Natural zones of the southern continents. Natural zones of the mainland Eurasia Features of the natural zones of the continents
The natural complexes of the Earth are very diverse. These are hot and icy deserts, evergreen forests, endless steppes, bizarre mountains. This diversity is the unique beauty of our planet.
You already know how natural complexes, “continents”, “oceans” were formed. But the nature of each continent, like each ocean, is not the same. Various natural zones are formed on their territory.
Theme: Nature of the Earth
Lesson: Natural areas of the Earth
1. Today we will find out
Why are natural areas formed,
On the patterns of placement of natural zones,
Features of the natural zones of the continents.
2. Formation of natural zones
A natural zone is a natural complex with uniform temperatures, moisture, similar soils, flora and fauna. The natural area is named after the type of vegetation. For example, taiga, deciduous forests.
The main reason for the heterogeneity of the geographic envelope is the uneven redistribution of solar heat on the Earth's surface.
In almost every climatic zone of land, the oceanic parts are more humid than the inland, continental ones. And it depends not only on the amount of precipitation, but also on the ratio of heat and moisture. The warmer it is, the more moisture that has fallen with precipitation evaporates. The same amount of moisture can lead to excess moisture in one zone and insufficient moisture in another.
Rice. 1. Swamp
So, the annual amount of precipitation of 200 mm in the cold subarctic zone is excessive moisture, which leads to the formation of swamps (see Fig. 1).
And in hot tropical zones - sharply insufficient: deserts are formed (see Fig. 2).
Rice. 2. Desert
Due to differences in the amount of solar heat and moisture, natural zones are formed within geographic zones.
3. Patterns of placement
In the placement of natural zones on the earth's surface, a clear pattern is visible, which can be clearly seen on the map of natural zones. They stretch in a latitudinal direction, replacing each other from north to south.
Due to the heterogeneity of the relief of the earth's surface and moistening conditions in different parts of the continents, natural zones do not form continuous bands parallel to the equator. More often they are replaced in the direction from the coasts of the oceans to the interior of the continents. In the mountains, natural zones replace each other from the foot to the peaks. This is where altitudinal zonality comes into play.
Natural zones are also formed in the World Ocean: from the equator to the poles, the properties of surface waters, the composition of vegetation and wildlife change.
Rice. 3. Natural areas of the world
4. Features of the natural zones of the continents
In the same natural areas on different continents, flora and fauna have similar features.
However, in addition to climate, other factors also influence the features of the distribution of plants and animals: the geological history of the continents, relief, and people.
The unification and separation of the continents, the change in their relief and climate in the geological past have led to the fact that in similar natural conditions, but on different continents, different species of animals and plants live.
So, for example, antelopes, buffaloes, zebras, African ostriches are characteristic of the African savannas, and several species of deer and a flightless rhea bird similar to an ostrich are common in the South American savannahs.
On each continent there are endemics - both plants and animals, characteristic only of this continent. For example, kangaroos are found only in Australia, and polar bears are found only in the Arctic deserts.
Geofocus
The sun heats the spherical surface of the Earth differently: the areas above which it stands high receive the most heat.
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.
Moist evergreen forests are located in narrow bands and patches along the equator. "Green Hell" - this is what many travelers of past centuries called these places, who had to be here. High multi-tiered forests stand like a solid wall, under the dense crowns of which darkness constantly reigns, monstrous humidity, constant high temperature, there is no change of seasons, downpours regularly fall in an almost continuous stream of water. The forests of the equator are also called permanent rain forests. The traveler Alexander Humboldt called them "hylaea" (from the Greek hyle - forest). Most likely, this is what the humid forests of the Carboniferous period looked like with giant ferns and horsetails.
The rainforests of South America are called "selva" (see Fig. 4).
Rice. 4. Selva
Savannahs are a sea of grasses with occasional islands of trees with umbrella crowns (see Fig. 5). Vast expanses of these amazing natural communities are found in Africa, although there are savannahs in South America, Australia, and India. A distinctive feature of the savannas is the alternation of dry and wet seasons, which take about half a year, replacing each other. The fact is that for the subtropical and tropical latitudes, where the savannahs are located, the change of two different air masses is characteristic - humid equatorial and dry tropical. Monsoon winds, which bring seasonal rains, significantly affect the climate of the savannahs. Since these landscapes are located between the very humid natural zones of the equatorial forests and the very dry zones of the deserts, they are constantly influenced by both. But moisture is not present in the savannas long enough for multi-tiered forests to grow there, and dry "winter periods" of 2-3 months do not allow the savannah to turn into a harsh desert.
Rice. 5. Savannah
The natural zone of the taiga is located in the north of Eurasia and North America (see Fig. 6). On the North American continent, it stretches from west to east for more than 5 thousand km, and in Eurasia, originating in the Scandinavian Peninsula, it spread to the shores of the Pacific Ocean. The Eurasian taiga is the largest continuous forest zone on Earth. It occupies more than 60% of the territory of the Russian Federation. The taiga contains huge reserves of wood and supplies a large amount of oxygen to the atmosphere. In the north, the taiga smoothly turns into the forest-tundra, gradually the taiga forests are replaced by light forests, and then by individual groups of trees. The furthest taiga forests enter the forest-tundra along river valleys, which are most protected from strong northern winds. In the south, the taiga also smoothly turns into coniferous-deciduous and broad-leaved forests. For many centuries, humans have interfered with natural landscapes in these areas, so now they are a complex natural-anthropogenic complex.
Rice. 6. Taiga
Under the influence of human activity, the geographical envelope is changing. Swamps are being drained, deserts are being irrigated, forests are disappearing, and so on. Thus, the appearance of natural areas is changing.
Homework
Read § 9. Answer the questions:
What determines the moisture content of an area? How do different moisture conditions affect natural complexes?
Are there natural areas in the ocean?
Bibliography
MainI
1. Geography. Earth and people. Grade 7: Textbook for general education. uch. / A. P. Kuznetsov, L. E. Savelyeva, V. P. Dronov, series "Spheres". – M.: Enlightenment, 2011.
2. Geography. Earth and people. Grade 7: atlas, series "Spheres".
Additional
1. N. A. Maksimov. Behind the pages of a geography textbook. – M.: Enlightenment.
Literature for preparing for the GIA and the Unified State Examination
geographic eurasia natural zone
Geographic zonality is a regularity in the differentiation of the geographic (landscape) shell of the Earth, manifested in a consistent and definite change in geographical zones and zones, due primarily to changes in the amount of radiant energy of the Sun incident on the Earth's surface, depending on the geographic latitude. Such zonality is also inherent in most components and processes of natural territorial complexes - climatic, hydrological, geochemical and geomorphological processes, soil and vegetation cover and wildlife, partly the formation of sedimentary rocks. A decrease in the angle of incidence of the sun's rays from the equator to the poles causes the allocation of latitudinal radiation belts - hot, two moderate and two cold. The formation of similar thermal and, moreover, climatic and geographical zones is already associated with the properties and circulation of the atmosphere, which are greatly influenced by the distribution of land and oceans (the reasons for the latter are azonal). The differentiation of natural zones on land depends on the ratio of heat and moisture, which varies not only in latitude, but also from the coasts inland (sector pattern), so we can talk about horizontal zonality, a particular manifestation of which is latitudinal zonality, well expressed on the territory of the Eurasian continent .
Each geographical zone and sector has its own set (spectrum) of zones and their sequence. The distribution of natural zones is also manifested in the regular change of altitudinal zones, or belts, in the mountains, which is also initially due to the azonal factor - relief, however, certain spectra of altitudinal zones are also characteristic of certain belts and sectors. Zoning in Eurasia is characterized for the most part as horizontal, with the following zones (their name comes from the predominant type of vegetation cover):
Arctic desert zone;
Tundra and forest-tundra zone;
Taiga zone;
Zone of mixed and deciduous forests;
Zone of forest-steppes and steppes;
Zone of semi-deserts and deserts;
The zone of hard-leaved evergreen forests and shrubs (the so-called
"Mediterranean" zone);
Zone of variable-humid (including monsoon) forests;
Zone of humid equatorial forests.
Now all the presented zones will be considered in detail, their main characteristics, whether it be climatic conditions, vegetation, wildlife.
The Arctic Desert (“Arktos” in Greek means bear) is a natural zone part of the Arctic geographical zone, the basin of the Arctic Ocean. This is the northernmost of the natural zones, characterized by an arctic climate. The spaces are covered with glaciers, rubble and stone fragments.
The climate of the Arctic deserts is not very diverse. Weather conditions are extremely severe, with strong winds, little rainfall, very low temperatures: in winter (up to?60 °C), on average -30?C in February, the average temperature of even the warmest month is close to 0 °C. Snow cover on land lasts almost all year round, disappearing only for a month and a half. Long polar days and nights lasting for five months, short off-seasons give a special flavor to these harsh places. Only the Atlantic currents bring additional heat and moisture to some areas, such as the western shores of Svalbard. Such a state is formed not only in connection with the low temperatures of high latitudes, but also in connection with the high ability of snow and ice to reflect heat - albedo. The annual amount of atmospheric precipitation is up to 400 mm.
