor

The semi-desert constitutes the transition from the steppes to the deserts. Its landscapes are different
the following features: while in the steppes the vegetation forms, as a rule,
solid carpet, in the semi-deserts we see patches between plants
bare soil, but still the area under vegetation, unlike deserts, is larger
areas of bare spaces; soils and soils, as well as surface and ground waters
usually salty; many salt lakes, a lot of solonchaks; salt licks freeze to the south;
maximum precipitation in June and May; soils in the north are light chestnut, in the south
gray-brown;
soil
and
vegetable
cover
is different
variegation.
Geographical position of semi-deserts in Russia. Semi-desert occupies the area
lower reaches of the Volga, starting on the right bank just below Dubovka, and in the Volga region it goes south
from the railroad Saratov - Uralsk. To the west, the semi-desert goes to the middle Don and
large Manych lakes, south to the lower reaches of the Sulak River, and beyond the Ural River, the southern
its border goes approximately along the line: the mouth of the Emba - the northern cliff of Ust-Urta -
north of the Aral Sea - north of Balkhash, attributing the Hungry Steppe or
Bedpakdala to the desert.

3. Climate. climate type.

Deserts are common in the temperate zone of the Northern Hemisphere, subtropical and
tropical
belts
Northern
and
Southern
hemispheres.
The temperature regime of the desert depends primarily on its geographical
provisions. Desert air, having extremely low humidity, practically does not
protects soil surface from solar radiation. Temperatures + 50 ° С are usual, and
the maximum temperature recorded in the Sahara is 58° C. At night
the temperature is much lower, as the heated soil quickly loses heat. per diem
temperature amplitudes in the deserts of the tropical belt can be 40 ° C.
Temperatures in temperate deserts have significant seasonal
fluctuations. Summers in such deserts are usually warm, even hot, and winters are cold, with
temperatures
below
0°
FROM.
The annual amount of precipitation is less than 200 mm, in extra-arid regions - less than 50 mm, and in
some deserts have not had rainfall for decades; moisture coefficient reflecting
the ratio of precipitation and evaporation, - 0-0.15).

4. Typical Soils

These are dry steppes. In the soil of dry steppes humus
comes less: grass less often, and black soil
cannot form. Plants have deep roots
because water often lies far from the surface,
and the humus horizon is quite powerful, but the humus in
it is much less than in the chernozems. These soils
lighter, brown, chestnut color, and therefore
are called chestnut soils.

5. Inland Waters

In semi-deserts, a kind of dense micronetwork of local runoff is formed,
consisting of weakly expressed hollows and shallow depressions, collecting
mostly melted snow waters. This semi-desert differs significantly from
desert zone, in which surface runoff is so small that it is not enough for
formation of even a rare micronetwork of local runoff. The presence in the relief of closed
basins and depressions contributes to the formation of shallow lakes containing usually
bitter salty water. Some lakes contain large stocks of self-planting
table salt and healing mineral mud (Elton, Baskunchak).
The difficulties of water supply in semi-deserts are exacerbated by the fact that groundwater here
not abundant, often lie at great depths and due to salinity in
in most cases unsuitable for economic use. Poverty
local fresh waters dramatically increases the importance of large transit rivers, which
relatively few here.

6. Typical Animals

The fauna of the deserts and semi-deserts of Russia is also quite diverse. It's only during the day when
the scorching rays of the sun spare no one and nothing, few people can be seen here, most of the animals
are nocturnal - geckos, gerbils, jerboas, boas hide in deep burrows during the day.
permanent residents here are mostly rodents: field mice, ground squirrels and jerboas,
hamsters. A real guard can be called a gopher, which, like a column, warily
peers in all directions, and if he suddenly sees a person, he immediately emits a whistle - that means it's time
hide. And everything seems to fall through the ground - into their holes. Once upon a time, the steppe also lived here
marmots are marmots, but today they are almost completely exterminated by hunters. Almost all rodents for the winter
fall into hibernation, and some of them fall asleep and when it becomes unbearably hot. Rodents are
the main food for many predators, birds and snakes, the abundance of which is simply amazing. Of the large
animals stand out saigas. More recently, these antelopes were on the verge of extinction, but
Thanks to conservation efforts, their numbers have increased. Saigas are very graceful even
when running at speeds up to 80 km/h!
A lot of birds appear in the semi-desert zone in spring and early summer. Some of them weave their
nests right in the ground. And camouflage coloring saves them from danger, but chicks very quickly
develop, while avoiding unnecessary risk.
Even a slight human intervention in the life of flora and fauna leads to its change and, to
Unfortunately, not always to the favorable. The same thing happened with this natural area. many plants,
birds and animals are listed in the Red Book. Reserves have been created to save endangered species -
Bogdinsko-Baskunchaksky and Astrakhansky, wildlife sanctuaries - Burley Sands, Stepnoy, Ilmenno-Bugrovoy,
35 natural monuments created

7.

saiga
KORSAK
STEPPE GROUT
HARVEST MOUSE
JERBOA

8. Typical Plants

BLOODROOT
CAMEL
THORN
SANDY
ACACIA
vegetation
deserts
Russia
relatively
varied.
Full
hosts
considered
wormwood and ephemeroids, but many other cereals, cacti, camel thorn, ephedra,
kendyr, sand locust, perennial
herbs and even flowers - tulips, remerias,
malcomia. The conditions in which they live
plants, provoked the development of various
abilities
for
fixtures
survival: some plants are fast
wither, but at the same time retain their
organs (bulbs, tubers), while others go through a full cycle of life in two or three months.

Deserts and semi-deserts of Russia

English RussianRules

Tropical and subtropical deserts and semi-deserts

A significant part of the land on the globe is occupied by deserts, semi-deserts and arid zones. The desert biome is characteristic of areas of the Earth where precipitation is less than 250 mm per year. The biomes of tropical and subtropical deserts are found in the driest areas of the tropical climate zone and in the zone subtropical arid climate, or trade wind zone.

