Description and features of the natural forest-steppe zone. Forest-steppe natural zone: characteristics, geographical location of the forest-steppe, climate and soils, map

The natural forest-steppe zone is a natural belt of vegetation in Eurasia, characterized by the alternation of forests (mostly deciduous) with steppe flora and fauna. It forms transitional ecoregions between temperate grasslands and temperate broadleaf and mixed forests.

As you move south, the forest-steppe has fewer trees and more steppe zones, more hot climate and less precipitation. In a northerly direction, the picture changes to reverse side, the forest-steppe gradually turns into forest, the climate is colder and more high level precipitation.

Natural conditions

The forest-steppe has a number of favorable natural conditions that allow it to be used for human needs. Vast areas of this natural area were plowed for agricultural purposes. Below are the main factors that shape natural conditions forest-steppe, ranging from geographical location and climate to the diversity of flora and fauna.

Geographical position

Map of natural areas of the world

Legend: - Forest-steppe and steppe.

In Europe and Asia, natural area forest-steppe extends in a continuous strip from the west of the Carpathian Mountains to east direction, through Ukraine and part of Russia to the Altai Mountains.

Isolated islands of forest-steppe are found in the vast expanses of the Tiso-Danube Lowland, in the intermountain depressions of southern Siberia, Northern Kazakhstan, Mongolia, Far East and some areas of the Manchurian Plain of Northeast China.

The forest-steppe of North America extends from southern Canada, through the Great Plains to 38° latitude in the United States.

Relief and soils

The relief of the forest-steppe is predominantly flat with minor elevation changes, a slight slope and ravines.

The soil cover of the forest-steppe natural zone is very diverse. The main types are gray forest soils with signs of podzolization, leached and podzolized chernozems, meadow-chernozem and chernozem-like prairie soils. Alkaline and saline soils are widespread in regions with continental climate(in western Siberia, Great Plains).

Forest-steppe soils are characterized by a high concentration of humus, slow mineralization of plant remains and a stable structure. They are very fertile and can therefore be intensively cultivated. Excessive plowing of land for agricultural purposes has caused soil degradation in many forest-steppe areas. Because of high speed evaporation, forest-steppe soil is subject to drying out within summer months, causing plants to wilt.

Climate

The forest-steppe is characterized by snowy, cool winters and relatively hot, humid summers. There are 100-130 kilocalories per 1 cm² of the earth's surface solar radiation per year (about 70% of which in warm months). Average temperatures in January range from -2 to -20° C. In some areas of Siberia frosts reach -35° C. Average temperatures in July vary between 18 and 25° C. Annual precipitation in the forest-steppe is about 400-1000 mm (high some of which occur in the summer).

Vegetable world

The natural vegetation of the natural forest-steppe zone consists of small forests alternating with areas of steppe meadows. In the European part of the forest-steppe, oak and linden predominate. In the western regions, the main species include ash and hornbeam; in Siberia, birch, pine and larch trees mainly grow; in northeast China, there are oaks and other broadleaf species trees. The forest-steppe of North America is characterized by such tree species as birch, aspen, oak and hazel.

Natural herbs, as a rule, remain only in national parks. They have a significant species diversity of turf grasses and weeds (about 70-80 species of ground vegetation per m2). Meadow grasses, fescue, reed grass and feather grass are common in North America. The annual increase in plant biomass is about 20 tons per hectare in wooded areas and about 13 tons per hectare in meadows.

Animal world

The typical forest fauna of the Eurasian forest-steppe includes squirrels, brown hares, and in some areas, moose. The large jerboa and spotted ground squirrel are steppe inhabitants found in the European part of the forest-steppe zone. Ground squirrels and hamsters are common in Siberia, and the North American forest-steppe is home to prairie dogs, mice, hares, woodchucks, and rattlesnakes.

Natural resources of the forest-steppe

The forest-steppe is a rich ecoregion of the world. It is famous for its fertile soils, diversity, many rivers, lakes and reserves groundwater, as well as significant deposits such as oil, gas, coal, peat, salt, etc.

