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Identification and explanation of the geographical zonality of the Earth's nature.
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Home > Wiki-textbook > Geography > 7th grade > Natural zones of North America: general characteristics of each zone
Due to the great elongation of the continent from south to north, the natural zones of North America (9 natural zones) are distinguished by a wide variety of flora and fauna.
Arctic deserts
Most of the Canadian Arctic Islands and Greenland.
Arctic. Negative or near-zero temperatures predominate.
Soils. Poor, rocky and swampy.
Vegetation. Mainly mosses and lichens.
Animal world. Muskox.
Tundra
The northern coast of the mainland with adjacent islands. To the east are the coast of Hudson Bay and the northern part of the Labrador Peninsula.
Predominantly subarctic (partially arctic).
Soils. Tundra - gley, with excess moisture.
Vegetation. In the northern part there are mosses and lichens; in the southern part there are marsh grasses, blueberries and blueberries, wild rosemary bushes, low-growing willows, birches, and alders.
Woody vegetation appears to the south.
Animal world. Polar wolf, caribou reindeer, arctic fox, ptarmigan and some others. A variety of migratory birds. In coastal waters there are seals and walruses. On the northern coast there is a polar bear.
Taiga
It stretches in a wide strip from east to west.
Difficult coniferous forests.
Climate. Moderate (with increased moisture).
Soils. Podzolics predominate.
Vegetation.
Mainly coniferous trees - balsam fir, black spruce, pine, sequoias, American larch. Hardwoods - paper birch, aspen. On the slopes of the Cordillera there are Sitka spruce and Douglas fir.
Animal world. Wolves, bears, deer and elk, foxes, lynxes, sables, beavers, muskrats. In mountain forests there are skunks, grizzly bears, and raccoons.
In the rivers there are salmon fish. There are seal rookeries on the islands.
Mixed and broad-leaved forests
South of the tundra zone.
(Variable moist forests predominate in the eastern part of the North American continent.)
Climate. Temperate, turning into subtropical.
Soils. Gray forest, brown forest, yellow soil and red soil.
Vegetation. In mixed forests there are sugar maple, yellow birch, white and red pine, linden, and beech. In the broad-leaved forests there are different types of oaks, plane trees, chestnuts, and tulip trees.
Animal world.
Wapiti deer, bears (grizzly), moose, lynx, wolves, wolverines, raccoons, hares, foxes.
Evergreen tropical forests
In the south of the Atlantic and Mississippian and lowlands.
Climate. Subtropical.
Soils. Gray - brown, brown.
Vegetation.
Oaks, magnolias, beeches, dwarf palms. The trees are entwined with vines.
Animal world. Diverse.
Forest-steppe
Treeless plains to the west of the forest zone. (In North America they are called prairies).
Climate. Subtropical.
Soils. Chernozems: podzolized and leached. Chestnut, forest gray.
Vegetation. Tall perennial grasses: wheatgrass, feather grass, etc.
In river valleys there is woody vegetation. Near the Cordillera there are low cereal grasses (Gram grass and buffalo grass).
Animal world. Diverse and rich.
Desert and semi-desert zone
A significant part of the California coast, the Mexican highlands and the interior plateaus of the Cordillera.
Climate. Moderate (arid).
Soils. Brown and gray desert.
Vegetation. Black wormwood; on salt licks - quinoa solyanka; thorny bushes, cacti.
Animal world.
Savannas and evergreen forests
On the slopes of the Caribbean and Central America.
Climate. There is a distinct change between dry and wet seasons.
Soils. Black, red-brown, brown, gray-brown
Vegetation. Tropical types of hard-leaved grasses. Trees with a long root system and umbrella-shaped crowns predominate.
Animal world. Versatile.
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§25. Natural areas of the Earth
1. List the main natural zones of the Earth.
Tundra, taiga, deciduous forest, grassy plain (savanna), deserts and semi-deserts, steppes and forest-steppes, tropical rainforest.
2. What determines the distribution of natural zones on Earth?
Natural zones are formed due to the distribution of heat and moisture on the planet. Relief and distance from the ocean affect the location of zones and their width.
Give brief description tundra
This natural zone is located in the polar zone (most of it in the permafrost zone), where the air temperature is quite low.
The flora is represented mainly by low-growing plants with poorly developed root systems: mosses, lichens, shrubs, and dwarf trees. The tundra is home to ungulates, small predators, and many migratory birds.
4. What trees form the basis of taiga, mixed and deciduous forests?
- The basis of the taiga is coniferous trees (pine, spruce, fir, larch, etc.);
- Mixed forests are characterized by a mixture of coniferous and broad-leaved tree species;
- Broad-leaved forests consist of deciduous trees (oak, hazel, beech, linden, maple, chestnut, hornbeam, elm, ash, etc.).
What do all the grassy plains on our planet have in common?
Answer: It is characterized by low precipitation and constantly high air temperatures. Savannas are characterized by a dry period, during which grasses dry out and animals tend to water bodies. The vegetation here is predominantly herbaceous, trees are rare. Savannas are characterized by an abundance of large herbivores and predators.
Give a brief description of the desert.
Deserts are characterized by very low humidity; the flora and fauna of deserts adapt to these difficult conditions. Animals have the property for a long time do without water, wait out the driest months in hibernation, many are nocturnal.
Many plants are able to store moisture; most have reduced evaporation; in addition, they have an extensive root system that allows them to collect crumbs of moisture from a large volume.
In general, the flora and fauna are very limited. The most common plants are leafless thorny bushes, and the animals are reptiles (snakes, lizards) and small rodents.
7. Why are there few trees in the steppes, savannas and deserts?
In savannas, steppes and deserts there is very little rainfall; the trees simply do not have enough water.
Why is the tropical rainforest the most species-rich community?
Answer: There is always high temperature and humidity here. These conditions are especially favorable for plants and animals. The topsoil is very fertile.
9. Using examples, prove that the distribution of natural zones on Earth depends on the distribution of heat and moisture.
Natural zones are formed as a result of the distribution of heat and moisture on the planet: high temperature and low humidity are characteristic of equatorial deserts, high temperature and high humidity are characteristic of equatorial and tropical forests.
Natural zones stretch from west to east, there are no clear boundaries between them.
For example, savannas are located where moisture is no longer sufficient for the growth of humid forests, in the interior of the continent, and also far from the equator, where for most of the year it is not the equatorial, but the tropical climate that dominates. air mass, and the rainy season lasts less than 6 months.
10. Characteristic features of which natural zones are listed?
- The largest variety of species is tropical rainforest.
- The predominance of herbaceous plants is Savannah.
- Abundance of mosses, lichens and dwarf trees - Tundra.
- Many coniferous plants of a few species - .
Analyze the pictures on p. 116-117 textbook. Is there a connection between the color of animals and their habitat (natural area)? What is this connected with?
Answer: Yes, there is a connection. This is called protective painting. Animals thus blend into their environment for various purposes. If it is a predator, then it is for attack. For example, a striped tiger successfully hides in the yellow grass, preparing for an attack.
The polar bear and arctic fox are almost invisible against the background of snow.
To protect themselves from predators, animals have also developed colors to hide. Examples: jerboa, roe deer, green frog and many others. etc.
In what natural areas do these organisms live?
- Dwarf birch - tundra.
