Variably humid forests interesting facts. Monsoon forests: description, climate, fauna and interesting facts. Landscape in the center of Venezuela

Geographical location, natural conditions

In the subequatorial belt, due to seasonal precipitation and uneven distribution of precipitation over the territory, as well as contrasts in annual course temperatures, on the plains of Hindustan, Indochina and in the northern half of the Philippine Islands, landscapes of subequatorial variable humid forests develop.

Variably humid forests occupy the wettest areas of the lower reaches of the Ganges-Brahmaputra, coastal regions of Indochina and the Philippine archipelago, are especially well developed in Thailand, Burma, the Malay 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, seasonally moist monsoon forests grow, which once covered large areas of the Hindustan peninsula and southern Indochina (Korat Plateau). With a decrease in precipitation to 800-600 millimeters and a reduction in the rainfall period from 200 to 150-100 days a year, forests are replaced by savannahs, woodlands and shrubs.

The soils here are ferralitic, 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 ferralitic weathering (the process is accompanied by the decay of most of the primary minerals, with the exception of quartz, and the accumulation of secondary ones - kaolinite, goethite, gibbsite, etc.) and humus accumulation under the forest vegetation of the humid tropics. They are characterized by low content of silica, high content of aluminum and iron, low cation exchange and high anion absorption capacity, predominantly red and variegated yellow-red color of the soil profile, very acid reaction. Humus contains mainly fulvic acids. Humus contain 8-10%.

The hydrothermal regime of seasonally humid tropical communities is characterized by constantly high temperatures and a sharp change in the 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 humid rainforest. 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 biome under consideration and outside it during the unfavorable dry season. Falling into full or partial anabiosis is typical for many terrestrial and soil invertebrates, for amphibians, and migration is typical for some insects capable of flight (for example, locusts), for birds, bats and large ungulates.

Vegetable world

Variably humid forests (Figure 1) are similar in structure to hylaea, differing at the same time in a smaller number of species. In general, the same set of life forms, variety of vines and epiphytes is preserved. Differences are manifested precisely in the seasonal rhythm, primarily at the level of the upper tier of the forest stand (up to 30% of the trees of the upper tier are deciduous species). At the same time, the lower tiers include a large number of evergreen species. The grass cover is represented mainly by ferns and dicots. In general, these are transitional types of communities, in places largely reduced by man and replaced by savannahs and plantations.

Figure 1 - Variably humid forest

The vertical structure of humid subequatorial forests is complex. Usually there are five tiers in this forest. The upper tree layer A is formed by the tallest trees, isolated or forming groups, the so-called emergents, raising their “heads and shoulders” above the main canopy - a continuous layer B. The lower tree layer C often penetrates into layer B. Tier D is commonly called shrub. It is formed mainly by woody plants, of which only a few can hardly be called shrubs in the exact sense of the word, or rather, these are “dwarf trees”. Finally, the lower tier E is formed by grasses and tree seedlings. The boundaries between adjacent tiers may be better or worse. Sometimes one tree layer imperceptibly passes into another. Tree layers are better expressed in monodominant communities than in polydominant ones.

The most common teak forest, which is characterized by a teak tree. Trees of this species can be considered an essential component of the summer green forests of India, Burma, Thailand and the relatively dry regions of eastern Java. In India, where very small patches of these natural zonal forests are still preserved, ebony and marada or Indian laurel grow together with teak mainly; all these types give valuable wood. But teak wood, which has a number of valuable properties, is especially in great demand: it is hard, resistant to fungi and termites, and also reacts poorly to changes in humidity and temperature. Therefore, teak growers specially grow teak (in Africa and South America). The monsoon forests are best explored in Burma and Thailand. In them, along with teak wood, there are Pentacme suavis, Dalbergia paniculata, Tectona hamiltoniana, whose wood is stronger and heavier than teak wood, then giving bast fibers Bauhinia racemosa, Callesium grande, Ziziphus jujuba, Holarrhenia dysenteriaca with white soft wood used for turning and woodcarving. One of the bamboo species, Dendrocalamus strictus, grows in the shrub layer. The layer of grasses consists mainly of grasses, among which the bearded vulture predominates. Along the shores of estuaries and in other areas of the sea coast protected from storms, the muddy tidal strip (littoral) is occupied by mangroves (Figure 2). The trees of this phytocenosis are characterized by thick stilted roots, like thin piles extending from the trunks and lower branches, as well as respiratory roots sticking out of the silt in vertical columns.

Figure 2 - Mangroves

Extensive swamps stretch along the rivers in the tropical rainforest zone: heavy rains lead to regular high floods, and floodplain areas are constantly flooded. The marshy forests are often dominated by palm trees, and the species diversity is less here than in drier places.

Animal world

The fauna of the seasonally humid subtropical communities is not as rich as the fauna of the humid equatorial forests due to the dry period, which is unfavorable for animals. Although the species composition of various groups of animals in them is specific, at the level of genera and families, a great similarity with the gilea fauna is noticeable. Only in the driest variants of these communities, in light forests and thorny bushes, do species related to typical representatives of the fauna of arid communities begin to noticeably predominate.

