The spherical shape of our planet is the reason for the uneven distribution of sunlight. As a result, in some areas the earth's surface warms up more, in others - much less. As a result, natural zones were formed, each of which has unique properties and climatic conditions.

What are natural areas?

Natural complexes are impressive land areas characterized by the same climate, soil composition, flora and fauna. The main reason for the appearance of natural zones is the uneven division of heat and moisture on Earth.

Table “Characteristics of natural areas”

Natural area	Climate zone	Average temperature in Celsius (winter/summer)
Antarctic and Arctic deserts	Antarctic, Arctic
Tundra and forest-tundra	Subarctic and subantarctic
	Moderate
Mixed forests	Moderate
Broadleaf forests	Moderate
Steppes and forest-steppes	Subtropical and temperate
Temperate deserts and semi-deserts	Moderate
Hardleaf forests	Subtropical
Tropical deserts and semi-deserts	Tropical
Savannas and woodlands		20+24 and above
Variable rain forests	Subequatorial, tropical	20+24 and above
Permanently wet forests	Equatorial

This characteristic is concise, since a lot can be said about the characteristics of the natural areas of the world.

Temperate climate zone

• Taiga . Occupies the largest area - almost 30% of all forest areas on the planet. Taiga is the kingdom of coniferous forests that can withstand low temperatures. Vast areas of this zone are covered with permafrost.

Rice. 1. Taiga forests occupy vast territories.

• Mixed forests . They have good resistance to long-term frosty winters. Although the soil is not very fertile, unlike the taiga, it is already suitable for farming.
• Broadleaf forests . This area is characterized by mild winters. The soil is fertile, with a high humus content. A significant part of broad-leaved forests is represented by deciduous trees. The fauna is very diverse.
• Temperate deserts and semi-deserts . Their distinguishing feature is sparse plant and animal world, aridity and sharp temperature changes between seasons.

Arctic deserts and semi-deserts

These are huge areas covered with a thick layer of ice and snow. By and large, the Arctic deserts are a lifeless place. Only on the coast can you find a few representatives of the local fauna: seals, walruses, polar bears, arctic foxes and penguins. Mosses and lichens grow in small areas of land that are not covered with thick ice.

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Rice. 2. Arctic desert.

Equatorial rainforests

A very hot climate and consistently high humidity created ideal conditions for equatorial forests. The impenetrable jungle is home to 70% of all living creatures inhabiting our planet. The trees remain evergreen throughout the year because they shed their leaves gradually.

The flora of this natural area is incredibly diverse. But what is most striking is the fact that such an abundance of plants became possible on soils in which the humus content is very small.

Fig.3. The nature of equatorial forests is rich.

Equatorial and subtropical climate zone

• Variably humid forests . Heavy rainfall occurs only during the rainy season, followed by a long dry period. The fauna and flora are also very diverse.
• Open woodlands and savannas . They appear on those areas of land where there is no longer enough moisture for variable-humid forests. The rainy season is very long and lasts at least six months.

Hardleaf forests

They got their name due to the dense shell of the leaves, which helps retain moisture. This zone is characterized by not very heavy rainfall. Such forests grow along the coasts of seas and oceans.

Steppes and forest-steppes

They are vast areas covered with grass. Steppe soils are the most fertile due to their high humus content, and are often used for farming.

Tundra and forest-tundra

It is characterized by a harsh climate that even the most resistant coniferous trees. This zone is characterized by a lack of heat and high humidity, which leads to swamping of the area. The flora of the tundra is represented only by lichens and mosses; there are no trees at all.

Today, the tundra is the most fragile and unstable ecosystem. Active mining has led to the fact that this zone is on the verge of complete extinction.

What have we learned?

The wide variety of natural zones is due to the uneven distribution of humidity and heat on the planet. Each natural complex has its own unique flora and fauna, soil composition, and climate.

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There are several principles according to which the territories of countries are divided. Thus, each state can be divided into territories, regions and districts, but biologists and zoologists prefer a different system - the allocation of natural zones. Since Russia has enough great length in the direction from north to south, it is also conventionally divided into natural zones. How many natural zones are there in Russia? Eight different natural areas. Each of these territories is characterized by its own special climate, and also has certain differences in the diversity of flora. Let's look at the natural zones on the territory of Russia in a little more detail (we'll figure out what they are and how many there are), and also give short description each of these territories.

What are the natural areas in Russia?

Arctic desert zone

This territory covers the islands of the Arctic Ocean, as well as the extreme north of the peninsula called Taimyr. A significant area of ​​this zone is covered with glaciers, long and quite severe winters reign here, and summers are cold and also very short. A large proportion of Arctic deserts consists of stone placers; the soils here are practically undeveloped. As for the vegetation cover, in this area it is quite sparse and spotty. Most of the flora is lichens, mosses, and algae. They can group only in a place sheltered from cold winds. In fertilized areas, there are also higher plants, represented by quarry, polar poppy, croup, chickweed, bluegrass, etc. Near patches of snow you can find ice buttercup and polar willow, the size of which does not exceed five centimeters.

Tundra zone

Includes territories near the coast of the seas of the Arctic Ocean, starting from the western border and up to the Bering Strait. The tundra is also characterized by long winters, but slightly warmer summers. A characteristic feature Such a zone is permafrost. The vegetation here is mainly represented by mosses, lichens, shrubs and shrubs. For all tundra plants, the root system can develop only in a small space that is not frozen, and the crops themselves do not rise particularly above the ground.

Forest-tundra zone

This territory is located along the southern borders of the tundra zone. It is considered a transitional area from the tundra to the taiga. Feature forest-tundra – the presence of sparse forests in the interfluves. The climate of this zone is represented by cold and snowy winters, as well as more warm summer and lower wind speeds than in the tundra.

The sparse forests of such areas consist of larches, birches and Siberian spruce. On the slopes river valleys and terraces there are many meadows composed of buttercups, valerian, berries and lights.

Taiga

This zone has the largest area; it stretches from the western border of Russia all the way to the coast of Okhotsk, as well as Sea of ​​Japan. The main type of vegetation in this zone is represented by light-coniferous and dark-coniferous forests. The bulk of forests consists of larch, slightly less common are pine, spruce forests, as well as forests of fir or Siberian cedar. In the territories of the Far Eastern Primorye, southern varieties of trees are also found, represented by Amur velvet and Manchurian walnut.

Mixed and broad-leaved forests

Such a zone is located just south of the taiga in the region of the Russian Plain; it is not inside the continent, but it is again observed in the southern territories of the Far East. The north of this zone is characterized by coniferous-deciduous forests mixed type, and for the south - broad-leaved forests with a multi-tiered structure. Today, forests occupy about thirty percent of the area of ​​such a zone, and contain many small-leaved species, represented by birches, aspens and alders.