- Sloth - tropical rainforest.
- Kedrovka - taiga.
- Zebra - savannah.
- Oak is a broad-leaved forest.
- Jeyran is a desert.
- White owl - tundra.
Using the map on p. 118-119 of the textbook, name the natural areas found on the territory of our country. Which of them occupy the largest territory?
The territory of Russia has a large extent from north to south, the relief is mostly flat. Thus, the following natural zones are consistently represented on the vast plains: arctic deserts, tundra, forest-tundra, forests, forest-steppes, steppes, semi-deserts, deserts, subtropics.
In the mountains- altitudinal zone. Large territory occupied by taiga, steppe, mixed forest and tundra.
§24. Life on different continents§26. Life in the seas and oceans
1. Natural complexes are very diverse. Which of them are called natural areas?
The natural complex of land, as well as the complex of the geographical shell as a whole, is a heterogeneous formation and includes natural complexes of lower ranks, differing in the quality of the natural components that make up the complex.
These lower-ranking natural areas are. After studying the map of natural zones, you will be able to independently name these natural zones and trace the patterns of their location.
2. Highlight the main features of the concept “natural area”.
Each natural zone differs from others in the quality of its constituent soils, flora and fauna.
And the quality of these components, in turn, depends on the climate, the combination of light, heat and moisture received.
3. What are the features of the location of natural zones on continents and in the ocean?
The boundaries of natural zones on land are most clearly visible by the nature of vegetation.
It is no coincidence that vegetation is taken as the basis for the name of natural land areas.
Natural zones are also distinguished in the World Ocean, but the boundaries of these zones are less clear, and the division into zones in the ocean is based on the qualitative characteristics of water masses.
4. What is latitudinal zonation and altitudinal zonation?
The pattern with which natural zones are located on the surface of the Earth is
called latitudinal zonality.
Changes in the quality of the components that make up a natural zone occur depending on their geographical location, especially on latitude, on which the amount of heat and moisture received depends.
In the mountains, unlike flat areas, natural areas change with altitude. The change in natural zones from the foot of the mountains to their peaks is similar to the change in natural zones from the equator to the poles. The pattern of changes in natural zones with altitude in the mountains is called altitudinal zonality or altitudinal zonation.
Which mountains have the largest number of altitudinal zones, and which have the smallest? Why?
The number of natural zones in the mountains depends on the geographical position of the mountains in relation to the equator and on their height.
On the southern slopes of the Himalayas, almost all natural zones alternate: from humid equatorial zones at the foot to arctic deserts at the peaks. In the mountains located more high latitudes, the number of natural areas will be smaller. Thus, it is possible to trace the relationship that exists between the number of natural zones in the mountains and the geographical position of the mountains in relation to the equator.
The reason for this pattern is the amount of heat and moisture received.
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Natural areas of the Earth
Complex Scientific research nature allowed V.V. Dokuchaev in 1898 to formulate the law of geographical zoning, according to which climate, water, soil, relief, vegetation and fauna on certain territory are closely interrelated and must be studied as a whole. He proposed dividing the Earth's surface into zones that are naturally repeated in the Northern and Southern Hemispheres.
Different geographical (natural) zones Earth are characterized by a certain combination of heat and moisture, soils, flora and fauna and, as a consequence, the characteristics of the economic activities of their population. These are zones of forests, steppes, deserts, tundra, savanna, as well as transitional zones of forest-tundra, semi-deserts, forest-tundra. Natural areas are traditionally named according to the predominant type of vegetation, reflecting the most important features landscape.
A regular change in vegetation is an indicator of a general increase in heat. In the tundra the average temperature is warm month in the year - July - does not exceed + 10°С, in the taiga it fluctuates between + 10... + 18°С in the strip of deciduous and mixed forests + 18...+20°С, in the steppe and forest-steppe +22. ..+24°С, in semi-deserts and deserts - above +30°С.
Most animal organisms remain active at temperatures from 0 to +30°C. However, temperatures from + 10°C and above are considered the best for growth and development. Obviously, such a thermal regime is typical for the equatorial, subequatorial, tropical, subtropical, and temperate climatic zones of the Earth. The intensity of vegetation development in natural areas also depends on the amount of precipitation. Compare, for example, their number in the forest and desert zones (see atlas map).
So, natural areas- these are natural complexes that occupy large areas and are characterized by the dominance of one zonal type of landscape. They are formed mainly under the influence of climate - the distribution of heat and moisture, their ratio. Each natural zone has its own type of soil, vegetation and animal life.
The appearance of a natural area is determined by the type of vegetation cover. But the nature of vegetation depends on climatic conditions - thermal conditions, moisture, light, soil, etc.
As a rule, natural zones are extended in the form of wide stripes from west to east. There are no clear boundaries between them; they gradually transform into one another. The latitudinal location of natural zones is disrupted by the unequal distribution of land and ocean, relief, distance from the ocean.
General characteristics of the main natural zones of the Earth
Let us characterize the main natural zones of the Earth, starting from the equator and moving towards the poles.
There are forests on all continents of the Earth, except Antarctica. Forest zones have both common features and special ones, characteristic only of taiga, mixed and broad-leaved forests or tropical forests.
General features of the forest zone include: warm or hot summers, fairly a large number of precipitation (from 600 to 1000 or more mm per year), large deep rivers, predominance of woody vegetation. The greatest amount of heat and moisture is received equatorial forests, occupying 6% of the land. They rightfully hold first place among the forest zones of the Earth in terms of diversity of plants and animals. 4/5 of all plant species grow here and 1/2 of all land animal species live here.
Climate equatorial forests hot and humid. Average annual temperatures are +24... + 28°C. The annual precipitation is more than 1000 mm. It is in the equatorial forest that you can find the largest number of ancient animal species, such as amphibians: frogs, newts, salamanders, toads or marsupials: possums in America, possums in Australia, tenrecs in Africa, lemurs in Madagascar, lorises in Asia; Ancient animals include such inhabitants of equatorial forests as armadillos, anteaters, and lizards.
In equatorial forests, the richest vegetation is located in several tiers. The treetops are home to many species of birds: hummingbirds, hornbills, birds of paradise, crowned pigeons, numerous species of parrots: cockatoos, macaws, Amazons, African Grays. These birds have tenacious legs and strong beaks: they not only fly, but also climb trees very well. Animals that live in treetops also have prehensile paws and tails: sloths, monkeys, howler monkeys, flying foxes, tree kangaroos. The largest animal that lives in the treetops is the gorilla. Such forests are home to many beautiful butterflies and other insects: termites, ants, etc. There are various types of snakes. Anaconda is the largest snake in the world, reaching a length of 10 m or more. The high-water rivers of the equatorial forests are rich in fish.
The largest areas of equatorial forests occupy in South America, in the Amazon River basin, and in Africa - in the Congo River basin. The Amazon is the deepest river on Earth. Every second she endures Atlantic Ocean 220 thousand m3 of water. The Congo is the second most water-rich river in the world. Equatorial forests are also common on the islands of the Malaysian archipelago and Oceania, in the southeastern regions of Asia, and in northeastern Australia (see map in the atlas).