The zone of trade winds is adjacent to the Northern and Southern tropics, extending approximately between 25° and 30° latitude. Average annual temperatures in this zone are high (25-30°C), but very sharp daily temperature drops of 40-50°C are characteristic, which significantly exceed the differences between winter and summer average daily temperatures (10-20°C); night frosts are possible. Precipitation in the form of rain, hoarfrost, dew or fog is scarce: less than 300 mm/year, and in many areas less than 100 mm/year.

They fall more or less evenly throughout the year or coincide with the "wet" season, which is either winter or summer. In some places there are two "wet" seasons, and in some places there are years without precipitation at all.

The zone of tropical and subtropical deserts and semi-deserts is most extensive in the Northern Hemisphere of the Old World, where it stretches from the eastern Canary Islands through all of North Africa (Sahara), South Eritrea, Somalia, the Arabian Peninsula, South Iran and Pakistan to Northwest India; in the New World, it is represented in Northern and Central Mexico, Arizona and California.

In the Southern Hemisphere, tropical and subtropical deserts and semi-deserts are limited to the western coasts of South America between 4° and 24° S.

sh. and South Africa between 18° and 28° S, as well as Central Australia, where they come to the coast in places in the northwest and south.

Desert vegetation varies from relatively dense thickets of low shrubs (Figure 23) to areas completely devoid of higher plants (northern Chile, some parts of the Libyan Desert).

The flora and structure of desert communities are greatly influenced not only by the amount of precipitation, but also by the characteristics of the substrate. Due to the scarcity of precipitation and the low production of mortmass by sparse vegetation, soil formation in deserts is extremely slow.

At the same time, the openness of the vegetation cover creates conditions for strong wind erosion of the substrate. The consequence of both processes is that soil properties are almost entirely determined by the granulometric composition of the bedrock.

It is the properties of geological rocks and the nature of their physical weathering that determine the type of desert.

Figure 23 – Tropical scrub desert profile

The least favorable for the life of higher plants rocky and gravel deserts in which intense wind erosion has led to the removal of a fine-grained component of the substrate.

Therefore, the surface of such deserts is represented by continuous layers of stones such as cobblestone or gravel. The surface of the stones practically does not retain moisture, which easily seeps through large cracks, becoming unavailable for use by plants. Therefore, such deserts are either completely devoid of higher vegetation, or very rare higher plants live in cracks and crevices of rocks.

Sandy deserts are generally more favorable for plant habitation, since sands retain water well in the soil horizon accessible to plants.

Semi-deserts and deserts of Russia - interesting areas in everything

These deserts vary greatly depending on the mobility of the substrate. Vegetation is completely absent on highly mobile sands. Slowly moving sands are inhabited by a few shrubs and perennial herbaceous species, adapted to endure both falling asleep with sand and exposing the root system when sand is blown out from under the plant.

The vegetation is richest on the still sands. Plants that develop very deep root systems, due to which they can extract water from constantly wet soil horizons, as well as succulents with a shallow root system, are found here, adapted to quickly absorb the water of rare rains and retain it for a long time in their body.

In some types of sandy deserts, ephemeroids and ephemera are diverse.

The fine-grained material blown out and washed out of the soil accumulates in low areas of the relief, which leads to the appearance there clayey desert. Such places receive more moisture coming with the flow of water through temporary surface watercourses and through the capillary system of the pound. With good drainage in the clay desert, ephemera develop especially well, using short periods of high soil moisture after rare rains.

If there is no outflow of water, then the moisture of soil solutions evaporates, and the salts brought by them accumulate in the soil. As a result, salinization develops, which is extremely depressing for most land plants (Figure 24). Only some higher plants-halophytes are able to live on saline soils. Very strongly saline areas, where a salt crust protrudes on the soil surface, are usually devoid of higher plants.

Tropical and subtropical deserts are floristically very different, as they are located on the territories of different floristic kingdoms, but the types of their formations are similar.

Shrub and shrub formations consist of clumps of scleromorphic and usually thorny plants with small, entire, deciduous leaves or with leaves strongly reduced to small scales and photosynthetic stems. During especially long droughts, such shrubs fall into suspended animation, in which some species can remain without harm for several years.

At the same time, they dry out a lot, some even to an air-dry state, and after rain they restore normal vegetation within a few days, flourish and form mature seeds in 2-3 weeks. The herbaceous layer consists of various ephemeroids and ephemera.

Ephemera can also form independent formations without the participation of shrubs. Some deserts are characterized by formations of perennial grasses, in which the main role is played by narrow-leaved and hard-leaved grasses, belonging to different roles in different phytochories.

In the American and African deserts, there are special formations of succulents that are difficult to compare with the usual types of formations in other regions due to the originality of the life forms of the plants that make them up.

Stem succulents range in size from large tree-like forms to small plants that can be likened to turf grasses. In the New World, all this diversity is represented by different species and genera of the Cactus family ( cactaceae), and in Africa - surprisingly similar to them cactus euphorbia (Euphorbia) and various members of the Lastovnevye family ( Asclepiadaceae).

A notable component of succulent formations are large rosette leaf succulents: agaves (agave) in America and rosette aloe (Aloe) and Aizoon ( Aizoaceae) in Africa.

An extremely peculiar type of deserts are coastal foggy deserts (Chile-Peruvian and Namib), stretching in a narrow strip up to 100 km wide along the western coasts of South America and South Africa, respectively.

Figure 24 – Profile of desert vegetation in relief depression: 1-sandy desert with double leaf (Zygophyllum sp.) and tamarisk (Tamarix sp.); 2- area of ​​salinity manifestation: 3 - saline clay desert with tamarisk (Tamarix sp.): 4 - crusty solonchak without higher plants.

In these deserts there is almost no rain, but fogs are very frequent, on the very coast - nightly.

It is the moisture of the fogs, condensing on the soil and plants, that becomes the main source of moisture for the plants and animals living there. Some plants of coastal foggy deserts have learned to absorb moisture condensing on their shoots directly with leaves and stems. A number of American tillandsia species ( Tillandsia) do it so successfully that they do without roots at all.

