Natural zones are certain areas of the Earth's surface that differ significantly from others in the originality of natural resources and especially in appearance. Such a division has been practiced for a long time and represents an opportunity to carry out natural-geographical zoning.
Simply put, natural areas are territories whose appearance, flora and fauna are strictly defined and are not like any others. The peculiarity characteristic of each of them can be clearly traced and allows certain types of plants or animals to be found in accordance with the zones in which they can grow or live.
Natural areas are easily recognizable by the change and character of the dominant vegetation type. It is by them that one can clearly trace where one ends and the next begins.
The conditions for the survival of individual tree species are determined by the special climatic characteristics that are provided for by various natural zones. Each of them is characterized by individual characteristics, due to the different amount of precipitation, humidity and air temperature.
Natural areas are so diverse that in one part of the planet the sun can mercilessly burn and the vegetation can be as scarce as the animal world, and in the other - permafrost and never melting snow. The contrast is more than obvious. Nevertheless, in nature everything is reasonable and harmonious, these transitions are not abrupt.
In the Arctic, the air temperature is low, there is very little precipitation, the entire territory is covered with ice, only lichens and moss are the only vegetation.
The Tundra has high humidity, strong winds, numerous lakes and swamps, and the soil is real permafrost. The peculiarity of the territory is treelessness, as well as moss-lichen cover. Nature in these parts is very scarce and monotonous.
The characterization of natural zones involves not only their description, but also takes into account smooth transitions, an example of which can be forest-tundra and woodlands. In such areas, there may be representatives of flora and fauna characteristic of both adjacent areas.
The natural areas of the world are revealed in their full beauty in the forest zone in the area where the real kingdom of broad-leaved and mixed forests is located. Trees such as oak, linden, ash, beech, maple are often found here. Summers in these places are quite warm, up to 20 ° C, and winters are severe, up to -50 ° C, humidity is high.
The forest-steppe can also be called a transitional natural zone, which is located in the Northern Hemisphere. In this area, one can observe the alternation of steppes, an abundance of tall grass, which can be clearly seen in the United States and Canada.
steppe zone located in the northern temperate region, there are no forests, and the territory is covered with grasses, but there is not enough moisture. Conditions for the growth of trees are only along the river valleys. The soil is black earth, which is intensively used by man.
They are found in the following zones: temperate, tropical and subtropical. There is very little rainfall here. These territories are characterized by flat surfaces, scarcity of flora and specificity of fauna. There are very different deserts: sandy, saline, rocky, clay.
Currently, scientists have calculated that the desert occupies more than 16.5 million km² (excluding Antarctica), which is 11% of the land surface. With Antarctica, this area is more than 20%. Grass in the desert is scarce, soils are underdeveloped, sometimes oases are found.
Perhaps the most exotic are tropical forests. There are no seasonal differences in the weather, and the trees do not show growth rings. This is a real paradise for plants and an attractive place for wildlife explorers.
"" Photo: Aziz J. Hayat Belt zoning
The sun heats the spherical surface of the Earth differently: 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 earth's surface and, consequently, less heat energy per unit area. Above the poles, the Sun's rays 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 connected with this. According to the features of heat distribution, seven thermal zones are distinguished. In each hemisphere there are zones of eternal frost (around the poles), cold, moderate. The hot belt at the equator is one for both hemispheres. Thermal belts- the basis for dividing the earth's surface into geographical areas: areas similar in the prevailing types of landscapes - natural-territorial complexes with a common climate, soils, vegetation and wildlife.
On the equator and near it there is a belt of humid equatorial and subequatorial forests (from Latin sub - under), to the north and south of it, replacing each other, belts of tropics and subtropics with forests, deserts and savannahs, a temperate belt with steppes, forest-steppes stretch and forests, then the treeless expanses of the tundra extend, and, finally, the polar deserts are located at the poles.
But the land surface of the Earth in different places receives not only a different amount solar energy, but it also has many additional dissimilar conditions - for example, remoteness from the oceans, uneven terrain ( mountain systems or plains) and, finally, unequal height above sea level. Each of these conditions strongly affects natural features Earth.
Hot belt. Near the equator there are practically no seasons, the whole year is humid and hot here. When moving away from the equator, in subequatorial zones, the year is divided into drier and wetter seasons. There are savannahs, 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 Sahara, Namib and Kalahari in Africa, 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, which are very different from each other. In the Northern Hemisphere, the northern border of the belt is adjacent coniferous forests- taiga, changing to the south by mixed and broad-leaved forests, and then by forest-steppes and steppes. In the inner regions of the continents, where the influence of the seas and oceans is almost not felt, there may even be deserts (for example, the Gobi desert in Mongolia, the Karakum 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 occurs in some places. At the poles, where the climate is the most severe, 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 height above sea level. When climbing mountains, the climate, soil type, vegetation and animal world. Interestingly, even in hot countries, you can find landscapes of the tundra and even the icy desert. But in order to see it, you 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 consistently change from humid rainforests to alpine meadows and zones of eternal glaciers and snows. It cannot be said that the altitudinal zonality completely repeats the latitudinal geographic zones, because in the mountains and on the plains, many conditions do not repeat. The most diverse range of altitudinal zones near the equator, for example, on the highest peaks of Africa, Mount Kilimanjaro, Kenya, Margherita Peak, in South America on the slopes of the Andes.
natural areas
Among the natural zones, there are those confined to a particular belt. For example, the zone of arctic and antarctic ice deserts and the zone of tundra are located in the arctic and antarctic belts; the forest-tundra zone corresponds to the subarctic and subantarctic belts, while the taiga, mixed and broad-leaved forests correspond to the temperate zone. And such natural zones as prairies, forest-steppes and steppes and semi-deserts are common both in the temperate and in the tropical and subtropical zones, having, of course, their own characteristics.
