Variably humid zone. Temperate monsoon forests
Alternately moist forests grow in those areas of the Earth where precipitation in the form of rain does not fall all year round, but the dry season lasts for a short time. They are located in Africa north and south of the humid equatorial forests, as well as in northeastern Australia.
Look geographical position zones of variably moist forests on the map of natural zones.
The life of variably humid forests is closely related to seasonal climatic changes: during the dry season, under conditions of moisture deficiency, plants are forced to shed their foliage, and during the wet season they have to put on foliage again.
Climate. In the summer months, the temperature in areas of variable moisture forests reaches 27 degrees Celsius, in the winter months the thermometer rarely drops below 21 degrees. The rainy season comes after the hottest month. During the summer rainy season, thunderstorms are frequent, for several days in a row there can be continuous clouds, often turning into rain. During dry periods, some areas may not rain for two to three months.
Variably humid forests are dominated by yellow-earth and red-earth soil... The structure of the soil is granular-lumpy, the humus content gradually decreases from top to bottom, on the surface - 2-4%.
Among the plants of variably moist forests, there are evergreen, coniferous and deciduous trees. Evergreens include palm trees, ficuses, bamboo, all kinds of magnolia, cypress, camphor tree, tulip tree. Deciduous trees are represented by linden, ash, walnut, oak, maple. Fir and spruce are often found among evergreens.
Animals.
The fauna of variably humid forests is rich and varied. The lower tier is inhabited by many rodents, from large animals - elephants, tigers and leopards, among the branches of trees monkeys, pandas, lemurs, all kinds of felines have found refuge. There are Himalayan bears, raccoon dog and wild boar. The variety of birds is represented by pheasants, parrots, partridges and black grouse. Pelicans and herons are found on the banks of rivers and lakes.
Man has destroyed a significant part of the variably moist forests. Rice, tea bush, mulberry, tobacco, cotton, citrus are grown on the site of the deforested forests. It will take a long time to restore the lost forest areas.
Natural zones of the Earth
A comprehensive scientific study of nature allowed V.V.Dokuchaev in 1898 to formulate the law of geographic zoning, according to which climate, waters, soils, relief, vegetation and fauna in a certain area are closely interconnected and should be studied as a whole. He proposed dividing the Earth's surface into zones that regularly repeat in the Northern and Southern Hemispheres.
Different geographical (natural) zones Of the earth are characterized by a certain combination of heat and moisture, soils, flora and fauna and, as a result, by the peculiarities of the economic activity of their population. These are zones of forests, steppes, deserts, tundra, savannah, as well as transitional zones of forest-tundra, semi-deserts, forest-tundra. The names of natural zones are traditionally given according to the prevailing type of vegetation, reflecting the most important features of the landscape.
The regular change of vegetation is an indicator of the general increase in heat. In the tundra, the average temperature of the warmest month of 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 characteristic of the equatorial, subequatorial, tropical, subtropical, and also temperate climatic zones of the Earth. The intensity of vegetation development in natural zones also depends on the amount of precipitation. Compare, for example, their number in the zone of forests and deserts (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 characteristics of the distribution of heat and moisture, their ratio. Each natural zone has its own type of soil, flora and fauna.
The appearance of the natural zone is determined by the type of vegetation cover. But the nature of the vegetation depends on climatic conditions - thermal regime, moisture, illumination, soil, etc.
As a rule, natural zones stretch in the form of wide stripes from west to east. There are no clear boundaries between them, they gradually merge into one another. The latitudinal location of natural zones is disturbed by the uneven distribution of land and ocean, relief distance from the ocean.
General characteristics of the main natural zones of the Earth
Let's characterize the main natural zones of the Earth, starting from the equator and moving towards the poles.
Forests are located on all continents of the Earth, except Antarctica. Forest zones have both common features and special features characteristic only of the taiga, mixed and broad-leaved forests or tropical forests.
The general features of the forest zone include: warm or hot summers, a fairly large amount of precipitation (from 600 to 1000 mm or more per year), large deep rivers, the predominance of woody vegetation. The greatest amount of heat and moisture is received by the equatorial forests, which occupy 6% of the land. They rightfully belong to the first place among the forest zones of the Earth in terms of the diversity of plants and animals. It is home to 4/5 of all plant species and 1/2 of all land animal species.