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semi-deserts- landscapes located between the steppe and the desert in temperate and subtropical geographical regions, as well as between the savannah and desert in the tropical geographical zone.

Semi-dry are formed in dry climatic conditions. In total, for all of them - a long hot and warm period (average temperature 20-25 ° C, and in the tropics and 30 ° C), strong evaporation, which is 3-5 times higher than the amount of annual precipitation (100-300 mm per year) , poor surface runoff, inland waters are poorly developed, many drying channels, vegetation is not closed.

Despite the common characteristics of all semi-desert deserts, they have many differences.

Temperate Crescents in Eurasia, a wide strip (up to 500 km) extends from the western part of the Caspian lowlands, through Kazakhstan, Mongolia to East China. In America, semi-deserts appear with shorter injuries in the interior and foothills.

From semi-deserts located in tropical and subtropical groups, they are distinguished by cold winters (down to -20 ° C).

semi-deserts

The soil here is light-colored chestnuts that suit the steppe and brown desert, often a physiological solution. If we move south along the semi-basins of the temperate zone, we will see that the signs of the stairs are disappearing and the characteristics of the deserts are intensifying. There are also meadows and corn stalks, and among them you already see wormwood and salt. Animals have many sages and turtles, snakes and lizards.

second Crescents of the subtropical group.

They are mainly located in the transition from the desert to the mountain steppes in the form of a zone of high altitude in the Cordillero and Andorra, in Western Asia, Australia and especially in Africa.

The floors here are pebbly, taupe and grey. Grains and various types of shrubs here are many cacti. The animal world is dominated by rodents, snakes and lizards.

third Tropical crescents.

These are desert savannahs. They define both the desert and the sea coast - in Africa, the Sahara and the Kalahari, in South America the Atacama in the north and northwest of the Brazilian Highlands, Asia and Australia.

The floors here are thin, red-brown.

The temperature in the tropical halves, even in the coldest months, does not fall below + 10 ° C, while in summer it rises to 35 ° C. Here they are very rare. Precipitation does not exceed 200 mm per year. Due to the lack of moisture, the corn is very thin. Groundwater in tropical deserts is very deep and partly saline.

In such conditions, only plants that can tolerate overheating and dehydration can live.

They have a deep root system, small narrow leaves or thorns; On some plants, the leaves are covered or coated with wax that protects them from sunlight. These include herbaceous grass, agave, cactus, sand locust.

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Deserts and semi-deserts of Russia

Plants of deserts and semi-deserts in Russia

The peninsular zone enters the Russian lowland only in the southeast, where Ergeni and the northern half of the Caspian plain are occupied. Its southern border to the west of the Volga is about 150 km from the coast of the Caspian Sea; in the Volga and the Urals, it moved even further away from the sea here too: the lake, Lake Baskunchak Aralsor - the mouth of the more or less Uzen - the Ural River south of Kalmykov.

The situation in the southeast of the Russian Plain in the depths of the Eurasian continent is determined by the harsh continental dry climate of this zone.

Summer in the semi-deserts is hot and sunny. The average July temperature reaches 23-25 ​​°, in the city of Novouzensk during the warm period of 85 days occurs with dry winds.

Winter is as cold as on the Kola Peninsula: the average January temperature is -7-8° in the southwest of the region and -13-14° in the northeast. The snow cover is thin from 10 to 30 cm.

Emptiness and semi-desert of the deserts of Russia: where is it located, map, climate, flora and fauna

The total amount of precipitation is 300-200 mm; this is three to four times less than the volatility value. For example, in Novouzensk, the annual precipitation is 250 mm, and the evaporation is 910 mm.

Surface runoff is not important for half of the shelf, so it does not have its own river network. Groundwater is salty and mostly not drinkable.

In addition to the climate, the landscape areas are most strongly influenced by the geological and geomorphological characteristics of the area - low absolute height, plains, weak erosion with clearing, the presence of saline bedrock and quartz.

There are few sludges and spills in the zone. Instead of these forms of erosion, the widespread form of the basin - steppe depressions, outflows, dung, etc. occurs differently: from suffusion to sedimentation and tectonic karst (some spills).

Continental climate, flat landscapes and physiological soil contribute to the accumulation of salt in the soil of semi-deserts, including those that dissolve well.

Salt licks are typical for semi-deserts as light chestnut soils, which are zonal here.

Lack of soil moisture and salinity results in incomplete, curious, spreading vegetation. The abundance of faces with cavities causes an extremely diverse and complex vegetation and soil cover. Due to the lack of moisture, even the smallest depression - a depth of 10-20 cm - causes dramatic changes in the soil and vegetation.

It can be said that this is a complex semi-desert zone, on which the grassy steps in the depression are closely intertwined, the pellino-salt desert on solonetzes and the bilni-chamomile desert are actually semi-precipitation on light brown soil.

In the animal world of the semi-desert, the exclusive role of rodents.

Among them, there are many squirrels present in abundance and influencing the landscape, which are represented here by two species - a small grass squirrel living on loamy plains and yellow soils inhabiting the sand.

The occurrence of claws is very large. In some places on one hectare we can count up to 740-750 holes of polite squirrels. Emissions of protein proteins create a microrelief characteristic of the Caspian Sea, which further increases the complexity of the soil cover and vegetation.

In addition to proteins, squirrels, rodents, coats of arms, sponges, voles, steppe varieties, mice are common in polvircinine.

Within the range there is a saga-antelope, which previously settled in the steppe and forest-steppe zones of the Russian Plain. There are wild pigs in the reeds of the river valleys. Wolves, wolves, leaf corsacs, steppe grouse are common.

The composition of birds (steppe eagle, back, back), reptiles and insects is also very diverse.

Most of the desert is used as pasture.

A lot of developed and irrigated agriculture is being developed.

In the semi-desert zone, two landscape landscapes can be distinguished.