Where everything is covered with ice, life seems to be impossible. But that's not the case at all. In places where nunatak rocks emerge from under the ice, there is its own flora. In the cracks of the rocks, where a small amount of soil accumulates, in the thawed areas of glacial deposits - moraines, mosses, lichens, some types of algae and even cereals and flowering plants settle near snowfields. Among them are bluegrass, cotton grass, polar poppy, dryad partridge grass, sedge, dwarf willows, birches, and various types of saxifrage. But, the recovery of vegetation is extremely slow. Although during the cold polar summer it manages to bloom and even bear fruit. Numerous birds find shelter and nest on the coastal rocks in the summer, arranging "bird colonies" on the rocks - geese, gulls, eiders, terns, waders.
Numerous pinnipeds live in the Arctic - seals, ringed seals, walruses, elephant seals. Seals feed on fish, swimming in search of fish to the ice of the Arctic Ocean. The elongated streamlined shape of the body helps them move in the water at great speed. The seals themselves are yellowish-gray, with dark spots, and their cubs have a beautiful snow-white coat, which they retain until they grow up. Because of her, they got the name of the pups.
Terrestrial fauna is poor: arctic fox, polar bear, lemming. The most famous inhabitant of the Arctic is the polar bear. This is the largest predator on Earth. The length of his body can reach 3 m, and the weight of an adult bear is about 600 kg and even more! The Arctic is the realm of the polar bear, where he feels himself in his element. The absence of land does not bother the bear, mainly its habitat is the ice floes of the Arctic Ocean. Bears are excellent swimmers and often swim far into the open sea in search of food. The polar bear feeds on fish, hunts seals, seals, walrus cubs. Despite its power, the polar bear needs protection, it is listed in the Red Book of both the International and Russian.
In the high northern latitudes (these are the territories and water areas lying north of the 65th parallel) there is a natural zone of the Arctic deserts, a zone of eternal frost. The boundaries of this zone, as well as the boundaries of the Arctic as a whole, are rather arbitrary. Although the space around the North Pole does not have land, its role here is played by solid and floating ice. In high latitudes there are islands, archipelagos washed by the waters of the Arctic Ocean, and within their borders lie the coastal zones of the Eurasian continent. These pieces of land are almost entirely or mostly bound by "eternal ice", or rather, the remains of huge glaciers that covered this part of the planet during the last ice age. The arctic glaciers of the archipelagos sometimes go beyond the land and descend into the sea, as, for example, some glaciers in Svalbard and Franz Josef Land.
In the Northern Hemisphere, along the outskirts of the Eurasian continent, south of the polar deserts, as well as on the island of Iceland, there is a natural tundra zone. Tundra is a type of natural zone lying beyond the northern limits of forest vegetation, an area with permafrost soil that is not flooded by sea or river waters. The tundra is located north of the taiga zone. By the nature of the surface of the tundra are swampy, peaty, rocky. The southern border of the tundra is taken as the beginning of the Arctic. The name comes from the Sami language and means "dead land".
These latitudes can be called subpolar, the winter here is severe and long, and the summer is cool and short, with frosts. The temperature of the warmest month - July does not exceed +10 ... + 12 ° C, it can snow in the second half of August, and the established snow cover does not melt for 7-9 months. Up to 300 mm of precipitation falls in the tundra annually, and in the regions of Eastern Siberia, where the climate becomes more continental, their amount does not exceed 100 mm per year. Although there is no more precipitation in this natural zone than in the desert, they fall mainly in summer and evaporate very poorly at such low summer temperatures, so excess moisture is created in the tundra. The ground frozen during the harsh winter thaws only a few tens of centimeters in summer, which does not allow moisture to seep deep into, it stagnates, and waterlogging occurs. Even in slight relief depressions, numerous swamps and lakes are formed.
Cold summers, strong winds, excessive moisture and permafrost determine the nature of vegetation in the tundra. +10… +12°C are the temperature limits at which trees can grow. In the tundra zone, they acquire special, dwarf forms. Infertile tundra-gley soils poor in humus grow dwarf willows and birches with twisted trunks and branches, low-growing shrubs and shrubs. They are pressed to the ground, densely intertwined with each other. The endless flat plains of the tundra are covered with a thick carpet of mosses and lichens, hiding small trunks of trees, shrubs and grass roots.
As soon as the snow melts, the harsh landscape comes to life, all the plants seem to be in a hurry to use the short warm summer for their vegetation cycle. In July, the tundra is covered with a carpet of flowering plants - polar poppies, dandelions, forget-me-nots, mytnik, etc. The tundra is rich in berry bushes - lingonberries, cranberries, cloudberries, blueberries.
Based on the nature of the vegetation, three zones are distinguished in the tundra. The northern arctic tundra is characterized by a harsh climate and very sparse vegetation. The moss-lichen tundra located to the south is softer and richer in plant species, and in the very south of the tundra zone, in the shrub tundra, you can find trees and shrubs reaching a height of 1.5 m. taiga. This is one of the most waterlogged natural areas, because there is more precipitation here (300-400 mm per year) than it can evaporate. In the forest-tundra, low-growing birch, spruce, and larch trees appear, but they grow mainly along river valleys. Open spaces are still occupied by vegetation typical of the tundra zone. To the south, the area of forests increases, but even there the forest-tundra is an alternation of light forests and treeless spaces, overgrown with mosses, lichens, shrubs and shrubs.
Mountain tundra form an altitudinal zone in the mountains of the subarctic and temperate zones. On stony and gravelly soils from high-altitude light forests, they begin with a shrub belt, as in the flat tundra. Above are moss-lichen with cushion-shaped subshrubs and some herbs. The upper belt of the mountain tundra is represented by scale lichens, sparse squat cushion-like shrubs and mosses among stone placers.
The harsh climate of the tundra and the lack of good food force the animals living in these parts to adapt to difficult living conditions. The largest mammals of the tundra and forest tundra are reindeer. They are easy to recognize by the huge horns that not only males, but also females have. The horns go back first, and then bend up and forward, their large processes hang over the muzzle, and the deer can rake snow with them, getting food. Deer see poorly, but have sensitive hearing and a subtle sense of smell. Their dense winter fur consists of long, hollow, cylindrical hairs. They grow perpendicular to the body, creating a dense heat-insulating layer around the animal. In summer, deer grow softer and shorter fur.
Large divergent hooves allow the deer to walk on loose snow and soft ground without falling through. In winter, deer feed mainly on lichens, digging them out from under the snow, the depth of which sometimes reaches 80 cm. They do not refuse lemmings, voles, they can destroy bird nests, and in famine years they even gnaw each other's horns.
Deer lead a nomadic lifestyle. In summer, they feed in the northern tundra, where there are fewer midges and gadflies, and in autumn they return to the forest-tundra, where there is more food and warmer winters. During seasonal transitions, animals cover distances of 1000 km. Reindeer run fast and swim well, which allows them to escape from their main enemies - wolves.
Reindeer of Eurasia are distributed from the Scandinavian Peninsula to Kamchatka. They live in Greenland, on the Arctic islands and on the northern coast of North America.
Since ancient times, the peoples of the North have domesticated deer, receiving from them milk, meat, cheese, clothes, shoes, material for plagues, vessels for food - practically everything necessary for life. The fat content of the milk of these animals is four times higher than cow's. Reindeer are very hardy, one reindeer can carry a load weighing 200 kg, passing up to 70 km per day.
Together with reindeer, polar wolves, polar foxes, polar hares, white partridges, polar owls live in the tundra. In summer, many migratory birds arrive, geese, ducks, swans, and waders nest along the banks of rivers and lakes.
Of the rodents, lemmings are especially interesting - touching fluffy animals the size of a palm. There are three types of lemmings that are common in Norway, Greenland and Russia. All lemmings are brown in color, and only the hoofed lemming changes its skin to white in winter. These rodents spend the cold period of the year underground, they dig long underground tunnels and actively breed. One female can give birth to up to 36 cubs per year.
In the spring, lemmings come to the surface in search of food. Under favorable conditions, their population can increase so much that there is not enough food for everyone in the tundra. Trying to find food, lemmings make mass migrations - a huge wave of rodents rushes along the endless tundra, and when a river or sea meets on the way, hungry animals fall into the water under the pressure of those running after them and die by the thousands. The life cycles of many polar animals depend on the number of lemmings. If there are few of them, the snowy owl, for example, does not lay eggs, and arctic foxes - polar foxes - migrate south, to the forest tundra, in search of other food.