The climate of the equatorial forests is hot and humid. Average annual temperatures +24 ... + 28 ° С. Annual precipitation is over 1000 mm. It is in the equatorial forest that the largest number of ancient species of animals can be found, for example, amphibians: frogs, newts, salamanders, toads or marsupials: possums in America, possums in Australia, tenrecs in Africa, lemurs in Madagascar, lorises in Asia; ancient animals are also such inhabitants of equatorial forests as armadillos, anteaters, lizards.
In the equatorial forests, the richest vegetation is located in several tiers. The crowns of trees are home to many species of birds: hummingbirds, hornbills, birds of paradise, crowned pigeons, numerous species of parrots: cockatoo, macaw, amazon, gray. These birds have tenacious legs and strong beaks: they not only fly, but also climb trees beautifully. Animals that live in tree crowns also have tenacious legs and a tail: sloths, monkeys, howler monkeys, flying foxes, tree kangaroos. The largest animal that lives in the crowns of trees 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 are equatorial forests in South America, in the Amazon basin, and in Africa - in the Congo basin. The Amazon is the deepest river on Earth. Every second, it carries 220 thousand m3 of water into the Atlantic Ocean. Congo is the second largest river in the world. Equatorial forests are also distributed on the islands of the Malaysian archipelago and Oceania, in the southeastern regions of Asia, in the northeast of Australia (see map in the atlas).
Valuable tree species: mahogany, black, yellow - the wealth of equatorial forests. Harvesting of valuable species of wood jeopardizes the preservation of the unique forests of the Earth. Space images have shown that in a number of regions of the Amazon, the destruction of forests is proceeding at a catastrophic pace, many times faster than their restoration. At the same time, many species of unique plants and animals disappear.
Variable wet monsoon forests
Variable wet monsoon forests can also be found on all continents of the Earth, except Antarctica. If in equatorial forests it is summer all the time, then there are three distinct seasons: 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 foliage, and the grass turns yellow.
The summer monsoon comes at the end of May with hurricane winds, thunderstorms, and torrential rains. Nature comes to life. Due to the alternation of dry and wet seasons, monsoon forests are called variable wet.
The monsoon forests of India are located in the tropical climatic zone... Valuable tree species, distinguished by the strength and durability of wood, grow here: teak, sal, sandalwood, satin and iron wood. Teak wood is not afraid of fire and water, it is widely used for the construction of ships. Sal also has a durable and sturdy wood. Sandalwood and satin trees are used in the manufacture of varnishes and paints.
The fauna of the Indian jungle is rich and varied: elephants, bulls, rhinos, monkeys. There are many birds and reptiles.
Monsoon forests of tropical and subtropical regions are also typical for Southeast Asia, Central and South America, northern and northeastern regions of Australia (see map in the atlas).
Temperate monsoon forests
Temperate monsoon forests are common only in Eurasia. The Ussuri taiga is a special place in the Far East. This is a real thicket: multi-tiered forests, dense, intertwined with lianas, wild grapes. Cedar, walnut, linden, ash and oak grow here. Lush vegetation is the result of an abundance of seasonal rainfall and a rather mild climate. Here you can meet the Ussuri tiger - the largest representative of its kind.
The rivers of the monsoon forests are rained and flood during the summer monsoon rains. The largest of them are Ganges, Indus, Amur.
Monsoon forests are heavily cut down. According to experts, in Eurasia only 5% of the former forest areas have survived. Monsoon forests have suffered not so much 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 and their tributaries. The development of agriculture required new territories - forests were cut down. For centuries, agriculture has adapted to the alternation of wet and dry seasons. The main growing season is the wet monsoon. Sowing of the most important crops - rice, jute, sugar cane - is timed to it. In the dry cool season, barley, legumes, potatoes are planted. In the hot dry season, farming is possible only with artificial irrigation. The monsoon is capricious, its delay leads to severe droughts, the death of crops. Therefore, artificial irrigation is needed.
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 pronounced. Average temperatures in January are generally negative, in some places up to -40 ° С, in July + 10 ... + 20 ° С; the amount of precipitation is 300-1000 mm per year. The vegetation of plants in winter ceases, for several months there is a snow cover.
Spruce, fir, pine, larch grow both in the taiga of North America and in the taiga of Eurasia. The fauna also has a lot in common. The bear is the master of the taiga. True, in the Siberian taiga it is called a brown bear, and in the taiga of Canada it is called a grizzly. You can find red lynx, elk, wolf, as well as marten, ermine, wolverine, sable. The largest rivers of Siberia - the Ob, Irtysh, Yenisei, Lena - flow through the taiga zone, which are second only to the rivers of the equatorial forest zone in terms of runoff.
