What determines the formation of natural zones? What natural areas stand out on our planet? You can answer these and some other questions by reading this article.

Natural zoning: the formation of natural zones on the territory

The so-called our planet is the largest natural complex. It is very heterogeneous, both in the vertical section (which is expressed in vertical zonality) and in the horizontal (latitudinal), which is expressed in the presence of various natural zones on Earth. The formation of natural zones depends on several factors. And in this article we will talk about the latitudinal heterogeneity of the geographic envelope.

This is a component of the geographical shell, which is distinguished by a certain set of natural components with its own characteristics. These components include the following:

• climatic conditions;
• the nature of the relief;
• hydrological network of the territory;
• soil structure;
• organic world.

It should be noted that the formation of natural zones depends on the first component. However, natural areas receive their names, as a rule, according to the nature of their vegetation. After all, flora is the brightest component of any landscape. In other words, vegetation acts as a kind of indicator that reflects the deep (those that are hidden from our eyes) processes of the formation of a natural complex.

It should be noted that the natural zone is the highest step in the hierarchy of the physical and geographical zoning of the planet.

Factors of natural zoning

We list all the factors in the formation of natural zones on Earth. So, the formation of natural zones depends on the following factors:

1. Climatic features of the territory (this group of factors should include the temperature regime, the nature of moisture, as well as the properties of the air masses that dominate the territory).
2. The general nature of the relief (this criterion, as a rule, affects only the configuration, the boundaries of a particular natural zone).

The formation of natural zones can also be influenced by proximity to the ocean, or the presence of powerful ocean currents off the coast. However, all these factors are secondary. The main root cause of natural zonality is that different parts (belts) of our planet receive unequal amounts of solar heat and moisture.

Natural areas of the world

What natural zones are distinguished today by geographers on the body of our planet? Let's list them from the poles - to the equator:

• Arctic (and Antarctic) deserts.
• Tundra and forest tundra.
• Taiga.
• Broadleaved forest zone.
• Forest-steppe.
• Steppe (or prairie).
• Semi-desert and desert zone.
• Savannah zone.
• Tropical rainforest zone.
• Humid zone (hylaea).
• The zone of rain (monsoon) forests.

If we look at the map of the natural zonality of the planet, we will see that all natural zones are located on it in the form of sublatitudinal belts. That is, these zones, as a rule, extend from west to east. Sometimes this sublatitudinal direction can be violated. The reason for this, as we have already said, is the features of the relief of a particular territory.

It is also worth noting that there are simply no clear boundaries between natural areas (as shown on the map). So, almost each of the zones smoothly "flows" into the neighboring one. At the same time, border "zones" can very often form at the junction. For example, such are semi-desert or forest-steppe zones.

Conclusion

So, we found out that the formation of natural zones depends on many factors. The main ones are the ratio of heat and moisture in a particular area, the properties of the prevailing air masses, the nature of the relief, and so on. The set of these factors is the same for any territory: mainland, country or small area.

Geographers distinguish over a dozen large natural zones on the surface of our planet, which are elongated in the form of belts and replace each other from the equator to the polar latitudes.

Main questions: What determines the distribution of natural zones across the territory? What are the main features of the climate of the arctic, subarctic, temperate, subtropical zones?

General patterns of natural zonality. In the composition of all geographical zones of the mainland, not one, but several natural zones stand out. In the north, the latitudinal zonality of natural zones is clearly manifested, which is due to the evenness of the relief and a uniform increase in the incoming heat. In the central part of the mainland, the change in climatic conditions in the belts occurs in two directions - from north to south and from the oceanic margins to the interior of the mainland. Therefore, natural zones have a location close to meridional.

Natural zone of the arctic deserts formed on the islands of the Arctic Ocean. Cold and high precipitation contribute to the development of glaciation. In summer, in depressions and cracks appear mosses, lichens, cold-resistant herbs and shrubs. arctic soils contain almost no nutrients. The poverty of the animal world is associated with harsh conditions. The life of its representatives is connected with the sea. On the islands are formed bird markets. They live in the waters of the seas seals, walruses, bowhead whales. Entering coastal areas from the mainland polar bears, wolves, polar foxes. In Greenland and the Canadian Arctic Archipelago lives muskox, or musk ox.

Natural zone of tundra and forest-tundra occupies the north of the mainland. The short summer quickly gives way to a snowy cold winter. Permafrost is widespread. Tundra in the north moss and lichen. Rare herbs appear in summer ( sedge, cotton grass) and polar flowers - forget-me-nots, polar poppies, dandelions. South of the tundra becomes shrubby: meet dwarf birch and willow, wild rosemary, blueberry, bilberry. Under the conditions of summer waterlogging during thawing, permafrost is formed tundra-gley soil. herds reindeer are the object of hunting of the Eskimos and Indians. Meet polar hare, lemmings. Small animals are prey polar bear, polar wolf, arctic fox. common white partridge, predatory snowy owl, in the summer waterfowl arrive - geese, ducks, waders. Trees appear in the south along the river valleys: black and white spruce.