The white, or polar, owl is undoubtedly the queen of the tundra. Its wingspan reaches 1.5 m. The old birds are dazzling white, and the young ones are variegated, both have yellow eyes and a black beak. This magnificent bird flies almost silently, hunting voles, lemmings, and muskrats at any time of the day. She attacks partridges, hares and even catches fish. In summer, the snowy owl lays 6-8 eggs, nesting in a small depression on the ground.
But because of human activity (and above all because of oil production, the construction and operation of oil pipelines), many parts of the Russian tundra are in danger of an ecological catastrophe. Due to fuel leaks from oil pipelines, the surrounding area is polluted, often there are burning oil lakes and completely burned out areas, once covered with vegetation.
Despite the fact that during the construction of new oil pipelines, special passages are made so that deer can move freely, animals cannot always find and use them.
Road trains move along the tundra, leaving behind garbage and destroying vegetation. The soil layer of the tundra damaged by caterpillar transport is being restored for more than a dozen years.
All this leads to an increase in the pollution of soil, water and vegetation, a decrease in the number of deer and other inhabitants of the tundra.
The forest-tumndra is a subarctic type of landscape, in which oppressed light forests alternate with shrub or typical tundras on the interfluves. Various researchers consider the forest-tundra to be a subzone of either the tundra, or the taiga, and, more recently, the tundro forest. Forest-tundra landscapes stretch in a strip from 30 to 300 km wide from the Kola Peninsula to the Indigirka basin, and to the east they are fragmented. Despite the low amount of precipitation (200--350 mm), the forest-tundra is characterized by a sharp excess of moisture over evaporation, which causes the wide distribution of lakes from 10 to 60% of the subzone area.
The average air temperature in July is 10-12°С, and in January, depending on the increase in the continentality of the climate, from? 10 ° to? 40 ° C. With the exception of rare taliks, the soils are everywhere permafrost. Soils are peaty-gley, peat-bog, and under light forests - gley-podzolic (podburs).
The flora has the following character: shrub tundra and light forests change in connection with the longitudinal zonality. On the Kola Peninsula - warty birch; east to the Urals - spruce; in Western Siberia - spruce with Siberian larch; east of Putoran - Dahurian larch with lean birch; to the east of the Lena - Cajander larch with lean birch and alder, and east of Kolyma cedar elfin is mixed with them.
The fauna of the forest-tundra is also dominated by lemmings of various species in different longitudinal zones, reindeer, arctic foxes, white and tundra partridges, snowy owls and a wide variety of migratory, waterfowl and small birds that settle in bushes. The forest-tundra is a valuable reindeer pasture and hunting grounds.
Reserves and national parks, including the Taimyr Reserve, have been created to protect and study the natural landscapes of the forest-tundra. Reindeer breeding and hunting are traditional occupations of the indigenous population, who use up to 90% of the territory for reindeer pastures.
The natural zone of the taiga is located in the north of Eurasia. Taiga is a biome dominated by coniferous forests. It is located in the northern subarctic humid geographical zone. Coniferous trees form the basis of plant life there. In Eurasia, originating on the Scandinavian Peninsula, it spread to the shores of the Pacific Ocean. The Eurasian taiga is the largest continuous forest zone on Earth. It occupies more than 60% of the territory of the Russian Federation. The taiga contains huge reserves of wood and supplies a large amount of oxygen to the atmosphere. In the north, the taiga smoothly passes into the forest-tundra, gradually the taiga forests are replaced by light forests, and then by individual groups of trees. The furthest taiga forests enter the forest-tundra along river valleys, which are most protected from strong northern winds. In the south, the taiga also smoothly turns into coniferous-deciduous and broad-leaved forests. For many centuries, humans have interfered with natural landscapes in these areas, so now they are a complex natural-anthropogenic complex.
On the territory of Russia, the southern border of the taiga begins approximately at the latitude of St. Petersburg, stretches to the upper Volga, north of Moscow to the Urals, further to Novosibirsk, and then to Khabarovsk and Nakhodka in the Far East, where they are replaced by mixed forests. All of Western and Eastern Siberia, most of the Far East, the mountain ranges of the Urals, Altai, Sayan, Baikal, Sikhote-Alin, Greater Khingan are covered with taiga forests.
The climate of the taiga zone within the temperate climate zone varies from maritime in the west of Eurasia to sharply continental in the east. In the west, relatively warm summers (+10 °C) and mild winters (-10 °C), more precipitation falls than can evaporate. Under conditions of excessive moisture, the decay products of organic and mineral substances are carried into the lower soil layers, forming a clarified podzolic horizon, according to which the predominant soils of the taiga zone are called podzolic. Permafrost contributes to moisture stagnation, therefore, significant areas within this natural zone, especially in the north of European Russia and Western Siberia, are occupied by lakes, swamps and swampy woodlands. In dark coniferous forests growing on podzolic and frozen-taiga soils, spruce and pine dominate and, as a rule, there is no undergrowth. Twilight reigns under the closing crowns, mosses, lichens, forbs, dense ferns and berry bushes grow in the lower tier - lingonberries, blueberries, blueberries. In the north-west of the European part of Russia, pine forests predominate, and on the western slope of the Urals, which is characterized by high cloudiness, sufficient precipitation and heavy snow cover, spruce-fir and spruce-fir-cedar forests.
On the eastern slope of the Urals, the humidity is less than on the western, and therefore the composition of forest vegetation is different here: light coniferous forests predominate - mostly pine, in places with an admixture of larch and cedar (Siberian pine).
The Asian part of the taiga is characterized by light coniferous forests. In the Siberian taiga, summer temperatures in continental climates rise to +20 °C, and in northeastern Siberia in winter they can drop to -50 °C. On the territory of the West Siberian Lowland, mainly larch and spruce forests grow in the northern part, pine forests in the central part, and spruce, cedar and fir in the southern part. Light coniferous forests are less demanding on soil and climatic conditions and can grow even on poor soils. The crowns of these forests are not closed, and through them the sun's rays freely penetrate into the lower tier. The shrub layer of the light coniferous taiga consists of alder, dwarf birches and willows, and berry bushes.
In Central and North-Eastern Siberia, under conditions of a harsh climate and permafrost, larch taiga dominates. For centuries, almost the entire taiga zone has suffered from the negative impact of human economic activity: slash-and-burn agriculture, hunting, haymaking in floodplains, selective logging, atmospheric pollution, etc. Only in hard-to-reach areas of Siberia today you can find corners of virgin nature. The balance between natural processes and traditional economic activity, which has evolved over thousands of years, is being destroyed today, and the taiga as a natural complex is gradually disappearing.
In general, the taiga is characterized by the absence or weak development of undergrowth (since there is little light in the forest), as well as the monotony of the grass-shrub layer and moss cover (green mosses). Types of shrubs (juniper, honeysuckle, currant, willow, etc.), shrubs (blueberries, lingonberries, etc.) and herbs (sour, wintergreen) are not numerous.
In the north of Europe (Finland, Sweden, Norway, Russia), spruce forests predominate. The taiga of the Urals is characterized by light coniferous forests of Scots pine. In Siberia and the Far East, sparse larch taiga dominates with an undergrowth of dwarf pine, Daurian rhododendron, etc.
The fauna of the taiga is richer and more diverse than that of the tundra. Numerous and widespread: lynx, wolverine, chipmunk, sable, squirrel, etc. Of the ungulates, there are reindeer and red deer, elk, roe deer; rodents are numerous: shrews, mice. Birds are common: capercaillie, hazel grouse, nutcracker, crossbills, etc.
In the taiga forest, in comparison with the forest-tundra, the conditions for the life of animals are more favorable. There are more settled animals here. Nowhere in the world, except for the taiga, there are so many fur-bearing animals.
The fauna of the taiga zone of Eurasia is very rich. Both large predators live here - brown bear, wolf, lynx, fox, and smaller predators - otter, mink, marten, wolverine, sable, weasel, ermine. Many taiga animals survive long, cold and snowy winters in a state of suspended animation (invertebrates) or hibernation (brown bear, chipmunk), and many species of birds migrate to other regions. Sparrows, woodpeckers, black grouses - capercaillie, hazel grouse, wild grouse constantly live in the taiga forests.