Forced adaptations to drought contributed to the formation of a number of special animal species characteristic of this particular biome. In addition, some species of phytophagous animals are here more diverse in species composition than in Hylaea, due to the greater development of the herbaceous layer and, accordingly, the greater diversity and richness of herbaceous food.

The layering of the animal population in seasonally humid communities is noticeably simpler than in humid tropical forests. The simplification of layering is especially pronounced in light forests and shrub communities. However, this applies mainly to the tree layer, since the stand itself is less dense, diverse and does not reach such a height as in the hylaea. On the other hand, the herbaceous layer is much more pronounced, since it is not shaded so strongly by woody vegetation. The population of the litter layer is also much richer here, since the deciduousness of many trees and the drying of grasses during the dry period ensure the formation of a rather thick litter layer.

The presence of a litter layer formed by leaf and grass decay ensures the existence of a trophic group of saprophages with a diverse composition. The soil-litter layer is inhabited by nematode roundworms, megacolocidal annelids, small and large nodule worms, oribatid mites, springtails, springtails, cockroaches, and termites. All of them are involved in the processing of dead plant mass, but the leading role is played by termites already familiar to us from the giley fauna.

Consumers of green mass of plants in seasonal communities are very diverse. This is determined primarily by the presence of a well-developed herbaceous layer in combination with a more or less closed tree layer. Thus, chlorophytophages specialize either in eating the leaves of trees, or in using herbaceous plants, many feed on plant sap, bark, wood and roots.

Plant roots are eaten by larvae of cicadas and various beetles - beetles, gold beetles, dark beetles. The juices of living plants are sucked by adult cicadas, bugs, aphids, worms and scale insects. Green plant mass is consumed by caterpillars of butterflies, stick insects, herbivorous beetles - beetles, leaf beetles, weevils. Seeds of herbaceous plants are used as food by reaper ants. The green mass of herbaceous plants is eaten mainly by various locusts.

Numerous and diverse consumers of green vegetation and among vertebrates. These are terrestrial turtles from the genus Testudo, granivorous and frugivorous birds, rodents and ungulates.

The monsoon forests of South Asia are home to the wild chicken (Callus gallus) and the common peacock (Pavochstatus). In the crowns of trees, Asian necklace parrots (Psittacula) get their food.

Figure 3 - Asian ratuf squirrel

Among herbivorous mammals, rodents are the most diverse. They can be found in all tiers of seasonal tropical forests and light forests. The tree layer is inhabited mainly by various representatives of the squirrel family - palm squirrels and a large ratuf squirrel (Figure 3). In the terrestrial layer, rodents from the mouse family are common. In South Asia, large porcupine (Hystrix leucura) can be found under the forest canopy, Rattus rats and Indian bandicots (Bandicota indica) are common everywhere.

Various predatory invertebrates live in the forest floor - large centipedes, spiders, scorpions, predatory beetles. Many spiders that build trapping nets, such as large nephilous spiders, also inhabit the tree layer of the forest. Praying mantises, dragonflies, ktyr flies, predatory bugs prey on small insects on the branches of trees and shrubs.

Small predatory animals prey on rodents, lizards and birds. The most characteristic are various viverrids - civet, mongoose.

Of the large carnivores in the seasonal forests, the leopard is relatively common, penetrating here from the hylae, as well as tigers.

South America is the fourth largest continent and lies in the southern hemisphere. Five climatic zones determine the characteristics of flora and fauna: equatorial, subequatorial, tropical, subtropical and temperate, most of the mainland has a warm climate.

The flora and fauna are very rich, many species are found exclusively here. South America is a record holder in many ways, the longest and most full-flowing river in the world, the Amazon, flows here, the longest Mountain chain Andes, the largest mountain lake Titicaca is located, it is the rainiest continent on earth. All this significantly influenced the development of wildlife.

Nature of different countries of South America:

Flora of South America

The flora of South America is rightfully considered the main wealth of the mainland. Such to everyone famous plants like tomatoes, potatoes, corn, chocolate tree, rubber tree were discovered here.

Wet rainforests The northern part of the mainland is still striking in its richness of species, and today scientists continue to discover new plant species here. In these forests there are different types of palm trees, melon tree. There are 750 species of trees and 1,500 species of flowers per 10 square kilometers of this forest.

The forest is so dense that it is extremely difficult to move through it, vines also make it difficult to move. A characteristic plant for the rainforest is ceiba. The forest in this part of the mainland can reach a height of over 100 meters and spread over 12 levels!

South of the selva are variable wet forests and savannas, where the quebracho tree grows, which is famous for its very hard and very heavy wood, a valuable and expensive raw material. In the savannas, small forests give way to thickets of cereals, shrubs and tough grasses.

Further south are the pampas - the South American steppes. Here you can find many types of herbs, common for Eurasia: feather grass, bearded vulture, fescue. The soil here is quite fertile, as there is less rainfall and it is not washed out. Shrubs and small trees grow among the grasses.