Forest-steppe zone

This area is transitional from steppe to forest; accordingly, both forest and steppe vegetation can be seen on it. In the interfluves of the forest-steppe, forests with broad-leaved and small-leaved trees alternate. The natural nature of such an area has changed greatly due to human activity. The main forest-forming species of the forest-steppe is oak; in Western Siberia there are many birch groves. And the steppes of such a zone are characterized by colorful forbs.

Steppe zone

Such territories in Russia have a fairly small area, covering the southern part of the European part, as well as the south of Western Siberia. Almost all steppes are now plowed.
Natural vegetation is represented by grasses and turf grasses (feather grass, fescue, steppe oats, bluegrass, etc.). The northern regions of the steppe are characterized by forbs and grasses, while the southern regions are characterized by feather grass and fescue vegetation.

Semi-deserts and deserts

Such territories in Russia are located in the Caspian region, as well as in the Eastern Ciscaucasia. Here, as in the steppe, there are no forests. Vegetation is represented different cultures, so in the depressions with significant amount In humus, fescue, wheatgrass, tonkonog, etc. are found, and salt licks are covered with blue-green algae. In the northern territories, the bulk of plants are represented by cereals with an admixture of wormwood, and in the southern territories there is more wormwood, the number of saltworts and ephemerals increases, and the overall plant cover is characterized by greater sparseness.

We have given a description of the natural zones of Russia. Each natural zone has a fairly large extent, maintaining certain common features on its territory: climate, humidity level, type of soil and vegetation.

Natural conditions in different places on the globe are not the same, but naturally change from the poles to the equator. The main reason for this is the spherical shape of the Earth. Indeed, if the Earth were flat, like a chalkboard, its surface, oriented (directed) strictly across the sun's rays, would heat up equally everywhere, both at the poles and at the equator.

But our planet has the shape of a ball, which is why the sun's rays fall on its surface at different angles, and therefore heat it differently. Above the equator, the sun during the day “looks” at the earth’s surface almost “point-blank”, and twice a year, at noon, its hot rays fall here at right angles (the sun in such cases is at its zenith, that is, directly overhead) . At the poles, the sun's rays fall obliquely, at an acute angle, the sun for a long time moves low above the horizon, and then does not appear in the sky at all for several months. As a result, the equator and even moderate latitudes receive much more heat than areas near the poles.

Therefore, in both hemispheres of the Earth, several thermal zones are distinguished: equatorial, two tropical, two temperate and two cold. Solar heat is driving force natural processes and the phenomena that we observe around us in the surface shell of the Earth. Now scientists call this shell the biosphere, that is, the sphere of life.

And since solar heat is distributed unevenly on Earth, large differences are clearly expressed in the biosphere and in the nature around us from one thermal zone to another. Accordingly, geographic zones are distinguished. Their boundaries coincide with the boundaries of thermal zones.

But in each geographical zones natural conditions are different. After all, the width of these belts in some places is more than 4 thousand. km! The closer to the equator this or that part of the geographical zone, the more heat it receives and the more it differs from other parts distant from the equator. Such differences are especially pronounced in climate, soils, vegetation and fauna. Therefore, within geographic zones, geographic, or natural, zones are clearly defined, i.e., areas that are more or less homogeneous in natural conditions. They are most often stretched in stripes along parallels. Thus, in temperate zones there are zones: forest, forest-steppe, steppe, semi-desert and desert.

The location of natural zones around the globe and their boundaries are determined not only by the amount of solar heat. The amount of moisture, which is also unevenly distributed on land, is also of great importance. This leads to large differences in natural conditions even at the same latitude. In Africa, near the equator, there is a lot of heat everywhere, but on the west coast, where there is also a lot of moisture, dense rainforests, and in the east, where there is not enough of it, there are savannas, sometimes quite dry.

In addition, the position of geographical land zones is influenced by mountain ranges, which change the direction of the zones along the parallels. The mountains have their own altitude zones, as it gets colder as you climb. At high altitudes, the earth's surface gives off a lot of heat to the surrounding space, “supplied” to it by the sun. This happens because the air at the top is rarefied, and although here it transmits more sunlight than at the foot of the mountains, heat loss from the earth’s surface increases to an even greater extent with height.

High-altitude zones occupy smaller spaces than plain (latitudinal) zones, and seem to repeat them: mountain glaciers - the polar zone, mountain tundra - tundra, mountain forests - forest zone, etc. The lower part of the mountains usually merges with the latitudinal zone, within which they are located. For example, the taiga approaches the foothills of the Northern and Middle Urals, and at the foot of some mountains Central Asia, which lie in the desert zone, there is a desert, and in the Himalayas the lower part of the mountains is covered with tropical jungle, etc. Largest quantity altitudinal zones (from glaciers at the tops of mountains to tropical forests at the foot) are observed in high mountains located near the equator. Although high-altitude zones are similar to plain zones, the similarity is very relative.

Indeed, the amount of precipitation in mountains usually increases with altitude, while in the direction from the equator to the poles it generally decreases. In mountains, the length of day and night does not change with altitude as much as when moving from the equator to the poles. In addition, climatic conditions in the mountains become more complex: the steepness of the slopes and their exposure (northern or southern, western or eastern slopes) play a significant role here, special wind systems arise, etc. All this leads to the fact that both soils and vegetation and fauna of each altitude zone acquire special features that distinguish it from the corresponding plain zone.

The differences in natural zones on land are most clearly reflected by vegetation. Therefore, most zones are named according to the type of vegetation that predominates in them. These are the zones of temperate forests, forest-steppes, steppes, tropical rainforests, etc.

Geographical zones can also be traced in the oceans, but they are less pronounced than on land, and only in upper layers water - to a depth of 200-300 m. Geographic zones in the oceans generally coincide with thermal zones, but not completely, since water is very mobile, sea currents constantly mix it, and in some places transfer it from one zone to another.

In the World Ocean, as on land, there are seven main geographical zones: equatorial, two tropical, two temperate and two cold. They differ from each other in temperature and salinity of water, the nature of currents, vegetation and wildlife.

Thus, the waters of cold zones have a low temperature. They contain slightly less dissolved salts and more oxygen than the waters of other zones. Vast areas of seas are covered thick ice, and the flora and fauna are poor in species composition. In temperate zones, surface layers of water heat up in summer and cool in winter. Ice in these zones appears only in places, and even then only in winter. The organic world is rich and diverse. Tropical and equatorial waters are always warm. Life is abundant in them. What are geographical land areas? Let's get acquainted With the most important of them.