Brown bears are typical inhabitants of vast forests, not only taiga, but also mixed forests. There are 125-150 thousand brown bears in the world, two thirds of them live in the Russian Federation. The sizes and colors of subspecies of brown bears (Kamchatka, Kodiak, grizzly, European brown) are different. Some brown bears reach three meters in height and weigh more than 700 kg. They have a powerful body, strong five-fingered paws with huge claws, a short tail, a large head with small eyes and ears. Bears can be reddish and dark brown, almost black, and by old age (by the age of 20-25) the tips of the wool turn gray and the animal becomes gray. Bears feed on grass, nuts, berries, honey, animals, carrion, dig up anthills and eat ants. In autumn, bears feed on nutritious berries (they can eat over 40 kg per day) and therefore quickly get fat, gaining almost 3 kg in weight every day. During the year, in search of food, bears travel from 230 to 260 kilometers, and as winter approaches, they return to their dens. Animals arrange winter "apartments" in natural dry shelters and line them with moss, dry grass, branches, needles and leaves. Sometimes male bears sleep in the open all winter. The winter sleep of a brown bear is very sensitive, in fact, this is a winter stupor. In the thaw, individuals who did not manage to work up a sufficient amount of fat during the autumn go in search of food. Some animals - the so-called connecting rods - do not hibernate at all for the winter, but wander in search of food, representing a great danger to people. In January-February, the female gives birth to one to four cubs in the den. Babies are born blind, without hair and teeth. They weigh just over 500 grams, but grow quickly on breast milk. In the spring, furry and nimble cubs come out of the den. They usually stay with their mother for two and a half to three years, and finally mature by the age of 10.
Wolves are common in many parts of Europe and Asia. They are found in the steppe, in the desert, in mixed forests and in the taiga. The body length of the largest individuals reaches 160 cm, and the weight is 80 kg. Mostly wolves are gray, but tundra wolves are usually somewhat lighter, and desert wolves are greyish-red. These ruthless predators are highly intelligent. Nature has provided them with sharp fangs, powerful jaws and strong paws, therefore, chasing the victim, they are able to run many tens of kilometers and can kill an animal much larger and stronger than themselves. The main prey of the wolf are large and medium-sized mammals, as a rule, ungulates, although they also hunt birds. Usually wolves live in pairs, and in late autumn they gather in packs of 15-20 animals.
The lynx is found in the taiga zone from Scandinavia to the shores of the Pacific Ocean. She climbs trees well, swims well and feels confident on the ground. High legs, strong torso, sharp teeth and excellently developed sense organs make it a dangerous predator. The lynx preys on birds, small rodents, less often on small ungulates, and sometimes on foxes, domestic animals, climbs into herds of sheep and goats. At the beginning of summer, in a deep, well-hidden hole, a female lynx gives birth to 2-3 cubs.
The Siberian chipmunk lives in the taiga forests of Siberia - a typical representative of the chipmunk genus, which is also found in Northern Mongolia, China and Japan. The body length of this funny animal is about 15 cm, and the length of its fluffy tail is 10 cm. There are 5 longitudinal dark stripes on a light gray or reddish background, characteristic of all chipmunks, on the back and sides. Chipmunks nest under fallen trees or, less commonly, in tree cavities. They feed on seeds, berries, mushrooms, lichens, insects and other invertebrates. Chipmunks store about 5 kg of seeds for the winter and, falling into hibernation in the cold season, do not leave their shelters until spring.
The color of squirrels depends on the habitat. In the Siberian taiga, they are reddish or copper-gray with a blue tint, and in European forests they are brown or reddish-red. The squirrel weighs up to a kilogram, and its body length reaches 30 cm, about the same length as its tail. In winter, the fur of the animal is soft and fluffy, and in summer it is more rigid, short and shiny. The squirrel is well adapted to life in trees. A long, wide and light tail helps her deftly jump from tree to tree. The squirrel swims well, raising its tail high above the water. She arranges a nest in a hollow or builds the so-called gayno from tree branches, which has the shape of a ball with a side entrance. The squirrel nest is carefully lined with moss, grass, rags, so even in severe frosts it is warm there. Squirrels bring cubs twice a year, in one litter there are from 3 to 10 squirrels. The squirrel feeds on berries, seeds of coniferous trees, nuts, acorns, mushrooms, and when there is a lack of food, it gnaws the bark from the shoots, eats leaves and even lichens, sometimes preys on birds, lizards, snakes, and destroys nests. The squirrel makes reserves for the winter.
The taiga of Eurasia, mainly the massifs of the Siberian taiga, is called the green “lungs” of the planet, since the oxygen and carbon balance of the surface layer of the atmosphere depends on the state of these forests. To protect and study the typical and unique natural landscapes of the taiga in North America and Eurasia, a number of reserves and national parks have been created, including Wood Buffalo, Barguzinsky Reserve, etc. Industrial timber reserves are concentrated in the taiga, large deposits of minerals (coal , oil, gas, etc.). Also a lot of valuable wood
The traditional occupations of the population are hunting for fur-bearing animals, collecting medicinal raw materials, wild fruits, nuts, berries and mushrooms, fishing, logging, (building houses), cattle breeding.
The zone of mixed (coniferous-deciduous) forests is a natural zone characterized by a symbiosis of coniferous and deciduous forests. The condition for this is the possibility for them to occupy specific niches in the ecological system of the forest. As a rule, it is customary to talk about mixed forests when an admixture of deciduous or coniferous trees is more than 5% of the total.
Mixed forests together with taiga and deciduous forests make up the forest zone. The forest stand of a mixed forest is formed by trees of various species. Within the temperate zone, several types of mixed forests are distinguished: coniferous-deciduous forest; secondary small-leaved forest with an admixture of coniferous or broad-leaved trees and a mixed forest consisting of evergreen and deciduous tree species. In the subtropics, in mixed forests, mainly laurel and coniferous trees grow.
In Eurasia, the zone of coniferous-deciduous forests is distributed south of the taiga zone. Fairly wide in the west, it gradually narrows towards the east. Small areas of mixed forests are found in Kamchatka and the south of the Far East. The zone of mixed forests is characterized by a climate with cold snowy winters and warm summers. Winter temperatures in areas of the maritime temperate climate are positive, and as they move away from the oceans, they drop to -10 ° C. The amount of precipitation (400-1000 mm per year) slightly exceeds evaporation.
Coniferous-broad-leaved (and in continental regions - coniferous-small-leaved) forests grow mainly on gray forest and soddy-podzolic soils. The humus horizon of soddy-podzolic soils, located between the forest litter (3-5 cm) and the podzolic horizon, is about 20 cm. The forest litter of mixed forests consists of many herbs. Dying and rotting, they constantly increase the humus horizon.
Mixed forests are distinguished by a clearly visible layering, that is, a change in the composition of vegetation along the height. The upper tree layer is occupied by tall pines and spruces, and oaks, lindens, maples, birches, and elms grow below. Shrubs, herbs, mosses and lichens grow under the shrub layer formed by raspberries, viburnum, wild rose, hawthorn.
Coniferous-small-leaved forests, consisting of birch, aspen, alder, are intermediate forests in the process of coniferous forest formation.
Within the zone of mixed forests, there are also treeless spaces. Elevated treeless plains with fertile gray forest soils are called opolia. They are found in the south of the taiga and in the zones of mixed and broad-leaved forests of the East European Plain.
Polissya - lowered treeless plains, composed of sandy deposits of melted glacial waters, are common in eastern Poland, in Polesie, in the Meshcherskaya lowland and are often swampy.
In the south of the Far East of Russia, where seasonal winds - monsoons - dominate within the temperate climatic zone, mixed and broad-leaved forests, called the Ussuri taiga, grow on brown forest soils. They are characterized by a more complex longline structure, a huge variety of plant and animal species.
The territory of this natural zone has long been mastered by man and is quite densely populated. Agricultural lands, towns, cities are spread over large areas. A significant part of the forests has been cut down, so the composition of the forest has changed in many places, and the proportion of small-leaved trees has increased in it.
Fauna of mixed and broad-leaved forests. Animals and birds living in mixed forests are typical for the forest zone as a whole. Foxes, hares, hedgehogs and wild boars are found even in well-developed forests near Moscow, and elk sometimes come out on roads and on the outskirts of villages. There is a lot of protein not only in forests, but also in city parks. Along the banks of rivers in quiet places, away from settlements, you can see beaver huts. Bears, wolves, martens, badgers are also found in mixed forests, the world of birds is diverse.
The European elk is called the forest giant for a reason. Indeed, this is one of the largest ungulates of the forest zone. The average weight of a male is about 300 kg, but there are giants weighing more than half a ton (the largest elks are East Siberian, their weight reaches 565 kg). In males, the head is decorated with huge spade-shaped horns. The coat of moose is coarse, gray-brown or black-brown in color, with a bright shade on the lips and legs.
Moose prefer young clearings and copses. They feed on branches and shoots of deciduous trees (aspen, willow, mountain ash), in winter - pine needles, mosses and lichens. Moose are excellent swimmers, an adult animal is able to swim for two hours at a speed of about ten kilometers per hour. Moose can dive underwater looking for tender leaves, roots and tubers of aquatic plants. There are cases when moose dived for food to a depth of more than five meters. In May-June, the moose cow brings one or two calves, they walk with their mother until autumn, eating her milk and green fodder.
The fox is a very sensitive and cautious predator. It is about a meter long and has a fluffy tail of almost the same size, on a sharp, elongated muzzle - triangular ears. Foxes are painted most often in a red color of various shades, the chest and abdomen are usually light gray, and the tip of the tail is always white.