And semi-deserts are specific natural zones, the main distinguishing feature of which is drought, as well as poor flora and fauna. Such a zone can form in all climatic zones - the main factor is the critically low amount of precipitation. Deserts and semi-deserts are characterized by a climate with a sharp daily temperature difference and a small amount of precipitation: no more than 150 mm per year (in spring). The climate is hot and dry, it evaporates without having time to soak into. Temperature fluctuations are characteristic not only for the change of day and night. The temperature difference between winter and summer is also very large. The general background of weather conditions can be defined as extremely severe.

Deserts and semi-deserts are waterless, dry regions of the planet, where no more than 15 cm of precipitation falls per year. The most important factor in 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.

Sometimes the air in deserts in summer reaches 50 degrees in the shade, and in winter the thermometer drops to minus 30 degrees!

Such temperature fluctuations cannot but affect the formation of the flora and fauna of the semi-deserts of Russia.

Deserts and semi-deserts are found in:

• The tropical belt is a large part of such territories - Africa, South America, the Arabian Peninsula of Eurasia.
• Subtropical and temperate zones - in South and North America, Central Asia, where a low percentage of precipitation is complemented by topographical features.

There is also a special type of desert - the Arctic and Antarctic, the formation of which is associated with a very low temperature.

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

Ice deserts formed for other reasons. In Antarctica and the Arctic, the main snow mass falls on the coast; snow practically does 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.

natural area desert

Climate features, desert classification

This natural zone occupies about 25% of the planet's land mass. In total there are 51 deserts, of which 2 are icy. Almost all deserts were formed on the most ancient geological platforms.

General signs

The natural zone called “desert” is characterized by:

• flat surface;
• critical volume of precipitation(annual rate - from 50 to 200 mm);
• rare and specific flora;
• peculiar fauna.

Deserts are often found in the temperate zone of the Northern Hemisphere of the Earth, as well as tropical and subtropical. The relief of such an area is very heterogeneous: it combines highlands, insular mountains, small hills and layered plains. Basically, these lands are drainless, but sometimes a river can flow through part of the territory (for example, the Nile, the Syrdarya), and there are also drying lakes, the outlines of which are constantly changing.

Important! Almost all desert areas are surrounded by mountains or are located next to them.

Classification

Deserts are of different types:

• Sandy. Such deserts are characterized by dunes and sandstorms often occur. The largest, the Sahara, is characterized by loose, light soil, which is easily blown by winds.
• Clayey. They have a smooth clay surface. They are found in Kazakhstan, the western part of Betpak-Dala, on the Ustyurt plateau.
• rocky. The surface is represented by stones and rubble, which forms placers. For example, Sonora in North America.
• saline. The soil is dominated by salts, the surface often looks like a salt crust or a bog. Distributed on the coast of the Caspian Sea, in Central Asia.
• arctic- located in the Arctic and Antarctica. They are snowless or snowy.

Climatic conditions

The desert climate is warm and dry. The temperature depends on the geographical location: the maximum +58°C was recorded in the Sahara on September 13, 1922. A distinctive feature of the desert area is a sharp temperature drop of 30-40°C. During the day the average temperature is +45°C, at night - +2-5°C. In winter, in the deserts of Russia, it can be frosty with little snow.

In desert lands it is characterized by low humidity. Strong winds often occur here at a speed of 15-20 m/s or more.

Important! The driest desert is the Atacama. There has been no precipitation on its territory for more than 400 years.

Flora

The desert flora is very sparse, mostly sparse shrubs that can extract moisture deep in the soil. These plants are specially adapted to live in hot and dry habitats. For example, a cactus has a thick, waxy outer layer to keep water from evaporating. Sagebrush and desert grasses need very little water to survive. Plants of deserts and semi-deserts have adapted to protect themselves from animals by growing sharp needles and thorns. Their leaves are replaced by scales and spines or covered with hairs that protect the plants from excessive evaporation. Almost all sand plants have long roots. In sandy deserts, in addition to grassy vegetation, there is also shrubby vegetation: zhuzgun, sand acacia, teresken. Shrub plants are low and slightly leafy. Saxaul also grows in deserts: white - on sandy, and black - on alkaline soils.

Most desert and semi-desert plants bloom in spring, reproducing flowers until the onset of hot summer. During wet winter and spring years, semi-desert and desert plants can produce surprisingly many spring flowers. In the desert canyons, on the rocky mountains, pine trees coexist, junipers and sage grow. They provide shelter from the scorching sun for many small animals.

The least known and underestimated species of desert and semi-desert plants are lichens and cryptogamous plants. Cryptogamous or mystogamous plants - spore fungi, algae, ferns, bryophytes. Cryptogamous plants and lichens need very little water to survive and live in dry, hot climates. These plants are important because they help stop erosion, which is very important for all other plants and animals because it helps keep the soil fertile during high winds and hurricanes. They also add nitrogen to the soil. Nitrogen is an important nutrient for plants. Cryptogamous plants and lichens grow very slowly.

In clay deserts, annual ephemera and perennial ephemeroids grow. In solonchaks - halophytes or saltworts.

One of the most unusual plants that grow in such an area is saxaul. It often moves from place to place under the influence of the wind.

Fauna

The animal world is also not numerous - reptiles, spiders, reptiles or small steppe animals (hare, gerbil) can live here. Of the representatives of the order of mammals, a camel, an antelope, a kulan, a steppe ram, a desert lynx live here.

In order to survive in the desert, animals have a specific sandy coloration, they can run fast, dig holes and live without water for a long time, they are preferably nocturnal.

Of the birds, you can meet a crow, a saxaul jay, a desert chicken.

Important! In sandy deserts, there are sometimes oases - this is a place that is located above the accumulation of groundwater. There is always dense and abundant vegetation, ponds.

Characteristics of the climate, flora and fauna of the semi-desert

Semi-desert is a type of landscape that is an intermediate option between desert and steppe. Most of them are located in the temperate and tropical zones.

General signs

This zone is distinguished by the fact that there is absolutely no forest on it, the flora is rather peculiar, as is the composition of the soil (very mineralized).

Important! There are semi-deserts on all continents except Antarctica.