Ice is the name given to the natural zone adjacent to the poles of the globe. In the northern hemisphere, the ice zone includes the northern edge of the Taimyr Peninsula, as well as numerous Arctic islands - areas lying around the North Pole, under the constellation Ursa Major ("arktos" in Greek - bear). These are the northern islands of the Canadian Arctic archipelago, Greenland, Spitsbergen, Franz Josef Land, etc.

In the southern polar region - Antarctica (from the Greek word "anti" - against, i.e. against the Arctic) - there is the ice-covered continent of Antarctica, which is part of the ice zone of the southern hemisphere.

The harsh nature of the ice zone. Snow and ice do not completely melt here even in summer. And although the sun shines for several months without interruption, around the clock, it does not warm the earth, which has cooled down during the long winter, since it rises low above the horizon. In addition, the sun is often hidden by thick clouds and fog, and the white surface of snow and ice reflects its rays. On the polar night, severe frosts rage.

In 1961, Soviet researchers in Antarctica had to work in temperatures of 88.3°. At the same time, hurricane winds were still blowing - up to 70 m/sec. Due to such low temperatures, gasoline did not ignite in engines, and metal and rubber became as fragile as glass.

Summer is coming, the sun is rising over the Arctic desert, and now it will not hide behind the horizon for a long time. And yet, clear, sunny weather is rare. The sky is overcast with low clouds, and it rains and even snows for several days in a row. There are very few plants here: the conditions are too harsh. Snow-covered ice fields spread out everywhere, and bare rocks and rocky outcrops darken on the islands and coastline. Even where plants are not hindered by ice and snow, strong winds destroy them. Only in places, in lowlands protected from icy breath, do they manage to form within short summer small "oases". But even here the plants do not stretch upward, but press themselves to the ground: this way it is easier for them to withstand the wind. The snow barely has time to melt before the first flowers appear. They develop very quickly because the sun shines around the clock.

In the most favorable conditions of the Arctic icy desert, patches of Arctic meadows and swamps are found. Polar poppies are turning yellow on the island of Spitsbergen. The flora of Franz Josef Land includes more than thirty species of flowering plants. Even in the icy expanses of central Greenland, you can see from an airplane red-brown or green fields formed by microorganisms.

It's noisy in the Arctic in the summer. Returning to their nesting places migratory birds: little auks, guillemots, guillemots, various gulls... There are not so many species, but each is represented by many thousands of birds. They nest on the ledges of coastal cliffs in huge colonies, making a terrible noise. That is why these colonies are called “bird colonies”. How can we explain the desire of birds to settle in such huge numbers in small areas? The fact is that steep cliffs with ledges and small platforms are very convenient for nesting, and nearby there is an abundance of fish on which birds feed. In addition, it is easier to drive away a predator together.

Other birds also fly to the Arctic: geese, terns, eiders. In the spring, the eider grows long fluff on its abdomen, with which it covers its nest. This down is unusually warm and light and is therefore highly valued. People collect it at eider nesting sites and even arrange artificial nests for her in the form of a half-open box.

In Greenland and on the islands of the Canadian Arctic archipelago, an animal has been preserved whose ancestors lived back in the days of mammoths and long-haired rhinoceroses. This is a wild musk ox, or musk ox. He really resembles both a ram and a bull at the same time. Its massive body is covered with long hair.

The nature of Antarctica is even poorer than that of the Arctic. The average altitude of Antarctica is 2200 m above sea level, but the earth's surface is much lower here, because it is hidden under a thick layer of ice, its average thickness is more than 1500 m, and the largest is 5000 m. Sparse vegetation is found here only on the coast of the mainland. These are mainly mosses and lichens. Only three species of flowering plants are known here. The Antarctic fauna is also not rich in species. There are no such large animals as polar bears here. Seals live off the coast of Antarctica, and petrels and albatrosses fly over the waters of the oceans washing it. Albatross wingspan up to 4 m. These birds spend most of their lives above water, catching fish.

The most wonderful animals of Antarctica are penguins. These birds have lost the ability to fly; their wings have turned into swimming flippers. Penguins are excellent swimmers and divers. But on land they are clumsy, waddle, resembling fat, funny little men in black tailcoats and white shirts. Penguins live in numerous colonies. Their only enemy is the leopard seal (one of the local seal species).

For a long time, the Arctic and especially the Antarctic were almost undeveloped by humans. Now, thanks to the achievements of science and technology, we can already talk not only about the study and use of these little-explored areas, not only about human adaptation to their harsh natural conditions, but also about the human influence on the nature of the ice zone.

At high altitudes in the mountains the same cold as in the ice zone, the same wind-blown rocks, only here and there covered with mosses and lichens. But there are no sea spaces nearby, and migratory birds do not organize “bazaars”. There are no months-long polar days and nights here either. On high mountains there is low atmospheric pressure, the air is poorer in oxygen, so not all animals can adapt to life in high mountain conditions. A large predator, the snow leopard, tolerates cold and altitude well. The whitish shade of the fur makes it inconspicuous against the background of snow and gray stones. In summer, the leopard usually stays on the line of eternal snow, and in winter it descends lower, following its prey - mountain sheep and mountain turkeys (sulars).

The more grass there is in the steppe, the more large herbivores there are. And the more predators there are. In our steppes characteristic predator- a wolf (although it is also found in other zones), and in North America - small wolves - coyotes.

Of the steppe birds, only the bustard and gray partridge live sedentary, not flying to warm countries for the winter. But in the summer, many representatives of the bird kingdom settle in the steppe: ducks, waders, demoiselle cranes, larks.

On high altitude Feathered predators soar over the steppe: eagles, vultures, etc. Open spaces allow them to spot prey from above at a distance of several kilometers. Predator birds they sit down to rest on mounds, telegraph poles and other elevations, from where they have a better view and are easier to take off.

The steppes of North America are called prairies. In them, along with plants common to our steppes (feather grass, wheatgrass), there are those that are not in the eastern hemisphere: bison grass, Graam's grass, etc. The steppes of South America - the pampa - are distinguished by an even greater variety of grasses.

Stiff grasses, one to one and a half meters high, in some places completely cover large areas of the pampa. Where the soil is somewhat wetter, bright green creeping plants appear and with them scarlet, pink, and white verbena. Yellow and white lilies grow in damp places. The most beautiful plant of the pampa is the silvery gynerium, whose silky panicles seem to have absorbed the most varied tones of heavenly azure. In this sea of ​​grass, herds of wild cattle and herds of horses roam, rhea ostriches stride importantly. Near lakes and rivers, where there are groves of trees and shrubs, you can see black squirrels, tiny hummingbirds, and noisy parrots.

In some mountains (Tian Shan, Altai, in the mountains of Transbaikalia, in the Greater Khingan, in the Cordillera, etc.) there are places where much resembles a flat steppe. In Central Asia mountain steppes almost no different from the lowland feather grass-fescue.

