The relief and soil of the hot desert. Message around the world on the topic: “Natural zones of Russia

Deserts and semi-deserts of Eurasia extend from the Caspian lowland to China. In Russia, this occupies the territory of the southeastern regions of the country. The Arctic desert is located on the territory of the northern. A distinctive feature of deserts and semi-deserts is the high fluctuation of winter and summer temperatures. Semi-deserts are located in the northern part of the natural zone. The climate here is milder, so they are characterized by a steppe landscape. Toward the south, where it becomes arid, and the vegetation cover practically disappears, there is a desert zone.

Geographical location and natural conditions

Arctic desert, as well as deserts and semi-deserts on the map of Russia

In the region of the left bank of the Volga, deserts and semi-deserts stretch to Kazakhstan. Lands from the right bank of the river extend to the foothills of the Caucasus. The territories lie on the Caspian lowland, which is a flat space. Millions of years ago, there was a seabed here. Most of the deserts are a flat earth's surface, and only in the west there are steep slopes.

Climate

The natural zone is located in the area of ​​sharply continental climate. Rain and snow fall infrequently, which is why the climate is dry but harsh. Most of the precipitation occurs in spring and summer. The level of evaporation exceeds the amount of precipitation.
In the desert, strong daily and annual temperature amplitudes are observed. During the day, the temperature difference can reach thirty degrees Celsius. In winter, the thermometer drops to -30°C, the winds are raging. Their gusts blow away the snow cover from the soil, due to which it acquires a black tint. Summer temperatures exceed +40°C. Rains are rare, but dust storms and dry winds often occur.

Vegetable world

Soils on the territory of semi-deserts are saline, as they are based on ancient marine rocks. On the territory of semi-deserts, wormwood-cereal vegetation grows. The lands contain little humus, and as a result of human activities they turn into moving sands, therefore they are infertile. Nevertheless, the vegetation cover of the natural zone is variegated. Here grows sarepta feather grass, fescue, white wormwood, black wormwood, desert wheatgrass, viviparous bluegrass. From April to November, semi-desert lands are used as pastures. In June, with the onset of the dry period, the vegetation disappears, and the semi-desert becomes like a desert.

Closer to the south, the climate becomes arid, and the land turns into a real desert. It is usually divided into two subzones: northern and southern. In the northern part the climate is mild. Semi-shrubs dominate here: saline barnyard grass, gray quinoa, krashennikovia. adapt to the conditions of existence, many of them are leafless in order to reduce moisture evaporation. Vegetation in one form or another is located throughout the desert. In the southern part there are small trees and shrubs: sandy acacia, Richter's saltwort, white saxaul. These areas also serve as pastures.

Animal world

In the zone of semi-deserts and deserts, there are many who have adapted to harsh conditions. Animals dig deep burrows to wait out the heat of the day. Jerboas, ground squirrels, mice and voles have developed optimal conditions for existence in the harsh conditions of the natural zone.

During the polar night, which lasts 90 days, winter sets in. Summer comes with a polar day. There are no transition seasons. Winter temperatures are low, down to -60°C. There is little rainfall. Winds blow snow off the ground. Summer doesn't last long. The air temperature in July is +3°C. During the polar day, the sun warms the air poorly. Snow does not melt 300 days a year, and winter comes in one night.

Trees and shrubs are completely absent. The grounds are covered with lichens and mosses in summer. Sedge and cereals grow on rocky ground. In the Arctic desert in summer you can find green oases with polar poppy, saxifrage, buttercup and arctic pike.

The soil thaws by 40 cm. Iron oxides accumulate in the upper part, due to which the earth acquires a brown tint. On the surface there is sand, stones. Spherical formations, spherulites, are a landmark of cold deserts.

The animal world is poor. Animals living in the Arctic desert feed on seafood. Polar bears, leading a semi-aquatic lifestyle, breed off the coast of Chukotka, on Franz Josef Land. Lairs have been created for them in the Wrangel Island Arctic Reserve. Arctic foxes, lemmings, hares, reindeer come from summer. Seals and walruses arrange their rookeries on the coast. Birds are considered the most numerous class. Bird markets are arranged by eiders, gulls, tundra partridges, guillemots, and terns. When the polar day comes, white geese, geese, plovers and dunlin rush to the Arctic.

Ecological problems of deserts and semi-deserts of Russia

The main threat of turning deserts into wastelands is human intervention. Recent scientific studies have shown that there are deposits of oil and natural gas in these zones. Due to technological progress, the need for them is constantly growing. Oil production pollutes the surrounding areas more than others. The hit of "black gold" in entails an ecological catastrophe.

In the zone of deserts and semi-deserts of Russia, many different species of animals live, some of them are listed in the Red Book. Poaching puts the existence of valuable animals into question of survival. The very process of desertification is detrimental to agriculture. The number of pastures is decreasing.

Due to anthropogenic influence, ice is melting in the Arctic, as a result of which the Arctic desert zone itself is shrinking. If it does not exist, a large number of representatives of flora and fauna will disappear from the face of the Earth. Snowmobiles and other land vehicles pollute with exhaust emissions. Ozone holes negatively affect the lives of animals. destroys mining, waste, . Large species of fish are under the threat of extinction. Their food, small fish and seafood, a person catches on an industrial scale.

Deserts and semi-deserts need our protection. Already today there are reserves in the territories, but this is not enough. Work on the protection of natural areas must be controlled at the state level. All efforts should be directed to solving existing problems so that new ones do not arise.

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

United States of America

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 the 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.