Climatic conditions

They are characterized by a hot and long summer period with a temperature of about 25°C. Evaporation here is five times higher than the level of precipitation. There are few rivers and they often dry up.

In the temperate zone, they run in an unbroken line across Eurasia in an east-west direction. In the subtropical zone, they are often found on the slopes of plateaus, highlands and plateaus (Armenian Highlands, Karru). In the tropics, these are very large areas (Sahel zone).

Flora

The flora of this natural zone is uneven and sparse. It is represented by xerophytic grasses, sunflowers and wormwood, ephemerals grow. On the American continent, cacti and other succulents are most common, in Australia and Africa - xerophytic shrubs and stunted trees (baobab, acacia). Here vegetation is often used to feed livestock.

In the desert-steppe zone, both steppe and desert plants are common. The vegetation cover is mainly made up of fescue, wormwood, chamomile, and hairy feather grass. Often wormwood occupies large areas, creating a dull monotonous picture. In some places, kokhiya, ebelek, teresken, and quinoa grow among the wormwood. Where groundwater comes close to the surface, thickets of brilliant chia come across on saline soils.

The soil, as a rule, is poorly developed, and water-soluble salts predominate in its composition. Among the soil-forming rocks, ancient alluvial and loess-like deposits predominate, which are processed by 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 semi-deserts, salt marshes are also found in steppes and deserts. Groundwater, which contains salts, when it reaches the soil surface, is deposited in its upper layer, resulting in soil salinization.

Fauna

The animal world is quite diverse. It is mostly represented by reptiles and rodents. The mouflon, antelope, caracal, jackal, fox and other predators and ungulates also live here. The semi-deserts are home to many birds, spiders, fish and insects.

Protection of natural areas

Part of the desert areas are protected by law and are recognized as nature reserves and national parks. Their list is quite large. From the deserts man guards:

• Etosha;
• Joshua Tree (in Death Valley).

From the semi-deserts are subject to protection:

• Ustyurt Reserve;
• Tiger beam.

Important! The Red Book includes such desert inhabitants as serval, mole rat, caracal, saiga.

Economic activity

The climatic features of these zones are unfavorable for economic life, but throughout history, entire civilizations have developed in the desert zone, for example, Egypt.

Special conditions made it necessary to look for a way to graze livestock, grow crops and develop industry. Taking advantage of the available vegetation, sheep are usually grazed in such areas. Bactrian camels are also bred in Russia. Farming here is possible only with additional irrigation.

The development of technological progress and the limited reserves of natural resources have led to the fact that man has reached the deserts. Scientific research has shown that in many semi-deserts and deserts there are considerable reserves of natural resources, such as gas, precious. The need for them is constantly increasing. Therefore, being equipped with heavy equipment, industrial tools, we are going to destroy previously miraculously untouched territories.

1. The two largest deserts on planet Earth are Antarctica and the Sahara.
2. The height of the highest dunes reaches 180 meters.
3. The driest and hottest area in the world is Death Valley. But, nevertheless, more than 40 species of reptiles, animals and plants live in it.
4. Approximately 46,000 square miles of arable land turns into desert every year. This process is called desertification. According to the UN, the problem threatens the lives of more than 1 billion people.
5. Passing through the Sahara, people often see mirages. To protect travelers, a map of mirages was drawn up for caravaners.

The natural zones of deserts and semi-deserts are 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.

And in and between and the desert in the tropical zone.

Semi-deserts are formed under conditions. What they all have in common is a long and hot warm period (average temperature 20-25°C, and up to 30°C in the tropics), strong evaporation, which is 3-5 times higher than the sum (100-300 mm per year), weak superficial, inland waters are poorly developed, there are many drying channels, the vegetation is not closed.

Despite the common features inherent in all semi-deserts, they also have many differences.

1. Semi-deserts of the temperate zone in they stretch in a wide strip (up to 500 km) from the western part of the Caspian lowland, through, to the East. In the Northern and semi-deserts, they are found in shorter broken sections in the inner parts and foothills. From semi-deserts located in the tropical and subtropical zones, they differ in cold winters (down to -20 ° C). here are light chestnut, which brings them closer to the steppe, and brown desert, often saline. If you move south along the semi-deserts of the temperate zone, you will notice that the signs of the steppes are fading away and the features of the deserts are intensifying. There are also steppe feather grass and fescue, but among them you can already notice wormwood and saltwort. Of the animals, saigas and turtles are found, snakes and lizards are more common.

2. Semi-deserts of the subtropical zone.

They are mainly located in the transitional part from deserts to mountain steppes in the form of an altitudinal zone in the inland parts and the Andes of America, in western Asia, and especially widely in. The soils here are gravelly, gray-brown and gray soils. Cereals and various types of shrubs, a wide variety of cacti are common here. Of the animal world, snakes and lizards predominate.

These are deserted savannahs. They delineate deserts, both inland and oceanic - in Africa and, in South America, the north of the Atacama and the northwest of the Brazilian Plateau, in Asia and in Australia.

The soils here are thin, red-brown. The temperature in tropical semi-deserts does not fall below +10°C even in the coldest months, and in summer it rises to 35°C. Rain falls very rarely here. Precipitation is not more than 200 mm per year. With a lack of moisture, the bark is very thin. The waters in tropical deserts lie very deep and may be partly saline.

In such conditions, only plants that can tolerate overheating and dehydration can live. They have a deep branched root system, small narrow leaves or spines; in some plants, the leaves are pubescent or covered with a wax coating, which protects them from sunlight. These include tree-like cereals, agaves, cacti, sandy acacias.

Deserts and semi-deserts are characterized by severe weather conditions and unique natural phenomena. Here there are animals and plants that practically do not use water, moving hills - dunes, evidence of the existence of ancient civilizations.

Deserts are natural areas with an arid climate. However, not all of them are characterized by hot weather and an abundance of sunlight; there are areas that are recognized as the coldest on planet Earth. Semi-deserts represent an average landscape between desert, steppe or savannah and form in arid (dry) climates on all continents except Antarctica.