Valuable tree species: mahogany, black, yellow - the wealth of equatorial forests. Harvesting valuable timber threatens the conservation of the Earth's unique forests. Satellite images have shown that in a number of areas of the Amazon, destruction the forest is coming at a catastrophic pace, many times faster than their recovery. At the same time, many species are disappearing unique plants and animals.
Variably wet monsoon forests
Variably humid monsoon forests can also be found on all continents of the Earth except Antarctica. If in the equatorial forests it is summer all the time, then three seasons are clearly defined here: dry cool (November-February) - winter monsoon; dry hot (March-May) - transitional season; humid hot (June-October) - summer monsoon. The hottest month is May, when the sun is almost at its zenith, rivers dry up, trees shed their leaves, and the grass turns yellow.
Summer monsoon arrives at the end of May hurricane winds, thunderstorms, torrential rains. Nature comes to life. Due to the alternation of dry and wet seasons, monsoon forests are called variable-wet.
India's monsoon forests are located in the tropical climatic zone. Valuable tree species grow here, characterized by the strength and durability of the wood: teak, sal, sandalwood, satin and ironwood. Teak wood is not afraid of fire and water, it is widely used for the construction of ships. Sal also has a durable and strong wood. Sandalwood and satin trees are used in the manufacture of varnishes and paints.
The fauna of the Indian jungle is rich and diverse: elephants, bulls, rhinoceroses, monkeys. Lots of birds and reptiles.
Monsoon forests in tropical and subtropical regions are also characteristic of Southeast Asia, Central and South America, and the northern and northeastern regions of Australia (see map in the atlas).
Temperate monsoon forests
Temperate monsoon forests are found only in Eurasia. The Ussuri taiga is a special place in the Far East. This is a real thicket: multi-tiered, dense forests, intertwined with vines and wild grapes. Cedar, walnut, linden, ash, and oak grow here. The lush vegetation is the result of abundant seasonal rainfall and a fairly mild climate. Here you can meet Ussuri tiger- himself major representative of its own kind.
The rivers of the monsoon forests are fed by rain and overflow during the summer monsoon rains. The largest of them are the Ganges, Indus, and Amur.
Monsoon forests have been heavily cut down. According to experts, in Eurasia only 5% of the former remains forest areas. Monsoon forests have suffered not only from forestry, but also from agriculture. It is known that the largest agricultural civilizations appeared on fertile soils in the valleys of the Ganges, Irrawaddy, Indus rivers and their tributaries. The development of agriculture required new territories - forests were cut down. Agriculture has adapted for centuries to alternating wet and dry seasons. The main agricultural season is the wet monsoon period. The most important crops are planted here - rice, jute, sugar cane. In the dry, cool season, barley, legumes, and potatoes are planted. During the dry hot season, farming is possible only with artificial irrigation. The monsoon is capricious, its delay leads to severe droughts and destruction of crops. Therefore, artificial irrigation is necessary.
Temperate forests
Temperate forests occupy significant areas in Eurasia and North America (see map in the atlas).
In the northern regions it is taiga, to the south - mixed and deciduous forests. In the forest zone of the temperate zone, the seasons of the year are clearly defined. Average temperatures in January are negative throughout, in some places down to - 40°C, in July + 10... + 20°C; the amount of precipitation is 300-1000 mm per year. The vegetation of plants stops in winter, and there is snow cover for several months.
Spruce, fir, pine, and larch grow both in the taiga of North America and in the taiga of Eurasia. The animal world also has a lot in common. The bear is the owner of the taiga. True, in the Siberian taiga it is called a brown bear, and in the Canadian taiga it is called a grizzly bear. You can meet red lynx, elk, wolf, as well as marten, ermine, wolverine, and sable. The largest rivers of Siberia flow through the taiga zone - the Ob, Irtysh, Yenisei, Lena, which in terms of flow are second only to the rivers of the equatorial forest zone.
To the south, the climate becomes milder: mixed and broad-leaved forests grow here, consisting of species such as birch, oak, maple, linden, among which there are also conifers. Characteristic of the forests of North America are: white oak, sugar maple, yellow birch. Red deer, elk, wild boar, hare; Among the predators, the wolf and the fox are representatives of the animal world of this zone known to us.
If the northern taiga is considered by geographers to be a zone slightly modified by humans, then mixed and broad-leaved forests have been cut down almost everywhere. Their place was taken by agricultural areas, for example, the “corn belt” in the United States; many cities and transport routes are concentrated in this zone. In Europe and North America, the natural landscapes of these forests have been preserved only in mountainous areas.
Savannah
Savannah is a natural zone of low latitudes in the subequatorial, tropical and subtropical zones of the Northern and Southern hemispheres. Occupies about 40% of the territory of Africa (sub-Saharan Africa), distributed in South and Central America, Southeast Asia, Australia (see map in the atlas). The savanna is dominated by herbaceous vegetation with isolated trees or groups of trees (acacia, eucalyptus, baobab) and bushes.
The fauna of African savannas is surprisingly diverse. To adapt to the conditions of endless dry spaces, nature endowed animals with unique properties. For example, the giraffe is considered the tallest animal on Earth. Its height exceeds 5 m, it has a long tongue (about 50 cm). The giraffe needs all this in order to reach the high branches of the acacia trees. The crowns of acacias begin at a height of 5 m, and giraffes have practically no competitors, calmly eating tree branches. Typical savannah animals are zebras, elephants, and ostriches.
Steppes
Steppes are found on all continents of the Earth, except Antarctica (in the temperate and subtropical zones of the Northern and Southern Hemispheres). They are characterized by an abundance of solar heat, low precipitation (up to 400 mm per year), and warm or hot summers. The main vegetation of the steppes is grass. Steppes are called differently. In South America, the tropical steppes are called pampa, which in the Indian language means “a large area without forest.” Animals characteristic of the pampa are the llama, the armadillo, and the viscacha, a rodent similar to a rabbit.
In North America, steppes are called prairies. They are located in both temperate and subtropical climate zones. The bison have long been the “kings” of the American prairies. By the end of the 19th century they were almost completely exterminated. Currently, through the efforts of the state and the public, the number of bison is being restored. Another resident of the prairies is the coyote - the steppe wolf. Along the banks of rivers in the bushes you can find a large spotted cat - a jaguar. Peccaries are a small boar-like animal also typical of the prairies.
The steppes of Eurasia are located in the temperate zone. They are very different from the American prairies and African savannas. It has a drier, sharply continental climate. In winter it is very cold (average temperature - 20°C), and in summer it is very hot (average temperature + 25°C), with strong winds. In summer, the vegetation of the steppes is sparse, but in spring the steppe is transformed: it blooms with many varieties of lilies, poppies, and tulips.
The flowering time does not last long, about 10 days. Then drought sets in, the steppe dries out, the colors fade, and by autumn everything turns yellow-gray.
The steppes contain the most fertile soils on Earth, so they are almost completely plowed. The treeless spaces of the temperate steppes are characterized by strong winds. Wind erosion of soils occurs very intensively here - dust storms are frequent. To preserve soil fertility, forest belts are planted, organic fertilizers and light agricultural machinery are used.
Deserts
Deserts occupy vast areas - up to 10% of the Earth's land area. They are located on all continents and in different climatic zones: temperate, subtropical, tropical and even polar.