In distant times, steppes occupied vast territories on the plains of North America and Eurasia. Now they are completely plowed open. Wheat, corn, millet, and various melons are grown on the fertile steppe soils.

The natural vegetation cover of the steppes is now almost non-existent. The animal world has also changed. The ancestors of our domestic animals - the wild bull aurochs and wild tarpan horses - have long disappeared here, and some birds have become rare. Now only in a few nature reserves, such as our Askania-Nova, you can see real virgin steppe.

Subtropical forests and shrubs

Approximately between 30 and 40° N. w. and S. are subtropical. Their nature is extremely diverse. At these latitudes you can also see lush evergreen forest, and the steppe, and the sultry desert - moisture is so unevenly distributed here - the source of life.

On the western edges of the continents there are subtropics, often called Mediterranean, because all the features of their nature are most clearly expressed on the coasts of the Mediterranean Sea.

Summers in these places are hot and dry, rain falls mostly in winter, during which even mild frosts rarely occur. The vegetation cover of the Mediterranean subtropics is dominated by thickets of evergreen shrubs and low trees. Noble laurel, strawberry tree, which annually sheds its bark, delicate myrtle, wild olives, roses, and junipers grow here. Many plants that have adapted to dry summers have leaves that turn into thorns. Entwined with the same thorny vines, they become an insurmountable obstacle for travelers.

When it's time to bloom, the bushes (called maquis) turn into a sea of ​​luxurious flowers - yellow, white, blue and red. A strong aroma fills the surrounding air.

One of the most beautiful plants Mediterranean subtropics - Italian pine, or pine. The wide, spreading crowns of pine trees seem especially magnificent next to the dense spindle-shaped crowns of cypress trees. These beautiful trees most often grow alone. Very few pine groves have survived. The small forests that can still be found in the Mediterranean subtropics consist mainly of evergreen oaks - cork and holm. Trees are rare here, and grasses and shrubs grow wildly between them. There is a lot of light in such a forest, and this makes it very different from the shady Russian oak forests.

The subtropics on the eastern edges of the continents present a different picture. In Southeast China and Southern Japan precipitation They also fall unevenly, but there is more rain in the summer (and not in the winter, as in the Mediterranean subtropics), i.e., at a time when vegetation especially needs moisture. Therefore, dense humid forests of evergreen oaks, camphor laurel, and magnolias grow here. Numerous vines entangling tree trunks, thickets of tall bamboos and various shrubs enhance the uniqueness of the subtropical forest.

The southeastern part of the United States is dominated by swampy subtropical forests, consisting of American species of pine, ash, poplar, and maple. Swamp cypress is widespread here - a huge tree reaching 45 m in height and 2 m in diameter. In Russia, subtropics include: Black Sea coast Caucasus, Lankaran lowland on the Caspian coast. The subtropics are the birthplace of valuable cultivated plants: oranges, tangerines, lemons, grapefruits, persimmons, etc. In addition to citrus fruits, olives, cherry laurel, figs, pomegranates, almonds, date palms and many others are grown here fruit trees and shrubs. See also: .

Deserts

Deserts occupy vast areas of the globe, especially in Asia, Africa and Australia. Their total area is estimated at 15-20 million. km 2 . There are temperate, subtropical and tropical deserts.

In the temperate zone, all the plains of Asia from the Caspian Sea in the west to Central China in the east are almost entirely desert spaces. In North America, some intermountain depressions in the west of the continent are deserted.

Subtropical and tropical deserts are located in northwestern India, Pakistan, Iran, and Asia Minor. They cover the Arabian Peninsula and the entire north of Africa, the western coast of South America for almost 3500 km and central Australia. The edges of the desert are usually bordered by transitional zones of semi-deserts.

The climate in deserts is sharply continental. Summer is very dry and hot, during the day the air temperature in the shade rises above 40° (at tropical deserts up to 58°). At night the heat subsides, the temperature often drops to 0°. In winter the cold comes, even in the Sahara there are frosts at this time. There is little precipitation in deserts - no more than 180 mm in year. The Chilean Atacama Desert receives less than 10 of them. mm. In some places in tropical deserts there is no rain for several years in a row.

In the hot, sultry summer, the meager plant remains in the desert soils seem to “burn out.” Hence the light gray or light yellow (sometimes almost white) color of the soils, which are called gray soils. Most often, the soil cover in deserts is very weak. Rocky or clayey areas are replaced here by seas of shifting sand. “Sand waves” - dunes - reach 12 m height. Their shape is semi-lunar or crescent-shaped, one slope (concave) is steep, the other is gentle. Connected at their ends, dunes often form entire dune chains. Under the influence of wind, they move at speeds from tens of centimeters to hundreds of meters per year. Unobstructed winds in the desert sometimes reach terrible strength. Then they raise clouds of sand into the air and sweep over the desert like a menacing sandstorm.

Clay deserts are almost devoid of vegetation. These are usually low-lying areas. They flood easily and during periods of light rains they look like lakes, although the depth of such “lakes” is only a few millimeters. The clay layer does not absorb water - it quickly evaporates in the sun, and the dry surface of the earth cracks. Such areas of the desert are called takyrs. Often in deserts they protrude directly to the surface various salts(cookery, Glauber's, etc.), forming barren salt marshes. Plants feel better in sand than in takyrs, because sand absorbs water better and is less saline. In summer, small reserves of moisture even form in the lower, cooler layers of sand: this is the condensation of water vapor coming from the atmosphere.

The name “desert” does not mean a complete absence of life. Some plants and animals are well adapted to living in dry climates and high temperatures.

In the deserts of Central Asia, saxaul grows - black and white. Large saxaul sometimes reaches 5 m height. Its leaves and branches are so small (this helps retain moisture) that on a hot summer day the trees seem bare in winter. But under the black saxaul in the lowlands there is even a faint shadow, saving animals and people from the sun.

In many desert plants, during the hot period, relatively large “spring” leaves are replaced by small “summer” ones. And if there are larger “summer” leaves, they are either fluffy (among wormwoods in Central Asia) or covered with a shiny waxy layer. Such leaves reflect the sun's rays and do not overheat. In some plants (sand acacia), the leaves have turned into thorns, which also prevents moisture evaporation. A small shrub - black wormwood - is usually devoid of leaves and looks very gloomy. And only in spring does black wormwood seem to come to life, briefly becoming covered with fluffy silver foliage.

There are many different cacti growing in the deserts of the Western Hemisphere. They have adapted to the arid climate in their own way: large reserves of water accumulate in the fleshy stems and leaves, sometimes 96% of the total weight of the plant. North American cactus Carnegia gianta (height up to 15 m) stores 2-3 thousand in its stems. l water. Desert plants typically have a well-developed root system. It allows them to extract moisture from deep layers of the soil. Some of these plants (desert sedge) can anchor sand with a powerful root system.