Forest-steppe natural zone table

Geographical position Relief and soils
Climate Flora and fauna Natural resources
On the territory of Eurasia it extends in a continuous strip from the Carpathian to the Altai mountains.

In North America, range from Southern Canada, through the Great Plains to 38° latitude in the USA.

 The terrain is predominantly flat with minor elevation changes, a slight slope and ravines.

The main soil types include gray forest and chernozem soils.

 Snowy, cool winters and relatively hot, humid summers. Average temperatures in January: from -2 to -20° C; July: from 18 to 25° C. Annual precipitation: 400-1000 mm. Animals

squirrels, hares, moose, ground squirrels, hamsters, mice, prairie dogs, woodchucks, snakes and lizards.

Plants

oak, linden, birch, pine, larch, aspen, hazel, grass and sedge.

 oil, gas, coal, peat, salt, fertile soils, reserves fresh water, as well as the biological diversity of flora and fauna.

Meaning for humans

The natural forest-steppe zone is important for humans. Vast areas were allocated to arable land where various crops were grown. Some species of forest-steppe animals and plants serve as a valuable source of food. The rivers and lakes of the forest-steppe zone are home to important commercial species fish Large reserves of mineral resources are used for industrial and national economic purposes.

Environmental threats

As a result of intensive plowing of forest-steppe lands and cutting down trees, they are subject to water and wind erosion. The condition of soils is deteriorating, and the diversity of flora and fauna is decreasing. Mining produces additional anthropogenic pressure on the forest-steppe environment, polluting it.

Protection of the natural forest-steppe zone

Programs for the protection of the forest-steppe zone should include a set of the following measures:

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Forest-steppe is a transition zone located between the forest and steppe zones.
The forest-steppe has both a moderately humid forest and a semi-arid climate. The average temperature in July is +19 °С…+22 °С. The annual precipitation is 400-600 mm. The frost-free period lasts 165 days in the west and 105-120 days in the east of the zone.

The forest-steppe vegetation is represented by a combination of forest areas and grassy steppe. Prevail deciduous forests with well-developed grass cover, growing on gray forest soils. On sands along rivers, and sometimes in interfluves, they are common pine forests. The most fertile soils in the world—chernozems—are formed under the mixed-grass steppe areas.
The forests of the forest-steppe zone are inhabited by elk, roe deer, pine marten etc. Gophers and mouse-like rodents in the south of the forest-steppe zone become so numerous that they turn into dangerous pests fields.
The forest-steppe is the northernmost natural zone, in which there is a need to take special measures to combat droughts and hot winds (hot and dry winds). The main ones are snow retention and planting shelterbelts. Forest-steppe is one of the most developed natural zones, highly modified economic activity person.

Steppe - natural area temperate zone Northern Hemisphere and subtropical zone Southern Hemisphere, stretching between forest-steppe and semi-desert. In Eurasia, the steppes stretch almost continuously from the Black Sea in the west to northeastern China in the east, North America occupy vast expanses of the Great Plains and western part Central Plains, and in South America — southern part La Plata lowland.

The average July temperature is within the zone +21…+23 °C. There is little precipitation, 350-400 mm per year, and evaporation significantly exceeds the amount of precipitation. The severity of winter increases away from the oceans.

Due to the lack of moisture, the steppes are characterized by treelessness and a predominance of herbaceous, mainly cereal, vegetation. Where the humidity is higher, tall grass steppes are formed. In North America they are called prairies, in South America - pampas, and in Russia - feather grass steppes. Where the climate becomes drier, feather grass is replaced by fescue. By mid-summer, the steppe completely burns out, acquiring a dull brownish tint. The fauna of the steppe zone is currently represented mainly by rodents. Small rodents predominate: gophers, marmots, jerboas, hamsters, voles.
The soils of tall grass steppes - chernozems - are considered the best in terms of fertility. In dry low-grass steppes, slightly less fertile soils—chestnut—are formed.

Currently, 50-70% of the steppe lands are plowed. Corn, wheat, sunflowers, and millet are grown here. Fruit and melon growing is developed, and vegetable growing is developed in the floodplains. The remaining steppe vegetation is used as pasture. Active plowing leads to soil erosion.