To the south, the climate becomes milder: mixed and deciduous forests grow here, consisting of such species as birch, oak, maple, linden, among which there are conifers. Typical for the forests of North America are: white oak, sugar maple, yellow birch. Red deer, elk, wild boar, hare; of the predators, the wolf and the fox are known to us representatives of the animal world of this zone.
If the northern taiga belongs to the zone of poorly altered man by scientists-geographers, then mixed and broad-leaved forests have been cut down almost everywhere. They were replaced by agricultural areas, for example, the "corn belt" in the United States, in this area are concentrated many cities and highways. In Europe and North America, the natural landscapes of these forests have survived only in mountainous regions.
Savannah
Savannah is a natural zone of low latitudes in the subequatorial, tropical and subtropical belts 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 savannah is dominated by herbaceous vegetation with freestanding trees or groups of trees (acacia, eucalyptus, baobab) and shrubs.
The fauna of the African savannah is surprisingly diverse. To adapt to the conditions of endless dry spaces, nature has endowed animals with unique properties. For example, the giraffe is considered the tallest animal on Earth. His height is more than 5 m, he has a long tongue (about 50 cm). All this is necessary for a giraffe in order to reach the tall branches of acacias. Crowns of acacias begin at a height of 5 m, and giraffes have practically no competitors, quietly eating tree branches. Typical savannah animals are zebras, elephants, ostriches.
Steppe
Steppes are found on all continents of the Earth, except for Antarctica (in the temperate and subtropical belts of the Northern and Southern Hemispheres). They are distinguished by an abundance of solar heat, a small amount of precipitation (up to 400 mm per year), as well as warm or hot summers. The main vegetation of the steppes is grasses. The steppes are called differently. In South America, tropical steppes are called pampas, which in the language of the Indians means "a large space without a forest." Animals characteristic of the pampa are a llama, an armadillo, a viscaca - a rodent that looks like a rabbit.
In North America, the steppes are called prairies. They are located in both temperate and subtropical climatic zones. Bison have long been the "kings" of the American prairies. By the end of the 19th century, they were almost completely exterminated. Currently, thanks to the efforts of the state and the public, the number of bison is being restored. Another prairie dweller is a coyote, a steppe wolf. On the banks of the rivers in the bushes, you can find a large spotted cat - the jaguar. The peccary is a small wild boar-like animal also typical of the prairie.
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. It is very cold in winter (average temperatures - 20 ° С), and in summer it is very hot (average temperature + 25 ° С), strong winds. In summer, the steppe vegetation is scarce, but in the spring the steppe is transformed: it blooms with many varieties of lilies and poppies, tulips.
The flowering time does not last long, about 10 days. Then a drought sets in, the steppe dries up, the colors fade, and by autumn everything takes on a yellow-gray color.
The most fertile soils of the Earth are located in the steppes, so they are almost completely plowed up. The treeless areas of the temperate steppe are characterized by strong winds. Wind erosion of soils is very intense 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 mass. They are located on all continents and in different climatic zones: temperate, subtropical, tropical and even polar.
There are common features in tropical and temperate desert climates. Firstly, the abundance of solar heat, secondly, a large range of temperatures in winter and summer, day and night, and thirdly, a low amount of precipitation (up to 150 mm per year). However, the latter feature is also typical for polar deserts.
In the deserts of the tropical zone, the average summer temperature is + 30 ° С, winter + 10 ° С. The greatest tropical deserts of the Earth are located in Africa: Sahara, Kalahari, Namib.
Desert plants and animals 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 Welwichia plant found in the Namib Desert is capable of absorbing water from the air. The camel is an indispensable helper for man in the desert. He can be without food and water for a long time, storing them in his humps.
The largest desert in Asia, Rub al-Khali, located on the Arabian Peninsula, is also located in the tropical zone. Desert regions of North and South America and Australia are found in tropical and subtropical climatic zones.
The deserts of the temperate zone of Eurasia are also characterized by a low amount of precipitation and a large amplitude of temperatures, 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 to the east of the Caspian Sea. The fauna is represented here by various types of snakes, rodents, scorpions, turtles, lizards. A typical plant is saxaul.
Polar deserts
Polar deserts are located in the polar regions of the Earth. In Antarctica, an absolute temperature minimum was recorded - 89.2 ° C.
On average, winter temperatures are -30 ° С, summer temperatures are 0 ° С. Just as in the deserts of the tropical and temperate zones, little precipitation falls in the polar desert, mainly in the form of snow. The polar night lasts almost half a year here, and the polar day for almost half a year. Antarctica is considered the tallest continent on Earth, given the thickness of its ice shell, 4 km.