Foxes prefer mixed forests, alternating with clearings, meadows and ponds. They can be seen near villages, on forest edges, on the edge of a swamp, in groves and bushes among fields. The fox navigates the terrain mainly with the help of smell and hearing, her eyesight is much less developed. She swims pretty well.
Usually the fox settles in abandoned badger burrows, less often independently pulls out a hole 2-4 m deep with two or three exits. Sometimes in a complex system of badger burrows, foxes and badgers settle side by side. Foxes lead a sedentary lifestyle, go hunting more often at night and at dusk, feed mainly on rodents, birds and hares, in rare cases they attack roe deer cubs. On average, foxes live 6-8 years, but in captivity they can live up to 20 years or longer.
The common badger is found in Europe and Asia up to the Far East. The size of an average dog, it has a body length of 90 cm, a tail of 24 cm, and a mass of about 25 kg. At night, the badger goes hunting. Its main food is worms, insects, frogs, nutritious roots. Sometimes he eats up to 70 frogs in one hunt! In the morning the badger returns to the hole and sleeps until the next night. The badger hole is a capital structure with several floors and about 50 entrances. Lined with dry grass, the central burrow, 5-10 m long, is located at a depth of 1-3 or even 5 m. The animals carefully bury all sewage in the ground. Badgers often live in colonies, and then the area of their holes reaches several thousand square meters. Scientists believe that the age of some badger holes exceeds a thousand years. By winter, the badger accumulates a significant supply of fat and sleeps in its hole all winter.
The common hedgehog is one of the most ancient mammals - its age is about 1 million years. The hedgehog has poor eyesight, but the sense of smell and hearing are well developed. Defending itself from enemies, the hedgehog curls up into a prickly ball, which no predator can cope with (the hedgehog has about 5000 needles 20 mm long). In Russia, hedgehogs with gray needles are more common, on which dark transverse stripes are visible. Hedgehogs live in birch forests with dense grass cover, in thickets of shrubs, in old clearings, in parks. The hedgehog feeds on insects, invertebrates (earthworms, slugs and snails), frogs, snakes, eggs and chicks of birds nesting on the ground, sometimes berries. Hedgehogs make winter and summer burrows. In winter they sleep from October to April, and in summer hedgehogs are born. Shortly after birth, the pups develop soft white needles, and 36 hours after birth, dark-colored needles appear.
The white hare lives not only in forests, but also in the tundra, birch groves, in overgrown clearings and burnt areas, and sometimes in steppe bushes. In winter, the brownish or gray color of the skin changes to pure white, only the tips of the ears remain black, and fur “skis” grow on the paws. The white hare feeds on herbaceous plants, shoots and bark of willow, aspen, birch, hazel, oak, maple. The hare does not have a permanent lair; in case of danger, he prefers to flee. In the middle lane, usually twice a summer, from 3 to 6 cubs are born from a hare. Young growth becomes adult after wintering. The number of hare from year to year varies significantly. In years of high abundance, hares severely damage young trees in forests and make mass migrations.
Deciduous forest - a forest in which there are no coniferous trees.
Deciduous forests are common in fairly humid areas with mild winters. Unlike coniferous forests, a thick layer of litter is not formed in the soils of deciduous forests, since a warmer and more humid climate contributes to the rapid decomposition of plant residues. Although the leaves fall annually, the mass of deciduous litter does not much exceed coniferous, since deciduous trees are more light-requiring and grow less frequently than conifers. Leaf litter, compared to coniferous, contains twice as many nutrients, especially calcium. Unlike coniferous humus, in less acidic deciduous humus, biological processes are actively taking place with the participation of earthworms and bacteria. Therefore, almost all the litter decomposes by spring, and a humus horizon is formed, which binds nutrients in the soil and prevents them from being washed out.
Deciduous forests are divided into broad-leaved forests and small-leaved forests.
European broadleaf forests are endangered forest ecosystems. Just a few centuries ago, they occupied most of Europe and were among the richest and most diverse on the planet. In the XVI - XVII centuries. natural oak forests grew on an area of several million hectares, and today, according to the forest fund records, there are no more than 100 thousand hectares left. So for several centuries the area of these forests has decreased tenfold. Formed by deciduous trees with wide leaf blades, broad-leaved forests are common in Europe, Northern China, Japan and the Far East. They occupy an area between mixed forests in the north and steppes, Mediterranean or subtropical vegetation in the south.
Broad-leaved forests grow in areas with a humid and moderately humid climate, which are characterized by a uniform distribution of precipitation (from 400 to 600 mm) throughout the year and relatively high temperatures. The average temperature in January is -8…0 °C, and in July +20…+24 °С. Moderately warm and humid climatic conditions, as well as the vigorous activity of soil organisms (bacteria, fungi, invertebrates) contribute to the rapid decomposition of leaves and the accumulation of humus. Under deciduous forests, fertile gray forest and brown forest soils, less often chernozems, are formed.
The upper tier in these forests is occupied by oak, beech, hornbeam and linden. In Europe, there are ash, elm, maple, elm. The undergrowth is formed by shrubs - hazel, warty euonymus, forest honeysuckle. The dense and high grass cover of European broad-leaved forests is dominated by goutweed, zelenchuk, hoof, lungwort, woodruff, hairy sedge, spring ephemeroids: corydalis, anemone, snowdrop, blueberry, goose onion, etc.
Modern broad-leaved and coniferous-broad-leaved forests were formed five to seven thousand years ago, when the planet warmed up and broad-leaved tree species could move far to the north. In subsequent millennia, the climate became colder and the zone of broad-leaved forests gradually decreased. Since the most fertile soils of the entire forest zone formed under these forests, the forests were intensively cut down, and arable land took their place. In addition, oak, which has a very durable wood, was widely used in construction.
The reign of Peter I was the time for Russia to create a sailing fleet. The "Tsar's idea" required a large amount of high-quality wood, so the so-called ship groves were strictly guarded. Forests that were not part of the protected areas, the inhabitants of the forest and forest-steppe zone were actively cut down for arable land and meadows. In the middle of the XIX century. the era of the sailing fleet ended, the ship groves were no longer guarded, and the forests began to be reduced even more intensively.
By the beginning of the XX century. only fragments of the once unified and vast belt of broad-leaved forests have survived. Even then, they tried to grow new oaks, but it turned out to be a difficult task: young oak groves died due to frequent and severe droughts. Research conducted under the guidance of the great Russian geographer V.V. Dokuchaev, showed that these disasters were associated with large-scale deforestation and, as a result, changes in the hydrological regime and climate of the territory.
Nevertheless, in the 20th century, the remaining oak forests were intensively cut down. Insect pests and cold winters at the end of the century made the extinction of natural oak forests inevitable.
Today, in some areas where deciduous forests used to grow, secondary forests and artificial plantations have spread, dominated by coniferous trees. It is unlikely that it will be possible to restore the structure and dynamics of natural oak forests not only in Russia, but throughout Europe (where they have experienced an even stronger anthropogenic impact).
The fauna of deciduous forests is represented by ungulates, predators, rodents, insectivores, and bats. They are distributed mainly in those forests where habitat conditions are least changed by man. Moose, red and spotted deer, roe deer, fallow deer, wild boars are found here. Wolves, foxes, martens, polecats, ermines and weasels represent a detachment of predators in broad-leaved forests. Among rodents there are beavers, nutrias, muskrats, squirrels. Rats and mice, moles, hedgehogs, shrews, as well as various types of snakes, lizards and marsh turtles live in the forests. Birds of deciduous forests are diverse. Most of them belong to the order of passerines - finches, starlings, tits, swallows, flycatchers, warblers, larks, etc. Other birds live here: crows, jackdaws, magpies, rooks, woodpeckers, crossbills, as well as large birds - hazel grouse and black grouse . From predatory there are hawks, harriers, owls, owls and eagle owls. In the swamps there are sandpipers, cranes, herons, different types of ducks, geese and gulls.
Red deer used to live in forests, steppes, forest-steppes, semi-deserts and deserts, but deforestation and plowing of the steppes led to the fact that their numbers declined sharply. Red deer prefer light, mainly broad-leaved forests. The body length of these graceful animals reaches 2.5 m, weight - 340 kg. Deer live in a mixed herd of about 10 individuals. The herd is most often led by an old female, with whom her children of different ages live.
In autumn, males gather a harem. Their roar, reminiscent of the sound of a trumpet, is heard for 3-4 km. Having defeated rivals, the deer acquires a harem of 2-3, and sometimes up to 20 females - this is how the second type of deer herds appears. At the beginning of summer, a deer is born to a deer. It weighs 8-11 kg and grows very quickly up to six months. A newborn deer is covered with several rows of light spots. From the year the males have antlers, after a year the deer shed their antlers, and immediately new ones begin to grow in them. Deer eat grass, leaves and shoots of trees, mushrooms, lichens, reeds and saltwort, they will not refuse bitter wormwood, but the needles are destructive for them. In captivity, deer live up to 30 years, and in natural conditions no more than 15.