The south of the mainland is desert, the climate there is more severe, and therefore the vegetation is much poorer. Shrubs, some types of grasses and cereals grow on the stony soil of the Patagonian desert. All plants are resistant to drought and constant weathering of the soil, among them are resinous chanyar, chukuraga, Patagonian fabiana.

Fauna of South America

The animal world, like vegetation, is very rich, many species have not yet been described and qualified. The richest region is the Amazonian selva. It is here that such amazing animals as sloths, the smallest hummingbirds in the world, a huge number of amphibians, among which poisonous frogs, reptiles, including huge anacondas, the world's largest rodent capybara, tapirs, jaguars, river dolphins. At night, a wild cat ocelot hunts in the forest, resembling a leopard, but found only in America.

According to scientists, 125 species of mammals, 400 species of birds and an unknown number of species of insects and invertebrates live in the selva. The water world of the Amazon is also rich, its most famous representative is predatory fish piranha. Other famous predators- crocodiles and caimans.

The savannahs of South America are also rich in fauna. Armadillos are found here, amazing animals covered with plates - “armor”. Other animals that can only be found here are anteaters, rhea ostriches, spectacled bear, puma, kinkajou.

In the pampas of this continent there are deer and llamas who live in open spaces and who can find here the grasses that they feed on. The Andes have their own special inhabitants - llamas and alpacas, whose thick wool saves them from the high mountain cold.

In the deserts of Patagonia, where only hard grasses and small shrubs grow on stony soil, mainly small animals, insects, and various types of rodents live.

South America includes the Pacific Galapogos Islands, which are home to amazing turtles, the largest representatives of the family on earth.

Natural zones of the Earth

Comprehensive Scientific research nature allowed V. V. Dokuchaev in 1898 to formulate the law of geographical zoning, according to which climate, water, soil, relief, flora 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 naturally repeat themselves in the Northern and Southern hemispheres.

Different geographical (natural) zones Earth are characterized by a certain combination of heat and moisture, soils, flora and fauna and, as a result, by the peculiarities of the economic activity of their population. These are zones of forests, steppes, deserts, tundra, savannas, as well as transitional zones of forest-tundra, semi-deserts, forest-tundra. The names of natural areas are traditionally given according to the prevailing type of vegetation, which reflects the most important features of the landscape.

The regular change of vegetation is an indicator of a 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 temperate climatic zones of the Earth. The intensity of vegetation development in natural areas also depends on the amount of precipitation. Compare, for example, their number in the zone of forests and deserts (see map of the atlas).

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 features of the distribution of heat and moisture, their ratio. Each natural zone has its own type of soil, vegetation and wildlife.

The appearance of the natural zone is determined by the type of vegetation cover. But the nature of vegetation depends on climatic conditions - thermal regime, moisture, illumination, soil, etc.

As a rule, natural zones are elongated in the form of wide strips from west to east. There are no clear boundaries between them, they gradually pass 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 us 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 for Antarctica. Forest zones have both common features and special features that are characteristic only of the taiga, mixed and broad-leaved forests or tropical forests.

Common features of the forest zone include: warm or hot summers, quite a large number of precipitation (from 600 to 1000 or more mm per year), large full-flowing rivers, the predominance of woody vegetation. The largest number equatorial forests, which occupy 6% of the land, receive heat and moisture. They rightfully hold the first place among the forest zones of the Earth in terms of the diversity of plants and animals. 4/5 of all plant species grow here and 1/2 of all land animal species live.

The climate of the equatorial forests is hot and humid. Average annual temperatures are +24... +28°С. The annual amount of precipitation is more than 1000 mm. It is in the equatorial forest that you can find the largest number of ancient animal species, such as amphibians: frogs, newts, salamanders, toads or marsupials: opossums in America, possums in Australia, tenrecs in Africa, lemurs in Madagascar, loris in Asia; ancient animals are also such inhabitants of the equatorial forests as armadillos, anteaters, pangolins.

In the equatorial forests, the richest vegetation is located in several tiers. Many species of birds live in the crowns of trees: hummingbirds, hornbills, birds of paradise, crowned pigeons, numerous species of parrots: cockatoo, macaw, Amazon, Jaco. These birds have tenacious paws and strong beaks: they not only fly, but also climb trees beautifully. Treetop animals also have prehensile paws and tails: sloths, monkeys, howler monkeys, flying foxes, tree kangaroo. The largest animal that lives in the crowns of trees is the gorilla. In such forests, many beautiful butterflies and other insects live: termites, ants, etc. Various types of snakes. Anaconda - the largest snake in the world, reaches a length of 10 m or more. The high-water rivers of the equatorial forests are rich in fish.

The equatorial forests occupy the largest areas in South America, in the Amazon River basin, and in Africa - in the Congo River basin. The Amazon is the deepest river in the world. Every second it carries 220 thousand m3 of water into the Atlantic Ocean. The Congo is the second largest river in the world. Equatorial forests are also common on the islands of the Malaysian archipelago and Oceania, in the southeastern regions of Asia, in northeastern Australia (see the map in the atlas).