Taiga natural zone extends south of the forest-tundra. The vegetation is represented by dark coniferous forests from black and white firs and balsam fir. Grow in dry places pines: white(Weymouth), Banks(stone) and red (fig. 39.1). In the taiga zone are typical podzolic and gray forest soils, in the lowlands - peat-marsh.

The coniferous forests of the mountainous Pacific coast are called "rain forests", they grow in conditions of high rainfall (Fig. 40.1). stands out in the forest stand Douglas fir (Fig. 41.1)- one of the world's giants, the diameter of its trunk reaches 1.5 -2 m, and the height is 100 m. Typical North American coniferous species: thuja, Sitka spruce, yellow pine. Mountains form under the forests brown forest soil.

The animal world is diverse (Fig. 42.1-45.1): many large ungulates: wapiti deer, American Moose, meet in the mountains bighorn goat and bighorn ram. typical brown and black american bear, puma(or cougar) gray and red squirrel, chipmunk, predators - marten, wolf, Canadian lynx, ermine, wolverine, fox, in the rivers - beavers, otters a and musky rat a (muskrat). Variety of forest birds crossbills, warblers etc. In rain forests are common hummingbird.

mixed forests occupy the vicinity of the Great Lakes and part of the Appalachians. It is warmer here in winter, deciduous trees appear among the conifers. : elm, beech, linden, oak, birch, maples: sugar, red(fig. 46.1) , silver. Leaf litter allows the formation sod-podzolic soils. The Appalachian coastline is dominated by broad-leaved forests with exceptional species richness. Diverse oaks, chestnuts, beeches, grow tree hickory, deciduous magnolia, yellow poplar, black walnut, tulip tree

Falling leaves give a lot of organic matter and contribute to the formation of fertile brown forest x soils used for arable land. Previously, the animal world of forests was distinguished by unique richness. Its representatives are Virginian deer, gray fox, lynx, baribal black bear, tree porcupine, American mink, weasel, badger, raccoon (Fig. 50.1). endemic flying squirrels, skunks, the only marsupials in North America opossums (Fig. 51.1).

1. What is natural zoning? What is its cause? Why can natural zones change in different directions? What factors determine the patterns of change in natural zones in North America? 3. List the geographical zones in which the territory of North America is located.

Slides and text of this presentation

NATURAL ZONING

Geography Grade 7

Geography teacher MOU Tver gymnasium No. 10

(Greek zone - belt), physical-geographical zone - part of a geographical zone with uniform climatic conditions.

Natural areas take their name from their natural vegetation and other geographical features. The zones regularly change from the equator to the poles and from the oceans deep into the continents; have similar temperature and moisture conditions, which determine homogeneous soils, vegetation, wildlife and other components of the natural environment. Natural zones are one of the stages of physical-geographical zoning.

They differ in water masses, organic world, etc. The natural zones of the ocean do not have clear external differences, with the exception of the ice cover, and are named according to their geographical location, like climatic zones.
From a physical-geographical point of view, differences in the nature of the ocean in the horizontal direction are of greatest interest. The greatest differences on a planetary scale are observed in the meridional direction, they are associated with latitudinal zonality.

In the surface layers, the following natural, or physiographic, belts are distinguished:

SP - north polar (arctic); SSP - northern subpolar (subarctic); SU - northern temperate; SST - northern subtropical; ST - northern tropical; E - equatorial; UT - southern tropical; YUST - southern subtropical; YuU - southern temperate; SSP - southern subpolar (subantarctic); UP - south polar (antarctic)

To identify patterns in the location of geographical belts and zones, a group of scientists (A.M. Ryabchikov et al., 1972) built a hypothetical continent, the size of which corresponds to half the land area, the configuration corresponds to its location in latitudes, the surface is a low plain washed by the ocean . The boundaries of belts and zones marked on a hypothetical continent reflect their average contours on the plains of real continents, and in the place of mountainous regions they are reduced to the level of this plain. It turned out that the greater distribution of land in the SP causes a strong stretching of the zones in the continental sectors of the northern temperate and subtropical belts. In the SP, these sectors wedge out. In general terms, the zonality of the SP repeats the zonality of the SP. Most geographic areas are meridional. Only in the territory of Canada and Russia, mainly in the continental sectors of the temperate and subarctic zones, the latitudinal position of the zones prevails.

The earth's land is divided into 13 main latitudinal belts: arctic and antarctic, subarctic and subantarctic, northern and southern temperate, northern and southern subtropical, northern and southern tropical, northern and southern subequatorial, equatorial.

The territory around the poles is covered by cold Arctic (in the Southern Hemisphere - Antarctic) deserts.

Subpolar regions of the Earth. From left to right: arctic desert (Greenland), tundra (Yakutia), forest tundra (Khibiny)

They are distinguished by an extremely harsh climate, extensive ice sheets and rocky deserts, undeveloped soils, and the scarcity and monotony of living organisms. Animals of the Arctic deserts are mainly associated with the sea - these are the polar bear, pinnipeds, in Antarctica - penguins.