In tropical and desert climates temperate zones there are common features. Firstly, an abundance of solar heat, secondly, a large amplitude of temperatures between winter and summer, day and night, and thirdly, a small amount of precipitation (up to 150 mm per year). However, the latter feature is also characteristic of polar deserts.
In the deserts of the tropical zone, the average summer temperature is +30°C, winter + 10°C. The greatest tropical deserts on Earth are located in Africa: the Sahara, Kalahari, Namib.
Plants and animals of deserts adapt to dry and hot climates. For example, a giant cactus can store up to 3000 liters of water and “not drink” for up to two years; and the Welwitschia plant, found in the Namib Desert, is capable of absorbing water from the air. The camel is an indispensable helper for humans in the desert. It can be without food and water for a long time, storing it in its humps.
The largest desert in Asia, the Rub al-Khali, located on the Arabian Peninsula, is also located in the tropical zone. The desert regions of North and South America and Australia are located in the tropical and subtropical climate zones.
The temperate deserts of Eurasia are also characterized by low precipitation and a large temperature range, both annual and daily. However, they are characterized by lower winter temperatures and a pronounced flowering period in the spring. Such deserts are located in Central Asia east of the Caspian Sea. The fauna here is represented by various species of snakes, rodents, scorpions, turtles, and lizards. A typical plant is saxaul.
Polar deserts
Polar deserts are located in the polar regions of the Earth. The absolute minimum temperature recorded in Antarctica is 89.2 °C.
On average, winter temperatures are -30 °C, summer temperatures are 0 °C. Just like in the deserts of the tropical and temperate zones, the polar desert receives little precipitation, mainly in the form of snow. The polar night lasts almost half a year here, and the polar day lasts almost half a year. Antarctica is considered the highest continent on Earth, given the thickness of its ice shell at 4 km.
The indigenous inhabitants of the polar deserts of Antarctica are emperor penguins. They cannot fly, but they swim perfectly. They can dive greater depth and swim vast distances, escaping from their enemies - the seals.
The northern polar region of the Earth - the Arctic - got its name from the ancient Greek arcticos - northern. The southern, as if opposite, polar region is Antarctica (anti - against). The Arctic occupies the island of Greenland, the islands of the Canadian Arctic Archipelago, as well as the islands and waters of the Arctic Ocean. This area is covered with snow and ice all year round. The polar bear is rightfully considered the owner of these places.
Tundra
Tundra is a treeless natural area with vegetation of mosses, lichens and creeping shrubs. The tundra is distributed in the subarctic climate zone only in North America and Eurasia, which are characterized by harsh climatic conditions (little solar heat, low temperatures, short cold summers, low precipitation).
The moss lichen was called “reindeer moss” because it is the main food of reindeer. Arctic foxes and lemmings - small rodents - also live in the tundra. Among the sparse vegetation there are berry bushes: blueberries, lingonberries, blueberries, as well as dwarf trees: birch, willow.
Permafrost in the soil is a phenomenon characteristic of the tundra, as well as the Siberian taiga. As soon as you start digging a hole, at a depth of about 1 m you will encounter a frozen layer of earth several tens of meters thick. This phenomenon must be taken into account during construction, industrial and agricultural development of the territory.
Everything grows very slowly in the tundra. This is precisely why the need for careful attention to its nature is connected. For example, pastures overrun by deer are restored only after 15-20 years.
Altitudinal zone
Unlike flat areas, climatic zones and natural zones in the mountains change according to the law of vertical zonation, i.e. from bottom to top. This is due to the fact that the air temperature decreases with altitude. Consider, as an example, the greatest mountain system in the world - the Himalayas. Almost all natural zones of the Earth are represented here: tropical forest grows at the foot, at an altitude of 1500 m it is replaced by broad-leaved forests, which in turn turn into mixed forests at an altitude of 2000 m. Further, as you climb the mountains, coniferous forests of Himalayan pine begin to predominate, fir and juniper. In winter, there is snow here for a long time and frosts persist.
Above 3500 m, shrubs and alpine meadows begin; they are called “alpine”. In summer, the meadows are covered with a carpet of brightly blooming herbs - poppies, primroses, gentians. Gradually the grasses become shorter. From approximately 4500 m altitude there is eternal snow and ice. The climatic conditions here are very harsh. They live in the mountains rare species animals: mountain goat, chamois, argali, snow leopard.
Latitudinal zonation in the ocean
The world's oceans occupy more than 2/3 of the planet's surface. The physical properties and chemical composition of ocean waters are relatively constant and create an environment favorable for life. It is especially important for the life of plants and animals that oxygen and carbon dioxide coming from the air dissolve in water. Photosynthesis of algae occurs mainly in the upper layer of water (up to 100 m).
Marine organisms live mainly in the surface layer of water illuminated by the Sun. These are the smallest plant and animal organisms - plankton (bacteria, algae, small animals), various fish and marine mammals (dolphins, whales, seals, etc.), squid, sea snakes and turtles.
On seabed there is life too. These are bottom algae, corals, crustaceans, and mollusks. They are called benthos (from the Greek benthos - deep). The biomass of the World Ocean is 1000 times less than the biomass of the Earth's land.
Distribution of life in world ocean unevenly and depends on the amount of solar energy received on its surface. Polar waters are poor in plankton due to low temperatures and the long polar night. The largest amount of plankton develops in the waters of the temperate zone in summer. The abundance of plankton attracts fish here. The temperate zones of the Earth are the most fishy areas of the World Ocean. In the tropical zone, the amount of plankton decreases again due to high salinity water and high temperatures.
Formation of natural areas
From today's topic, we learned how diverse the natural complexes of our planet are. The natural zones of the Earth are replete with evergreen forests, endless steppes, various mountain ranges, hot and icy deserts.
Each corner of our planet is distinguished by its uniqueness, varied climate, relief, flora and fauna, and therefore different natural zones are formed on the territories of each continent.
Let's try to figure out what natural areas are, how they were formed, and what was the impetus for their formation.
Natural zones include those complexes that have similar soils, vegetation, fauna and similar temperature conditions. Natural zones received their names based on the type of vegetation, and are called such as taiga zone or deciduous forests, etc.
Natural areas are diverse due to the uneven redistribution of solar energy on the Earth's surface. This is where it lies main reason heterogeneity of the geographical envelope.
After all, if we consider one of the climatic zones, we will notice that those parts of the belt that are located closer to the ocean are more humidified than its continental parts. And this reason lies not so much in the amount of precipitation, but rather in the ratio of heat and moisture. Because of this, on some continents we experience a more humid climate, while on others we experience a drier climate.
And with the help of the redistribution of solar heat, we see how the same amount of moisture in some climate zones leads to excess moisture, and in others to a lack of moisture.
For example, in a hot tropical zone, a lack of moisture can cause drought and the formation of desert areas, while in the subtropics, excess moisture contributes to the formation of swamps.
So you learned that due to the difference in the amount of solar heat and moisture, different natural zones were formed.
Patterns of natural zones location
Natural zones of the Earth have clear patterns of their location, extending in the latitudinal direction and changing from north to south. Most often, a change in natural zones is observed in the direction from the coast making its way inland.
In mountainous areas there is an altitudinal zone, which changes from one zone to another, starting from the foot and moving towards the mountain peaks.
In the World Ocean, zones change from the equator to the poles. Here, changes in natural areas are reflected in the surface composition of waters, as well as differences in vegetation and fauna.