Valuable tree species: mahogany, black, yellow - the wealth of equatorial forests. The harvesting of valuable wood species threatens the preservation of the Earth's unique forests. Space images have shown that in a number of areas of the Amazon, the destruction scaffolding is coming catastrophic pace, many times faster than their recovery. At the same time, many species of unique plants and animals are disappearing.

Variable wet monsoon forests

Variably humid monsoon forests can also be found on all continents of the Earth, except for Antarctica. If it is summer all the time in the equatorial forests, then three seasons are pronounced here: dry cool (November-February) - winter monsoon; dry hot (March-May) - transitional season; humid hot (June-October) - summer monsoon. Most hot month- May, when the sun is almost at its zenith, the rivers dry up, the trees shed their leaves, the grass turns yellow.

The summer monsoon comes at the end of May with hurricane winds, thunderstorms, heavy 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 species of trees grow here, distinguished by the strength and durability of wood: teak, sal, sandalwood, satin and ironwood. Teak wood is not afraid of fire and water, it is widely used for building ships. Sal also has a durable and strong wood. Sandalwood and satin wood are used in the manufacture of varnishes and paints.

The fauna of the Indian jungle is rich and varied: elephants, bulls, rhinos, monkeys. Lots of birds and reptiles.

Monsoon forests of tropical and subtropical regions are also characteristic of Southeast Asia, Central and South America, northern and northeastern regions of Australia (see the map in the atlas).

Temperate monsoon forests

Temperate monsoon forests are found only in Eurasia. Ussuri taiga is a special place on Far East. This is a real thicket: the forests are multi-tiered, dense, intertwined with lianas and wild grapes. Cedar, walnut, linden, ash and oak grow here. Rough vegetation is the result of an abundance of seasonal rainfall and a rather mild climate. Here you can meet Ussuri tiger- the largest representative of its kind.
The rivers of the monsoon forests are rain-fed and flood during the summer monsoon rains. The largest of them are the Ganges, Indus, Amur.

The monsoon forests are heavily cut down. According to experts, in Eurasia only 5% of the former forests remained. Monsoon forests 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. Farming has adapted over the centuries to alternating wet and dry seasons. The main agricultural season is the wet monsoon period. The most important crops - rice, jute, sugarcane - are dated for it. In the dry cool season, barley, legumes, and potatoes are planted. In dry hot season agriculture is possible only with artificial irrigation. The monsoon is capricious, its delay leads to severe droughts and the death of crops. Therefore, artificial irrigation is necessary.

temperate forests

Temperate forests occupy significant areas in Eurasia and North America (see map in the atlas).

In the northern regions - this is the taiga, to the south - mixed and broad-leaved forests. In the forest zone of the temperate zone, the seasons of the year are pronounced. Average temperatures in January are negative everywhere, in some places up to -40°С, in July + 10 ... + 20°С; the amount of precipitation is 300-1000 mm per year. Vegetation of plants in winter stops, 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 animal world also has a lot in common. The bear is the master of the taiga. True, in the Siberian taiga it is called - Brown bear, and in the taiga of Canada - grizzlies. You can meet 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 flow.

To the south, the climate becomes milder: mixed and broad-leaved forests grow here, consisting of such species as birch, oak, maple, linden, among which there are also conifers. Typical for the forests of North America are: white oak, sugar maple, yellow birch. Red deer, elk, wild boar, hare; from predators - a wolf and a fox - representatives of animal world of this zone known to us.

If the northern taiga is classified by scientists-geographers as a zone slightly modified by man, then mixed and broad-leaved forests have been cut down almost everywhere. Their place was taken by agricultural areas, such as the "corn belt" in the United States, in this zone many cities and highways are concentrated. In Europe and North America, the natural landscapes of these forests have been preserved only in mountainous regions.

Savannah

Savannah is a natural zone of low latitudes in the subequatorial, tropical and subtropical zones of the Northern and Southern Hemispheres. It occupies about 40% of the territory of Africa (south of the Sahara), distributed in South and Central America, Southeast Asia, Australia (see the map in the atlas). The savanna is dominated by herbaceous vegetation with isolated trees or groups of trees (acacia, eucalyptus, baobab) and shrubs.

The fauna of the African savannas is surprisingly diverse. To adapt to the conditions of endless dry spaces, nature endowed animals with unique properties. For example, the giraffe is considered the tallest animal on Earth. Its height exceeds 5 m, it has a long tongue (about 50 cm). All this is necessary for a giraffe in order to reach the high branches of acacias. Crowns of acacias begin at a height of 5 m, and giraffes have practically no competitors, calmly eating tree branches. Typical animals of the savannas are zebras, elephants, ostriches.

steppes

Steppes are found on all continents of the Earth, except for Antarctica (in the temperate and subtropical zones of the Northern and Southern Hemispheres). They are distinguished by an abundance of solar heat, low rainfall (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, the tropical steppes are called pampas, which in the language of the Indians means "a large expanse without a forest." Animals characteristic of the pampa are the llama, the armadillo, the viscacha, 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. The "kings" of the American prairies have long been bison. TO late XIX century they were almost completely exterminated. Currently, through the efforts of the state and the public, the number of bison is being restored. Another inhabitant of the prairies is the coyote - the steppe wolf. On the banks of the rivers in the bushes you can meet a large spotted cat - a jaguar. The peccary is a small boar-like animal also typical of the prairies.