In the Southern Hemisphere, tundra is represented only on some subantarctic islands. The cold climate and soils underlain by permafrost determine the predominance of mosses, lichens, herbaceous plants and shrubs here. To the south, small trees appear (for example, dwarf birch), and the tundra is replaced by forest-tundra. The fauna of the tundra is quite homogeneous and scarce: reindeer, arctic foxes, lemmings and voles, as well as extensive bird colonies. Of the insects, mosquitoes are plentiful. Most vertebrates leave the tundra with the onset of winter (migrating or flying to warmer climes). Near the seas and oceans, the tundra and forest-tundra give way to a zone of oceanic meadows.

Natural zones of temperate zones

First, conifers (taiga), then mixed, and finally, broad-leaved (the southern temperate zone almost completely covers the world's oceans). Temperate forests cover vast areas in Eurasia and North America. The climate here is already much warmer, and the species diversity is several times greater than in the tundra. Podzolic soils are dominated by large trees - pine, spruce, cedar, larch, to the south - oak, beech, birch. Predatory animals (wolf, fox, bear, lynx), ungulates (deer, wild boars), songbirds, and certain groups of insects are common among animals.

From left to right: taiga (Sayan Mountains), broad-leaved forest (Krasnoyarsk Territory), steppe (Stavropol Territory), desert (Gobi)

Slide #10

The zone of temperate zones is replaced by the forest-steppe and then the steppe

The climate is getting warmer and drier, and among the soils, chernozems and chestnut soils are most common. Cereals predominate, among animals - rodents, predatory (wolf, fox, weasel), birds of prey (eagle, hawk), reptiles (vipers, snakes), beetles. A large percentage of the steppes is occupied by agricultural land. Steppes are common in the Midwest of the United States, Ukraine, the Volga region and Kazakhstan.

Slide #11

Semi-deserts and deserts (Central and Central Asia, western part of North America, Argentina)

The desert climate is characterized by low rainfall and large daily temperature fluctuations. Reservoirs in deserts, as a rule, are absent; only occasionally deserts are crossed by large rivers (Huang He, Syr Darya, Amu Darya). The fauna is quite diverse, most of the species are adapted to living in arid conditions.

Slide #12

As you approach the equator, the temperate zone is replaced by the subtropics.

In the coastal strip (the northern coast of the Mediterranean Sea, the southern coast of Crimea, the Middle East, the southeast of the United States, the extreme south of South Africa, the southern and western coasts of Australia, the North Island of New Zealand), evergreen subtropical forests are common; far from the sea there is a forest-steppe (in North America - prairies), steppe and deserts (the latter - in South Australia, on the southern coast of the Mediterranean Sea, in Iran and Tibet, Northern Mexico and the western part of South Africa). The fauna of the subtropics is characterized by a mixture of temperate and tropical species.

subtropical belts. From left to right: evergreen forest (Abkhazia), prairies (Nebraska), desert (Karakum)

Slide #13

Largely plowed up and used for plantations. Large animals are practically exterminated. Western Hindustan, Eastern Australia, the Paraná basin in South America and South Africa are zones of distribution of more arid tropical savannahs and light forests. The most extensive zone of the tropical belt is deserts (Sahara, Arabian Desert, Pakistan, Central Australia, Western California, Kalahari, Namib, Atacama). Huge expanses of pebbly, sandy, rocky and saline surfaces are devoid of vegetation here. The animal world is small.

Tropical belts. From left to right: deciduous forest (Costa Rica), veld (South Africa), desert (Namibia)

The warmth of the sun, clean air and water are the main criteria for life on Earth. Numerous climatic zones led to the division of the territory of all continents and water space into certain natural zones. Some of them, even separated by vast distances, are very similar, others are unique.

Natural areas of the world: what is it?

This definition should be understood as very large natural complexes (in other words, parts of the geographic belt of the Earth), which have similar, uniform climatic conditions. The main characteristic of natural zones is the flora and fauna that inhabits this territory. They are formed as a result of uneven distribution of moisture and heat on the planet.

Table "Natural zones of the world"

natural area	climate zone	Average temperature (winter/summer)
Antarctic and Arctic deserts	Antarctic, arctic	24-70°С /0-32°С
Tundra and forest tundra	Subarctic and Subantarctic	8-40°С/+8+16°С
	Moderate	8-48°C /+8+24°C
mixed forests	Moderate	16-8°С /+16+24°С
broadleaf forests	Moderate	8+8°С /+16+24°С
Steppes and forest-steppes	subtropical and temperate	16+8 °С /+16+24°С
temperate deserts and semi-deserts	Moderate	8-24 °С /+20+24 °С
hardwood forests	Subtropical	8+16 °С/ +20+24 °С
Tropical deserts and semi-deserts	Tropical	8+16 °С/ +20+32 °С
Savannahs and woodlands		20+24°C and above
Variable rainforests	subequatorial, tropical	20+24°C and above
Permanently wet forests	Equatorial	above +24°C

This characteristic of the natural areas of the world is only introductory, because you can talk about each of them for a very long time, all the information will not fit in the framework of one table.