Natural zones, their climatic features, soils, vegetation and wildlife 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.
Zone of Arctic and Antarctic deserts
Air temperatures are constantly very low, there is little precipitation. On rare ice-free land areas - rocky deserts (in Antarctica they are called oases), sparse vegetation is represented by lichens and mosses, flowering plants are rare (only two species are found in Antarctica), soils are practically absent.
Tundra zone
The tundra zone is widespread in the arctic and subarctic belts, 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 southern hemisphere areas with tundra vegetation are found on some islands near Antarctica.
The climate is harsh with strong winds, the snow cover lasts up to 7-9 months, the long polar night is replaced by a short and humid summer (summer temperatures do not exceed 10 ° C). Precipitation is 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 widespread permafrost. The main distinguishing feature of the tundra is treelessness, the predominance of sparse moss-lichen, sometimes grassy, cover; in the southern parts with shrubs and shrubs of dwarf and creeping forms. The soils are tundra-gley.
Zone of forest-tundra and light forests
Zone of forest-tundra and woodlands. This is a transitional zone, which is characterized by the alternation of treeless tundra areas and forests (light forests), combines the features of the zones bordering it. Tundra natural complexes are characteristic of watershed spaces, light forests climb north along river valleys. To the south, the areas occupied by forests increase.
In the Southern Hemisphere (subantarctic belt), the place of the forest-tundra on the islands (for example, South Georgia) is occupied by oceanic meadows. For more information about the tundra zone, see tundra characteristics.
forest zone
The forest zone in the Northern Hemisphere includes the subzones of taiga, mixed and broad-leaved forests and the subzone of temperate forests, in the Southern Hemisphere only the subzone of mixed and broad-leaved 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, winter severity increases with distance from the ocean (up to -50 °c in Eastern Siberia), and precipitation decreases (from 600 to 200 mm). rich in water, poor in terms of species composition dark coniferous (from spruce and fir) and light coniferous (from larch in Siberia, where permafrost soils are common) forests with an admixture of small-leaved species (birch, aspen) and pine, in eastern Eurasia - cedar. The soils are podzolic and permafrost-taiga.
The subzone of mixed and broad-leaved forests (sometimes two independent subzones are distinguished) is distributed mainly in the oceanic and transitional zones of the continents. It occupies small areas in the Southern Hemisphere, winters are much warmer here and snow cover is not formed everywhere. Coniferous-broad-leaved forests on soddy-podzolic soils are replaced by internal parts continents with coniferous-small-leaved and small-leaved forests, and to the south (in North America) or west (in Europe) broad-leaved oak, maple, linden, ash, beech and hornbeam on gray forest soils.
forest-steppe
Forest steppe - transitional natural area northern hemisphere, with alternating forest and steppe natural complexes. According to the nature of natural vegetation, forest-steppes with broad-leaved and coniferous-small-leaved forests and prairies are distinguished.
Prairie is a forest-steppe subzone (sometimes considered as a steppe subzone) with abundant moisture, stretching along the eastern coasts of the Rocky Mountains in the USA and Canada with tall grass on chernozem-like soils. The natural vegetation here is practically not preserved. Similar landscapes are characteristic of the subtropics of the eastern regions of South America and East Asia.
Steppe
This natural zone is common in the northern temperate or both subtropical geographical zones and is a treeless expanse with grassy vegetation. The growth of woody vegetation here, in contrast to the tundra, is not prevented by low temperatures and lack of moisture. Trees can grow only along river valleys (the so-called gallery forests), in large erosive forms, such as gullies that collect water from the surrounding interfluve spaces. Now most of the zone is plowed up, in sub tropical 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, thin-legged). Soils are fertile - chernozems, dark chestnut and chestnut in temperate zone; brown, gray-brown, saline in places in the subtropical).
The subtropical steppe in South America (Argentina, Uruguay) is called the pampa (i.e. plain, steppe in the language of the Quechua Indians). See vegetation and animals of the steppe.
Deserts and semi-deserts
These natural zones are distributed in six geographical zones - temperate, subtropical and tropical on both sides of the equator, where precipitation is so small (10-30 times less than evaporation) that the existence of living organisms is extremely difficult. Therefore, the herbaceous cover is sparse, the soils are poorly developed. Under such conditions, the rocks that make up the territory acquire great importance, and depending on them, clay deserts (takyrs in Asia), stony deserts (hamads of the Sahara, middle Asia, Australia), sandy (Thar Desert in India and Pakistan, North American deserts). In the temperate zone, deserts form in regions with a sharply continental climate, subtropical and tropical deserts owe their existence to constant baric maxima at 20-30 ° latitudes. Rare areas of increased moisture (high groundwater levels, spring outlets, irrigation from nearby rivers, lakes, wells, etc.) - centers of population concentration, growth of tree, shrub and herbaceous vegetation are called oases. Sometimes such oases occupy vast areas (for example, the Nile Valley stretches over tens of thousands of hectares). For more details, see: natural zone of deserts.