The indigenous inhabitants of the polar deserts of Antarctica are emperor penguins. They cannot fly, but they swim beautifully. They can dive to great depths and swim great distances, fleeing from their enemies - seals.
The northern polar region of the Earth - the Arctic - got its name from the ancient Greek arcticos - northern. South, as it were, the opposite polar region - 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
The tundra is a treeless natural area with vegetation of mosses, lichens and creeping shrubs. Tundra is widespread in the subarctic climatic zone only in North America and Eurasia, characterized by severe climatic conditions (little solar heat, low temperatures, short cold summers, low rainfall).
Lichen lichen was called "reindeer moss" because it is the main food for reindeer. Arctic foxes also live in the tundra, and lemmings are small rodents. 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 and Siberian taiga. It is worth starting to dig a hole, as at a depth of about 1 m, a frozen layer of earth with a thickness of several tens of meters is encountered. This phenomenon must be taken into account in construction, industrial and agricultural development of the territory.
Everything grows very slowly in the tundra. It is with this that the need for an attentive attitude to its nature is connected. For example, pastures poisoned by deer are restored only after 15-20 years.
Altitudinal zonality
Unlike flat areas, climatic zones and natural zones in the mountains are replaced according to the law of vertical zoning, that is, 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: a 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 from the Himalayan pine begin to prevail. fir and juniper. In winter, snow lies 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 flowering herbs - poppies, primroses, gentians. Gradually the grasses become lower. Eternal snow and ice lie from about 4500 m. The climatic conditions are very harsh here. Rare species of animals live in the mountains: mountain goat, chamois, argali, snow leopard.
Latitudinal zonation in the ocean
The 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 conducive to life. It is especially important for the life of plants and animals that oxygen and carbon dioxide coming from the air are dissolved in water. Photosynthesis of algae occurs mainly in the upper water layer (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, the smallest animals), various fish and marine mammals (dolphins, whales, seals, etc.), squids, sea snakes and turtles.
There is life on the seabed too. These are benthic algae, corals, crustaceans, molluscs. 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 Oceans unevenly and depends on the amount of solar energy received on its surface. Polar waters are poor in plankton due to low temperatures and long polar nights. The largest amount of plankton develops in temperate waters in summer. The abundance of plankton attracts fish here. The temperate zones of the Earth are the most fishy regions of the World Ocean. In the tropical zone, the amount of plankton decreases again due to the high salinity of water and high temperatures.
Formation of natural zones
From today's topic, we learned how diverse the natural complexes of our planet are. The natural zones of the Earth are full of evergreen forests, endless steppes, various mountain ranges, hot and icy deserts.
Every 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 zones are, how they were formed, and what was the impetus for their formation.
Natural zones include such complexes that have similar soils, vegetation, fauna and similar temperature conditions. The natural zones got their names according to the type of vegetation, and bear such names as the zone of taiga or deciduous forests, etc.
Natural zones are diverse due to the uneven redistribution of solar energy on the Earth's surface. This is the main reason for the heterogeneity of the geographic envelope.
After all, if you consider any one of the climatic zones, you will notice that those parts of the belt that are located closer to the ocean are more humid 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 observe a more humid climate, and on another - arid.
And with the help of the redistribution of solar heat, we see how the same amount of moisture in some climatic zones leads to excessive moisture, and in others - to their lack.
So, 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.
Regularities in the placement of natural zones
The natural zones of the Earth have clear patterns of their location, stretching 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 into the interior of the mainland.
In mountainous areas, there is an altitudinal zonation, which changes from one zone to another, starting from the foot and moving towards the mountain peaks.
In the oceans, the change of zones occurs from the equator to the poles. Here, changes in natural zones are reflected in the surface composition of waters, as well as differences in flora and fauna.
Features of the natural zones of the continents
Since the planet Earth has a surface in the form of a ball, the Sun also heats it unevenly. Those areas of the surface over 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 vegetation and animals have similar features, they are influenced by climate, relief, geology and man. Therefore, it so happened historically that due to changes in the relief and climate, different types of plants and animals live on different continents.
There are continents where endemics are found, on which only a certain type of living creatures and plants live, which are characteristic of these continents. For example, polar bears can be found in nature only in the Arctic, and kangaroos - in Australia. But in African and South American shrouds there are similar species, although they have certain differences.