Camel-thorn

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 all over the world, national parks and reserves are being created.

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.

Today we will continue our acquaintance with the natural zones of our planet. The theme of our tour will be places where camels slowly walk, and the wind and the scorching sun are the undivided masters. Let's talk about deserts.

Here, among the sands and heat, there is its own flora and fauna, people live and work. What are the distinguishing features of this zone?

Where are the deserts

Deserts are areas with a continental climate and sparse vegetation. Such places can be found on all continents except Europe. They extend through the temperate zone of the Northern Hemisphere and through the subtropics and tropics of both hemispheres.

The largest deserts are the Sahara, Victoria, Karakum, Atacama, Nazca, and the Gobi Desert.

Russian deserts are located in the east of Kalmykia and in the south of the Astrakhan region.

Climate features

The main features of the climate of this zone are high daytime temperatures and extremely dry air. During the day, the content of water vapor in the atmosphere is 5–20%, which is several times lower than the norm. The driest are the deserts of South America. The main reason - almost complete absence of rain. In some places, they fall no more than once every few months or even several years. Sometimes abundant rain streams fall on the dry, heated ground, but evaporate instantly, without having time to saturate the soil.

Often these places are "dry rain" From the resulting rain clouds, ordinary raindrops fall out, but colliding with heated air, they evaporate without reaching the ground. Snowfall is rare here. Only in some cases the snow cover reaches a thickness of more than 10 cm.

In this natural area, the daytime temperature can rise to +50°C, while at night it can drop to 0°C. In the northern regions, the thermometer can drop to minus 40 °C. For these reasons, the desert climate is considered continental.

Often, residents and tourists become witnesses of amazing optical phenomena - mirages. At the same time, tired travelers see in the distance oases with life-giving moisture, wells with drinking water .... But all this is an optical illusion caused by the refraction of the sun's rays in the heated layers of the atmosphere. As they approach these objects, they move away from the observer. To get rid of these optical illusions, you can make a fire. The smoke creeping along the ground quickly dispels this haunting vision.

Relief features

Most of the surface of the deserts is covered with sand and the wild wind becomes the "culprit" of sandstorms. At the same time, they rise above the surface of the earth huge masses of sand. The sandy curtain erases the horizon line, outshines the bright sunlight. Hot air mixed with dust makes breathing difficult.

After 2-3 days, the sand settles. And before the eyes of others, a renewed surface of the desert appears. In some places, rocky areas are exposed, or vice versa, new dunes appear against the background of frozen sandy waves. In the relief of the deserts there are small hills, alternating with plains, ancient river valleys and depressions from once existing lakes.

Deserts tend to light soil color thanks to the lime accumulated in it. The reddish color of the soil has surface areas containing an excess amount of iron oxides. Fertile soil layer - humus is almost absent. In addition to sandy deserts, there are zones with stony, clayey and saline soils.

Vegetable world

In most deserts precipitation falls in spring and winter. Moist soil is literally transformed. In a few days, it blooms with a wide variety of colors. The duration of flowering depends on the abundance of precipitation and on the soil of the area. Local residents and tourists come to admire the bright beautiful flower carpet.

The heat and lack of moisture soon return the desert to its normal state, where only the most resilient plants can grow.

Tree trunks are most often strongly curved. The most common plant in this area is saxaul bushes. They grow in groups, forming small groves. However, do not look for shadows under their crowns. Instead of the usual foliage, the branches are covered with small scales.

How does this shrub survive in such arid soils? Nature has provided them with mighty roots that go into the ground to a depth of 15 meters. And another desert plant - camel-thorn its roots can get moisture from a depth of up to 30 meters. The thorns or very small leaves of desert plants allow them to expend moisture very economically when evaporating.

Among the various cacti growing in the desert, there is Echinocactus Gruzoni. The juice of this one and a half meter plant perfectly quenches thirst.

In the South African desert there is a very amazing flower - fenestraria. Only a few of its leaves are visible on the surface of the earth, but its roots are like a tiny laboratory. It is in it that the development of nutrients occurs, thanks to which this plant even blooms underground.

One can only wonder at the adaptability of plants to the extreme conditions of the desert.

Animal world

In the heat of the day, the desert really seems devoid of all life. Only occasionally there is a nimble lizard, but some bug is in a hurry about its business. But with the onset of night coolness, the desert comes to life. Small and large enough animals crawl out of their shelters to replenish food supplies.

How do animals escape the heat? Some burrow into the sand. Already at a depth of 30 cm the temperature is 40°C lower than on the ground. This is exactly how the kangaroo jumper behaves, which manages not to get out of its underground shelter for several days. In its minks stocks of grains are stored, which absorb moisture from the air. They also satisfy his hunger and thirst.

Close "canine relatives" of jackals and coyotes from the heat saves rapid breathing and protruding tongue.

Saliva evaporating from the tongue cools these curious animals well. African foxes, hedgehogs radiate excess heat with large ears.

Long legs ostriches and camels help to escape from the hot sand, because they are high enough above the ground, and there the temperature is lower.

In general, the camel is more adapted to life in the desert than other animals. Thanks to his wide, callused feet, he can walk on hot sand without getting burned or falling through. And its thick and dense coat prevents the evaporation of moisture. Fat accumulated in the humps, if necessary, is processed into water. Although without water, he may well live for more than two weeks. And in food, these giants are not picky - they chew a camel thorn for themselves, and even branches of saxaul or acacia are already a luxury in a camel diet.

Desert insects "thought of" reflecting the scorching sun's rays the surface of your body.

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