The steppes of Eurasia are located in the temperate zone. They are very different from the American prairies and African savannas. It has a drier, sharply continental climate. It is very cold in winter (average temperature - 20°С), and very hot in summer (average temperature + 25°С), strong winds. In summer, the vegetation of the steppes is sparse, but in spring the steppe is transformed: it blooms with many varieties of lilies 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 spaces of the steppes of the temperate zone differ strong winds. Here, wind erosion of soils is very intensive - dust storms are frequent. Forest belts are planted to preserve soil fertility, organic fertilizers, light agricultural machinery.

desert

Deserts occupy vast spaces - 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 the climate of the deserts of the tropical and temperate zones. Firstly, the abundance of solar heat, secondly, the large amplitude of temperatures in winter and summer, day and night, and thirdly, a small amount of precipitation (up to 150 mm per year). However, the latter feature is also characteristic of the polar deserts.

In the deserts of the tropical zone, the average summer temperature is +30°C, winter + 10°C. The Greatest tropical desert The lands are located in Africa: Sahara, Kalahari, Namib.

Desert plants and animals adapt to dry and hot climates. So, for example, a giant cactus can store up to 3000 liters of water and “not drink” for up to two years; and the Welwitschia plant, found in the Namib Desert, is able to absorb water from the air. A camel is an indispensable helper of a person 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. The desert regions of North and South America and Australia are located 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 spring. Such deserts are located in Central Asia to the east of the Caspian Sea. The fauna here is represented by various species of snakes, rodents, scorpions, turtles, lizards. A typical plant is saxaul.

polar deserts

Polar deserts are located in the polar regions of the Earth. An absolute minimum temperature of 89.2°C has been recorded in Antarctica.

Average winter temperatures are -30°С, summer - 0°С. Just like 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 here lasts almost half a year, the polar day lasts almost half a year. Antarctica is considered the highest continent on Earth, given the thickness of its ice shell of 4 km.

Indigenous inhabitants of the polar deserts of Antarctica - emperor penguins. They cannot fly, but they are excellent swimmers. They can dive to great depths and swim great distances, escaping from their enemies - seals.

The northern polar region of the Earth - the Arctic - got its name from the ancient Greek arcticos - northern. The southern, as it were, opposite polar region is Antarctica (anti - against). The Arctic occupies the island of Greenland, the islands of the Canadian Arctic Archipelago, as well as the islands and waters of the Arctic Ocean. This area is covered with snow and ice throughout the year. The owner of these places is considered to be a polar bear.

Tundra

Tundra is a treeless natural area with vegetation of mosses, lichens and creeping shrubs. Tundra is common in the subarctic climatic zone only in North America and Eurasia, which are characterized by harsh climatic conditions (little solar heat, low temperatures, short cold summers, low rainfall).

Moss moss lichen was called "reindeer moss" because it is the main food reindeer. Arctic foxes also live in the tundra, lemmings are small rodents. Among the sparse vegetation are found berry bushes: blueberries, lingonberries, blueberries, as well as dwarf trees: birch, willow.

Permafrost in the soil - characteristic of the tundra, as well as Siberian taiga phenomenon. It is worth starting to dig a hole, as at a depth of about 1 m there will be a frozen layer of earth several tens of meters thick. This phenomenon must be taken into account in the construction, industrial and agricultural development of the territory.

In the tundra, everything grows very slowly. It is with this that the need for careful attention to its nature is connected. For example, pastures damaged by deer are restored only after 15-20 years.

Altitudinal zonality

Unlike flat territories, climatic zones and natural zones in the mountains change according to the law of vertical zonality, i.e., from bottom to top. This is because 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 ones at an altitude of 2000 m. fir and juniper. In winter, there is snow 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. Approximately from a height of 4500 m, eternal snow and ice lie. The climatic conditions here are very harsh. Rare species of animals live in the mountains: mountain goat, chamois, argali, snow leopard.

Latitudinal zonality in the ocean

The world ocean occupies more than 2/3 of the planet's surface. Physical Properties And chemical composition 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 dissolve in water. Photosynthesis of algae occurs mainly in the upper layer of water (up to 100 m).

Marine organisms live mainly in the surface layer of water illuminated by the Sun. These are the smallest plant and animal organisms - plankton (bacteria, algae, smallest animals), various fish and marine mammals (dolphins, whales, seals, etc.), squids, sea ​​snakes and turtles.

On seabed there is life too. These are bottom algae, corals, crustaceans, molluscs. They are called benthos (from the Greek benthos - deep). The biomass of the World Ocean is 1000 times smaller than the biomass of the land of the Earth.

The distribution of life in oceans uneven 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 greatest amount of plankton develops in the waters of the temperate zone in summer. The abundance of plankton attracts fish here. The temperate zones of the Earth are the most fishy areas of the oceans. In the tropical zone, the amount of plankton again decreases due to the high salinity of the water and high temperatures.

