Kazakhstan is the largest landlocked state in the world located in Central Asia. It is dominated by a large flat steppe (grassy lands), stretching from the Volga in the west to the Altai mountains in the east and from the plains Western Siberia in the northern part to the deserts and oases of Central Asia in the south. Various climatic and natural zones of the country allow a wide range of species and structural diversity of the flora of Kazakhstan.
Characteristic
Kazakhstan has a very clear division into soil and vegetation zones. In the north, beyond 52 ° latitude, the strip of black soils occupies 9% of the country's total land area. This soil is comparatively thin, practically unsuitable for Agriculture without irrigation. The same applies to the southern belt of dark chestnut-brown soil, on which a virgin land reclamation program was carried out.
In many ways, most of Kazakhstan is poor in fertile soil. The overall picture is dominated by gravel, sands and loams, while deserts, semi-deserts and steppes occupy 84% of the country's territory. However, the vegetation has adapted well to the harsh conditions.
Saksaul ( Haloxylon) is a shrub or woody plant with moisture-absorbing needle-like leaves and long, deep roots that thrive in the desert. It grows slowly and produces extremely hard and resistant wood. If the plant gets too dry, it sheds its leaves. Unfortunately, this wood is systematically plundered to make barbecue, and if the state does not intervene, saxaul will soon be found only in nature reserves.
Karagach (ligature) - quite hardy deciduous tree, with 20 meter pile-like roots and is therefore planted as a windbreak in erosion-sensitive areas.
Tamarisk is a genus of shrubs and woody plants with beautiful colors that are well adapted to life in scarce soils, and their charming flowers and berries that adorn the tan desert landscape.
Bulbous plants wait out the harsh winter of the steppe and come to life in April-May, when melt water penetrates the soil. During this short period, apart from small steppe tulips, one can see wonderful cistanches, feruls, eremurus, graceful lilies, crocuses and anemones; even garlic has attractive flowers. Many cultural garden plants are descendants of local flora - steppes and protected mountain valleys of Kazakhstan.
At the end of May, stripes of common poppy cover the vast steppe like a purple carpet. Only a month later, when everything dries up, the time for more modest plants comes. Many unassuming types of drought-resistant and hardy grasses, sedges and shrubs give the steppe its characteristic appearance.
In the foothills, grassy steppes give way to wormwood meadows. The sheep grazing here are known for their exceptionally aromatic flavor, and these herbaceous areas are popular with many other herbivores. On the numerous slopes of the highlands, the elegant spruce of the Tien Shan grows like an arrow, and the valleys are covered with a juniper forest. The wild apple, pear, cherry and apricot trees that grow in the lower mountains are relatives of the usual fruit trees... On mountain meadows under glaciers, marigolds, primrose, edelweiss and gentian grow abundantly. In the alpine zone of the Tien Shan, it contains twice more species plants than in the Alps.
A wide variety of plants thrive in the fertile wetlands of the lower river valleys. Torgai forests are bordered by rivers when they flow through semi-deserts and steppes. In some places, primeval millennial forests have been preserved. The most amazing is the forest located downstream of the Charyn River, where mixed willow and ash have been preserved since the last ice age. It is also worth noting the tall pine forests in Ertis.
The vegetation of Kazakhstan has 5700 plant species, of which 700 are endemic, 2000 species of seaweed and 485 species of lichens. As an example, below is a list of some native flora species in the country:
Shrub cherry ( Prunus fruticosa)
Shrub cherry, or steppe cherry - kind shrub plants originally from Kazakhstan, Belarus, Germany, Italy, Serbia, Romania, Western Siberia, Xinjiang, China, Ukraine, Poland and the Czech Republic. Grows best on loamy soils and requires a lot sunlight... The plant has a dark brown bark, and its leaves change from dark green to yellow during the fall. The flowers are white in May and the red fruits ripen in early August. Steppe cherry grows on the outskirts of the forest, forming thickets. The fruits of the plant are light dark red in color with a sour taste.
Iris Ludwig ( Iris ludwigii)
This plant mainly grows in East Kazakhstan and is easy to spot due to its crowding. Flowers range from purple to blue. Iris Ludwig grows up to 30 centimeters on soils with good drainage and open areas to get sunshine, which abound in places for grazing animals and agricultural activities. In late August - early September, the plant produces seed capsules.
Nedzvetskia Semirechenskaya ( Niedzwedzkia semiretschenskia)
This plant was named after the Russian botanist Vladislav Nedzvetsky. It grows on dry and rocky slopes. At Nedzvetskia purple flowers that appear between late April and August. Found in the Altai Mountains of Kazakhstan, Siberia, Russia and Central Asia... The preferred habitat of the plant is steppes, meadows, gravelly slopes and thickets of feather grass. Nedzvetskia Semirechenskaya is included in the IUCN Red Book as an endangered species. The main threats to the plant are overgrazing and other agricultural activities.