Beavers - large rodents - are common in Europe and Asia. The body length of a beaver reaches 1 m, weight - 30 kg. The massive body, flattened tail and swimming membranes on the toes of the hind legs are maximally adapted to the aquatic lifestyle. Beaver fur is from light brown to almost black, animals lubricate it with a special secret, protecting it from getting wet. When a beaver dives into the water, its auricles fold lengthwise and its nostrils close. A dived beaver consumes air so economically that it can stay under water for up to 15 minutes. Beavers settle on the banks of slowly flowing forest rivers, oxbow lakes and lakes, preferring water bodies with abundant aquatic and coastal vegetation. Near the water, beavers make burrows or huts, the entrance to which is always located under the surface of the water. In reservoirs with unstable water levels below their "houses", beavers build famous dams. They regulate the flow so that it is always possible to get into the hut or hole from the water. Animals easily gnaw through branches and fell large trees, gnawing them at the base of the trunk. A beaver fells an aspen with a diameter of 5-7 cm in 2 minutes. Beavers feed on aquatic herbaceous plants - reed, egg capsule, water lily, iris, etc., and in autumn they cut down trees, preparing food for the winter. In the spring, beaver cubs are born, which can swim in two days. Beavers live in families, only in the third year of life, young beavers leave to create their own family.
Wild pigs - wild boars - are typical inhabitants of deciduous forests. The boar has a huge head, an elongated muzzle and a long strong snout ending in a movable "patch". The jaws of the beast are equipped with serious weapons - strong and sharp triangular fangs, bent up and back. Vision in wild boars is poorly developed, and the sense of smell and hearing are very subtle. Boars can collide with a stationary hunter, but they will hear even the slightest sound made by him. Boars reach a length of 2 m, and some individuals weigh up to 300 kg. The body is covered with elastic strong bristles of dark brown color.
They run fast enough, swim excellently and are able to swim across a reservoir several kilometers wide. Boars are omnivorous animals, but their main food is plants. Wild boars are very fond of acorns and beech nuts, which fall to the ground in autumn. Do not refuse frogs, worms, insects, snakes, mice and chicks.
Piglets are born usually in the middle of spring. They are covered on the sides with longitudinal dark brown and yellow-gray stripes. After 2-3 months, the stripes gradually disappear, the piglets become first ash-gray, and then black-brown
Small-leaved forests - forests formed by deciduous (summer green) trees with narrow leaf blades.
Tree species are represented mainly by birch, aspen and alder, these trees have small leaves (compared to oak and beech).
Distributed in the forest zone of the West Siberian and East European Plains, widely represented in the mountains and on the plains of the Far East, they are part of the Central Siberian and West Siberian forest-steppe, form a strip of birch forests (pegs). Small-leaved forests make up a strip of deciduous forests that stretches from the Urals to the Yenisei. In Western Siberia, small-leaved forests form a narrow subzone between the taiga and the forest-steppe. Ancient stone-birch forests in Kamchatka form the upper forest belt in the mountains.
Small-leaved forests are light forests, they are distinguished by a wide variety of grass cover. These ancient forests were later replaced by taiga forests, but under human influence on taiga forests (cutting down taiga forests and fires), they again occupied large areas. Small-leaved forests, due to the rapid growth of birch and aspen, have good renewability.
Unlike birch forests, aspen forests are very resistant to human impact, since aspen reproduces not only by seeds, but also vegetatively, they are characterized by the highest rates of average growth.
Small-leaved forests often grow in floodplains, where they are most widely represented by willows. They stretch along the channels in some places for many kilometers, formed by several types of willows. Most often these are trees or large shrubs with narrow leaves, developing long shoots and having high growth vigor.
Forest-steppe is a natural zone of the Northern Hemisphere, characterized by a combination of forest and steppe areas.
In Eurasia, forest-steppes stretch in a continuous strip from west to east from the eastern foothills of the Carpathians to Altai. In Russia, the border with the forest zone passes through such cities as Kursk, Kazan. To the west and east of this strip, the continuous stretch of the forest-steppe is broken by the influence of the mountains. Separate forest-steppe areas are located within the Middle Danube Plain, a number of intermountain basins in Southern Siberia, Northern Kazakhstan, Mongolia and the Far East, and also occupy part of the Songliao Plain in northeast China. The climate of the forest-steppe is temperate, usually with moderately hot summers and moderately cool winters. Evaporation slightly prevails over precipitation.
The forest-steppe is one of the zones that make up the temperate zone. The temperate zone implies the presence of four seasons - winter, spring, summer and autumn. In the temperate zone, the change of seasons is always clearly expressed.
The climate of the forest-steppe is, as a rule, temperate continental. The annual rainfall is 300-400 mm per year. Sometimes evaporation is almost equal to precipitation. Winter in the forest-steppe is mild, the average January temperature is -7 degrees in the city of Kharkov, Ukraine (the southern border of the forest-steppe) to about -10 degrees in Orel, where the zone of mixed forests begins. Sometimes, in the forest-steppe, both severe frosts and mild winters can rage in winter. The absolute minimum in the forest-steppe zone is usually ?36?40 degrees. Summer in the forest-steppe is sometimes hot and dry. Sometimes it can be cold and rainy, but this is rare. Most often, summer is characterized by unstable, unstable weather, which can be very different, depending on the activity of certain atmospheric processes. The average temperature in July, depending on the location, ranges from 19.50С to 250С. The absolute maximum in the forest-steppe is about 37-39 degrees in the shade. However, heat in the forest-steppe occurs less frequently than severe cold, while in the steppe zone it is the opposite. One of the features of the forest-steppe is that the flora and fauna of the forest-steppe is intermediate between the flora and fauna of the mixed forest zone and the steppe zone. In the forest-steppe, both drought-resistant plants and plants characteristic of the forest, more northern, zone grow. The same applies to the animal world.
Description, as well as a comparative description of the steppes and deserts, I will give in the second part of this chapter. Now let's move on to the consideration of the natural zone - the semi-desert.
Semi-desert, or deserted steppe - a type of landscape that is formed in an arid climate.
Semi-deserts are characterized by the absence of forests and specific vegetation and soil cover. They combine elements of steppe and desert landscapes.
Semi-deserts are found in the temperate, subtropical and tropical zones of the Earth and form a natural zone located between the steppe zone in the north and the desert zone in the south.
In the temperate zone, semi-deserts are located in a continuous strip from the west to the east of Asia from the Caspian lowland to the eastern border of China. In the subtropics, semi-deserts are widespread on the slopes of plateaus, plateaus, and uplands (the Anatolian Plateau, the Armenian Highlands, the Iranian Highlands, and others).
Semi-desert soils, formed in dry and semi-arid climates, are rich in salts, since precipitation is scarce, and salts are retained in the soil. Active soil formation is possible only where soils receive additional moisture from rivers or groundwater. Compared to atmospheric precipitation, underground and river waters are much saltier there. Due to the high temperature, evaporation is high, during which the soil dries out, and the salts dissolved in the water crystallize.
The high salt content causes an alkaline soil reaction, to which plants have to adapt. Most cultivated plants do not tolerate such conditions. Sodium salts are especially harmful, since sodium prevents the formation of a granular soil structure. As a result, the soil turns into a dense structureless mass. In addition, excess sodium in the soil interferes with physiological processes and plant nutrition.
The highly sparse plant cover of the semi-desert often appears as a mosaic consisting of perennial xerophytic grasses, turf grasses, saltworts and wormwoods, as well as ephemers and ephemeroids. In America, succulents are common, mainly cacti. In Africa and Australia, thickets of xerophytic shrubs (see Scrub) and sparse low-growing trees (acacia, doum palm, baobab, etc.) are typical.
Among the animals of the semi-desert, hares, rodents (ground squirrels, jerboas, gerbils, voles, hamsters) and reptiles are especially numerous; from ungulates - antelopes, bezoar goat, mouflon, kulan, etc. Small predators are ubiquitous: jackal, striped hyena, caracal, steppe cat, fennec fox, etc. Birds are quite diverse. Many insects and arachnids (karakurt, scorpions, phalanges).
To protect and study the natural landscapes of the semi-deserts of the world, a number of national parks and reserves have been created, including the Ustyurt Reserve, Tigrovaya Balka, Aral-Paygambar. The traditional occupation of the population is grazing. Oasis agriculture is developed only on irrigated lands (near water bodies).