Features of the natural zones of the continents
Since planet Earth has a spherical surface, the Sun heats it unevenly. Those areas of the surface above which the Sun is high receive the most heat. And where the sun's rays only glide over the Earth, a more severe climate prevails.
And although on different continents the vegetation and animals have similar features, they are influenced by climate, topography, geology and people. Therefore, historically, due to changes in relief and climate, different species of plants and animals live on different continents.
There are continents where endemics are found, where only a certain type of living beings and plants live, which are peculiar to these continents. For example, polar bears can only be found in nature in the Arctic, and kangaroos can only be found in Australia. But in African and South American shrouds there are similar species, although they have certain differences.
But human activity contributes to changes that occur in the geographical environment, and under such influence natural areas also change.
Questions and tasks to prepare for the exam
1. Draw up a diagram of the interaction of natural components in a natural complex and explain it.
2. How do the concepts “natural complex”, “geographical envelope”, “biosphere”, “natural zone” relate to each other? Show with a diagram.
3. Name the zonal type of soil for tundra, taiga, mixed and deciduous forest zones.
4. Where is the soil cover more difficult to restore: in the steppes of Southern Russia or in the tundra? Why?
5. What is the reason for the difference in the thickness of the fertile soil layer in different natural zones? What does soil fertility depend on?
6. What types of plants and animals are characteristic of the tundra and why?
7. What organisms live on the surface of the waters of the World Ocean?
8. Which of the following animals can be found in the African savanna: rhinoceros, lion, giraffe, tiger, tapir, baboon, llama, hedgehog, zebra, hyena?
9. In what forests is it impossible to determine its age from the cut of a cut tree?
10. What measures, in your opinion, will help preserve the human habitat?
Maksakovsky V.P., Petrova N.N., Physical and economic geography of the world. - M.: Iris-press, 2010. - 368 pp.: ill.
The Russian Federation stretches from west to east and from north to south for many kilometers, so the zoning of the territory is clearly visible. The sun illuminates and warms different parts of the earth differently. The most heat falls on the equator, the least on the northern and South Pole. Different zones of the globe receive a certain amount of heat, light, and moisture. These conditions define individual zones with their own special climate.
There are the following natural zones: arctic deserts, tundra, forest-tundra, taiga, forests, forest-steppes, steppes, semi-deserts, deserts, subtropics.
A natural zone is a territory that is determined by uniform climatic conditions, soil characteristics, vegetation and fauna. The names of natural zones correspond to the name of the predominant vegetation in this zone.
Arctic desert zone or ice zone
The Arctic desert zone is located in the very north of Russia, on the islands of the Arctic Ocean. Most of the zone's territory (about 85%) is covered with glaciers. In mid-summer the temperature here is no more than 2-4 degrees Celsius, and in winter there is frost down to -50°C, strong winds, and fog. The climate is very harsh.
The soils in this zone are very weak, there is no fertile layer, and there are many stone ruins. Only mosses and lichens grow on the rocks.
Reindeer and polar bears live in the Arctic desert, and seabirds live on the rocky shores of the ocean: auks, gulls, polar owls and partridges. The Arctic Ocean is home to baleen whales, seals, walruses, seals, and beluga whales.
As humans invade, the Arctic desert is changing. Thus, industrial fishing has led to a reduction in their populations, which is one of the environmental problems of this zone. Every year the number of seals and walruses, polar bears and arctic foxes decreases here. Some species are on the verge of extinction due to human activities. In the Arctic desert zone, scientists have discovered significant reserves of minerals. Sometimes accidents occur during their extraction, and oil is spilled on the territory of ecosystems, harmful substances enter the atmosphere, and global pollution of the biosphere occurs. It is impossible not to touch upon the topic of global warming. Human activities contribute to the melting of glaciers. As a result, the territories of Arctic deserts are shrinking and the water level in the World Ocean is rising. This contributes not only to changes in ecosystems, but also to the movement of some species of flora and fauna to other habitats and their partial extinction.
Tundra zone
The Arctic tundra stretches along the coast of the Arctic Ocean. The climate of the tundra is harsh. In this cold natural zone, summers are short and cool, and winters are long, with severe frosts and winds from the Arctic Ocean.
The vegetation is sparse, mainly mosses and lichens. Further to the south, in the middle part of the zone there is a lichen-moss tundra with islands of moss and lichens, among them moss and many cloudberries. In the south of the zone there is a shrub tundra with more abundant vegetation: bush willows, dwarf birches, herbs and berries. Tundra soils are usually swampy, poor in humus, and highly acidic.
For the most part, there are no trees in the tundra. Low-growing plants huddle close to the ground, using its warmth and hiding from strong winds. Lack of heat, strong wind, lack of moisture for the root system prevent shoots from turning into big trees. In the south of the tundra zone, dwarf birches and shrubby willows grow. In winter, the lack of food for animals is compensated by evergreen plants that overwinter under the cover of snow.
The swamps are home to ducks, geese, brant geese and waders. Herds of reindeer wander across the tundra in search of moss, their main food. Deer, white partridges, owls, and crows constantly live in the tundra.
Forest-tundra zone
Forest-tundra is a transition zone from the harsh tundra to the taiga forests. The width of the forest-tundra territory ranges from 30 to 300 km in different regions of the country. The climate is warmer than in the tundra. The forest-tundra has warmer summers and the winds are weaker than the tundra. Winter is cold and snowy for more than 9 months.
The soils of the forest-tundra are permafrost-swamp, peat-podzolic. These low fertile soils with low humus content and nutrients, with high acidity.
The flora of the tundra - meadows with willow bushes, sedge and horsetail grasses - serve as good pasture for deer. Due to the harsh climate, the forest islands are very sparse. These forests contain Siberian spruce, larches and birches.
Animals of the forest-tundra - wolves, arctic foxes. In summer, lakes and swamps are inhabited by geese, ducks, and swans. In summer, the forest-tundra is full of blood-sucking horse flies and mosquitoes. Closer to the south, in the forest-tundra there are squirrels, moose, brown bears, and wood grouse.
Taiga zone
Taiga is the largest natural zone in Russia; to the south of it there is a forest zone, or forest-steppe. Winter here is quite warm, 16-20 degrees below zero, in summer 10-20 degrees above zero. There are significant natural differences within the zone, as it is located in two climatic zones - subarctic and temperate. The large rivers Ob, Yenisei and Lena flow from south to north of the zone.
The taiga is rich in swamps, lakes, and groundwater. The amount of heat and moisture is sufficient for the formation of fertile podzolic and bog-podzolic soils.
Coniferous trees grow in the taiga - pine, spruce, fir, cedar and deciduous trees: birch, aspen, alder, larch. There are many meadows in the forests, there are swamps, and many berries and mushrooms.
There are many different animals in the taiga - sable, capercaillie, hazel grouse, elk, squirrel. Brown bears, wolverines, and lynxes are widespread. There are many blood-sucking insects in the taiga.
Zone of mixed and deciduous forests
To the south of the taiga, on the East European Plain and in the Far East, there is a forest zone. It has a lot of heat and moisture, many deep rivers, lakes, and much fewer swamps than in the taiga. Summers are long and warm (18-20 degrees Celsius), winters are quite mild. This zone has large reserves of timber, and in the bowels of the earth there are deposits of minerals.