Natural zones of the temperate climate zone

1. Taiga. Surpasses all other natural areas of the world in terms of the area occupied on land (27% of the territory of all forests on the planet). It is characterized by very low winter temperatures. Deciduous trees do not withstand them, so the taiga is dense coniferous forests (mainly pine, spruce, fir, larch). Very large areas of the taiga in Canada and Russia are occupied by permafrost.

2. Mixed forests. Characteristic to a greater extent for the Northern Hemisphere of the Earth. It is a kind of border between the taiga and the broad-leaved forest. They are more resistant to cold and long winters. Tree species: oak, maple, poplar, linden, as well as mountain ash, alder, birch, pine, spruce. As the table "Natural areas of the world" shows, the soils in the zone of mixed forests are gray, not very fertile, but still suitable for growing plants.

3. Broad-leaved forests. They are not adapted to harsh winters and are deciduous. They occupy most of Western Europe, the south of the Far East, the north of China and Japan. Suitable for them is a maritime or temperate continental climate with hot summers and fairly warm winters. As the table "Natural zones of the world" shows, the temperature in them does not fall below -8 ° C even in the cold season. The soil is fertile, rich in humus. The following types of trees are characteristic: ash, chestnut, oak, hornbeam, beech, maple, elm. The forests are very rich in mammals (ungulates, rodents, predators), birds, including commercial ones.

4. Temperate deserts and semi-deserts. Their main distinguishing feature is the almost complete absence of vegetation and sparse wildlife. There are a lot of natural areas of this nature, they are located mainly in the tropics. There are temperate deserts in Eurasia, and they are characterized by sharp temperature changes during the seasons. Animals are represented mainly by reptiles.

Arctic deserts and semi-deserts

They are huge areas of land covered with snow and ice. The map of natural zones of the world clearly shows that they are located on the territory of North America, Antarctica, Greenland and the northern tip of the Eurasian continent. In fact, these are lifeless places, and polar bears, walruses and seals, arctic foxes and lemmings, penguins (in Antarctica) live only along the coast. Where the land is free of ice, lichens and mosses can be seen.

Moist equatorial forests

Their second name is rainforests. They are located mainly in South America, as well as in Africa, Australia and the Greater Sunda Islands. The main condition for their formation is constant and very high humidity (more than 2000 mm of precipitation per year) and a hot climate (20 ° C and above). They are very rich in vegetation, the forest consists of several tiers and is an impenetrable, dense jungle that has become home to more than 2/3 of all types of creatures that now live on our planet. These rainforests are superior to all other natural areas of the world. Trees remain evergreen, changing foliage gradually and partially. Surprisingly, the soils of moist forests contain little humus.

Natural zones of the equatorial and subtropical climatic zone

1. Variably humid forests, they differ from rainforests in that precipitation falls there only during the rainy season, and during the period of drought that follows it, the trees are forced to shed their leaves. The animal and plant world is also very diverse and rich in species.

2. Savannas and woodlands. They appear where moisture, as a rule, is no longer enough for the growth of variable-humid forests. Their development occurs in the depths of the mainland, where tropical and equatorial air masses dominate, and the rainy season lasts less than six months. They occupy a significant part of the territory of subequatorial Africa, the interior of South America, partly Hindustan and Australia. More detailed information about the location is reflected in the map of natural areas of the world (photo).

hardwood forests

This climate zone is considered the most suitable for human habitation. Hardwood and evergreen forests are located along sea and ocean coasts. Precipitation is not so plentiful, but the leaves retain moisture due to the dense leathery shell (oaks, eucalyptus), which prevents them from falling off. In some trees and plants, they are modernized into thorns.

Steppes and forest-steppes

They are characterized by the almost complete absence of woody vegetation, this is due to the meager level of precipitation. But the soils are the most fertile (chernozems), and therefore are actively used by man for agriculture. Steppes occupy large areas in North America and Eurasia. The predominant number of inhabitants are reptiles, rodents and birds. Plants have adapted to the lack of moisture and most often manage to complete their life cycle in a short spring period, when the steppe is covered with a thick carpet of greenery.

Tundra and forest tundra

In this zone, the breath of the Arctic and Antarctic begins to be felt, the climate becomes more severe, and even coniferous trees cannot withstand it. Moisture is in excess, but there is no heat, which leads to swamping of very large areas. There are no trees at all in the tundra, the flora is mainly represented by mosses and lichens. It is believed that this is the most unstable and fragile ecosystem. Due to the active development of gas and oil fields, it is on the verge of an ecological disaster.

All natural areas of the world are very interesting, whether it is a desert that seems completely lifeless at first glance, boundless Arctic ice or thousand-year-old rain forests with boiling life inside.