Formation of natural areas

From today's topic, we have learned how diverse the natural complexes of our planet are. natural areas The lands are full of evergreen forests, endless steppes, various mountain ranges, hot and icy deserts.

Each corner of our planet is distinguished by its uniqueness, diverse climate, relief, flora and fauna, and therefore various natural zones are formed on the territories of each continent.

Let's try to figure out what natural zones are, how they formed, and what was the impetus for their formation.

Natural zones include such complexes that have similar soils, vegetation, wildlife and the similarity of the temperature regime. Natural zones got their names according to the type of vegetation, and bear such names as the taiga zone or deciduous forests etc.

Natural areas are diverse, due to the uneven redistribution of solar energy on the surface of the Earth. This is what lies main reason geographic heterogeneity.

After all, if we consider one of the climatic zones, we can see that those parts of the belt that are 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 the other - 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 excess 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 territories, while in the subtropics, an excess of moisture contributes to the formation of swamps.

So you learned that due to the difference in the amount of solar heat and moisture, various natural zones were formed.

Patterns of placement of natural zones

The natural zones of the Earth have clear patterns of their location, extending in a 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 deep into the mainland.

IN mountainous areas there is altitudinal zonality, which changes one zone for 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 the difference in vegetation and wildlife.

Features of the natural zones of the continents

Since the planet Earth has a spherical surface, the Sun also heats it unevenly. Those areas of the surface above which the Sun is high receive the most heat. And where the sun's rays only glide over the Earth, a more severe climate prevails.

And although vegetation and animals on different continents have similar features, they are influenced by climate, topography, geology and people. Therefore, it so happened historically that due to changes in the relief and climate on different continents There are also different types of plants and animals.

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. So, for example, polar bears can only be found in nature in the Arctic, and kangaroos in Australia. But in African and South American shrouds, similar species are found, although they have certain differences.

But human activity contributes to the changes that occur in the geographical shell, and under such influence, natural areas also change.

Questions and tasks for preparing for the exam

1. Make a diagram of the interaction of natural components in the natural complex and explain it.
2. How do the concepts of “natural complex”, “ geographical envelope”, “biosphere”, “natural zone”? Show with a diagram.
3. Name the zonal soil type for the tundra, taiga, zones of mixed and broad-leaved 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 does soil fertility depend on?
6. What types of plants and animals are characteristic of the tundra and why?
7. What organisms live on the surface of the oceans?
8. Which of the following animals can be found in the African savannah: rhinoceros, lion, giraffe, tiger, tapir, baboon, llama, hedgehog, zebra, hyena?
9. In what forests is it impossible to find out its age from a cut of a cut tree?
10. What measures, in your opinion, will help preserve the human habitat?

Maksakovskiy V.P., Petrova N.N., Physical and economic geography of the world. - M.: Iris-press, 2010. - 368 pp.: ill.

"Peoples of Eurasia" - Romance peoples are dark-haired, swarthy. Russian Ukrainians Belarusians. Frenchwoman. Oriental. On the territory of Eurasia live peoples belonging to different language families and groups. 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 blond hair and fair skin.

"Climatic features of Eurasia" - High average annual and summer temperatures. Temperature. Definition of climate types. Climatic zones and regions of Eurasia. The climate is mild. Arctic air. January temperature. You have learned to read. Temperature and winds in January. Climate charts. Relief. Climatic features Eurasia. The greatest amount of precipitation.

"Eurasia Geography Lesson" - To introduce students to the idea of ​​​​Eurasia. Explain the effect of size on natural features. Semenov-Tan-Shansky P.P. The most high mountain in the world Chomolungma - 8848 m. Geographical position of Eurasia. General information about Eurasia. Name the names of travelers and explorers of the continent. Obruchev V.A.

"Nature of Eurasia" - Square. Minerals. Inland waters. natural areas. Climate. Eurasia. Relief. organic world. Geographical position. Mainland records.

"Lakes of Eurasia" - The correct answer. -Tectonic lakes in faults have a great depth, an elongated shape. Lake basin of glacial origin. Such lakes are lakes - seas: Caspian and Aral. Internal waters of Eurasia. Determination of the types of lake basins in Eurasia. Lake basin of tectonic origin.

"Natural zones of the temperate zone of Eurasia" - Flora. The flora of the taiga. Animal world of the taiga. Fauna: very similar to the fauna of the taiga... Animal world. In Eurasia, forest-steppes stretch 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), beech, linden, chestnut, ash, etc. are typical.

For tropical wet evergreens, or as they are sometimes called, rainforests are characterized by a three-tier structure of the tree canopy. The tiers are poorly demarcated. The upper tier consists of giant trees 45 m or more in height, 2-2.5 m in diameter. The middle tier is represented by trees about 30 m high with a trunk diameter of up to 90 cm. Smaller, exceptionally shade-tolerant trees grow in the third tier. There are many palm trees in these forests. The main area of ​​\u200b\u200btheir growth is the Amazon basin. Here they occupy vast areas, including, in addition to the northern part of Brazil, French Guiana, Suriname, Guyana, southern part Venezuela, western and southern Colombia, Ecuador and eastern Peru. In addition, this type of forest is found in Brazil in a narrow strip along the Atlantic coast between 5 and 30°S. Similar evergreen forests also grow along the Pacific coast from the border of Panama to Guayaquil in Ecuador. Here are concentrated all types of the genus Svitania (or mahogany), rubber-bearing genus Hevea, Brazil nut (Bertolletia excelsa) and many other valuable species.