But human activity contributes to the changes that occur in the geographic envelope, and under such influence natural zones also change.
Questions and tasks to prepare for the exam
1. Make a diagram of the interaction of natural components in a natural complex and explain it.
2. How do the concepts of “natural complex”, “geographic envelope”, “biosphere”, “natural zone” relate to each other? Show with a diagram.
3. Name the zonal soil type for the tundra, taiga, mixed and deciduous forests.
4. Where is the soil cover more difficult to restore: in the steppes of the South of 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 determines soil fertility?
6. What types of plants and animals are typical for the tundra and why?
7. What organisms live on the surface of the World Ocean?
8. Which of the following animals can be found in the African savannah: rhino, lion, giraffe, tiger, tapir, baboon, llama, hedgehog, zebra, hyena?
9. In what forests is it impossible to find out its age by 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.: Ayris-press, 2010 .-- 368s.: Ill.
"Peoples of Eurasia" - Romanesque peoples with dark hair, dark skin. Russian Ukrainians Belarusians. Frenchwoman. Eastern. Peoples belonging to different linguistic families and groups live on the territory of Eurasia. About 3/4 of the world's population lives in Eurasia. Slavic peoples. Religions of Eurasia. Poles Czechs Slovaks. The Germanic peoples are characterized by light hair and fair skin.
"Climatic features of Eurasia" - High average annual and summer temperatures. Temperature. Determination of climate types. Climatic zones and regions of Eurasia. The climate is mild. Arctic air. January temperature. You learned to read. Temperatures and winds in January. Climate charts. Relief. Climatic features of Eurasia. The largest amount of precipitation.
"Geography Lesson Eurasia" - Introduce students to the concept of Eurasia. Explain the influence of size on natural features. Semyonov-Tan-Shansky P.P. The highest mountain in the world is Chomolungma - 8848 m. Geographical position of Eurasia. General information about Eurasia. Give the names of travelers and explorers of the continent. Obruchev V.A.
"Nature of Eurasia" - Square. Minerals. Inland waters. Natural areas. Climate. Eurasia. Relief. The organic world. Geographical position. Continental records.
“Lakes of Eurasia” - Correct answer. -Tectonic lakes in the faults are deep, elongated. Lacustrine basin of glacial origin. Such lakes are lakes - seas: Caspian and Aral. Inland waters of Eurasia. Determination of the types of lake basins in Eurasia. Lacustrine basin of tectonic origin.
"Natural zones of the temperate zone of Eurasia" - Flora. The flora of the taiga. Fauna of the taiga. Fauna: very similar to the animal world of the taiga ... Animal world. In Eurasia, the forest-steppe stretches in a continuous strip from west to east from the eastern foothills of the Carpathians to Altai. Taiga. In Europe and in the European part of Russia, light broad-leaved forests of oak (oak groves), beech, linden, chestnut, ash, etc. are typical.
Introduction
Eurasia is the largest continent on Earth, with an area of 53 893 thousand square kilometers, which is 36% of the land area. The population is over 4.8 billion people.
The continent is located in the Northern Hemisphere between approximately 9 ° and 169 ° West longitude, with part of the Eurasian islands located in the Southern Hemisphere. Most of continental Eurasia lies in the Eastern Hemisphere, although the extreme western and eastern ends of the continent are in the Western Hemisphere. Contains two parts of the world: Europe and Asia.
All climatic zones and natural zones are represented in Eurasia.
The natural zone is a part of a geographic zone with homogeneous climatic conditions.
Natural areas take their name from the vegetation inherent in them and other geographic features. The zones regularly change from the equator to the poles and from the oceans deep into the continents; have similar temperature and moisture conditions, which determine homogeneous soils, vegetation, fauna and other components of the natural environment. Natural zones are one of the stages of physical and geographical zoning.
The main natural zones of the subequatorial and equatorial belts of Eurasia considered in the course work are the zone of variably humid, including monsoon forests, the zone of savannas and woodlands, and the zone of equatorial forests.
A zone of variably humid, monsoon forests develops on the plains of Hindustan, Indochina and in the northern half of the Philippine Islands, a zone of savannas and woodlands - on the Deccan Plateau and inland parts of the Indo-China Peninsula, moist equatorial forests - throughout the Malay Archipelago, the southern half of the Philippine Islands, and the southwestern the islands of Ceylon and the Malacca Peninsula.
The course work describes in detail the characteristics of these natural zones, reflects the geographical location, climate, soil, flora, its ecological features, animal population and its ecological features. Also, an urgent topic has been developed - the ecological problems of the equatorial and subequatorial belts of Eurasia. First of all, these include deforestation of humid equatorial forests and desertification of savannas under the influence of grazing.