Desert animals also have their own adaptations to their surrounding conditions. Many desert inhabitants are colored yellow and gray, which allows them to hide from enemies or sneak up on prey unnoticed.

All desert inhabitants try to hide from the scorching heat. Pigeons, sparrows and owls manage to nest and rest in the walls of wells. Birds of prey (eagles, crows, falcons) make nests on hillocks and in the ruins of buildings, choosing the shadow side. Many animals hide in burrows, where it is not so dry and hot in summer and not too cold in winter. And if the inhabitants of most temperate zones hibernate in the winter, then other desert animals fall asleep in the summer, thus enduring a lack of moisture.

And the thin-toed ground squirrel does without drinking water: the moisture contained in the plants it eats is sufficient for it. The hairy jerboa also does not “know how” to drink: when water is offered to it in captivity, it wets its paws in it and licks them.

Like many inhabitants of the steppes, some desert animals are excellent runners. Wild kulan asses run vast distances in search of water and food. They can reach speeds of up to 70 km/hour Cheetahs run even faster - wild cats on long legs with semi-retractable claws.

The dry desert climate is extremely unfavorable for amphibians, but there are a lot of reptiles here: various snakes, lizards (including very large monitor lizards), turtles. To escape the heat and enemies, many of them quickly bury themselves in the sand. And the agama lizard, on the contrary, climbs onto the bushes - away from the hot sand.

The camel is perfectly adapted to life in the desert. He can eat grass that is not digestible by other animals, drinks little, and can even drink salt water. Camels tolerate prolonged hunger well: a reserve of fat is deposited in their humps (up to 100 kg and more). The camel has calluses on its body and legs, allowing it to lie down on the hot sand. Leaning on a wide cloven hoof, the camel moves freely along the sands. All these features make it an indispensable assistant for humans in desert conditions. A camel walks in harness, under a pack and a saddle, and provides warm wool. It was domesticated 4 thousand years ago.

Traces of ancient settlements and irrigation systems are often found under the desert sands. They were destroyed during wars, and, abandoned by people, the once flourishing lands became the prey of the desert. But even now, where grazing areas have not changed for a long time or too many shrubs are cut down, the sands, not already held together by plant roots, go on the offensive.

Fixing loose sand with plants is one of the the surest ways conquering the desert. In addition, sand can be “bound” with special emulsions, the thin film of which is easily penetrated by young plant shoots.

If you irrigate the desert with enough moisture, its appearance will change. Then it will be possible to grow rice, cotton, melons, corn, wheat, orchards, and vineyards here. Desert oases provide 25-30% of the world's cotton harvest and almost 100% of the world's date harvest. On irrigated lands in the deserts of Central Asia, two harvests of various crops can be harvested per year. Read more about the desert zone.

Savannah

In the equatorial zones of the northern and southern hemispheres there are tropical steppes - savannas (from the Spanish “sabana” - wild plain). In Africa, the Brazilian Highlands in South America and northern Australia, they occupy vast areas.

The climate of the savannas is tropical. There are two very clearly defined seasons here - dry and wet. In this regard, the entire life of nature is subject to a certain rhythm.

During the dry period the heat reaches 50°. At this time, the savannah produces a dull impression: yellowed and dried grasses, leafless trees, red-brown, cracked soil, and the absence of visible signs of life.

Savannas are vast spaces covered with grassy vegetation with sparsely scattered acacias, baobabs and shrubs.

But then the rains begin, and the savannah awaits literally before our eyes. The soil greedily absorbs moisture and is covered with tall grass, taller than human height. Trees and shrubs growing in groups or alone are green everywhere. The crowns of trees are umbrella-shaped, especially those of acacias.

The most large plant African savannas - baobab. It is not taller than our pine, but its trunk is extremely thick - up to 10 m in diameter. Outwardly, this tree is unattractive; only its large white flowers are beautiful. Baobab fruits are not tasty, but for monkeys they are a real delicacy.

Eucalyptus trees grow in the savannas of Australia - giant trees height up to 150 m. There are many types of them. In some types of eucalyptus, the leaves can turn edge-on towards the sun's rays and therefore do not provide almost any shade, but this reduces the evaporation of moisture. Among the sparsely scattered trees there is scrub - dense thickets of brigolow acacia, desert oak, and sandalwood. Between them there are bizarre “bottle trees” with a trunk swollen from the base to the crown.

The fauna of savannas, especially African ones, is extremely rich and diverse. Large representatives of land animals live here: clumsy hippopotamuses live on the shores of lakes and in the water, heavy buffaloes come, and among the branches of mimosa you can see the beautiful heads of giraffes. In the thick of the grass, crouched to the ground, a lion is guarding its prey. And the fast legs of antelopes do not always save these light, graceful animals from the formidable ruler of the African savannah. But more often its victims are careless zebras.

The slight rustle of grass indicates the presence of other inhabitants. These are snakes. There are a lot of them here, and the most terrible of them is the asp. Both people and animals are afraid of him: the bite of an asp is fatal. Only the buffoon eagle fearlessly fights this snake and almost always wins. See also: .

The abundance of heat, and during the humid period, precipitation, fertile soils like our black soil make it possible to grow various grain crops, cotton, peanuts, sugar cane, bananas, and pineapples in the savannah zone. Therefore, people have been farming here since time immemorial, and grazing livestock on the luxurious savannah pastures. The largest modern bird, the African ostrich, lives in the African savannas.

Rainforests

Tropical forests grow near the equator, on both sides, between the northern and southern tropics. It's very hot and humid here. The annual rainfall in some places reaches 10 thousand. mm, and in Cherrapunj (India) - 12 thousand. mm. This is 20 times more than in temperate forests. The abundance of heat and moisture is the main reason for the fabulous wealth and diversity of plants and animals in the tropical rainforest.

The weather here is amazingly constant. Before sunrise, the forest is quite cool and quiet, the sky is cloudless. The sun rises and the temperature begins to rise. By noon the heat sets in and the air becomes suffocating. Two or three hours later, clouds appear in the sky, lightning flashes, deafening rumbles of thunder shake the air and rain begins. The water flows as if in a continuous stream. Tree branches break and fall under its weight. Rivers overflow their banks. The rain usually lasts no more than an hour. Before sunset, the sky clears, the wind subsides, and soon the forest plunges into the darkness of night, which comes quickly, almost without twilight.

Under tropical rainforests, red lateritic soils up to several tens of meters thick are formed. Their color is due to the presence of a large amount of iron oxides. Sometimes yellow-white aluminum oxides are also mixed in - then the soil becomes spotty. During tropical rainfalls, a significant part of the humus is washed out of the soil, and in order to grow cultivated plants (sugar cane, citrus fruits, etc.) it has to be fertilized.