Zoning - change in natural components and the natural complex as a whole from the equator to the poles. The basis of zonality is the different supply of heat, light, and precipitation to the Earth, which, in turn, is already reflected in all other components, and above all, soils, vegetation, and wildlife.

Zoning is characteristic of both land and the oceans.

The largest zonal divisions of the geographical shell - geographic zones. Belts differ from each other primarily in temperature conditions.

The following geographical zones are distinguished: equatorial, subequatorial, tropical, subtropical, temperate, subpolar, polar (antarctic and arctic).

Within the belts on land, natural zones are distinguished, each of which is characterized not only by the same type of temperature conditions and moisture, which leads to a commonality of vegetation, soils and wildlife.

You are already familiar with the arctic desert zone, tundra, temperate forest zone, steppes, deserts, wet and dry subtropics, savannahs, humid equatorial evergreen forests.

Within natural zones, transitional areas are distinguished. They are formed as a result of gradual changes in climatic conditions. Such transitional zones include, for example, forest-tundra, forest-steppes and semi-deserts.

Zoning is not only latitudinal, but also vertical. Vertical zonality is a regular change in natural complexes in height and depth. For mountains, the main cause of this zonality is the change in temperature and amount of moisture with height, and for the depths of the ocean, heat and sunlight.

The change of natural zones depending on the height above sea level in mountainous areas is called, as you already know, altitudinal zonation.

It differs from horizontal zonality in the length of belts and the presence of a belt of alpine and subalpine meadows. The number of belts usually increases in high mountains and as we approach the equator.

natural areas

natural areas- large subdivisions of the geographical envelope, which have a certain combination of temperature conditions and moisture regime. They are classified mainly according to the prevailing type of vegetation and regularly change in the plains from north to south, and in the mountains - from the foot to the peaks. The natural zones of Russia are shown in fig. one.

The latitudinal distribution of natural zones on the plains is explained by the supply of unequal amounts of solar heat and moisture to the earth's surface at different latitudes.

Resources of flora and fauna of natural zones are biological resources territory.

The set of altitudinal belts depends primarily on the latitude at which the mountains are located and what their height is. It should also be noted that for the most part the boundaries between the altitudinal zones are not clear.

Let us consider in more detail the features of the placement of natural zones on the example of the territory of our country.

polar desert

The very north of our country - the islands of the Arctic Ocean - are located in the natural zone polar (arctic) deserts. This area is also called ice zone. The southern boundary roughly coincides with the 75th parallel. The natural zone is characterized by the dominance of arctic air masses. The total solar radiation is 57-67 kcal/cm2 per year. Snow cover lasts 280-300 days a year.

In winter, the polar night dominates here, which at a latitude of 75 ° N. sh. lasts 98 days.

In summer, even round-the-clock lighting is not able to provide enough heat to this area. The air temperature rarely rises above 0 °C, and the average July temperature is +5 °C. For several days there may be drizzling precipitation, but there are practically no thunderstorms and showers. But there are frequent fogs.

Rice. 1. Natural areas of Russia

A significant part of the territory is characterized by modern glaciation. There is no continuous vegetation cover. The near-glacial areas of land on which vegetation develops are small areas. On placers of pebbles, fragments of basalt and boulders, mosses and scale lichens “settle”. Occasionally there are poppies and saxifrages that begin to bloom when the snow barely has time to melt.

The fauna of the Arctic desert is represented mainly by marine life. These are the harp seal, walrus, ringed seal, sea hare, white whale, porpoise, killer whale.

Species of baleen whales are diverse in the northern seas. Blue and bowhead whales, sei whale, fin whale, humpback whale are rare and endangered species and are listed in the Red Book. The inner side of the long horny plates that replace the teeth of whales is split into hairs. This allows the animals to filter large volumes of water, harvesting the plankton that forms the basis of their diet.

The polar bear is also a typical representative of the animal world of the polar desert. The "maternity hospitals" of polar bears are located on Franz Josef Land, Novaya Zemlya, about. Wrangel.

In summer, numerous colonies of birds nest on the rocky islands: gulls, guillemots, guillemots, auks, etc.

There is practically no permanent population in the polar desert zone. The meteorological stations operating here monitor the weather and the movement of ice in the ocean. On the islands, foxes are hunted in winter and game birds in summer. Fishing is carried out in the waters of the Arctic Ocean.

Steppes

Steppes extend south of the forest-steppe zone. They are distinguished by the absence of forest vegetation. The steppes stretch in a narrow continuous strip in the south of Russia from the western borders to Altai. Further to the east, the steppe areas have a patchy distribution.