Savannah
Savannah is a natural zone, distributed mainly in the subequatorial belts, but is also found in tropical and even subtropical regions. main feature The climate of the savannas is a clear change of dry and rainy periods. The duration of the rainy period decreases when moving from equatorial regions (here it can last 8-9 months) to tropical deserts (here the rainy season is 2-3 months). The savannahs are characterized by a dense and high grassy cover, standing separately or in small groups of trees (acacia, baobab, eucalyptus) and the so-called gallery forests along the rivers. The soils of typical tropical savannahs are red soils. In deserted savannahs, 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, called llanos (from Spanish "plain"). See also: vegetation and animals of the savanna.
Forest subtropics
Forest subtropics. The monsoonal subtropical subzone is characteristic of the eastern margins of the continents, where seasonally changing circulation is formed at the contact of the ocean and the continent. air masses and there is a dry winter period and a wet summer with abundant monsoon rains, often with typhoons.
Thermal belts and natural zones
Evergreen and deciduous (dropping leaves in winter due to lack of moisture) with a wide variety of tree species grow here on red earth and yellow earth soils.
The Mediterranean subzone is characteristic of the western regions of the continents (Mediterranean, California, Chile, southern Australia and Africa). Precipitation falls 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 arid conditions: they have a wax coating or pubescence on the leaves, thick or dense leathery bark, emit fragrant essential oils. See: animals of the subtropics.
Rainforests
More on the topic:
Taiga zone, plants and animals
Savannah
Characteristics of the forest tundra
Characteristics of the tundra
equatorial forest
equatorial moist forests . equatorial climate. Warm all year round(about 25 °C), slight temperature fluctuation throughout the year, a large number of rainfall all year round. Low pressure.
Savannah. Subequatorial climate. Hot all year round. Precipitation falls unevenly throughout the year, there are dry and wet seasons of the year. The main vegetation is grasses.
desert. Rainfall is very rare in tropical deserts. There is very little vegetation. The temperate deserts have humid spring period(in March-April).
Steppes. Continental climate with cold winters with little snow and hot dry summers.
Broad-leaved and mixed forests. Favorable climatic conditions - enough moisture, many sunny days, a frost-free period of about or more than six months.
Taiga. Enough moisture, but the cold period is significant. Summers are quite warm (up to 20 °C), winters are severely frosty ( average temperature-30°C).
Tundra. The soil is permafrost. The climate is subarctic.
natural areas
Strong winds. Long cold winter, polar night in many parts. In summer the temperature is about +5 °C.
arctic desert. The dominance of ice, the absence of plants, the animal world is quite poor. In winter, the average temperature is -30 ° C and strong winds, in summer it can be a little above 0, frequent rains and fogs. Polar night and day.
antarctic desert. In winter it is down to –70 °C, in summer it is not higher than –20 °C (it rises to 10 °C on the coast of the Antarctic Peninsula). Strong winds blowing towards the coast and central regions of Antarctica.
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Natural zones of Russia and their features
Nature is a complex of interrelated components that are in constant relationship with each other and depend on each other. Changes in one natural chain will necessarily lead to disturbances in related components. There is a constant exchange of resources and energy between individual participants natural community. The presence of certain relationships is typical for each specific territory. This is how natural areas are formed. They, in turn, affect the economic activity of a person and its features.
The natural areas of Russia are very diverse. This is due to the vast territory, the difference in relief and climatic conditions.
Among the main natural zones of our country are steppes, semi-deserts, taiga, forests, forest-steppes, tundra, arctic desert, forest-tundra. The natural zones of Russia have a fairly large area that stretches for thousands of kilometers. Each of them is characterized by a certain climate, soil types, flora and fauna, as well as the degree of moisture in the territory.
The Arctic desert zone is distinguished by the presence of a large amount of snow and ice all year round. The air temperature here varies within 4-2 degrees. Glaciers are formed as a result of solid precipitation. The soil is poorly developed and is at the initial level. The formation of salt spots is observed in dry windy weather. The climatic conditions of this zone also affect the nature of the vegetation. Low mosses and lichens predominate here. The polar poppy, saxifrage and some other plants are less common. The animal world is also not very rich. Arctic fox, deer, owl, partridge and lemming are almost the only inhabitants of the Arctic desert.
The natural zones of Russia also include the tundra zone. This is a less cold zone than arctic deserts. But, nevertheless, it is distinguished by cold and strong winds, due to the proximity of the Arctic Ocean. Frosts and snowfall are possible all year round. The climate of the tundra zone is humid. The soil is also very poorly developed, which affects the vegetation cover. Mostly low shrubs and trees, mosses and lichens predominate.
The natural zones of Russia are gradually replacing each other. Next comes the forest tundra. There are already more warm weather in summer, but winters are cold with lots of snow. Among the plants, spruce, birch and larch predominate. During the warm period, the forest-tundra serves as a pasture for deer.
The forest-tundra is replaced by the taiga. It is characterized by warmer weather and less severe winters. The relief is characterized by the presence of a large number of water bodies (rivers, lakes and swamps). The soil here is more favorable for the plant world, and therefore the animal world is numerous here. Sable, hazel grouse, capercaillie, hare, squirrel, bear and many other species live in the taiga.