Tropical variable-humid deciduous forests distributed in the southeast of Brazil and in the south of Paraguay. Tree species in them are relatively small in height, but often with thick trunks. Legumes are widely represented in the forests. Subtropical deciduous broadleaf forests most common in the south of Brazil and Parguay, in the west of Uruguay and in the north of Argentina along the Parana and Uruguay rivers. montane evergreen forests cover the slopes of the Andes from Venezuela to central Bolivia. These forests are characterized by thin-stemmed low trees forming dense stands. Due to the fact that these forests occupy steep slopes and are far from populated areas, they are exploited very little.

Araucaria forests located in two isolated regions. Brazilian Araucaria (Araucaria brasiliana) is predominant in the states of Parana, Santa Catarina and Rio Grande do Sul in Brazil, as well as in Uruguay, Eastern Paraguay and Argentina. A less significant massif is formed by forests of Chilean araucaria (A. araucana) found in the Andes at 40°S. in the altitude range from 500 to 3000 m above sea level. seas. These forests are characterized by hardwood species, among which the most important is embuya (Phoebe porosa). In the undergrowth of the araucaria forests, the mate shrub, or Paraguayan tea (Ilex paraguariensis), is also widespread on plantations.

Low growing xerophilous forests distributed in the east of Brazil, in the northern part of Argentina and in the western part of Paraguay. The most important tree species in these forests is the red querbacho (Schinopsis sp.), from which tannin is obtained. mangrove forests occupy the coastal strip of the Atlantic part of South America. These forests are dominated by red mangrove (Rhizophora mangle), forming pure stands or mixed with Avicenna (Avicennia marina) and Conocarpus erecta.

In addition to timber harvesting, rubber, food products (seeds, nuts, fruits, beans, leaves, etc.), oils, medicinal substances, tannins, resins, including chicle (Zschokkea lascescens), raw materials for the production of chewing gum.

Venezuela. Evergreen (on laterites) and deciduous forests grow on the slopes of the spurs of the Andes and the Guiana Highlands. On the territory of the low llanos, tall-grass savannah with groves of the Mauritian palm is widespread, and in the high llanos, xerophilic light forests and shrub communities are common. Mangroves stretch around Lake Maracaibo, giving way to undersized xerophilous, and to the south - evergreen tropical forests. In the south of the country, in the upper reaches of the river. Orinoco and its right tributaries grow moist evergreen tropical forests, almost inaccessible to exploitation. Of the tree species of economic value, mahogany, roble-colorado, baku, balsa, espave (Anacardium spp.), angelino (Ocotea caracasana), oleo-vermelho (Myroxylon balsamum), pao-roxo, guaiacum, tabebuya (Tabebuia pentaphylla ), ceiba (Ceiba pentandra), almasigo (Bursera simaruba), kurbaril (Hymenaea courbaril), adobe (Samanea saman), etc.

Landscape in the center of Venezuela

Colombia. By natural conditions two areas are distinguished: the eastern (plain) and the western (mountainous, where the Colombian Andes stretch). The first region is largely occupied by humid evergreen forests of the Magdalena basins and the left tributaries of the Amazon. In the north of the Guajira peninsula and west of it, along the coast caribbean, low-growing xerophilous forests extend, in which divi-divi beans (Libidibia coriaria) are harvested for tannin. Guaiac wood (Guaiacum spp.) is also harvested here - this is one of the hardest and heaviest woods in the world, used for the manufacture of rollers, blocks and other engineering products.

Mangrove forests stretch along the Pacific and Caribbean coasts. In evergreen tropical hylaea, especially in the lower part of the Magdalena basin and along the mouth of the river. Atrato, cativo wood (Prioria copaifera) is harvested for export, as well as baku, or "Colombian mahogany" (Cariniana spp.), caoba, or real mahogany (Swietenia macrophylla), roble colorado, or Panamanian mahogany (Platymiscium spp.) , purple tree, or paoroxo (Peltogyne spp.), etc. In the eastern part of the elevated plain along the tributaries of the Orinoco, savanna-llanos with rare trees and gallery forests with Mauritian palm (Mauricia sp.) are common. The forests of the Andean mountain regions are characterized by a peculiar altitudinal zonality. On lower parts leeward slopes and on the northern ridges, deciduous forests or thorny shrubs are common. In the adjacent part of the mountains (from 1000 to 2000 m) mountain broad-leaved evergreen forests grow with tree ferns, wax palm (Copernicia cerifera), cinchona, coca (Erythroxylon coca) and various orchids. Cultivated crops include cocoa and coffee trees. At an altitude of 2000 to 3200 m, humid alpine hylaea, in which there are many species of evergreen oaks, shrubs and bamboos.