The subtropical climate of the Mediterranean is dry, precipitation in the form of rain falls in winter, even mild frosts are extremely rare, summers are dry and hot. In the subtropical forests of the Mediterranean, thickets of evergreen shrubs and low trees predominate. Trees rarely stand, and various herbs and shrubs grow wildly between them. Here grow junipers, noble laurel, strawberry tree, which sheds its bark every year, wild olives, tender myrtle, roses. Such types of forests are characteristic mainly in the Mediterranean, and in the mountains of the tropics and subtropics.
The subtropics on the eastern outskirts of the continents are characterized by a more humid climate. Atmospheric precipitation falls unevenly, but it rains more in summer, that is, at a time when vegetation is especially in need of moisture. Dense moist forests of evergreen oaks, magnolias, and camphor laurels predominate here. Numerous creepers, thickets of tall bamboos and various shrubs enhance the originality of the humid subtropical forest.
From humid tropical forests, the subtropical forest differs in lower species diversity, a decrease in the number of epiphytes and lianas, as well as the appearance of coniferous, tree-like ferns in the forest stand.
Moist evergreen forests are located in narrow bands and patches along the equator. The largest tropical rain forests exist in the Amazon River Basin (Amazonian Rainforest), in Nicaragua, in the southern part of the Yucatan Peninsula (Guatemala, Belize), in most of Central America (where they are called "selva"), in equatorial Africa from Cameroon to Democratic Republic of the Congo, in many parts of Southeast Asia from Myanmar to Indonesia and Papua New Guinea, in the Australian state of Queensland.
Tropical rainforests are characterized by:
continuous vegetation of vegetation throughout the year;
diversity of flora, the predominance of dicots;
· the presence of 4-5 tree tiers, the absence of shrubs, a large number of epiphytes, epiphalls and lianas;
· the predominance of evergreen trees with large evergreen leaves, poorly developed bark, buds not protected by bud scales, in monsoon forests - deciduous trees;
The formation of flowers and then fruits directly on the trunks and thick branches (caulifloria).
"Green Hell" - this is what many travelers of past centuries called these places, who had to be here. High multi-tiered forests stand like a solid wall, under the dense crowns of which darkness constantly reigns, monstrous humidity, constant high temperature, there is no change of seasons, downpours regularly fall in an almost continuous stream of water. The forests of the equator are also called permanent rainforests.
The upper floors are at a height of up to 45 m and do not have a closed cover. As a rule, the wood of these trees is the most durable. Below, at a height of 18-20 m, there are tiers of plants and trees, forming a continuous closed canopy and almost not allowing sunlight to pass down to the ground. The rarer lower belt is located at a height of about 10 m. Shrubs and herbs grow even lower, such as pineapples and bananas, ferns. Tall trees have thickened overgrown roots (they are called board-shaped), helping the gigantic plant maintain a strong connection with the soil.
In a warm and humid climate, the decomposition of dead plants occurs very quickly. From the resulting nutrient composition, substances are taken for the life of the gilea plant. Among such landscapes flow the most full-flowing rivers of our planet - the Amazon in the selva of South America, the Congo in Africa, the Brahmaputra in Southeast Asia.
Some of the rainforests have already been cleared. In their place, man cultivates various crops, including coffee, oil and rubber palms.
Like vegetation, the fauna of moist equatorial forests is located on different high-rise floors of the forest. In the less populated lower tier, various insects and rodents live. In India, Indian elephants live in such forests. They are not as large as African ones, and can move under the cover of multi-storey forests. Hippos, crocodiles and water snakes are found in full-flowing rivers and lakes and on their banks. Among rodents there are species that do not live on the ground, but in the crowns of trees. They acquired devices that allow them to fly from branch to branch - leathery membranes that look like wings. Birds are very diverse. Among them there are very small bright nectary birds that extract nectar from flowers, and rather large birds, like a huge turaco or banana-eater, a hornbill with a powerful beak and a growth on it. Despite its size, this beak is very light, like the beak of another forest dweller - the toucan. The toucan is very beautiful - a bright yellow plumage of the neck, a green beak with a red stripe, and turquoise skin around the eyes. And of course, one of the most common birds of the humid evergreen forests is a variety of parrots.
Monkeys. Jumping from branch to vine, monkeys use their paws and tails. Chimpanzees, monkeys, and gorillas live in the equatorial forests. The permanent habitat of gibbons is at a height of about 40-50 m above the ground, in the crowns of trees. These animals are quite light (5-6 kg) and literally fly from branch to branch, swaying and clinging with flexible front paws. Gorillas are the largest representatives of monkeys. Their height exceeds 180 cm, and they weigh much more than a person - up to 260 kg. Despite the fact that their impressive size does not allow gorillas to jump on branches as easily as orangutans and chimpanzees, they are quite fast. Packs of gorillas live mainly on the ground, settling in the branches only for rest and sleep. Gorillas eat only plant foods, which contain a lot of moisture and allow them to quench their thirst. Adult gorillas are so strong that large predators are afraid to attack them.
Anaconda. The monstrous size (up to 10 meters) of the anaconda allows it to hunt large animals. Usually these are birds, other snakes, small mammals that came to the watering hole, but crocodiles and even people can be among the victims of the anaconda. When attacking a victim, pythons and anacondas first strangle it; and then gradually swallow, "putting on" the prey's body like a glove. Digestion is slow, so these huge snakes go without food for a long time. Anacondas can live up to 50 years. Boas give birth to live cubs. Unlike them, pythons living in the humid forests of India, Sri Lanka, and Africa lay eggs. Pythons also reach very large sizes and can weigh up to 100 kg.
Comparative analysis of the steppe and desert zones
In the process of writing this course work, a comparison of two natural zones was carried out and the following picture was obtained. It will be presented in the form of a table (Annex 1).
Common features are:
1) a type of landscape characterized by a flat surface (only with small hills)
2) complete absence of trees
3) similar fauna (both in species composition and in some ecological features)
4) similar humid conditions (both zones are characterized by excessive evaporation and, as a result, insufficient moisture)
5) it is possible to distinguish the types of these zones (say, in the forest-steppe zone it is impossible to indicate additional types)
6) the location of the steppes and deserts of Eurasia in the temperate zone (with the exception of the desert territories of the Arabian Peninsula)
The differences appear in the following:
1) latitudinal localization: deserts are located to the south than the steppe zone
2) a significant difference is the types of soils: the steppes have chernozems, and the deserts have brown soils
3) in the soils of the steppes, the humus content is high, and the desert soils are highly saline
4) the climatic regime is not the same: in the steppe one can observe a sharp change of seasons, in the deserts, the temperature imbalance is observed during the day
5) the amount of precipitation in the steppe is much higher
6) grasses growing in the steppe form an almost closed carpet; in deserts, the distance between individual plants can reach several tens of meters.
The earth's surface and moistening conditions in different parts of the continents natural zones do not form continuous bands parallel to the equator. Only in and on some large plains do they extend in a latitudinal direction, replacing each other from north to south. More often they change in the direction from the coasts of the oceans to the depths of the continents, and sometimes they stretch almost along the meridians.
Natural zones are also formed in: from the equator to the poles, the properties of surface waters, the composition of vegetation and wildlife change. There is also . However, oceanic natural complexes do not have pronounced external differences.
There is great diversity on earth. However, against the background of this diversity, large parts stand out - natural zones and. This is due to the different ratio of heat and moisture that the earth's surface receives.
Formation of natural zones
The uneven distribution of solar heat over the Earth's surface is the main reason for the heterogeneity of the geographic envelope. In almost every land area, the oceanic parts are better moistened than the inland, continental regions. Humidification depends not only on the amount of precipitation, but also on the ratio of heat and moisture. The warmer it is, the more moisture that has fallen with precipitation evaporates. The same amount of precipitation can lead to excessive moisture in one zone and insufficient moisture in another. Thus, the annual precipitation of 200 mm in the cold subarctic zone is excessive (bogs are formed), while in the hot tropical zones it is sharply insufficient (there are deserts).
Due to differences in the amount of solar heat and moisture within geographic zones, natural zones are formed - large areas with uniform temperature and moisture conditions, similar surface and groundwater features, and wildlife.
Features of the natural zones of the continents
In the same natural areas on different continents, vegetation and fauna have similar features.
At the same time, other factors, in addition to climate, also influence the distribution of plants and animals: the geological history of the continents, the relief and features of rocks, and people. The unification and separation of the continents, the change in their relief and climate in the geological past have caused different types of plants and animals to live in similar natural conditions, but on different continents. The African savannahs, for example, are characterized by antelopes, buffaloes, zebras, African ostriches, and in the South American savannas, several species of deer, armadillos and an ostrich-like flightless nandu bird are common. On each continent there are endemic species (endemic), characteristic only of this continent.
Under the influence of human activity, the geographic shell is undergoing significant changes. To preserve representatives of the organic world and typical natural complexes in all natural zones of the world, specially protected areas are created - nature reserves, etc. In national parks, unlike, nature protection is combined with tourism and people's recreation.