The semi-desert zone is the smallest in area. It typically has hot summers and harsh winters with little rainfall. It is mainly used for pasture.
The division of the territory into zones also affects human activities. Numerous natural and economic zones of Russia also determine its extensive activities in the economic sphere.
Each zone is subdivided into smaller types.
Natural zones of the world: a brief description. Table "Natural zones of the world"
There are also transition zones, which are characterized by climatic features of each adjacent region. Therefore, each natural area is inextricably linked with the neighboring one. Violations occurring in a certain region of the country lead to changes not only in the climate, but also in the world of animals and plants in another zone.
The characteristic of the natural zones of Russia implies the features of each of them, but they do not have clear boundaries and the division is conditional. In addition, human activities can affect the nature and climate of the environment.
A latitudinal natural strip of land or the World Ocean, which has uniform thermal conditions and atmospheric moisture, and, accordingly, relatively homogeneous elements of landscapes, is integral part geographic zone of the earth. Syn.:… … Geography Dictionary
natural area- — EN natural area An area in which natural processes predominate, fluctuations in numbers of organisms are allowed free play and human intervention is minimal. (Source: LANDY) EN sensitive natural area Terrestrial or aquatic area or other fragile natural setting with unique or highly valued environmental features. (Source: EPAGLO)… … Technical Translator's Handbook
Specially protected natural area- 025 Specially protected natural area (Figure A.24) Standardized graphic content: silhouette of a tree next to the silhouette of an animal. Purpose: indication of the location of a protected area designed to protect flora and fauna. Region… … Dictionary-reference book of terms of normative and technical documentation
GEOGRAPHICAL ZONE- a natural zone, a regional landscape unit, meaning a significant area with a special type of climate, specific vegetation and soil cover and wildlife. The geographical zone is one of the highest levels of the latitudinal zonal physical ... ... Ecological dictionary
ARID ZONE- natural zone with arid climate; desert and semi-desert zone. Here agriculture is possible only with artificial irrigation. Ecological encyclopedic dictionary. Chisinau: Main edition of the Moldavian Soviet Encyclopedia. I.I. Grandpa. 1989... Ecological dictionary
SECONDARY CONTACT ZONE- a zone of secondary intergradation, a natural zone within the range of a species in which secondary contact (meeting, gene exchange) of previously geographically isolated (divergent, allopatric) populations occurs. It is of decisive importance for... Ecological dictionary
MORPHOCLIMATE ZONE- a natural zone, allocated according to the features of relief-forming processes. Ecological encyclopedic dictionary. Chisinau: Main edition of the Moldavian Soviet Encyclopedia. I.I. Grandpa. 1989... Ecological dictionary
antarctic desert zone- The natural zone, including Antarctica and nearby islands, has a harsh Antarctic climate and sparse polar vegetation ... Geography Dictionary
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- The Elusive World: The Ecological Consequences of Habitat Loss, Hansky I. The book analyzes the ecological consequences of habitat loss and fragmentation resulting from intensive economic activity people who have great importance for…
- The elusive world. Ecological Impacts of Habitat Loss, Ilkka Hanski. The book is devoted to the analysis of the ecological consequences of the loss and fragmentation of habitats that occur as a result of intensive economic activity of people and are of great importance for…
The desert is a natural area characterized by the virtual absence of flora and fauna. There are sandy, rocky, clayey, saline deserts. Arctic and Antarctic landscapes are called snow deserts. The largest sandy desert of the Earth - Sahara (from the ancient Arabic as-sahra - "desert, desert steppe") - covers an area of more than 8 million square meters. km.
Deserts are located in the temperate zone of the Northern Hemisphere, subtropical and tropical zones of the Northern and Southern Hemispheres. During the year, less than 200 mm falls in the desert, and in some areas - less than 50 mm. Desert soils are poorly developed, the content of water-soluble salts in them exceeds the content of organic matter. The vegetation cover usually occupies less than 50% of the soil surface, and may be completely absent for several kilometers.
Due to the infertility of soils and lack of moisture, animal and vegetable worlds deserts are quite poor. In such conditions, only the most persistent representatives of flora and fauna survive. From plants, mainly leafless thorny shrubs are common, from animals - reptiles (snakes, lizards) and small rodents. The vegetation cover of the subtropical deserts of North America and Australia is more diverse, and there are almost no areas devoid of vegetation. Low-growing acacia and eucalyptus trees are not uncommon here.
Life in deserts is concentrated mainly near oases - places with dense vegetation and reservoirs, as well as in river valleys. Deciduous trees are common in oases: turanga poplars, dzhidy, willows, elms, and in river valleys - palm trees, oleanders.
The Arctic and Antarctic deserts are located beyond the polar circles. The flora and fauna there are also quite poor, hence the comparison with the sandy deserts of the tropics. From plants there are mosses and lichens, and from animals, reindeer, arctic foxes, lemmings and other rodents resistant to cold. The polar deserts are dominated by permafrost, and the snow cover usually does not melt throughout the year.
(savannah)
Forest-steppe (savannah) - vast expanses in the tropical zone, covered with grassy vegetation with sparsely scattered trees and shrubs. Typical of a monsoonal tropical climate with a sharp division of the year into dry and rainy seasons.