The vegetation of the zone has been greatly modified by humans; most of the territory is used for agriculture and cattle breeding.
Soils are formed by litter under trees and are rich in ash elements. Have upper layer fertile humus. The soils are soddy-podzolic, in the southern part - gray forest soils.
There are different trees in this zone: in the northern part mixed forests with deciduous and coniferous trees: spruce, pine, birch, maple and aspen. Closer to the south, broad-leaved trees predominate: oak, elm, linden, maple. There are many shrubs in the forests: elderberry, raspberry; berries and mushrooms; abundance of herbs.
Availability of food all year round allows animals and most birds to live in the forest. There are many different animals in the forests: squirrels, owls, pine martens, moose, brown bear, foxes, and among birds - orioles, woodpeckers, etc.
Forest-steppe
The forest-steppe zone is part of the temperate climate zone. This is a transition zone between the forest zone and the steppe zone, combining forest belts and meadows covered with grasses. The flora and fauna are represented by plants and animals and forests and steppes. The closer to the south, the fewer forests, the fewer forest animals.
Steppe
The south of the forest-steppe passes into the steppe zone. The steppe zone is located on plains with grassy vegetation in a temperate and subtropical climate. In Russia, the steppe zone is located in the south near the Black Sea and in the valleys of the Ob River.
The soil in the steppe is fertile black soil. There are many arable lands and pastures for livestock. The climate of the steppes is characterized by very dry weather, hot summers, and lack of moisture. Winters in the steppe are cold and snowy.
The vegetation is mainly grasses growing in tufts with bare soil between them. A lot of different types feather grass, which can serve as food for sheep.
In summer, animals are active mainly at night: jerboas, ground squirrels, marmots. Birds typical of the steppe: bustard, kestrel, steppe eagle, lark. Reptiles live in the steppe.
Semi-deserts
The semi-desert zone is located in the southeast of the East European Plain, along the northwestern edge Caspian lowland.
A characteristic feature of semi-deserts is the dominance of wormwood-grass plant communities. The vegetation cover is very sparse and does not have a continuous distribution: patches of drought-resistant turf-like grasses and clumps of wormwood alternate with areas of bare soil.
Semi-deserts have a dry, sharply continental climate. This is due to the fact that cyclones are extremely rare here, and anticyclones constantly come from the depths of Eurasia. The annual amount of precipitation varies between 250-400 mm, which is 2.5-3 times less than the evaporation value. Despite the southern position, winter in the semi-desert is cold. The average temperature in January is from -5 to -8, and on some days the thermometer drops to -30. The average July temperature is +20 - +25.
The soils of semi-deserts are light chestnut, which brings them closer to the steppe, and brown - desert, often saline.
Despite the harsh climatic conditions, the flora in the deserts and semi-deserts of Russia is relatively diverse. Vegetation - steppe turf grasses and desert wormwood, subshrubs and others
The fauna of semi-deserts has a number of features associated with specific living conditions. Many animals have adaptations for digging holes. Most have a protective coloring. In the fauna of semi-deserts, rodents play an important role; their activity led to the formation of tuberculate microrelief.
Many semi-deserts and deserts have significant reserves of oil and gas, as well as precious metals, which has become the reason for the development of these territories by people. Oil production increases the level of danger; in the event of an oil spill, entire ecosystems are destroyed. But the main environmental problem is the expansion of desert areas. Thus, many semi-deserts are transitional natural zones from steppes to deserts, but under the influence of certain factors they increase in territory and also turn into deserts. This process is most stimulated by anthropogenic activities - cutting down trees, killing animals (poaching), construction industrial production, soil depletion. As a result of this, the semi-desert lacks moisture, plants die out, as do some animals, and some migrate. So the semi-desert quickly turns into a desert.
Desert zone
Desert is an area with a flat surface, sand dunes or clay and rocky surfaces. In Russia, there are deserts in the east of Kalmykia and in the south of the Astrakhan region.
In the desert grow drought-resistant small shrubs, perennials that bloom and grow in early spring when there is moisture. Some herbaceous plants, after they dry out, turn into balls of dry branches, they are called tumbleweeds. The wind drives them across the desert, scattering the seeds.
Deserts are inhabited by hedgehogs, gophers, jerboas, snakes, and lizards. Birds include larks, plovers, bustards.
The main environmental problem of deserts is their expansion due to irrational human activities. Problem nuclear tests and nuclear waste disposal is also high on the desert's list of environmental problems. Previously, many tests were carried out in deserts, which led to the problem of radioactive contamination. There is a problem of pollution from military waste. Various burials, military and nuclear, lead to the pollution of groundwater and the extinction of flora and fauna.
Today, desert and semi-desert territories are a specially protected natural zone in Russia. The desert and semi-desert are divided into special reserves, such as Astrakhansky, Bogdinsko-Baskunchaksky and Caucasian, as well as reserves - Ilmenno-Bugrovoy, Stepnoy, Burley Sands and other protected areas.
Most of the plants and animals of the Russian desert were listed in the Red Book, and more than 35 natural monuments were created in the vast region of the Caspian lowland.
Subtropical zone
In Russia, the subtropical territory is small - it is a narrow part of the coastal land near the Black Sea to the Caucasus Mountains. This zone has hot summers and warm winters. According to climatic conditions, Russian subtropics are divided into dry and wet. From the southern coast of Crimea to the city of Gelendzhik there are dry subtropics. Summer is dry and only drought-tolerant plants survive: thorny blackberries and rose hips. Pitsunda pine and shrubs grow here: juniper, cherry plum. Further along the coast, the amount of precipitation in summer increases and from Gelendzhik to the border with Georgia, including the Sochi region, these are humid subtropics. The flora is very diverse and rich.
The mountains are covered with a thick green carpet of trees and bushes. There are broad-leaved trees - oaks, chestnuts, beech, notable coniferous yew, growing evergreen shrubs: laurel, rhododendron and boxwood.
In the forests near Sochi you can meet bears, wolves, forest cats, badgers, and jackals. There are many rodents in the forests - squirrels, mice, and snakes. There are a lot of mollusks on the coast: snails, slugs. Birds live in the mountains - kites, eagles, owls.
On the map, each natural zone is usually designated by its own color:
Arctic deserts – blue, light purple.
Tundra – purple.
Forest-tundra is swampy.
Taiga, forests - different shades of green.
Forest-steppe – yellow-green.
Steppes – yellow.
Semi-deserts and deserts – orange.
High belt areas are brown.
It's sad to realize, but even minor interference by people in life natural world always leads to some changes, and not always to favorable ones. Deforestation, destruction of animals (poaching), environmental pollution are the main environmental problems that exist in Russia, regardless of the climate zone. And a lot depends on people in changing the deplorable environmental situation for the better.
Desert is a natural area characterized by the virtual absence of flora and fauna. There are sandy, rocky, clayey, and saline deserts. Arctic and Antarctic landscapes are called snow deserts. The biggest sandy desert The Earth - Sahara (from the ancient Arabic as-sakhra - "desert, desert steppe") - occupies 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. Less than 200 mm falls in the desert per year, 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 substances. Vegetation cover usually occupies less than 50% of the soil surface, and may be completely absent for several kilometers.