Forest-steppe and steppe

Geographical position

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 cities such as Kursk and Kazan. To the west and east of this strip, the continuous extension of the forest-steppe is disrupted by the influence of the mountains.
Certain areas of forest-steppes are located within the Middle Danube Plain and a number of intermountain basins Southern Siberia, Northern Kazakhstan and the Far East.

The climate of the forest-steppe is usually temperate continental. Annual precipitation is 600 mm per year. Sometimes evaporation is almost equal to precipitation. Winter in the forest-steppe is moderately mild
Summer in the forest-steppe is often hot and dry, especially in the south of the forest-steppe, but on average it is still less hot than in the steppe zone. Sometimes it can be cold and rainy, but this is rare.

The soils under forest-steppes are gray forest soils (under forest areas) and chernozems (under steppe areas).

Vegetation

Characteristically complex alternation on the watersheds of picturesque massifs deciduous forests with areas of mixed-grass steppes. In Europe and the European part of Russia, light broad-leaved forests of oak, linden, chestnut, ash, etc. are typical. There are also grove forests. Island small-leaved birch-aspen trees are common in Siberia.

Animal world

In the forest-steppe there are no special species of animals unique to it. Typically steppe species (gopher, marmot, bustard, etc.) combine and coexist here with typically forest representatives (squirrel, marten, elk) and the like. Species composition changes from steppe to forest when moving north.

Human activity

The nature of the forest-steppe zone has been greatly changed by human economic activity. In Europe, the plowed area reaches 80%.
Since the soils here are fertile, wheat, corn, sunflowers, sugar beets and other crops are grown in this area.

Forest-steppe is a natural zone that is located between forests and steppe. The forest-steppe zone stretches continuously across the East European Plain and West Siberian Plain, and also through Southern Urals. Individual areas of forest-steppe are located within the Middle Danube Plain, Northern Kazakhstan, Mongolia, the Far East, and also occupy most of the Songliao Plain, located in northeast China.

Characteristics of the forest-steppe natural zone.

Climate. Unlike the taiga, as well as coniferous-deciduous forests, the forest-steppe has a relatively warm and sometimes even dry climate. Summer temperatures and the duration of the warm season are increasing. During the period with temperatures greater than 10°, the sum of average daily temperatures increased to 1800-2000° in the east of the zone and 2600-2800° in the southwest. The frost-free period, as a rule, lasts 105-120 days in the east and 165 days in the west. The absolute maximum in the forest-steppe depends on latitude and is usually around 40 °C in the shade. But heat in this natural zone occurs noticeably less often than extreme cold, which is the opposite in comparison with the steppe zone.

The dominant forest-forming species within the European forest-steppe is oak. And the greatest species diversity is found in the western part of the forest-steppe, which is facilitated by warm and humid climate. In the territory Western Siberia forests are often found near the depressions of flat watersheds and are formed by birch groves - kolkas. Steppe zone It is dominated by colorful forbs, and most of them are rhizomatous (meadow bluegrass, reed grass, steppe timothy, etc.).

As for the fauna, within the forest-steppe there are no species of animals unique to it. As a rule, steppe species (marmot, gopher, bustard) are combined here with typical representatives of the forest zone (squirrel, elk, marten). Animal species change from the steppe to the forest zone when moving north.

Soils forest-steppe zone are determined under conditions of variable moisture on forests and forest-like loams. Gray forest soils predominate on the East European Plain, while under the steppes there are podzolized, leached and ordinary chernozems.

The forest-steppe zone is a transition zone from forest to steppe. The ratio of heat and moisture in the forest-steppe is close to optimal, but the moisture is unstable, which led to the formation various types vegetation. In the forest-steppe zone, broad-leaved (oak) and small-leaved forests alternate on gray forest soils with forb steppes on chernozems. The soils of the forest-steppe zone are fertile. The main enemies of these soils are water and wind erosion. Droughts are frequent, and dry winds blow away the top fertile layer of soil. With the rainfall pattern and the rapid melting of snow, the humus horizon is also washed away and ravines form in the fields. To preserve arable land, it is necessary to combat water and wind erosion; one of the types of such control is planting forest belts. That's why modern look forest-steppe is a combination of agricultural landscapes with artificial forest plantations.