Savannahs are steppe-like places, characteristic of more elevated tropical countries with a dry continental climate. Unlike real steppes (as well as North American prairies), savannas, in addition to grasses, also contain shrubs and trees, sometimes growing in a whole forest, as, for example, in the so-called "campos cerrados" of Brazil. The herbaceous vegetation of the savannas consists mainly of tall (up to 1 meter) dry and hard-skinned grasses, usually growing in tufts. Turfs of other perennial grasses and shrubs are mixed with grasses, and in damp places flooded in spring, also various representatives of the sedge family (Cyperaceae).
Shrubs grow in savannahs, sometimes in large thickets, covering an area of many square meters. Savannah trees are usually stunted; the highest of them are no higher than ours fruit trees, to which they are very similar in their crooked stems and branches. Trees and shrubs are sometimes entwined with vines and overgrown with epiphytes. There are not many bulbous, tuberous and fleshy plants in the savannas, especially in South America. Lichens, mosses and algae are extremely rare in savannahs, only on rocks and trees.
The general appearance of the savannahs is different, which depends, on the one hand, on the height of the vegetation cover, and on the other hand, on the relative amount of grasses, other perennial grasses, semi-shrubs, shrubs and trees; for example, the Brazilian shrouds ("campos cerrados") are actually light, rare forests, where you can freely walk and drive in any direction; the soil in such forests is covered with a herbaceous (and semi-shrub) cover 0.5 m and even 1 meter high. In the savannahs of other countries, trees do not grow at all or are extremely rare and are very short. The grass cover is also sometimes very low, even pressed to the ground.
A special form of savannas is the so-called llanos of Venezuela, where trees are either completely absent or are found in a limited number, with the exception of damp places where palm trees (Mauritia flexuosa, Corypha inermis) and other plants form entire forests (however, these forests do not belong to savannas); in llanos there are sometimes single specimens of Rhopala (trees from the Proteaceae family) and other trees; sometimes the cereals in them form a cover as tall as a man; Compositae, leguminous, labiate, etc. grow between cereals. Many llanos in the rainy season are flooded by the floods of the Orinoco River.
Savannah vegetation is generally adapted to dry continental climate and to periodic droughts that occur in many savannahs for whole months. Cereals and other grasses rarely form creeping shoots, but usually grow in tufts. The leaves of cereals are narrow, dry, hard, hairy or covered with a waxy coating. In grasses and sedges, young leaves remain rolled up into a tube. In trees, the leaves are small, hairy, shiny (“lacquered”) or covered with a waxy coating. The vegetation of the savannas generally has a pronounced xerophytic character. Many species contain large amounts of essential oils, especially those of the Verbena, Labiaceae, and Myrtle families of South America. The growth of some perennial grasses, semi-shrubs (and shrubs) is especially peculiar, namely, that the main part of them, located in the ground (probably, the stem and roots), grows strongly into an irregular tuberous woody body, from which then numerous, mostly unbranched or weakly branched offspring. In the dry season, the vegetation of the savannas freezes; savannahs turn yellow, and dried plants are often subjected to fires, due to which the bark of trees is usually scorched. With the onset of rains, the savannahs come to life, covered with fresh greenery and dotted with numerous different flowers.
Savannahs are characteristic of South America proper, but in other countries one can point out many places that are very similar in the nature of their vegetation to savannahs. Such, for example, are the so-called Campine in the Congo (in Africa); in South Africa, some places are covered with a vegetation cover consisting mainly of grasses (Danthonia, Panicum, Eragrostis), other perennial grasses, shrubs and trees (Acacia horrida), so that such places resemble both the prairies of North America and the savannas of South America; similar places are found in Angola.
The eucalyptus forests of Australia are quite similar to the "campos cerratos" of the Brazilians; they are also light and so rare (the trees are far apart from each other and do not close in crowns) that it is easy to walk in them and even drive in any direction; the soil in such forests during the rainy season is covered with green thickets, consisting mainly of cereals; in the dry season, the soil is exposed.
The fauna of the forest-steppes is represented mainly by herbivores (giraffes, zebras, antelopes, elephants and rhinos), which are able to travel long distances in search of food. Predators include lions, cheetahs and hyenas.
Steppes are more or less even, dry, treeless spaces covered with abundant herbaceous vegetation. The spaces are flat and treeless, but wet, they are not called the steppe. They form either swampy meadows or, in the far north, tundra. Spaces with very sparse vegetation, which does not form a herbaceous cover, but consists of separate, scattered bushes far from each other, are called deserts. Deserts do not differ sharply from the steppe, and often mix with each other.
Hilly or mountainous countries are not called steppes. But they can just as well be treeless and can feed the same flora and fauna as flat steppes. Therefore, one can speak of steppe mountains and steppe slopes as opposed to forested mountains and forested slopes. The steppe is, first of all, the original treeless space, regardless of the relief.
The steppes are characterized by special climatic relationships and special flora and fauna. Steppes are especially developed in southern Russia, and purely Russian word the steppe has passed into everything foreign languages. The distribution of steppe spaces on the earth's surface is undoubtedly influenced by climate. On everything the globe areas with a very hot and dry climate are deserts. Territories with a less hot climate and with a large amount of annual precipitation are partly or entirely covered by the steppe. Spaces with more humid climate, temperate or warm, covered with forests.