The climate of the steppes is temperate continental, but drier than in the zone of forests and forest-steppes. The amount of annual total solar radiation reaches 120 kcal/cm 2 . The average January temperature in the west is -2 °С, and in the east -20 °С and lower. Summer in the steppe is sunny and hot. The average temperature in July is 22-23 °С. The sum of active temperatures is 3500 °C. Precipitation falls 250-400 mm per year. Showers are frequent in summer. The moisture coefficient is less than unity (from 0.6 in the north of the zone to 0.3 in the southern steppes). Steady snow cover lasts up to 150 days a year. In the west of the zone, thaws often occur, so the snow cover there is thin and very unstable. The predominant soils of the steppes are chernozems.

Natural plant communities are predominantly represented by perennial, drought- and frost-resistant herbs with a strong root system. First of all, these are cereals: feather grass, fescue, wheatgrass, snake, thin-legged, bluegrass. In addition to cereals, there are numerous representatives of herbs: astragalus, sage, cloves - and bulbous perennials, such as tulips.

The composition and structure of plant communities change significantly both in the latitudinal and in the meridional direction.

In the European steppes, narrow-leaved grasses form the basis: feather grass, fescue, bluegrass, fescue, thin-legged, etc. There are many brightly flowering herbs. In summer, like waves in the sea, feather grass sways, here and there you can see lilac irises. In the drier southern regions, in addition to cereals, wormwood, thorax, and cinquefoil are common. Lots of tulips in spring. In the Asian part of the country, tansy and cereals predominate.

Steppe landscapes are fundamentally different from forest ones, which determines the uniqueness of the animal world of this natural zone. Typical animals of this zone are rodents (the most numerous group) and ungulates.

Ungulates are adapted to long-term movements across the vast expanses of the steppes. Due to the thinness of the snow cover, plant food is also available in winter. An important role in nutrition is played by bulbs, tubers, rhizomes. For many animals, plants are also the main source of moisture. Typical representatives of ungulates in the steppes are tours, antelopes, tarpans. However, most of these species were exterminated or driven south as a result of human economic activity. In some areas, saigas, which were widely distributed in the past, have been preserved.

Of the rodents, the most common are ground squirrel, vole, jerboa, etc.

The polecat, badger, weasel, and fox also live in the steppe.

Of the birds, the bustard, little bustard, gray partridge, steppe eagle, buzzard, kestrel are typical for the steppes. However, these birds are now rare.

There are much more reptiles than in the forest zone. Among them, we single out the steppe viper, snake, common snake, nimble lizard, muzzle.

The wealth of the steppes is fertile soils. The thickness of the humus layer of chernozems is more than 1 m. It is not surprising that this natural zone is almost completely developed by man and natural steppe landscapes are preserved only in reserves. In addition to the high natural fertility of chernozems, climate conditions favorable for horticulture, the cultivation of heat-loving grains (wheat, corn) and industrial (sugar beet, sunflower) crops also contribute to agriculture. Due to insufficient precipitation and frequent droughts, irrigation systems have been built in the steppe zone.

The steppes are a zone of developed animal husbandry. Cattle, horses, poultry are bred here. Conditions for the development of animal husbandry are favorable due to the presence of natural pastures, fodder grain, waste from the processing of sunflowers and sugar beets, etc.

Various branches of industry are developed in the steppe zone: metallurgy, mechanical engineering, food, chemical, textile.

Semi-deserts and deserts

Semi-deserts and deserts are located in the southeast of the Russian Plain and in the Caspian lowland.

The total solar radiation here reaches 160 kcal/cm 2 . The climate is characterized by high air temperatures in summer (+22 - +24 °С) and low in winter (-25-30 °С). Because of this, there is a large annual temperature amplitude. The sum of active temperatures is 3600 °C and more. In the zone of semi-deserts and deserts, a small amount of precipitation falls: an average of up to 200 mm per year. In this case, the moisture coefficient is 0.1-0.2.

The rivers located in the zone of semi-deserts and deserts are fed almost exclusively by the spring melting of snow. A significant part of them flows into lakes or is lost in the sands.

Typical soils of the semi-desert and desert zone are chestnut. The amount of humus in them decreases in directions from north to south and from west to east (this is primarily due to a gradual increase in the sparseness of vegetation in these directions), therefore, in the north and west, the soils are dark chestnut, and in the south - light chestnut ( the content of humus in them is 2-3%. In depressions of the relief, the soils are saline. There are solonchaks and solonetzes - soils, from the upper layers of which, due to leaching, a significant part of the easily soluble salts has been carried away to the lower horizons.

Plants in semi-deserts are usually low, drought-resistant. The semi-deserts of the south of the country are characterized by such plant species as tree-like and gnarled saltwort, camel's thorn, and juzgun. On the hills, feather grass and fescue dominate.

Steppe grasses alternate with patches of wormwood and romance of yarrow.

The deserts of the southern part of the Caspian lowland are the kingdom of semi-shrub polynyas.

For life in conditions of lack of moisture and salinity of the soil, plants have developed a number of adaptations. Solyanka, for example, have hairs and scales that protect them from excessive evaporation and overheating. Others, such as tamarix, kermek, “acquired” special salt-removing glands to remove salts. In many species, the evaporative surface of the leaves has decreased, and their pubescence has occurred.