Starfruit chastukh ( Damaceium alisma)
The chasticus starfar is a plant of marshlands that grows in Kazakhstan, Spain, Portugal, Great Britain, Russia and France. Grows favorably in swamps and ponds, where it grows up to half a meter in height. Flowers appear from June to August. According to the IUCN Red List, the species is classified as Vulnerable. Plant populations are highly fermented and continue to decline due to loss of habitat, decrease in growing area due to pasture and stabilization of water levels. There is no evidence of a reduction in negative factors causing a decrease in the plant's population, and soon the Aiticus starfruit may become eligible for an endangered category, since 50% of its range and previous population size have been lost.
Madder bedstraw ( Galium rubioides)
This species is found in Kazakhstan, Central Asia and Europe. The plant prefers moist areas such as swamps and streams. It has green, needle-shaped leaves and flowers can be green, yellow, or white. The madder bedstraw is grown for its pleasant aroma and is widely used in the perfumery and beverage industry. The plant grows up to 100 cm in height with wide leaves, the length of which can reach 15-20 cm. Fruits and roots are reddish.
Late tulip ( Tulipa tarda)
Late tulip - perennial with green leaves and yellow flowers. This species is native to Kazakhstan and other countries of Central Asia and grows in rocky areas. Blooms in April and May. It grows from a bulb and has a leather tunic. The flowers are yellow with white tips, and the stamens and pistils are yellowish.
Kazakhstan is a country with a beautiful environment but most of its native plants are endangered due to risks such as grazing and loss of habitat from human activities. Best method conservation of local flora - priority plant protection with high degree risk of extinction.
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Many years ago, large tracts of land were occupied by the endless steppe or wild field. However, unusually fertile land typical for the steppe zone, steel the main reason her plowing and now this natural area in its original form can be found only on the territory of reserves and national parks. Let's take a closer look at what the plants and animals of the steppe are.
general characteristics
In the steppe zone, a flat relief with a complete absence of trees prevails. A thick sod layer formed as a result of a strong plexus of rhizomes of steppe plants, a lack of moisture and long dry periods are unfavorable factors for the germination of tree seeds.
For this reason, the flora of the steppes is represented by all kinds of herbs, bulbous plants and rare shrubs.
A typical representative of the steppe flora is feather grass. It is a perennial herb with a short rhizome and long narrow leaves that look like a wire. The main enemy of feather grass, like all steppe plants, is uncontrolled grazing, in which the grass is mercilessly trampled down.
Rice. 1. Feather grass.
Per long years evolution, all steppe plants were able to adapt to the conditions of the arid natural zone.
Their features include:
- Small narrow leaves- to reduce the surface of moisture evaporation. Some plant species are able to curl leaves during dry periods, so as not to waste precious moisture.
- Foliage color - grayish, sandy, gray-green. It is almost impossible to meet plants with bright green leaves in the steppe.
- Many plants have branched root system, with which they extract moisture from the earth.
- Steppe grasses can tolerate heat and long dry periods very well.
On the banks of the rivers flowing in the steppe areas, you can find small trees and shrubs: willow, wild grapes, hawthorn. In places with saline soil, special plants grow that can survive in such difficult conditions: sveda, saline wormwood, saltwort. Among the animals of the steppe, insects and rodents are distinguished by the greatest variety of species.
Rice. 2. Soleros.
Steppe plants in spring
Always low-key most of the year in early spring the steppe is literally transforming before our eyes. Thanks to the spring rains, the earth is covered with a variegated carpet of various flowering plants: wild tulips, daffodils, hyacinths, poppies, crocuses.
TOP-4 articleswho read along with this
Steppe flowers differ from their domesticated counterparts in much more modest sizes and several unusual shapes... A typical example is the Schrenck tulip - an unusually colorful steppe flower, listed in the Red Book. Collecting plants, digging out bulbs, and selling bouquets of these flowers and their bulbs are under the strictest prohibition.
Rice. 3. Schrenck's tulip.
Before the onset of heat, steppe plants have time to bloom and form seeds, store the necessary nutrients in the tubers, which will allow them to bloom next year.
Steppe zone
Steppe is a territory, the zonal vegetation of which is made up of communities of herbaceous xerophytes. The steppes stretch in a wide strip along the European and Asian parts of Russia from west to east to the river. Obi. IN Eastern Siberia steppes are found in separate spots. Steppe plants have adapted to life in arid conditions. Natural steppes remained only in reserves and reserves, the rest of the steppe land was plowed up for agricultural crops. Steppe soils - chernozems different types.