Ecuador. The country has three natural areas: 1) watershed plateau with wet equatorial forests - hylaea, or selva(together with the upper reaches of the left tributaries of the Amazon); 2) Andes ranges; 3) the Pacific forest-savannah plain and the western slopes of the Andes. The evergreen tropical forests of the first region are poorly studied and difficult to access. On the western slopes of the Andes, up to a height of 3000 m, evergreen mountain broad-leaved forests (hylaea) grow, largely disturbed by slash-and-burn agriculture. They produce a lot of cinchona bark, as well as balsa, kapok from the fruits of ceiba, leaves of the toquilla palm, or hipihapa (Carludovica palmata), used to make Panama hats. Tagua palm (Phytelephas spp.) is also found here, the hard endosperm of the fruits of which is used to produce buttons, and various rubber plants. The lower part of the western slopes is characterized by evergreen tropical forests. In the river valley Guayas is intensively harvested for export balsa wood.

Guyana, Suriname, Guiana. The forests of these countries, located along the coast of the Atlantic Ocean and along the Guiana Highlands, are evergreen tropical with a number of valuable species. The green tree, or betabaro (Ocotea rodiaei), which is exported in Guyana and Suriname, stands out in particular. Apomate (Tabebuia pentaphylla), canalette (Cordia spp.), pekia (Caryocar spp.), espave (Anacardium spp.), habillo (Hura crepitans), wallaba (Eperua spp.), carap (Carapa guianensis), virola are no less valuable. (Virola spp.), Simaruba (Simaruba spp.), etc.

Brazil. There are more than 7 thousand species of woody and shrubby plants in the flora, of which there are over 4.5 thousand species in the Amazonian selva. High bertholecia grow (giving brazil nuts, etc.), various rubber plants, including brazilian hevea, which has become a valuable plantation crop in many countries of South Asia and Africa, laurels, ficuses, brazilian mahogany, or "pau brazil", which gave the name to the country (Caesalpinia echinata), chocolate tree, or cocoa, mahogany, jacaranda, or rosewood, oleo vermelho, roble colorado and sapukaya, or paradise nut (Lecythis ustata), and many others. In the east, the selva turns into light palm forests, among which we note the valuable babasu palm (Orbignya speciosa), which has highly nutritious nuts. South Amazonian selva landscapes of tropical dry woodlands are common - caatinga, in which trees grow that shed their leaves in the dry season and accumulate moisture in the rainy season, for example, the bottle tree (Cavanillesia arborea), thorny shrubs, cacti (Cereus squamulosus). In the floodplains, there is a carnauba, or wax, palm (Copernicia cerifera), from the leaves of which wax is collected, which is used in technology. From the south, subtropical deciduous forests adjoin forests dominated by palms and savannahs. In the southeast of the country, along the Brazilian Highlands, there are araucaria forests from the Brazilian, or Paran, araucaria (pinheiro, or "Brazilian pine"). Together with it, embuya, tabebuya, cordia grow, and in the undergrowth of yerbamate, Paraguayan tea is prepared from its leaves. Araucaria forests are involved in intensive exploitation.

Along the Atlantic coast and at the mouth of the Amazon, mangrove forests grow, dominated by red mangrove with an admixture of black mangrove (Avicennia marina) and white mangrove (Conocarpus erecta). Tannin is extracted from the bark of these trees.

Argentina. There are several natural regions. The east is dominated by evergreen forests, in which more than 100 species of trees of great economic importance grow. Among them are cabreuva (Myrocarpus frondosus), kanzherana (Cabralea oblongifolia), Brazilian araucaria, tabebuya, etc. In the west, evergreen ice grows along the slopes of the Andes at an altitude of 2000-2500 m above sea level. seas. Palo blanco (Calycophyllum multiflorum), cedro salteno (Cedrela balansae), roble cryolo (Amburana cearensis), nogal cryolo (Juglans australis), tarco (Jacaranda mimosifolia), type blanco (Tipuana tipu), etc. In the south, along the slopes of the Andes, subantarctic vegetation extends, among which several species of southern beech, alerce, "Cordillera cypress" (Austrocedrus chilensis), etc., are distinguished. palosanto (Bulnesia sarmientoi), guaiacan (Caesalpinia paraguarensis), and others. To the south, along the eastern slopes of the Andes, there are xerophilic broad-leaved forests of the temperate zone with algarrobo, acacias (Acacia caven), carcass (Celtis spinosa), quebracho-blanco.

Paraguay. Forest cover 51%. In the east of the country, mixed tropical evergreen and deciduous forests are common, turning in the west (in the Gran Chaco region) into woodlands and savannahs. The main tree species is quebracho blanco (Aspidosperma quebracho-blanco).

Uruguay. Forests occupy a small part common territory countries and are located in the lower Rio Negro and in the valley of the river. Uruguay. The forest cover of the country is 3%. Large areas are beginning to be occupied by artificial plantations - pines on coastal dunes and eucalyptus plantations.

Published according to the monograph: A.D. Bukshtynov, B.I. Groshev, G.V. Krylov. Forests (Nature of the world). M.: Thought, 1981. 316 p.