The growing season for many desert plants is short. They manage to complete the entire development cycle in a favorable time of the year - spring.

The fauna of semi-deserts and deserts is poor compared to the forest zone. The most common reptiles are lizards, snakes, turtles. There are many rodents - gerbils, jerboas and poisonous arachnids - scorpions, tarantulas, karakurts. Birds - bustard, little bustard, lark - can be seen not only in the steppes, but also in semi-deserts. Of the largest mammals, we note the camel, saiga; there is a corsac, a wolf.

A special area in the zone of semi-deserts and deserts of Russia are the Volga delta and the Akhtuba floodplain. It can be called a green oasis among the semi-desert. This territory is distinguished by its thickets of reed-bulrush (it reaches a height of 4-5 m), shrubs and shrubs (including blackberries), intertwined with climbing plants (hops, bindweed). In the backwaters of the Volga delta there are a lot of algae, white water lilies (including the Caspian rose and water chestnut preserved from the pre-glacial period). Among these plants there are many birds, among which herons, pelicans and even flamingos stand out.

The traditional occupation of the population in the zone of semi-deserts and deserts is cattle breeding: they breed sheep, camels, and cattle. As a result of overgrazing, the area of ​​unfixed windblown sands is increasing. One of the measures to combat the onset of the desert is phytomelioration - a set of measures for the cultivation and maintenance of natural vegetation. To fix the dunes, plant species such as giant grate, Siberian wheatgrass, and saxaul can be used.

Tundra

Huge expanses of the coast of the Arctic Ocean from the Kola Peninsula to the Chukotka are occupied tundra. The southern border of its distribution is practically owls
falls e by the July isotherm of 10 °C. Farthest to the north, the southern border of the tundra moved away in Siberia - north of 72 ° N. In the Far East, the influence of cold seas has led to the fact that the tundra border reaches almost the latitude of St. Petersburg.

The tundra receives more heat than the polar desert zone. The total solar radiation is 70-80 kcal/cm2 per year. However, the climate here continues to be characterized by low air temperatures, short summers, and severe winters. The average air temperature in January reaches -36 °С (in Siberia). Winter lasts 8-9 months. At this time of the year, southerly winds blowing from the mainland dominate here. Summer is characterized by an abundance of sunlight, unstable weather: strong northerly winds often blow, bringing cooling and precipitation (especially in the second half of summer there are often severe drizzling rains). The sum of active temperatures is only 400-500 °C. The average annual rainfall reaches 400 mm. Snow cover lasts 200-270 days a year.

The predominant types of soils in this zone are peat-bog and weakly podzolic. Due to the spread of permafrost, which has a water-resistant property, there are many swamps here.

Since the tundra zone has a significant length from north to south, within its limits, climatic conditions change markedly: from severe in the north to more moderate in the south. In accordance with this, arctic, northern, they are also typical, and southern tundras are distinguished.

arctic tundra occupy mainly the arctic islands. The vegetation is dominated by mosses, lichens, there are flowering plants, in comparison with the Arctic deserts there are more of them. Flowering plants are represented by shrubs and perennial herbs. Polar and creeping willow, dryad (partridge grass) are common. Of the perennial grasses, the most common are the polar poppy, small sedges, some grasses, and saxifrage.

northern tundra distributed mainly on the mainland coast. Their important difference from the arctic ones is the presence of a closed vegetation cover. Mosses and lichens cover 90% of the soil surface. Green mosses and bushy lichens predominate, moss is often found. The species composition of flowering plants is also becoming more diverse. There are saxifrages, ozhiki, highlander viviparous. Of the shrubs - lingonberries, blueberries, ledum, crowberry, as well as dwarf birch (dwarf birch), willows.

AT southern tundra, as in the northern ones, the vegetation cover is continuous, but it can already be divided into tiers. The upper tier is formed by dwarf birch and willows. Medium - herbs and shrubs: crowberry, lingonberry, blueberry, wild rosemary, sedge, cloudberry, cotton grass, cereals. Lower - mosses and lichens.

The harsh climatic conditions of the tundra "forced" many plant species to "acquire" special adaptations. So, plants with creeping and creeping shoots and leaves collected in a rosette better "use" a warmer ground layer of air. Short stature helps to survive the harsh winter. Although due to strong winds, the thickness of the snow cover in the tundra is small, it is enough to cover and survive.

Some devices "serve" plants in the summer. For example, cranberries, dwarf birch, crowberry “fight” for moisture retention by “reducing” the size of the leaves as much as possible, thereby reducing the evaporating surface. In the dryad and the polar willow, the underside of the leaf is covered with dense pubescence, which impedes the movement of air and thereby reduces evaporation.

Almost all plants in the tundra are perennial. For some species, the so-called live birth is characteristic, when instead of fruits and seeds, bulbs and nodules appear in the plant, which quickly take root, which provides a “gain” in time.