How are formed

Predisposing factors for the emergence of deserts and semi-deserts are individual for each of them and include territorial location (continental or oceanic), features of the atmosphere and land structure, uneven distribution of heat and moisture.

The reasons for the formation of such natural zones are high rates of solar radiation and radiation, a small volume or lack of precipitation.

Cold deserts appear for other reasons. In the Arctic and Antarctica, snow mainly falls on the coast; clouds with precipitation practically do not reach the inner regions. In this case, the annual rate can fall for 1 time. As a result, snow drifts form over hundreds of years.

The relief in hot desert zones is diverse. They are open to the wind, the gusts of which carry small stones, sand, creating undulating sediments.

They are called dunes, their common type is a dune, the height of which reaches 30 meters. Ridge dunes grow up to 100 meters and have a length of up to 100 meters.

Where are: location on the map

Deserts and semi-deserts are located in the tropical, subtropical and temperate zones. Natural areas on planet Earth are presented on a map with names.

Mira

In the northern latitudes there are deserts and semi-deserts of the subtropical and temperate zones. At the same time, tropical ones are also present - in Mexico, on the Arabian Peninsula, the southwestern United States, and the Indo-Gangetic lowland.

Arabian Peninsula

USA

In Eurasia, desert zones are located in the Caspian lowland, on the Central Asian and South Kazakh plains, Central Asia, and the Near Asian highlands.

In the southern hemisphere, natural areas are less common. This includes a list of names: Namib in the Republic of Namibia, the desert zones of Peru and Venezuela, Gibson, Atacama, Victoria, Kalahari, Patagonia, Gran Chaco, Great Sandy, Karoo in Southwest Africa, Simpson.

Namib and Kalahari

Venezuela

Deserts Victoria, Gibson, Great Sandy, Simpson

Patagonia

Gran Chaco

One of the largest deserts in the world, Rub al-Khali occupies a third of the Arabian Peninsula. Tourists visiting Dubai often opt for a safari tour of hot spots.

The vast deserts of Israel are presented on the map - these are the Judean and Negev.

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

Greenland

The desert regions of Asia, Africa, Australia are located at a level of 200-600 meters above sea level, in Central Africa and North America - 1000 meters. The borders of deserts with mountains are widespread. They prevent the advance of cyclones. Most of the precipitation falls only on one side of the highlands, on the other side they are absent or present in small volumes.

Sources of information about how many deserts there are on earth give the number 51, while 49 are real (not icy).

Russia

The country occupies a vast area with different types of climate, so the answer to the question of whether there are deserts in Russia is in the affirmative. There are not only hot zones, but also cold ones. On the territory of Russia, deserts and semi-deserts are distributed from the Caspian lowland to China, in the east of Kalmykia and in the southern part of the Astrakhan region. On the section of the left bank of the Volga, deserts and semi-deserts stretch to Kazakhstan. The Arctic zone is located in the region of the northern islands.

As you can see in the picture, semi-deserts are located in the northern part, they are characterized by a steppe landscape. To the south, the climate becomes arid, the vegetation cover thins out. The desert zone begins.

The largest desert in Russia, Europe is called the Ryn-sands, located in the Caspian Sea.

Kinds

Depending on the type of soil and soil, there are types of deserts:

• Sandy and sandy-gravel- are formed on loose deposits of ancient alluvial plains. In different territories they are called differently: in Africa - ergs, in Central Asia - kums, in Arabia - nefuds. At the same time, sands do not occupy the largest part of the desert zone. For example, in the Sahara they make up only 10%.

  

  sandy deserts

  

  Sand and gravel deserts

• Stony (hamadas), gypsum, gravel, gravel-pebble- their location on mountain ranges, uplands, low mountains, and so on. The formation of a solid surface is due to the physical weathering of material from cracks in the rocks, which fills the depressions. This species is the most common - in the Sahara, 70% of the territory belongs to it.

  

• Saline. They are characterized by a high concentration of salts. Territories are covered with a crust or bog that can suck a person or animal.

  

• clayey- the surface of the territory is a clay layer, characterized by low mobility and low water properties (dry quickly, do not allow moisture to penetrate under the clay).

  

• Loess- are formed in areas of accumulation of dusty, porous particles. They are characterized by a heterogeneous relief, the presence of a network of potholes, ravines.

  

• arctic- allocate snowy and snowless (dry). The former occupy 99% of the area of ​​the Arctic deserts.

  

  Arctic snow deserts

  

  Arctic snowless deserts

Depending on the nature of precipitation, deserts are distinguished:

The driest desert - Atacama

Atacama is located on the west coast of South America in Chile. The coastal desert is located at the foot of the mountains, covering it with ridges from the rain, cold sea waters wash the hot shores.

Atacama is considered the driest natural area, with an average rainfall of 1 millimeter per year. In some areas, rain is observed 1 time in several decades. Significant precipitation was absent from 1570 to 1971. Some weather stations in the desert zone have never recorded rain.

In 2010, an anomalous phenomenon occurred there - snow fell, which covered several cities with snowdrifts.

In Atacama, there is a famous eleven-meter sculpture "Hand of the Desert", depicting a human palm, which protrudes three quarters from the sand. It symbolizes loneliness, grief, injustice, helplessness.

Atacama is known for a mysterious find - a humanoid mummy discovered in 2003 in the village of La Noria. Its size is 15 centimeters, instead of the usual 12 ribs, there are only 9, the skull has a pronounced elongated shape. For the outward resemblance to an alien creature, she received the name "Atakama humanoid".

However, scientists in their reports after the research are inclined to the earthly origin of the mummy girl. She probably suffered from progeria (rapid aging) and died either in the womb or after birth. There is a version that she lived for 7 years - this is due to the age of the skeleton.

In the desert on Mount Cerro Unica, there is the largest anthropomorphic geoglyph - a drawing 86 meters long, whose age is about 9 thousand years. He is called "Tarapaka", the Giant. The creators are unknown, it is possible to fully view the image from the aircraft.