The Russian steppe zone is small in area. It occupies the south of the European part of the country and Western Siberia. Using the example of steppes, it is especially clear that it is impossible to judge moisture content only by the amount of precipitation. There is little precipitation here - from 300 to 450 mm, approximately the same as in the tundra zone. But the tundra is swampy and characterized by excessive moisture. In the steppes, there is a lack of moisture. The humidification coefficient in the steppe zone varies from 0.6-0.8 northern border up to 0.3 in the south.

High summer temperatures ( average temperature July is + 21-23 SS) and strong winds cause significant evaporation from the surface. Therefore, droughts and hot winds periodically occur here. dust storms causing great damage to vegetation. Since there is little precipitation, and evaporation is 2 times higher than the amount of precipitation, there are no conditions for washing out humus into the depths of the soil horizons. In the steppe, chernozems with a very dark color and a granular structure are common. The thickness of the humus horizon in them is 50-100 cm. Chernozems are the most fertile soils in our country. In the southern strip of steppes, dark chestnut soils are common; they are less fertile and are often saline.

What did the steppe look like before development began? Nowadays, areas of virgin steppe can only be seen in the reserve. But the name of the zone remained unchanged, since the steppe is not only vegetation, but also the entire landscape with a relatively dry climate, a special water regime, with its own set of soils. Main sign the steppe - both pristine and cultivated - treelessness, limitless open spaces.

The most typical steppe landscapes are flat plains, often dissected by a network of ravines and gullies. Before the beginning of their intensive agricultural development, they were covered with grassy steppe vegetation with a predominance of feather grass. The feather grass, agitated by the winds, really resembles sea ​​waves, which is why the steppe is often called a sea of ​​grassy vegetation. Even in small areas, you can observe how the color of the steppe changes from month to month depending on the flowering of lumbago, cinquefoil or primrose. Steppe grasses die off annually, forming litter that replenishes the humus layer.

The steppe is dominated by various small rodents - ground squirrels, marmots, jerboas, hamsters, voles. Back in the 19th century. herds of wild horses - tarpans and wild bulls- tours, later completely destroyed. In modern steppes it is becoming increasingly rare to see foxes, badgers and large steppe birds- bustard, little bustard. The steppe vegetation is also changing greatly - some species are disappearing, others are being greatly reduced. The steppe is losing its main grasses - feather grass and fescue.

The nature of the steppe and forest-steppe zones has been greatly changed by human economic activity. In the west, the zone's plowed area reaches 80%. The steppe is the main grain granary of the country. Wheat, corn, sunflowers and other important crops are grown here.

One of the forms of disturbance of the ecological balance in the steppe zone was overgrazing of livestock. Plant species that are not eaten by livestock are replacing traditional steppe grasses. Livestock tramples vegetation, and wind erosion of the soil increases. As a result, the vast steppe spaces in Kalmykia became by the end of the 90s. of our century in the semi-desert.

Desert and semi-desert zone. Semi-deserts and deserts of Russia are located in the Caspian region and Eastern Ciscaucasia. The semi-desert is treeless, like the steppe. It is characterized by transitional features from steppes to deserts. The climate here is sharply continental. There is little precipitation in this zone - 50 mm per year. Evaporation is 4-7 times higher than precipitation. Together with evaporated moisture, they move to the upper soil horizons. soluble substances, which leads to their salinization. Soils are chestnut. These soils are dominated by wormwood-grass vegetation. Sparse, sparse vegetation is sensitive to the proximity of groundwater.

The main reason for the formation of deserts (as well as other zones) is climate. Deserts are characterized by an even greater moisture deficit (less than 150 mm per year) and higher average July temperatures of -25 ° C. The humidification coefficient in the desert zone does not exceed 0.1-0.3



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