Animals and birds permanently living in the tundra have also adapted well to the harsh natural conditions. They are saved by thick fur or fluffy plumage. In winter, animals are white or light gray in color, and in summer they are grayish-brown. It helps to disguise.

Typical animals of the tundra are arctic fox, lemming, white hare, reindeer, white and tundra partridge, snowy owl. In summer, the abundance of food (fish, berries, insects) attracts such birds as waders, ducks, geese, etc. to this natural area.

The tundra has a relatively low population density. The indigenous peoples here are the Saami, Nenets, Yakuts, Chukchi, etc. They are mainly engaged in reindeer herding. The extraction of minerals is actively carried out: apatites, nephelines, non-ferrous metal ores, gold, etc.

Railway communication in the tundra is poorly developed, and permafrost is an obstacle to the construction of roads.

forest tundra

forest tundra- transitional zone from tundra to taiga. It is characterized by the alternation of areas occupied by forest and tundra vegetation.

The climate of the forest-tundra is close to the climate of the tundra. The main difference: the summer here is warmer - the average July temperature is + 11 (+14) ° С - and long, but the winter is colder: the influence of the winds blowing from the mainland affects.

The trees in this zone are stunted and bent to the ground, with a twisted appearance. This is due to the fact that permafrost and waterlogging of the soil do not allow plants to have deep roots, and strong winds bend them to the ground.

In the forest-tundra of the European part of Russia, spruce predominates, and pine is less common. In the Asian part, larch is common. Trees grow slowly, their height usually does not exceed 7-8 m. Due to strong winds, a flag-shaped crown shape is common.

The few animals that remain in the forest-tundra to spend the winter are perfectly adapted to local conditions. Lemmings, voles, tundra partridge make long passages in the snow, feed on the leaves and stems of evergreen tundra plants. With an abundance of food, lemmings even bring offspring at this time of the year.

Animals from the forest zone enter the southern regions through small forests and bushes along the rivers: mountain hare, brown bear, ptarmigan. There are wolf, fox, ermine, weasel. Small insectivorous birds fly in.

Subtropics

This zone, which occupies the Black Sea coast of the Caucasus, is characterized by the smallest length and area in Russia.

The value of total solar radiation reaches 130 kcal/cm2 per year. Summer is long, winter is warm (average January temperature is 0 °C). The sum of active temperatures is 3500-4000 °C. In these conditions, many plants can develop all year round. In the foothills and on the mountain slopes, 1000 mm or more of precipitation falls annually. In the flat areas, snow cover is practically not formed.

Fertile red earth and yellow earth soils are widespread.

Subtropical vegetation is rich and varied. The flora is represented by evergreen hard-leaved trees and shrubs, among which we will name boxwood, laurel, laurel cherry. Widespread forests of oak, beech, hornbeam, maple. Thickets of trees intertwine liana, ivy, wild grapes. There are bamboo, palm trees, cypress, eucalyptus.

Of the representatives of the animal world, we note the chamois, deer, wild boar, bear, pine and stone marten, Caucasian black grouse.

The abundance of heat and moisture makes it possible to grow such subtropical crops here as tea, tangerines, and lemons. Significant areas are occupied by vineyards and tobacco plantations.

Favorable climatic conditions, proximity to the sea and mountains make this area a major recreational area of ​​our country. Numerous camp sites, rest houses, sanatoriums are located here.

In the tropical zone there are moist forests, savannahs and light forests, deserts.

Largely open tropical rainforests(South Florida, Central America, Madagascar, Eastern Australia). They are used, as a rule, for plantations (see map of the atlas).

The subequatorial belt is represented by forests and savannahs.

Subequatorial moist forests located mainly in the Ganges valley, southern Central Africa, on the northern coast of the Gulf of Guinea, northern South America, in Northern Australia and on the islands of Oceania. In drier areas they are replaced savannas(Southeast Brazil, Central and East Africa, central regions of Northern Australia, Hindustan and Indochina). Characteristic representatives of the animal world of the subequatorial belt are ruminant artiodactyls, predators, rodents, termites.

At the equator, an abundance of precipitation and high temperatures led to the presence of a zone here evergreen rainforests(Amazon and Congo basin, on the islands of Southeast Asia). The natural area of ​​evergreen moist forests holds the world record for the diversity of animal and plant species.

The same natural areas are found on different continents, but they have their own characteristics. First of all, we are talking about plants and animals that have adapted to the existence in these natural areas.

The natural zone of the subtropics is widely represented on the coast of the Mediterranean Sea, the southern coast of Crimea, in the southeast of the United States and in other regions of the Earth.

Western Hindustan, Eastern Australia, the Paraná basin in South America and South Africa are areas of distribution of more arid tropical savannas and woodlands. The most extensive natural zone of the tropical belt - desert(Sahara, Arabian desert, deserts of Central Australia, California, as well as the Kalahari, Namib, Atacama). Huge expanses of pebbly, sandy, rocky and saline surfaces are devoid of vegetation here. The animal world is small.