Typical steppes represent a flat or gently sloping country, completely devoid of forests, with the exception of river valleys. The soil is chernozem, lying most often on the thickness of loess-like clays with a significant content of lime. This chernozem in the northern strip of the steppe reaches the greatest thickness and obesity, as it sometimes contains up to 16% of humus. To the south, the chernozem becomes poorer in humus, becomes lighter and turns into chestnut soils, and then completely disappears.
The vegetation consists mainly of grasses growing in small tussocks, between which bare soil is visible. The most common types of feather grass, especially the common feathery feather grass. It often covers completely large areas and with its silky white feathery awns gives the steppe some special undulating appearance. On very fat steppes, a special kind of feather grass develops, which is much larger in size. Smaller feather grass grows on dry barren steppes. After species of feather grass, the most important role is played by Kipets or tipets. It is found everywhere in the steppe, but plays a special role east of the Ural Mountains. Kipets is an excellent fodder for sheep.
It is more or less dense in its natural state, usually hard to reach, coniferous thicket with swampy soil with windbreak and windblow. The northern border of the Taiga coincides with the northern border of the forests. The southern border runs in the European part of Russia from the Gulf of Finland to the northeast to the Urals, goes around it from the south and coincides further, in Siberia, with the northern border of the steppes to the Ob River. To the east, the taiga captures mountainous spaces from Altai to the Amur and the Ussuri Territory. The extreme north-east of Siberia has no forests. In Kamchatka, the taiga occupies two small islands north of Petropavlovsk.
The main tree species of the taiga are spruce, European and Siberian pine, larch, fir, and cedar. In Siberia, the same species, with the exception of European spruce. Dahurian larch dominates in Eastern Siberia, and cedar schist is high on the mountains. In the taiga Far East new conifers appear: fir, Ayan spruce, Manchurian cedar, and on Sakhalin - yew. In European Russia, the taiga turns south into coniferous forests with an admixture of large-leaved species (oak and others), which are absent throughout Siberia, but reappear on the Amur. In the taiga, there are only birch, aspen, mountain ash, bird cherry, alder and willow from hardwoods. Of the large-leaved species in the taiga, only linden comes across, and only in the European taiga and sometimes in Western Siberia up to the Yenisei River. There is a fairly large linden island in Altai, along the western slope of the Kuznetsk Alatau.
Relatively recently (until the mid-1990s), the taiga and urman areas of Siberia were completely unexplored and were considered unsuitable for settlement and, in particular, for agricultural colonization. It was assumed that the taiga and urmans consisted more or less entirely of mountainous or swampy areas covered with dense forest. It was believed that these lands were inconvenient for agriculture, both in terms of soil and climatic conditions(extreme severity of the climate, excess moisture), and the difficulty of clearing the forest for land.
The attempts that were sometimes made to allocate land for settlement along the outskirts of the taiga almost always ended in failure: either the plots were not populated, or the settlers who settled on them moved to more convenient places. Serious attention was paid to the question of the settlement of the taiga spaces only in 1893-1895, when, in general, measures for the settlement of Siberia were put more widely. It was recognized as impossible to ignore such vast expanses of land as the taiga.
Soil conditions in many places in the taiga are quite favorable for agriculture. Obstacles such as excess moisture and the severity of the climate are largely eliminated under the influence of settlement and culture. In view of this, in many taiga regions, work was opened to form resettlement areas, which, in general, gave very satisfactory results.
Forest tundra is a transitional type of landscape in which light forests alternate with shrub or typical tundra. The forest tundra is located in a strip from 30 to 300 km wide across the whole of North America and from the Kola Peninsula to the Indigirka basin.
Quantity precipitation in the forest-tundra it is small (200-350 mm), however, due to permafrost and low temperatures, moisture evaporates very slowly. The result of this is the presence of a large number of lakes and swamps, which occupy up to 60% of the area of this natural zone. Average air temperatures in the forest-tundra in July are 10-12°C, and in January from -10° to -40°C. The soils here are peaty-gley, peat-bog, and under light forests - gley-podzolic.
The vegetation of the forest-tundra varies with longitude. Of the trees in the forest-tundra zones, the most common are dwarf birch, polar willow, spruce, fir and larch. Mosses and lichens, as well as small shrubs, are also common.
The fauna of the forest-tundra is dominated by lemmings, reindeer, arctic foxes, white and tundra partridges, snowy owls and a wide variety of migratory, waterfowl and small birds that settle in the bushes.
The tundra includes areas lying beyond the northern limits of forest vegetation with permafrost soil that is not flooded by sea or river waters. By the nature of the surface, the tundra can be rocky, clayey, sandy, peaty, hummocky or swampy. The idea of the tundra as a hard-to-reach space is true only for the marshy tundra, where permafrost can disappear by the end of summer. In the tundra of European Russia, the thawed layer reaches, by September, about 35 cm on peat, about 132 cm on clay, and about 159 cm on sand. standing water the permafrost sinks by the middle of summer, depending on the amount of water and the admixture of solid plant residues, to a depth of about 52–66 cm.