Some trees lose leaves alternately from different branches. Falling leaves usually do not turn yellow, and therefore green color predominates everywhere here. In the tropics there are up to 600 species of different ficuses, some of them are much larger than our oak. Tree ferns, similar to palm trees, grow in the forest. There are a lot of palm trees in the tropics. They have no branches - the leaves are collected at the top of the tall trunk. The fruits of date, coconut, oil and other palm trees are used by humans.

The wilds of the tropical forest are home to a variety of animals. From giant elephants, rhinoceroses, hippos to barely noticeable insects - everyone finds shelter and food here. Representatives of some groups of fauna in tropical forests are numerous. This is where most monkeys live, including apes. Of the birds alone

There are more than 150 species of parrots in South America. The Amazon parrot is easy to teach to speak. The parrot does not understand the meaning of the spoken words - it simply imitates the combination of sounds. There are a lot of insects in the tropical forest: over 700 species of butterflies are known in Brazil, which is almost five times more than in Europe. Some of them are giants, such as the tizania butterfly: its wingspan is up to 30 cm.

In tropical forests rich in water, along with various reptiles (crocodiles, turtles, lizards, snakes), many amphibians are found. On the island of Kalimantan alone there are 7 times more species of amphibians than in Europe. Reptiles of the tropics reach enormous sizes: some crocodiles are up to 10 m, and the South American anaconda boa reaches 9 m. There are a lot of different ants in the tropics. The abundance of plant food attracts many herbivorous animals to the tropical forests, which in turn are followed by predators: leopards (panthers), jaguars, tigers, various mustelids, etc. The striped or spotted coloring of many inhabitants, although it seems very bright and noticeable, in fact, it helps animals hide in the twilight of the lower tiers of the tropical forest, permeated here and there with sunlight.

The nature of the so-called mangrove tropical forests is unique. They grow on low-lying sea coasts, protected from the surf, but flooded during high tides. Mangrove forests are dense thickets of low (5-10 m) trees and shrubs. They grow on sticky muddy soil. In such conditions, the plant is supported by branched aerial (stilted) roots, which are immersed in silt. But since the silty soil here is poisoned with hydrogen sulfide, plants receive oxygen only from the air - with the help of other, special aerial roots. In this case, reserves of fresh water necessary for young foliage are formed in old leaves. The fruits of plants have air cavities and do not sink in water, but can float in the ocean for a long time until they linger somewhere on the shallows and germinate. Mangrove forests, by fixing silt and sand, interfere with navigation at the mouths of tropical rivers.

The rich nature of tropical forests has long provided people with its gifts. But even today, large areas of wild jungle are inaccessible, swampy, and poorly developed by humans. The rainforest is growing very quickly. Fields, roads, clearings and clearings that are abandoned for some reason immediately become overgrown. People constantly have to fight the jungle that is advancing on the fields. Raids of predators on villages, monkeys and ungulates on plantations cause a lot of harm.

Many wonderful representatives of tropical fauna (elephants, rhinoceroses, antelopes) were barbarously exterminated by European colonialists. Now some states have already taken measures to protect rare tropical animals: hunting is prohibited and nature reserves have been created.

The appearance of the Earth's natural zones and their boundaries have not always been the same as they are now. Over the long history of our planet, the relief, climate, vegetation, and fauna have repeatedly changed.

In the distant past, cold snaps occurred many times on Earth. During the last such period, large parts of Eurasia and North America were covered with thick ice.

In the southern hemisphere, ice penetrated into South America and Australia. But then it became warmer again and the ice retreated in the northern hemisphere to the north, and in the southern hemisphere to the south, leaving huge ice caps only in Greenland and Antarctica.

After the end of the last ice age, modern natural zones arose on Earth. But even now they do not remain unchanged, because nature has not stopped in its eternal development, it continues to continuously change and renew itself. A significant role in this process is played by the person and his work activity. Man grows cultivated plants in place of wild steppes and dense forests, destroys some animals and breeds others, irrigates arid areas and drains swamps, connects rivers and creates artificial seas - it transforms the face of the Earth.

But sometimes human impact on nature leads to undesirable consequences. Plowing of land is often accompanied by erosion and washing away of soils, their dispersal and, consequently, deterioration of the living conditions of plants. Therefore, in the USA, after 2/3 of the forests were destroyed, the area of ​​deserts doubled.

The burning of forests in Africa has caused deserts to encroach on savanna, which in turn appears where tropical forests are being destroyed.

Such changes in geographical areas reduce natural resources of our planet. The transformation of nature must be reasonable. We must not impoverish her, but make her even richer and more beautiful.



Formation of natural areas

A natural zone is a natural complex with uniform temperatures, moisture, similar soils, flora and fauna. A natural area is called according to the type of vegetation. For example, taiga, deciduous forests.

The main reason for the heterogeneity of the geographic envelope is the uneven redistribution of solar heat on the Earth's surface.

Almost every climatic zone The oceanic parts of the land are moistened more than the internal continental parts. And this depends not only on the amount of precipitation, but also on the ratio of heat and moisture. The warmer it is, the more moisture that falls with precipitation evaporates. The same amount of moisture can lead to excess moisture in one zone and insufficient moisture in another.

Rice. 1. Swamp

Thus, the annual precipitation amount of 200 mm in the cold subarctic zone is excessive moisture, which leads to the formation of swamps (see Fig. 1).

And in hot weather tropical zones– sharply insufficient: deserts are formed (see Fig. 2).

Rice. 2. Desert

Due to differences in the amount of solar heat and moisture, natural zones are formed within geographic zones.

Patterns of placement

There is a clear pattern in the distribution of natural zones on the earth's surface, which is clearly visible on the map of natural zones. They extend in the latitudinal direction, replacing each other from north to south.

Due to the heterogeneity of the relief of the earth's surface and moisture conditions in different parts of the continents, natural zones do not form continuous strips parallel to the equator. More often they change in the direction from the coasts of the oceans to the interior of the continents. In the mountains, natural zones replace each other from the foothills to the peaks. This is where the altitudinal zone appears.

Natural zones are also formed in the World Ocean: from the equator to the poles, the properties of surface waters, the composition of vegetation and fauna change.

Rice. 3. Natural areas of the world

Features of the natural zones of the continents

In the same natural zones on different continents, the flora and fauna have similar features.

However, in addition to climate, the distribution of plants and animals is influenced by other factors: the geological history of the continents, relief, and people.

The unification and separation of continents, changes in their topography and climate in the geological past became the reason that different species of animals and plants live in similar natural conditions, but on different continents.