The largest hot desert - Sahara

The natural zone is located on the territory of 10 states: Algeria, Egypt, Morocco, Libya, Mali, Niger, Mauritania, Chad, Sudan.

Her definition of "Queen of the Desert" is due to the huge area of ​​\u200b\u200bthe territory (9,065,000 square kilometers). Many areas of the zone are uninhabited, settlements are observed only at reliable sources of water and vegetation.

The Sahara is full of secrets and mysteries.

She is known for mirages that lead travelers astray and doom them to death. People see oases, lakes and even entire cities, but it is impossible to get closer to them - they move away until they disperse altogether.

The version explaining the phenomenon calls the mirage a kind of lens that visually approximates objects that are actually much further away.

For tourists, special maps have been compiled indicating the places where phantom images are likely to appear.

In the Sahara, on the territory of Mauritania, astronauts discovered an amazing object - a ring with a diameter of 50 kilometers, called the Eye of Africa or the Richat Structure.

Its age is estimated at 500-600 million years, the origin is unknown.

The largest cold desert - Antarctica

In terms of the area occupied by the territory, it is recognized as the leader among all desert places, ahead of even the Sahara. According to Wikipedia, the area of ​​the polar zone is 13,828,430 square kilometers. It is located on the island and mainland land of Antarctica.

In winter, the air temperature drops to -70 degrees, in summer the characteristic level is from -30 to -50 (not higher than -20). On the coast of the Antarctic Peninsula, it is possible to increase the indicators in summer up to 10-12 degrees.

Precipitation is presented in the form of snow, their amount is from 30 mm to 1000 mm per year. Characterized by strong winds, storms, snowstorms. Nature is poor, flora and fauna are scarce and monotonous.

The most popular desert is the Mojave

Located in the southwestern United States of America, most of the territory is uninhabited.

However, the desert is popular with tourists, here are the major cities of Lancaster, St. George, Henderson and, of course, gambling Las Vegas.

Famous museums, national parks, reserves in the Mojave. Death Valley stands out among them. This is a national park, where bizarre forms of salt flats, canyons, sand dunes, and valleys are presented.

Even an experienced tourist is not easy to navigate in such a variety. Poisonous snakes, spiders, scorpions, coyotes will not let you lose your vigilance.

Description of desert places

Natural zones are characterized by a variety of landscape and climate. Despite the harsh conditions, adapted species of animals, plants, and insects live in deserts and semi-deserts.

People also inhabit hot zones, run a household, find ways to interact with nature. However, in vast areas, due to the harsh environmental conditions, life is absent, the existence there for almost all organisms becomes impossible.

The soil

In desert zones, a weak development of soils is noted, in which water-soluble salts predominate over organic components. Vegetation covers less than 50% of the surface or is completely absent.

The gray-brown soil is characteristic of the elevated plains.

In deserts and semi-deserts, solonchaks with 1% concentration of easily soluble salts are often found.

Groundwater is predominantly mineralized. Upon reaching the surface of the soil, they are located in its upper layer, forming salinization.

The soil in subtropical deserts and semi-deserts is orange and brick red. Such soil is called red soil and yellow soil.

In the north of Africa, South and North America, gray soils are found in the deserts.

Climate

The climate in deserts and semi-deserts depends on its location. It is arid, hot, the air is slightly humidified, practically does not protect the soil from solar radiation.

The average temperature is +52 degrees, the maximum is +58. Excessive heating is associated with the lack of clouds and, accordingly, protection from direct sunlight. For the same reason, the temperature decreases markedly at night, since heat is not stored in the atmosphere.

Daily amplitudes in the deserts of the tropical zone are up to 40 degrees, in the temperate - up to 20. The latter are characterized by significant seasonal fluctuations. There are hot summers with temperatures in the range of +50 degrees and harsh winters, when the thermometer drops to -50, while the snow cover is small.

In hot deserts, rain is rare, but sometimes there are heavy downpours in which water is not absorbed into the soil. It flows into dry channels called wadis.

A characteristic feature of deserts is strong winds at a speed of 15-20 meters per second, sometimes more.

They transport surface material, forming sand and dust storms.

The desert zones of Russia are characterized by a sharply continental climate: dry and harsh with strong daily and seasonal temperature fluctuations. In summer, the level reaches more than +40 degrees, in winter it drops to -30.

Evaporation of precipitation exceeds the amount of precipitation, they are mainly observed in spring and summer.

Strong winds, dust storms and dry winds are typical.

There are no transitional seasons in the Arctic deserts. The polar night lasts 90 days, winter sets in with temperatures down to -60 degrees. Then summer comes with the polar day. It does not last long, while the temperature is within +3 degrees. Snow cover is constant, winter comes in 1 night.

Animal world

Living organisms living in deserts and semi-deserts have managed to adapt to harsh conditions.

From cold or heat, they hide in burrows, feed on insects, underground parts of plants.

reed cat

The carnivorous animals of the desert zones include the fennec fox, reed cats, cougars, and coyotes.

In the semi-desert you can meet a tiger.

Some representatives of the animal world have a developed system of thermoregulation. They withstand fluid loss up to a third of their own body weight (camel, gecko), and certain types of invertebrates - up to two-thirds of their weight.

North America and Asia are inhabited by a large number of reptiles: lizards, snakes, there are insects, including poisonous ones.

A large mammal, the saiga is also considered an inhabitant of hot natural areas.

In the Chihuahua Desert, located on the border of Texas, New Mexico and the Mexican states, pronghorn is often found feeding on all plants, including poisonous ones.

In the hot natural zone of Danakil, where the air temperature can rise to +60 degrees, wild donkeys, Grevy's zebra, Somali gazelle live on sparse vegetation.

wild donkey

In the deserts and semi-deserts of Russia, there are sandstone hares, hedgehogs, kulans, goitered gazelle, snakes, jerboas, ground squirrels, mice, and voles.

sandstone hare

Among predators, the steppe fox, polecat, and wolf are distinguished.

steppe fox

Spiders also live in natural areas: karakurt and tarantula. Among the birds there are steppe eagle, white-winged lark, white heron and so on.

steppe eagle

In the polar deserts, the animal world is scarce. Its representatives feed on seafood, vegetation. Polar bears, musk ox, arctic fox, seals, walruses, reindeer, hares live here.