Due to infertility of soils and lack of moisture, animals and plant worlds deserts are quite poor. In such conditions, only the most resilient representatives of flora and fauna survive. The most common plants are leafless thorny bushes, and the animals are 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 common here.
Life in deserts is concentrated mainly near oases - places with dense vegetation and bodies of water, as well as in river valleys. Deciduous trees are common in oases: turanga poplars, jidas, willows, elms, and in river valleys - palms and oleanders.
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. Plants include mosses and lichens, and animals include cold-resistant reindeer, arctic foxes, lemmings and other rodents. In the polar deserts, permafrost prevails; the snow cover usually does not melt throughout the year.
(savannah)
Forest-steppe (savanna) is a vast expanse in the tropical zone, covered with herbaceous vegetation with sparsely scattered trees and shrubs. Typical for monsoon tropical climate with a sharp division of the year into dry and rainy seasons.
Savannas are steppe-like places characteristic of more elevated tropical countries with a dry continental climate. Unlike true steppes (as well as North American prairies), savannas, in addition to grasses, also contain shrubs and trees, sometimes growing as a whole forest, as, for example, in the so-called “campos cerrados” of Brazil. The herbaceous vegetation of savannas consists mainly of tall (up to 1 meter) dry and tough-skinned grasses, usually growing in turf. Mixed with the cereals are turfs of other perennial grasses and subshrubs, and in damp places flooded in spring, also various representatives of the sedge family (Cyperaceae).
Shrubs grow in savannas, sometimes in large thickets, occupying an area of many square meters. Savannah trees are usually short-growing; the tallest of them are no taller than our fruit trees, which they are very similar to with 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 savannas, especially in South America. Lichens, mosses and algae are found extremely rarely in savannas, only on stones and trees.
The general appearance of savannas is different, which depends, on the one hand, on the height of the vegetation cover, and on the other hand, on relative amount cereals, other perennial herbs, subshrubs, shrubs and trees; for example, the Brazilian savanas (“campos cerrados”) represent actually light, sparse forests, where you can freely walk and drive in any direction; the soil in such forests is covered with herbaceous (and semi-shrub) plant cover 0.5 m and even 1 meter high. In savannas of other countries, trees do not grow at all or are extremely rare and are very stunted. The grass cover is also sometimes very low, even pressed to the ground.
A special form of savannah is made up of the so-called llanos of Venezuela, where trees are either completely absent or found in limited numbers, 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 the llanos there are sometimes single specimens of Rhopala (trees from the family Proteaceae) and other trees; sometimes the grains in them form a cover as tall as a person; Between the cereals grow Compositae, legumes, Lamiaceae, etc. During the rainy season, many llanos are flooded by floods of the Orinoco River.
Savannah vegetation is generally adapted to a dry continental climate and to periodic droughts, which occur in many savannas for months at a time. Cereals and other herbs rarely form creeping shoots, but usually grow in tussocks. The leaves of cereals are narrow, dry, hard, hairy or covered with a waxy coating. In cereals and sedges, young leaves remain rolled into a tube. Tree leaves are small, hairy, shiny (“varnished”) or covered with a waxy coating. The vegetation of savannas generally has a pronounced xerophytic character. Many species contain large amounts of essential oils, especially species from the Verbenaceae, Lamiaceae and Myrtle families of South America. The growth of some perennial herbs, semi-shrubs (and shrubs) is especially peculiar, namely in 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. During the dry season, savannah vegetation freezes; savannas turn yellow, and dried out plants are often exposed to fires, due to which the tree bark is usually scorched. With the onset of rains, the savannas come to life, becoming covered with fresh greenery and speckled with numerous different flowers.
Savannas are characteristic of South America itself, but in other countries one can point out many places that are very similar in the nature of their vegetation to savannas. Such, for example, are the so-called Campine in the Congo (in Africa); in South Africa, some places are covered with vegetation 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 sparse (the trees are far apart from one another and their crowns do not meet) that it is easy to walk in them and even drive in any direction; the soil in such forests in the rainy season is covered with green thickets, consisting mainly of cereals; During the dry season, the soil is exposed.
The fauna of forest-steppes is represented mainly by herbivores (giraffes, zebras, antelopes, elephants and rhinoceroses), which are capable of traveling long distances in search of food. Common predators are lions, cheetahs and hyenas.
Steppes are more or less flat, dry, treeless spaces covered with abundant herbaceous vegetation. The spaces are flat and treeless, but wet, and are not called steppe. They form either swampy meadows or, in the far north, tundras. Spaces with very sparse vegetation, which does not form a grassy cover, but consists of individual bushes scattered far from each other, are called deserts. Deserts are not sharply different from the steppe, and often mix with each other.
Hilly or mountainous countries are not called steppe. But they can just as well be treeless and can support the same flora and fauna as flat steppes. Therefore, we can talk about steppe mountains and steppe slopes as opposed to forested mountains and forest slopes. The steppe is, first of all, a primordial treeless space, regardless of the relief.
The steppe is characterized by special climatic conditions and special flora and fauna. The steppes are especially developed in southern Russia, and purely Russian word the steppe has passed into all foreign languages. For distribution on earth's surface steppe spaces are undoubtedly influenced by climate. All over the globe, deserts represent areas with a very hot and dry climate. Territories with a less hot climate and high annual precipitation are covered partly or entirely with steppe. Areas with a more humid climate, temperate or warm, are covered with forests.
Typical steppes represent a flat or gently rolling country, completely devoid of forests, with the exception of river valleys. The soil is chernozem, most often lying on a layer of loess-like clay with a significant lime content. This chernozem in the northern strip of the steppe reaches its greatest thickness and fatness, as it sometimes contains up to 16% humus. To the south, the black soil 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, with bare soil visible between them. The most common types of feather grass, especially the common feathery feather grass. It often completely covers large spaces and with its silky white feathery awns gives the steppe a special, undulating appearance. On very rich steppes, a special variety of feather grass develops, differing much large sizes. On the dry, barren steppes, smaller feather grass grows. After the types of feather grass, the most important role is played by the kipets or typets. It is found throughout the steppe, but plays a special role east of the Ural Mountains. Kipets is an excellent food for sheep.
This is a more or less dense in its natural state, usually inaccessible, coniferous thicket with swampy soil with windbreaks and windfalls. 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 covers mountainous spaces from Altai to the Amur and Ussuri region. The extreme northeast of Siberia has no forests. In Kamchatka, the taiga occupies two small islands north of Petropavlovsk.
The main tree species of the taiga: spruce, European and Siberian pine, larch, fir, cedar. In Siberia the same species exist, with the exception of European spruce. In Eastern Siberia, Dahurian larch dominates, and cedar slate dominates high in the mountains. In the taiga of the Far East, new conifers appear: fir, Ayan spruce, Manchurian cedar, and on Sakhalin - yew. In European Russia, the taiga moves south into coniferous forests with an admixture of large-leaved species (oak and others), which are absent throughout Siberia, but appear again on the Amur. In the taiga, the only hardwood species available are birch, aspen, rowan, bird cherry, alder and willow. Of the large-leaved species in the taiga, only linden is found, 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, on the western slope of the Kuznetsk Alatau.
Relatively recently (until the mid-90s of the 19th century), the taiga and urman spaces 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 spaces covered with dense forest. It was believed that these lands were inconvenient for agriculture due to both soil and climatic conditions (extreme severity of climate, excess moisture) and the difficulty of clearing forests for land.