After very frosty and little snow winters and in cold summers, the permafrost, of course, is closer to the surface, while after mild and snowy winters and in warm summers, the permafrost sinks. In addition, the thawed layer is thinner on flat ground than on slopes, where the permafrost may even disappear completely. Peat-hummocky tundra dominates on the Kola Peninsula, on Kanin and along the coast of the Czech Bay of the Arctic Ocean to the Timan Ridge.
The surface of the tundra here consists of large, about 12–14 m high and up to 10–15 m wide, isolated, steep-sided, extremely dense peat mounds, frozen inside. The gaps between the hillocks, about 2 - 5 m wide, are occupied by a very watery, hard-to-reach swamp, "Ersei" Samoyeds. The vegetation on the mounds consists of various lichens and mosses, usually with cloudberries on the slopes. The body of the mound is composed of moss and small tundra shrubs, which can sometimes even prevail.
Peaty-hummocky tundra turns south or closer to the rivers, where there are already forests, into sphagnum peat bogs with cranberries, cloudberries, gonobol, bagun, birch dwarf. Sphagnum peat bogs protrude very far into the forest area. To the east of the Timansky Ridge, peat mounds and Ersei are already rare and only in small areas in low places where water accumulates more. In the north-east European Russia and in Siberia the following types of tundra are developed.
Peaty tundra. The peat layer, consisting of mosses and tundra shrubs, is continuous but thin. The surface is covered mainly with a carpet of reindeer moss, but cloudberries and other small shrubs are sometimes found in abundance. This type, developed on more level ground, is widely distributed, especially between the Timan and Pechora rivers.
Bald, fissured tundra is very common in places that do not present conditions for stagnant water and are accessible to the action of the wind, which blows away snow and dries up the soil, which is covered with cracks. These cracks break the soil into small (the size of a plate, the size of a wheel and larger) areas completely devoid of vegetation, so that frozen clay or frozen sand comes out. Such sites are separated from each other by strips of small shrubs, grasses and saxifrages sitting in cracks.
Herbaceous and shrubby tundra develops where the soil is more fertile. Lichens and mosses recede into the background or disappear completely, and shrubs dominate.
The hummocky tundra. Tussocks up to 30 cm high consist of cotton grass with mosses, lichens and tundra shrubs. The gaps between the tussocks are occupied by mosses and lichens, and gray lichens also dress the tops of old, dead cottongrass tussocks.
Marshy tundra covers large areas in Siberia, where various sedges and grasses predominate in swamps. Swampy spaces occupy, as already noted, the gaps between the hillocks in the peaty-hummocky tundra.
Stony tundra is developed on outcrops of stony rocks (for example, the Khibiny Mountains on the Kola Peninsula, Kaninsky and Timansky Stones, Northern Ural, mountains of Eastern Siberia). The stony tundra is covered with lichens and tundra shrubs.
Plants characteristic of the tundra are reindeer moss or lichens, which give the surface of the tundra a light gray color. Other plants, mostly small shrubs clinging to the soil, are usually found in spots against a background of reindeer moss. In the southern parts of the tundra and closer to the rivers, where islands of forests are already beginning to appear, birch dwarf birch and some willows, about 0.7–8 m tall, are widespread in treeless places.
Belt zoning
The sun heats the spherical surface of the Earth differently: the areas above which it stands high receive the most heat. The farther from the equator, the greater the angle of the rays reaching the earth's surface and, consequently, less thermal energy per unit area. Above the poles, the Sun's rays 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 connected with this. According to the features of heat distribution, seven thermal zones are distinguished. In each hemisphere there are zones of eternal frost (around the poles), cold, moderate. The hot belt at the equator is one for both hemispheres. Thermal belts are the basis for dividing the earth's surface into geographical zones: areas similar in their predominant types of landscapes - natural territorial complexes with a common climate, soils, vegetation and wildlife.
On the equator and near it there is a belt of humid equatorial and subequatorial forests (from Latin sub - under), to the north and south of it, replacing each other, belts of tropics and subtropics with forests, deserts and savannahs, a temperate belt with steppes, forest-steppes stretch and forests, then the treeless expanses of the tundra extend, and, finally, the polar deserts are located at the poles.
But the land surface of the Earth in different places receives not only a different amount of solar energy, but also has many additional dissimilar conditions - for example, remoteness 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. Near the equator there are practically no seasons, the whole year is humid and hot here. When moving away from the equator, in subequatorial zones, the year is divided into drier and wetter seasons. There are savannahs, 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 Sahara, Namib and Kalahari in Africa, 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, which are very different from each other. In the Northern Hemisphere, coniferous forests adjoin the northern border of the belt - taiga, which gives way to the south with mixed and broad-leaved forests, and then forest-steppes and steppes. In the inner regions of the continents, where the influence of the seas and oceans is almost not felt, there may even be deserts (for example, the Gobi desert in Mongolia, the Karakum 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 occurs in some places. At the poles, where the climate is most severe, land ice (as in Antarctica) or sea ice (as in the Arctic) develops. 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 height above sea level. When climbing mountains, the climate, soil type, vegetation and wildlife change. Interestingly, even in hot countries, you can find landscapes of the tundra and even the icy desert. But in order to see it, you 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 consistently change from humid rainforests to alpine meadows and zones of eternal glaciers and snows. It cannot be said that the altitudinal zonality completely repeats the latitudinal geographic zones, because in the mountains and on the plains, many conditions do not repeat. The most diverse range of altitudinal zones near the equator, for example, on the highest peaks of Africa, Mount Kilimanjaro, Kenya, Margherita Peak, in South America on the slopes of the Andes.
natural areas
Among the natural zones, there are those confined to a particular belt. For example, the zone of arctic and antarctic ice deserts and the zone of tundra are located in the arctic and antarctic belts; the forest-tundra zone corresponds to the subarctic and subantarctic belts, and the taiga, mixed and broad-leaved forests correspond to the temperate one. And such natural zones as prairies, forest-steppes and steppes and semi-deserts are common both in the temperate and in the tropical and subtropical zones, having, of course, their own characteristics.