Polar bear and walruses

Reindeer

Among the birds, eiders, gulls, terns, penguins and so on stand out.

penguins

Plants

In deserts and semi-deserts, the flora is not rich and includes prickly cactus, date palm, hard-leaved grasses, acacia, saxaul, psammophyte shrubs, ephedra, soap tree, edible lichen.

Date palm

Psammophyte shrubs

Sandy natural zones are characterized by oases - "islands" with rich vegetation and reservoirs.

In Russian deserts and semi-deserts, there are white and black wormwood, fescue, sarepta feather grass, viviparous bluegrass. The soil is not fertile.

Sarepta feather grass

Semi-deserts from April to November serve as pastures for livestock.

In some periods, natural areas flourish, filled with rich vegetation. For example, the Kyzylkum desert (“red sands”), which belongs to Uzbekistan, Kazakhstan, and partly Turkmenistan, blooms in spring with a bright carpet of flowers and herbs.

Subsequently, they disappear under the rays of the scorching summer sun.

In the Takla-Makan desert in western China, most of the territory is completely devoid of vegetation cover, only in rare areas of groundwater occurrence thickets of tamarisk, reed appear, camel thorn, saxaul, and poplar grow along river valleys.

Camelthorn plant

In the Arctic desert, vegetation is practically absent. In summer, the surface of the earth is covered with moss and lichens, there are sedge and cereals, polar poppy, saxifrage, buttercup, and so on.

locals

People living in hot natural areas are forced to adapt to environmental conditions. In economic activity, pasture cattle breeding is distinguished.

Agriculture is used only in the valleys of large rivers, irrigation is used.

Oil and gas are produced in many natural areas. This is especially true for Asia.

In the deserts and semi-deserts of Russia, irrigated agriculture is practiced in the floodplains and deltas of large rivers (Volga, Syrdarya, Amudarya). A large number of wells and wells have been created for watering cattle, places for their wintering.

The most severe conditions for economic activity are noted in the stony and gravelly deserts, where agriculture is practically absent.

With a shortage of water, local residents develop various ways to get it. For example, in the driest Atacama Desert, the natives use "fog eliminators" - cylinders the size of a person to collect moisture. The fog condenses on the walls of the vessel, made of nylon threads, and flows into the barrel. With it, it is possible to collect up to 18 liters of water per day.

The nomadic inhabitants of Arabia, the Near and Middle East are called Bedouins.

Their culture is based on the invention of the tent and the domestication and breeding of camels. The Bedouin, together with his family, roams on a camel, which carries a portable dwelling and utensils.

reserves

Human interference is recognized as the main threat to deserts and their inhabitants. In addition to hunting for rare and endangered species of animals and birds, natural resources are being extracted in these zones - oil and gas.

Technological progress increases the need for them, which leads to an increase in the development of deposits. Mining pollutes nearby areas, causing an environmental disaster.

Anthropogenic impact in the Arctic contributes to the melting of ice, reducing the territory of cold deserts. Its disappearance will cause the death of a large number of representatives of the flora and fauna of the natural zone.

Environmental work is being carried out in Russia and throughout the world, national parks and reserves are being created.

Semi-desert zones of temperate zones

natural land areas in the temperate zones of the Northern and Southern Hemispheres with a predominance of semi-desert landscapes. The largest area is occupied in the inner part of Eurasia, where they extend (approximately 10 thousand km). km) from the Caspian lowland in the north to the eastern edge of the Ordos plateau in the east; the width of the strip of semi-deserts, within which plains predominate, reaches in places 500 km. In North America P. z. y. The settlements are located in the meridionally elongated strip of the foothills of the Rocky Mountains and the basins of the Great Basin, where they mosaically alternate with desert landscapes. In the southern hemisphere, they are distributed in the south of South America (to the east of the Andes, in Patagonia).

Climate P. h. y. The northern hemisphere is arid, continental, with cold winters and long hot and dry summers. The radiation balance is about 5 MJ/m2 or 120 kcal / cm 2 per year, evaporation is several times higher than the annual amount of precipitation (usually 200-300 mm). The average temperature in July is 22-25 °C, in January it is up to -20 °C. Winters are usually snowy with strong winds. In the Southern Hemisphere (in Patagonia) the climate is less continental. In summer, the air temperature is 15-20 °C, in winter - about 1 °C. The Andes retain most of the moisture brought by the dominant west. winds, so precipitation falls only 100-150 mm(in places - up to 250) per year.

Surface runoff is poorly developed, in summer many rivers dry up, they are usually full of water only in spring, during the melting of seasonal snows. Significant areas are generally devoid of surface runoff. There are numerous brackish and salt lakes. Constant deficit of moisture in the soil from the middle of the growing season.

Light chestnut and brown soils predominate, often in combination with solonets soils; saline soils and meadow solonchak soils are common along relief depressions. Soils are characterized by complexity, low humus content (1.5-3°%); Soils are often distinguished by a high content of gypsum, carbonates, and the manifestation of solonetzic processes. They are often suitable for agriculture, but they need irrigation, and in some places, the elimination of solonetsousness and resettlement.

The vegetation is xerophilous, often complex. In the semi-deserts of temperate latitudes of the Northern Hemisphere, grass-wormwood communities with a significant participation of ephemers and ephemeroids predominate. On sandy soils, tree and shrub vegetation is common (loch, birch, pine, dzhuzgun, sand acacia). In the Southern Hemisphere, the vegetation of semi-deserts is sparse, predominantly semi-shrub with the participation of grasses and succulents. Desert and steppe animal species predominate. Semi-deserts of temperate latitudes are usually good pastures for year-round grazing.

M. P. Petrov, Yu. K. Efremov.

Great Soviet Encyclopedia. - M.: Soviet Encyclopedia. 1969-1978 .

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