The southern continents include Africa, South America, Australia and Antarctica. Connects their location in the southern hemisphere of the Earth, as well as for the most part hot climate, with the exception of Antarctica. The natural zones of the southern continents have many common features, but the peculiarities of vegetation and wildlife determine the geographical zones in which they are located.
Antarctica
It is the southernmost continent, but its entire surface is covered with blocks of ice and snow. Even in summer, the temperature here rarely exceeds 0-5 degrees Celsius. Soils are bound by permafrost, which does not allow vegetation to develop. In the natural zone of the Antarctic deserts, only a meager growth of mosses and lichens can be found. The local fauna is also very poor. Polar bears live here, seals and walruses can be found on the coast, and in summer bird colonies form on the rocks.
Rice. 1. Antarctica is the southernmost continent on the planet.
Africa
Africa is considered to be the hottest continent on Earth. Its distinctive feature is its symmetrical arrangement with respect to the equator. This means that the equatorial line divides the mainland into two identical parts. As a result, Africa is characterized by the presence of several natural zones, including humid equatorial and variable-humid forests, savannahs, tropical deserts, and hardwood forests.
The largest desert in the world, the Sahara, is located on the African continent. Despite the seeming lifelessness, here you can still find sparse vegetation and representatives of the animal world, adapted to life in the difficult conditions of the desert.
Australia
Australia is considered the driest continent, so it is not surprising that you will not find lush and diverse vegetation here. There are practically no forests in Australia, but there are many deserts.
Due to the flat relief of the mainland, latitudinal zonality is most pronounced here. Since the main part of the continent is located in tropical latitudes, tropical deserts and semi-deserts prevail here. A much smaller area is occupied by savannahs, humid tropical and subtropical forests.
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Rice. 2. Nature of Australia.
For a long time Australia was in great isolation. This explains the antiquity and originality of the local flora and fauna, whose representatives are mostly endemic - species that live exclusively on this mainland.
South America
This is a unique continent, on which more than half of all tropical and equatorial forests of the planet grow. The climate on the mainland is moderately humid and warm, the temperature difference between the seasons is insignificant.
Rice. 3. Equatorial forests of South America.
Natural zones are located unevenly due to the strong differences between the western and eastern parts of the continent, and are represented by several species:
- selva- rain equatorial forests;
- llanos- zone of savannas and woodlands;
- pampas- steppes of subtropics;
- Patagonia- deserts and semi-deserts;
- temperate forests.
The animal and plant world is mostly represented by endemic species.
What have we learned?
Due to their geographical location, the southern continents have many similarities. However, each of them has natural areas with a unique flora and natural world that cannot be found anywhere else on the planet.
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The warmth of the sun, clean air and water are the main criteria for life on Earth. Numerous climatic zones led to the division of the territory of all continents and water space into certain natural zones. Some of them, even separated by vast distances, are very similar, others are unique.
Natural areas of the world: what is it?
This definition should be understood as very large natural complexes (in other words, parts of the geographic belt of the Earth), which have similar, uniform climatic conditions. The main characteristic of natural zones is the flora and fauna that inhabits this territory. They are formed as a result of uneven distribution of moisture and heat on the planet.
Table "Natural zones of the world"
natural area | climate zone | Average temperature (winter/summer) |
Antarctic and Arctic deserts | Antarctic, arctic | 24-70°С /0-32°С |
Tundra and forest tundra | Subarctic and Subantarctic | 8-40°С/+8+16°С |
Moderate | 8-48°C /+8+24°C |
|
mixed forests | Moderate | 16-8°С /+16+24°С |
broadleaf forests | Moderate | 8+8°С /+16+24°С |
Steppes and forest-steppes | subtropical and temperate | 16+8 °С /+16+24°С |
temperate deserts and semi-deserts | Moderate | 8-24 °С /+20+24 °С |
hardwood forests | Subtropical | 8+16 °С/ +20+24 °С |
Tropical deserts and semi-deserts | Tropical | 8+16 °С/ +20+32 °С |
Savannahs and woodlands | 20+24°C and above |
|
Variable rainforests | subequatorial, tropical | 20+24°C and above |
Permanently wet forests | Equatorial | above +24°С |
This characteristic of the natural zones of the world is only introductory, because you can talk about each of them for a very long time, all the information will not fit in the framework of one table.
Natural zones of the temperate climate zone
1. Taiga. Surpasses all other natural zones of the world in terms of the area occupied on land (27% of the territory of all forests on the planet). It is characterized by very low winter temperatures. Deciduous trees do not withstand them, so the taiga is dense coniferous forests (mainly pine, spruce, fir, larch). Very large areas of the taiga in Canada and Russia are occupied by permafrost.
2. Mixed forests. Characteristic to a greater extent for the Northern Hemisphere of the Earth. It is a kind of border between the taiga and the broad-leaved forest. They are more resistant to cold and long winters. Tree species: oak, maple, poplar, linden, as well as mountain ash, alder, birch, pine, spruce. As the table "Natural areas of the world" shows, the soils in the zone of mixed forests are gray, not very fertile, but still suitable for growing plants.
3. Broad-leaved forests. They are not adapted to harsh winters and are deciduous. They occupy most of Western Europe, the south of the Far East, the north of China and Japan. Suitable for them is a maritime or temperate continental climate with hot summers and fairly warm winters. As the table "Natural zones of the world" shows, the temperature in them does not fall below -8 ° C even in the cold season. The soil is fertile, rich in humus. The following types of trees are characteristic: ash, chestnut, oak, hornbeam, beech, maple, elm. The forests are very rich in mammals (ungulates, rodents, predators), birds, including commercial ones.
4. Temperate deserts and semi-deserts. Their main distinguishing feature is the almost complete absence of vegetation and sparse wildlife. There are a lot of natural areas of this nature, they are located mainly in the tropics. There are temperate deserts in Eurasia, and they are characterized by sharp temperature changes during the seasons. Animals are represented mainly by reptiles.
Arctic deserts and semi-deserts
They are huge areas of land covered with snow and ice. The map of natural zones of the world clearly shows that they are located on the territory of North America, Antarctica, Greenland and the northern tip of the Eurasian continent. In fact, these are lifeless places, and polar bears, walruses and seals, arctic foxes and lemmings, penguins (in Antarctica) live only along the coast. Where the land is free of ice, lichens and mosses can be seen.
Moist equatorial forests
Their second name is rainforests. They are located mainly in South America, as well as in Africa, Australia and the Greater Sunda Islands. The main condition for their formation is constant and very high humidity (more than 2000 mm of precipitation per year) and a hot climate (20 ° C and above). They are very rich in vegetation, the forest consists of several tiers and is an impenetrable, dense jungle that has become home to more than 2/3 of all types of creatures that now live on our planet. These rainforests are superior to all other natural areas of the world. Trees remain evergreen, changing foliage gradually and partially. Surprisingly, the soils of moist forests contain little humus.
Natural zones of the equatorial and subtropical climatic zone
1. Variably humid forests, they differ from rainforests in that precipitation falls there only during the rainy season, and during the period of drought that follows it, the trees are forced to shed their leaves. The animal and plant world is also very diverse and rich in species.
2. Savannas and woodlands. They appear where moisture, as a rule, is no longer enough for the growth of variable-humid forests. Their development occurs in the depths of the mainland, where tropical and equatorial air masses dominate, and the rainy season lasts less than six months. They occupy a significant part of the territory of subequatorial Africa, the interior of South America, partly Hindustan and Australia. More detailed information about the location is reflected in the map of natural areas of the world (photo).
hardwood forests
This climate zone is considered the most suitable for human habitation. Hardwood and evergreen forests are located along sea and ocean coasts. Precipitation is not so plentiful, but the leaves retain moisture due to the dense leathery shell (oaks, eucalyptus), which prevents them from falling off. In some trees and plants, they are modernized into thorns.
Steppes and forest-steppes
They are characterized by the almost complete absence of woody vegetation, this is due to the meager level of precipitation. But the soils are the most fertile (chernozems), and therefore are actively used by man for agriculture. Steppes occupy large areas in North America and Eurasia. The predominant number of inhabitants are reptiles, rodents and birds. Plants have adapted to the lack of moisture and most often manage to complete their life cycle in a short spring period, when the steppe is covered with a thick carpet of greenery.
Tundra and forest tundra
In this zone, the breath of the Arctic and Antarctic begins to be felt, the climate becomes more severe, and even coniferous trees cannot withstand it. Moisture is abundant, but there is no heat, which leads to swamping of very large areas. There are no trees at all in the tundra, the flora is mainly represented by mosses and lichens. It is believed that this is the most unstable and fragile ecosystem. Due to the active development of gas and oil fields, it is on the verge of an ecological disaster.
All natural areas of the world are very interesting, whether it is a desert that seems completely lifeless at first glance, boundless Arctic ice or thousand-year-old rain forests with boiling life inside.