For example, African savannas are characterized by antelopes, buffalos, zebras, and African ostriches, and in South American savannas several species of deer and the ostrich-like flightless bird rhea are common.

On every continent there are endemics - both plants and animals that are unique to that continent. For example, kangaroos are found only in Australia, and polar bears are found only in the Arctic deserts.

Geofocus

The Sun heats the spherical surface of the Earth unequally: the areas above which it stands high receive the most heat.

Above the poles, the rays of the Sun only glide over the Earth. The climate depends on this: hot at the equator, harsh and cold at the poles. The main features of the distribution of vegetation and fauna are also associated with this.

Moist evergreen forests are located in narrow stripes and spots along the equator. “Green Hell” - this is what many travelers of past centuries who visited here called these places. Tall multi-tiered forests stand as a solid wall, under the thick crowns of which darkness, monstrous humidity, constant heat, there is no change of seasons, rainfalls regularly fall with an almost continuous stream of water. The forests of the equator are also called permanent rain forests. The traveler Alexander Humboldt called them “hyleia” (from the Greek hyle - forest). Most likely, this is what the humid forests of the Carboniferous period looked like with giant ferns and horsetails.

The rainforests of South America are called “selvas” (see Fig. 4).

Rice. 4. Selva

Savannas are a sea of ​​grasses with rare islands of trees with umbrella crowns (see Fig. 5). Vast areas of these amazing natural communities are located in Africa, although there are savannas in South America, Australia, and India. A distinctive feature of savannas is the alternation of dry and wet seasons, which take about six months, replacing each other. The fact is that subtropical and tropical latitudes, where savannas are located, are characterized by a change of two different air masses– wet equatorial and dry tropical. The monsoon winds, which bring seasonal rains, significantly influence the climate of the savannas. Because these landscapes are located between the very wet natural zones of equatorial forests and the very dry zones of deserts, they are constantly influenced by both. But moisture is not present in savannas long enough for multi-tiered forests to grow there, and dry “winter periods” of 2-3 months do not allow the savanna to turn into a harsh desert.

Rice. 5. Savannah

The natural taiga zone is located in the north of Eurasia and North America (see Fig. 6). On the North American continent it stretches from west to east for more than 5 thousand km, and in Eurasia, starting on the Scandinavian Peninsula, it spread to the coast Pacific Ocean. The Eurasian taiga is the largest continuous forest zone on Earth. It occupies more than 60% of the territory Russian Federation. The taiga contains huge reserves of wood and supplies large amounts of oxygen to the atmosphere. In the north, the taiga smoothly turns into forest-tundra, gradually taiga forests are replaced by open forests, and then by separate groups of trees. The taiga forests extend farthest into the forest-tundra along river valleys, which are most protected from strong northern winds. In the south, the taiga also smoothly transitions into coniferous-deciduous and broad-leaved forests. In these areas, humans have interfered with the natural landscapes for many centuries, so now they represent a complex natural-anthropogenic complex.

Rice. 6. Taiga

Under the influence of human activity, the geographical environment is changing. Swamps are drained, deserts are irrigated, forests disappear, and so on. This changes the appearance of natural areas.

Bibliography

MainI

1. Geography. Land and people. 7th grade: Textbook for general education. uch. / A.P. Kuznetsov, L.E. Savelyeva, V.P. Dronov, series “Spheres”. – M.: Education, 2011.

2. Geography. Land and people. 7th grade: atlas, “Spheres” series.

Additional

1. N.A. Maksimov. Behind the pages of a geography textbook. – M.: Enlightenment.

1. Russian geographical society ().

3. Textbook on geography ().

4. Gazetteer ().

5. Geological and geographical formation ().

Belt zoning

The Sun heats the spherical surface of the Earth unequally: the areas above which it stands high receive the most heat. The farther from the equator, the greater the angle at which the rays reach the earth's surface and, therefore, the less thermal energy per unit area. Above the poles, the rays of the Sun only glide over the Earth. The climate depends on this: hot at the equator, harsh and cold at the poles. The main features of the distribution of vegetation and fauna are also associated with this. Based on the characteristics of heat distribution, seven thermal zones are distinguished. In each hemisphere there are zones of eternal frost (around the poles), cold, temperate. The hot zone at the equator is one for both hemispheres. Thermal zones are the basis for dividing the earth's surface into geographical zones: areas that are similar in the prevailing types of landscapes - natural-territorial complexes that have common climate, soil, vegetation and wildlife.

On the equator and near it there is a belt of humid equatorial and subequatorial forests (from the Latin sub - under), to the north and south of it, replacing each other, there are belts of tropics and subtropics with forests, deserts and savannas, a temperate zone with steppes, forest-steppes and forests, then the treeless spaces of the tundra extend, and finally, the polar deserts are located at the poles.

But the Earth's land surface in different places not only receives different amounts of solar energy, but also has many additional dissimilar conditions - for example, distance from the oceans, uneven terrain (mountain systems or plains) and, finally, unequal height above sea level. Each of these conditions greatly affects the natural features of the Earth.

Hot belt. The equator itself has virtually no seasons; it is humid and hot here all year round. When moving away from the equator, in subequatorial zones, the year is divided into drier and wetter seasons. There are savannas, woodlands and mixed evergreen deciduous tropical forests. Near the tropics, the climate becomes drier; deserts and semi-deserts are located here. The most famous of them are the Sahara, Namib and Kalahari in Africa, the Arabian Desert and Thar in Eurasia, Atacama in South America, Victoria in Australia.

There are two temperate zones on Earth (in the Northern and Southern Hemispheres). There is a clear change of seasons here, which differ greatly from each other. In the Northern Hemisphere, the northern border of the belt is bordered by coniferous forests - taiga, which are replaced to the south by mixed and broad-leaved forests, and then by forest-steppes and steppes. In the interior regions of continents, where the influence of seas and oceans is almost not felt, there may even be deserts (for example, the Gobi Desert in Mongolia, the Karakum Desert in Central Asia).

Polar belts. The lack of heat leads to the fact that in these zones there are practically no forests, the soil is swampy, and permafrost is found in places. At the poles, where the climate is the harshest, continental ice appears (as in Antarctica) or sea ​​ice(as in the Arctic). Vegetation is absent or represented by mosses and lichens.

Vertical zonality is also related to the amount of heat, but it only depends on the altitude above sea level. As you climb the mountains, the climate, soil type, vegetation and wildlife change. Interestingly, even in hot countries you can find tundra landscapes and even icy deserts. But in order to see this, you will have to climb high into the mountains. Thus, in the tropical and equatorial zones of the Andes of South America and in the Himalayas, landscapes successively change from wet rain forests to alpine meadows and zones of eternal glaciers and snow. It cannot be said that the altitudinal zone completely repeats the latitudinal geographical zones, because in the mountains and on the plains many conditions are not repeated. The most diverse range of altitudinal zones is near the equator, for example on the highest peaks of Africa, Mount Kilimanjaro, Kenya, Margherita Peak, and in South America on the slopes of the Andes.