Zone of variably humid, including monsoon forests
Geographical location, natural conditions
In the subequatorial zone, due to seasonal precipitation and uneven distribution of precipitation over the territory, as well as contrasts in the annual course of temperatures, landscapes of subequatorial variably humid forests develop on the plains of Hindustan, Indochina and in the northern half of the Philippine Islands.
Variably moist forests occupy the most humid areas of the lower reaches of the Ganges-Brahmaputra, the coastal areas of Indochina and the Philippine archipelago, especially well developed in Thailand, Burma, the Malacca Peninsula, where at least 1500 millimeters of precipitation falls. On drier plains and plateaus, where the amount of precipitation does not exceed 1000-800 millimeters, there are seasonally moist monsoon forests that once covered large areas of the Indian subcontinent and southern Indochina (the Korat plateau). With a decrease in precipitation to 800-600 millimeters and a reduction in the period of rainfall from 200 to 150-100 days a year, forests are replaced by savannas, woodlands and shrubs.
The soils are ferralite, but predominantly red. With a decrease in the amount of rain, the concentration of humus in them increases. They are formed as a result of ferralite weathering (the process is accompanied by the disintegration of most of the primary minerals, with the exception of quartz, and the accumulation of secondary minerals - kaolinite, goethite, gibbsite, etc.) and humus accumulation under the forest vegetation of the humid tropics. They are characterized by a low content of silica, a high content of aluminum and iron, a low cation exchange and high anionic absorption capacity, predominantly red and variegated yellow-red color of the soil profile, and a very acidic reaction. The humus contains mainly fulvic acids. Humus contains 8-10%.
The hydrothermal regime of seasonally humid tropical communities is characterized by constantly high temperatures and a sharp change in wet and dry seasons, which determines the specific features of the structure and dynamics of their fauna and animal population, which noticeably distinguish them from communities of tropical rainforests. First of all, the presence of a dry season lasting from two to five months determines the seasonal rhythm of life processes in almost all animal species. This rhythm is expressed in the confinement of the breeding period mainly to the wet season, in the complete or partial cessation of activity during the drought, in the migratory movements of animals both within the considered biome and outside it during the unfavorable dry season. Falling into full or partial hibernation is typical for many terrestrial and soil invertebrates, for amphibians, and migration is typical for some insects capable of flying (for example, locusts), for birds, bats and large ungulates.
Variable wet monsoon forests
Variable wet 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 there are three distinct seasons: 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 foliage, and the grass turns yellow. The summer monsoon comes at the end of May with hurricane winds, thunderstorms, and torrential rains. Nature comes to life. Due to the alternation of dry and wet seasons, monsoon forests are called variable wet. The monsoon forests of India are located in the tropical climate zone. Valuable tree species, distinguished by the strength and durability of wood, grow here: teak, sal, sandalwood, satin and iron wood. Teak wood is not afraid of fire and water, it is widely used for the construction of ships. Sal also has a durable and sturdy wood. Sandalwood and satin trees are used in the manufacture of varnishes and paints.
Monsoon forests of tropical and subtropical regions are also typical for Southeast Asia, Central and South America, northern and northeastern regions of Australia (see map in the atlas).
Temperate monsoon forests
Temperate monsoon forests are common only in Eurasia. The Ussuri taiga is a special place in the Far East. This is a real thicket: multi-tiered forests, dense, intertwined with lianas, wild grapes. Cedar, walnut, linden, ash and oak grow here. Lush vegetation is the result of an abundance of seasonal rainfall and a rather mild climate. Here you can meet the Ussuri tiger - the largest representative of its kind.
The rivers of the monsoon forests are rained and flood during the summer monsoon rains. The largest of them are Ganges, Indus, Amur.
Monsoon forests are heavily cut down. According to experts, only 5% of the former forest areas have survived in Eurasia. Monsoon forests have suffered not so much 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 and their tributaries. The development of agriculture required new territories - forests were cut down. For centuries, agriculture has adapted to the alternation of wet and dry seasons. The main growing season is the wet monsoon. Sowing of the most important crops - rice, jute, sugar cane - is timed to it. In the dry cool season, barley, legumes, potatoes are planted. In the hot dry season, farming is possible only with artificial irrigation. The monsoon is capricious, its delay leads to severe droughts, the death of crops. Therefore, artificial irrigation is needed.