Natural zones, their climatic features, soils, vegetation and wildlife 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.
Zone of Arctic and Antarctic deserts
Air temperatures are constantly very low, there is little precipitation. On rare ice-free land areas - rocky deserts (in Antarctica they are called oases), sparse vegetation is represented by lichens and mosses, flowering plants are rare (only two species are found in Antarctica), soils are practically absent.
Tundra zone
The tundra zone is widespread in the arctic and subarctic belts, 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 with tundra vegetation are found on some islands near Antarctica.
The climate is harsh with strong winds, the snow cover lasts up to 7-9 months, the long polar night is replaced by a short and humid summer (summer temperatures do not exceed 10 ° C). Precipitation is 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 widespread permafrost. The main distinguishing feature of the tundra is treelessness, the predominance of sparse moss-lichen, sometimes grassy, cover; in the southern parts with shrubs and shrubs of dwarf and creeping forms. The soils are tundra-gley.
Zone of forest-tundra and light forests
forest zone
The forest zone in the Northern Hemisphere includes the subzones of taiga, mixed and broad-leaved forests and the subzone of temperate forests, in the Southern Hemisphere only the subzone of mixed and broad-leaved 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, winter severity increases with distance from the ocean (up to -50 °c in Eastern Siberia), and precipitation decreases (from 600 to 200 mm). dark-coniferous (from spruce and fir) and light-coniferous (from larch in Siberia, where permafrost soils are widespread) forests with an admixture of small-leaved species (birch, aspen) and pine prevail, poor in species composition, in eastern Eurasia - cedar. - taiga.
The subzone of mixed and broad-leaved forests (sometimes two independent subzones are distinguished) is distributed mainly in the oceanic and transitional zones of the continents. It occupies small areas in the Southern Hemisphere, winters are much warmer here and snow cover is not formed everywhere. Coniferous-broad-leaved forests on soddy-podzolic soils are replaced in the inner parts of the continents by coniferous-small-leaved and small-leaved forests, and to the south (in North America) or west (in Europe) by broad-leaved oak, maple, linden, ash, beech and hornbeam forests on gray forest forests. soils.
forest-steppe
The forest-steppe is a transitional natural zone of the Northern Hemisphere, with alternation of forest and steppe natural complexes. According to the nature of natural vegetation, forest-steppes with broad-leaved and coniferous-small-leaved forests and prairies are distinguished.
Prairie is a forest-steppe subzone (sometimes considered as a steppe subzone) with abundant moisture, stretching along the eastern coasts of the Rocky Mountains in the USA and Canada with tall grass on chernozem-like soils. The natural vegetation here is practically not preserved. Similar landscapes are characteristic of the subtropics of the eastern regions of South America and East Asia.
Steppe
This natural zone is common in the northern temperate or both subtropical geographical zones and is a treeless expanse with grassy vegetation. The growth of woody vegetation here, unlike the tundra, is prevented not by low temperatures, but by a lack of moisture. Trees can grow only along river valleys (the so-called gallery forests), in large erosive forms, such as gullies that collect water from the surrounding interfluve spaces. Now most of the zone has been plowed up, irrigated agriculture and pastoral cattle breeding are developing in the subtropical zone. 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, thin-legged). The soils are fertile - chernozems, dark chestnut and chestnut in the temperate zone; brown, gray-brown, saline in places in the subtropical).
The subtropical steppe in South America (Argentina, Uruguay) is called the pampa (i.e. plain, steppe in the language of the Quechua Indians). Media .
Deserts and semi-deserts
Savannah
Savannah is a natural zone, distributed mainly in subequatorial belts, but is also found in tropical and even subtropical regions. The main feature of the climate of the savannas is a clear change of dry and rainy periods. The duration of the rainy period decreases when moving from equatorial regions (here it can last 8-9 months) to tropical deserts (here the rainy season is 2-3 months). The savannahs are characterized by a dense and high grassy cover, standing separately or in small groups of trees (acacia, baobab, eucalyptus) and the so-called gallery forests along the rivers. The soils of typical tropical savannahs are red soils. In deserted savannahs, 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, called llanos (from Spanish "plain"). See also: .
Forest subtropics
Forest subtropics. The monsoonal 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 humid summer with heavy monsoon rains, often with typhoons. Evergreen and deciduous (dropping leaves in winter due to lack of moisture) with a wide variety of tree species grow here on red earth and yellow earth soils.
The Mediterranean subzone is characteristic of the western regions of the continents (Mediterranean, California, Chile, southern Australia and Africa). Precipitation falls 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 arid conditions: they have a wax coating or pubescence on the leaves, thick or dense leathery bark, emit fragrant essential oils. Cm: .
Rainforests