Natural areas

Among the natural zones there are those confined to a specific zone. For example, the zone of Arctic and Antarctic ice deserts and the tundra zone are located in the Arctic and Antarctic belts; the forest-tundra zone corresponds to the subarctic and subantarctic zones, and the taiga, mixed and deciduous forests correspond to the temperate zone. And such natural zones as prairies, forest-steppes and steppes and semi-deserts are common in both temperate, tropical and subtropical zones, having, of course, their own characteristics.

Natural areas, their climatic features, soils, vegetation and fauna of each continent are described in Chapter 10 and in the table "Continents (reference information)". Here we will dwell only on the general features of natural zones as the largest natural-territorial complexes.

Arctic and Antarctic desert zone

Air temperatures are constantly very low and there is little precipitation. On rare ice-free areas of land - rocky deserts (in Antarctica they are called oases), sparse vegetation is represented by lichens and mosses, flowering plants are rare (only two species have been found in Antarctica), soils are practically absent.

Tundra zone

The tundra zone is widespread in the Arctic and subarctic zones, forming a strip 300-500 km wide, stretching along the northern coasts of Eurasia and North America and the islands of the Arctic Ocean. In the Southern Hemisphere, areas of tundra vegetation are found on some islands near Antarctica.
The climate is harsh with strong winds, snow cover lasts up to 7-9 months, the long polar night gives way to short and humid summers (summer temperatures do not exceed 10 °C). Precipitation falls a little 200-400 mm, mostly in solid form, but they do not have time to evaporate, and the tundra is characterized by excessive moisture, an abundance of lakes and swamps, which is facilitated by the ubiquitous permafrost. The main distinctive feature of the tundra is treelessness, the predominance of sparse moss-lichen, and sometimes grass, cover; in the southern parts with dwarf and creeping shrubs and shrubs. The soils are tundra-gley.

Forest-tundra and woodland zone

Forest zone

The forest zone in the Northern Hemisphere includes the subzones of taiga, mixed and deciduous forests and the subzone of temperate forests; in the Southern Hemisphere only the subzone of mixed and deciduous forests is represented. Some scientists consider these subzones to be independent zones.
In the taiga subzone of the Northern Hemisphere, the climate varies from maritime to sharply continental. Summers are warm (10-20 °C, the severity of winter increases with distance from the ocean (in Eastern Siberia up to -50 °C), and the amount of precipitation decreases (from 600 to 200 mm). The amount of precipitation exceeds evaporation, and watersheds are often swampy, rivers are rich in water. Dark coniferous (spruce and fir) and light coniferous (larch in Siberia, where permafrost soils are common) forests predominate, poor in species composition, with an admixture of small-leaved species (birch, aspen) and pine, in the east of Eurasia - cedar. The soils are podzolic and permafrost. -taiga.
The subzone of mixed and deciduous forests (sometimes two independent subzones are distinguished) is distributed mainly in the oceanic and transitional zones of the continents. In the Southern Hemisphere it occupies small areas, winters here are much warmer and snow cover does not form everywhere. Coniferous-deciduous forests on soddy-podzolic soils are replaced in the interior parts of the continents by coniferous-small-leaved and small-leaved forests, and to the south (in North America) or to the west (in Europe) by broad-leaved forests of oak, maple, linden, ash, beech and hornbeam on gray forests soils.

Forest-steppe

Forest-steppe is a transitional natural zone of the Northern Hemisphere, with alternating forest and steppe natural complexes. Based on the nature of natural vegetation, forest-steppes with broad-leaved and coniferous-small-leaved forests and prairies are distinguished.

Prairies are a subzone of forest-steppe (sometimes considered as a subzone of steppe) with abundant moisture, stretching along the eastern coasts of the Rocky Mountains in the United States and Canada with tall grasses on chernozem-like soils. Almost no natural vegetation has been preserved here. Similar landscapes are characteristic of the subtropics of eastern South America and East Asia.

Steppe

This natural zone is distributed in the northern temperate or both subtropical geographical zones and is a treeless area with herbaceous vegetation. Unlike the tundra, the growth of woody vegetation here is hampered not by low temperatures, but by a lack of moisture. Trees can grow only along river valleys (so-called gallery forests), in large erosive forms, such as ravines, collecting water from the surrounding interfluve spaces. Now most of the zone is plowed, in subtropical zone Irrigated agriculture and pasture cattle breeding are developing. Soil erosion is highly developed on arable lands. Natural vegetation is represented by drought- and frost-resistant herbaceous plants with a predominance of turf grasses (feather grass, fescue, tonkonogo). The soils are fertile - chernozems, dark chestnut and chestnut in the temperate zone; brown, gray-brown, in places saline in the subtropical).
The subtropical steppe in South America (Argentina, Uruguay) is called pampa (i.e. plain, steppe in the language of the Quechua Indians). Mass media .

Deserts and semi-deserts

Savannah

Savanna is a natural zone, distributed mainly in subequatorial zones, but also found in tropical and even subtropical zones. The main feature of the savannah climate is the clear alternation of dry and rainy periods. The duration of the rainy season decreases when moving from equatorial regions (here it can last 8-9 months) to tropical deserts (here the rainy season is 2-3 months). Savannas are characterized by dense and tall grass cover, trees standing alone or in small groups (acacia, baobab, eucalyptus) and so-called gallery forests along rivers. The soils of typical tropical savannas are red soils. In deserted savannas, the grass cover is sparse and the soils are red-brown. Tall grass savannas in South America, on the left bank of the river. Orinoco is called llanos (from Spanish “plain”). See also: .

Forest subtropics

Forest subtropics. The monsoon subtropical subzone is characteristic of the eastern margins of the continents, where seasonally changing circulation of air masses is formed at the contact between the ocean and the continent and there is a dry winter period and a wet summer with heavy monsoon rains, often with typhoons. Evergreen and deciduous (those that lose their leaves in winter due to lack of moisture) with a wide variety of tree species grow here on red and yellow earth soils.
The Mediterranean subzone is characteristic of the western regions of the continents (Mediterranean, California, Chile, southern Australia and Africa). Precipitation occurs mainly in winter; summer is dry. Evergreen and broad-leaved forests on brown and brown soils and hard-leaved shrubs are well adapted to summer drought, the plants of which have adapted to hot and dry conditions: they have a waxy coating or pubescence on the leaves, thick or dense leathery bark, and emit fragrant essential oils. Cm: .

Rainforests