Sometimes attempts were made to allocate land for settlement on 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. The question of settling taiga spaces was paid serious attention only in 1893 - 1895, when in general measures to settle Siberia were taken more broadly. It was considered impossible to ignore such vast expanses of land as the taiga.
Soil conditions in many places in the taiga are quite favorable for farming. Such obstacles as excess moisture and harsh climate are largely eliminated under the influence of settlement and culture. In view of this, work was opened in many taiga regions to create resettlement sites, which gave generally very satisfactory results.
Forest-tundra is a transitional type of landscape in which open forests alternate with shrubby or typical tundras. Forest-tundras are located in a strip from 30 to 300 km wide across the entire North America and from the Kola Peninsula to the Indigirka basin.
The amount of precipitation in the forest-tundra 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 territory in July are 10-12°C, and in January from −10° to −40°C. The soils here are peaty-gley, peat-swamp, and under open forests - gley-podzolic.
Forest-tundra vegetation varies depending on longitude. Of the trees in the forest-tundra zones, the most common are dwarf birches and polar willows; spruce, fir and larches are also found. 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, polar owls and a wide variety of migratory, waterfowl and small bush-dwelling birds.
The tundra includes spaces with permafrost soil that lies beyond the northern limits of forest vegetation and is not flooded by sea or river waters. According to the nature of the surface, the tundra can be rocky, clayey, sandy, peaty, hummocky or swampy. The idea of the tundra as an inaccessible space is true only for swampy 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. In swampy places with standing water, the permafrost drops by mid-summer, depending on the amount of water and the admixture of solid plant residues on depth about 52 – 66 cm.
After very frosty and little snowy 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 descends. In addition, on level areas the thawed layer is thinner than on slopes, where permafrost may even disappear completely. On the Kola Peninsula, on Kanin and along the coast of the Czech Bay of the Arctic Ocean to the Timan Ridge, peaty-hilly tundra dominates.
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 spaces between the mounds, about 2–5 m wide, are occupied by a very watery, inaccessible swamp, “ersei” of Samoyeds. The vegetation on the hillocks 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 predominate.
The peaty-hilly tundra passes to the south or closer to the rivers, where there are already forests, into sphagnum peat bogs with cranberries, cloudberries, gonobol, bagoon, and birch dwarf. Sphagnum peat bogs extend very far into the forest area. To the east of the Timan Ridge, peat mounds and ersei are no longer found and only in small areas in low places where more water accumulates. 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, enjoys widespread especially between the Timan and Pechora rivers.
Bald, fissured tundra is very common in places that do not provide conditions for stagnant water and are exposed to the action of wind, blowing away snow and drying out the soil, which becomes covered with cracks. With these cracks, the soil is divided into small (the size of a plate, the size of a wheel, or larger) areas, completely devoid of vegetation, so that frozen clay or frozen sand protrude out. Such areas are separated from each other by strips of small shrubs, grasses and saxifrage sitting in cracks.
Herbaceous-shrub tundra develops where the soil is more fertile. Lichens and mosses recede into the background or disappear completely, and shrubs dominate.
Hummocky tundra. The hummocks, up to 30 cm high, consist of cotton grass with mosses, lichens and tundra shrubs. The spaces between the hummocks are occupied by mosses and lichens, and gray lichens also cover the tops of old, dead cotton grass tussocks.
Swampy tundra covers large areas of Siberia, where the swamps are dominated by various sedges and grasses. Swampy spaces, as already noted, also occupy the spaces between hillocks in the peat-hilly tundra.
Rocky tundra is developed on outcrops of rocky rocks (for example, the Khibiny Mountains on the Kola Peninsula, Kaninsky and Timansky Kamni, the Northern Urals, the mountains of Eastern Siberia). The rocky 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 birch and some willows, about 0.7 - 8 m tall, are widespread in treeless areas.
The geographical envelope is not tripled equally everywhere; it has a “mosaic” structure and consists of individual natural complexes (landscapes). Natural complex – This is a part of the earth's surface with relatively homogeneous natural conditions: climate, topography, soils, waters, flora and fauna.
Each natural complex consists of components between which there are close, historically established relationships, and a change in one of the components sooner or later leads to a change in the others.
The largest, planetary natural complex is the geographic envelope; it is divided into natural complexes of a smaller rank. The division of the geographical envelope into natural complexes is due to two reasons: on the one hand, differences in the structure of the earth's crust and the heterogeneity of the earth's surface, and on the other, the unequal amount of solar heat received by its different parts. In accordance with this, zonal and azonal natural complexes are distinguished.
The largest azonal natural complexes are continents and oceans. Smaller ones are mountainous and flat areas within the continents (West Siberian Plain, Caucasus, Andes, Amazonian Lowland). The latter are divided into even smaller natural complexes (Northern, Central, Southern Andes). Natural complexes of the lowest rank include individual hills, river valleys, their slopes, etc.
The largest of the zonal natural complexes are geographical zones. They coincide with climatic zones and have the same names (equatorial, tropical, etc.). In turn, geographical zones consist of natural zones, which are distinguished by the ratio of heat and moisture.
Natural area is a large area of land with similar natural components - soils, vegetation, wildlife, which are formed depending on the combination of heat and moisture.
The main component of a natural area is climate, since all other components depend on it. Vegetation has a great influence on the formation of soils and fauna and is itself dependent on soils. Natural zones are named according to the nature of their vegetation, since it most obviously reflects other features of nature.
The climate naturally changes as it moves from the equator to the poles. Soil, vegetation and fauna are determined by climate. This means that these components should change latitudinally, following climate change. The natural change of natural zones when moving from the equator to the poles is called latitudinal zonality. At the equator there are humid equatorial forests, and at the poles there are icy arctic deserts. Between them are other types of forests, savannas, deserts, and tundra. Forest zones, as a rule, are located in areas where the ratio of heat and moisture is balanced (equatorial and most of the temperate zone, eastern coasts of continents in the tropical and subtropical zone). Treeless zones form where there is a lack of heat (tundra) or moisture (steppes, deserts). These are continental regions of the tropical and temperate zones, as well as the subarctic climate zone.
The climate changes not only in latitude, but also due to changes in altitude. As you go up the mountains, the temperature drops. Up to an altitude of 2000-3000 m, the amount of precipitation increases. A change in the ratio of heat and moisture causes a change in soil and vegetation cover. Thus, different natural zones are located in the mountains at different altitudes. This pattern is called altitudinal zone.
The change in altitudinal zones in the mountains occurs in approximately the same sequence as on the plains, when moving from the equator to the poles. At the foot of the mountains there is a natural area in which they are located. The number of altitudinal zones is determined by the height of the mountains and their geographical location. The higher the mountains, and the closer they are located to the equator, the more diverse the set of altitudinal zones. Vertical zonality is most fully expressed in the Northern Andes. In the foothills there are moist equatorial forests, then there is a belt of mountain forests, and even higher - thickets of bamboo and tree ferns. With an increase in altitude and a decrease in average annual temperatures, coniferous forests appear, which are replaced by mountain meadows, often turning into rocky areas covered with moss and lichens. The peaks of the mountains are crowned with snow and glaciers.
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