The steppes have a continental type of climate with hot dry summers and cold winter with a stable snow cover. The amount of precipitation (300 - 500 mm) is less than the amount of evaporation, therefore, in the steppes, plants are in conditions of a lack of moisture.
The maximum precipitation in the form of showers occurs in the middle of summer, during the heat wave. Plants do not have time to absorb moisture, and it evaporates quickly. The evaporation of water is also accelerated by the drying summer winds, which blow almost constantly in the steppes. Sometimes dry winds blow - drying, hot winds.
Steppe plants are herbaceous xerophytes, all of them are quite drought-resistant and tolerate a lack of moisture well. These are mainly dense bush cereals, primarily species of the genus feather grass (Stipa), fescue (Festuca), thin-legged (Koeleria)... Some legumes grow in the steppes, such as types of clover (Trifoliuni), sainfoin (Onobrychis), astragalus (Astragalus), tumbleweed, or kermek (Statice, rice. 252), wormwood (Artemisia, see fig. 226), etc.
The steppe is characterized by steppe ephemeroids that bloom in early spring and cover the steppe with a multi-colored carpet; by summer, the aboveground part dies off, and the underground living part prepares for flowering next year. Ephemeroid plants include bulbous bluegrass (Poa bulbosa), types of tulips (Tulipa), bows (Allium) and etc.
In addition to perennial ephemeroids, ephemerals are also common in the steppes - annual plants, all life cycle which goes away within a few weeks. These are types of grits (Draba),
bedbug (Lepidium), sickle hornhead (Ceratocephalafalcata) and etc.
In the steppes, as a rule, on the border with the forest zone, shrubs can also be seen: blackthorn, or wild plum (Prunus spinosa), wild almond, or bean (Amygdalus daddy), types of spirea (Spiraea), caragana (Caragana).
When moving from north to south in the steppes of the European part, the following regularities are observed: 1) the grass stand is increasingly thinned out; 2) the colorfulness of the steppes is decreasing, the number of dicotyledons in the floristic list is decreasing; 3) perennials predominate in the north, the role of annuals increases in the south and the number of narrow-leaved grasses increases; 4) takes turns whole line feather grass: from Stipa joannis up north to S. ucrainica on South; 5) the species composition is depleted (from 30 species in the north to 12 in the south).
All these features of the steppes made it possible to divide them into three subzones.
Northern, or meadow, steppes characterized by alternation of oak forests and steppe vegetation, and forest areas are found only along ravines and depressions, in conditions high humidity... Some geobotanists assign this subzone to the forest-steppe zone. The moisture content of meadow steppes is higher than in other subzones, the grass cover is higher (up to 1 m) with a predominance of forbs from meadowsweet (Filipendula), sage (Salvia) and others. Broad-leaved cereals grow here: pubescent oats (Helictotrichon pubescens), wheatgrass medium (Agropyron intermedium) and other narrow-leaved grasses - feather grass and fescue - quite a few. Meadow steppes are characterized by species diversity... So, in the Central Chernozem Reserve, there are up to 90 plant species per 1 m 2. During the growing season, there is a change in aspects (yellow, white, blue, blue, etc.).
Subzone of forb-fescue-feather grass steppes characterized by an increase in the role of narrow-leaved turf grasses and a greater drought resistance of plants. Among the grasses here you can find prickly zopnik (Phlomispungens), drooping sage (Salvia nutans) and etc.
Fescue-feather grass steppes- the southernmost ones and are distinguished by a very sparse and low grass stand (up to 40 cm). Narrow-leaved turf grasses dominate here - fescue, Lessing feather grass (Stipa lessingiana) ", annual ephemera; some ephemeroids; of life forms prevail "tumbleweed" (swing paniculata - Gypsophila paniculata)... The species composition of the herbage is poor (no more than 15 species per 1 m 2).
Siberian steppes have many similarities with European ones. Behind the Urals, due to the much less dissected relief, the steppes in the Asian part of the country stretch in a continuous strip to the river. Obi. On the vast depressions of Siberia, a large role among the steppes
"Zaimishcha" play - grassy swamps on solonetzes and saline soils, where steppe species are combined with plants of more humid habitats. Floristically, the Siberian steppes are poorer than the European ones, and in the extreme east of the steppe zone, you can find species of Mongolian origin.
In the Siberian steppes, subzones of forb-sod-grass and sod-grass steppes are distinguished.
Plants in the steppe are usually herbaceous. Their flora is distinguished by a luxurious variety of species. The steppe is a plain with herbaceous vegetation, where there are rare bushes. Trees are found only along artificially planted ponds and forest belts.
Plants in the steppe are usually narrow-leaved, with a rich root system that can withstand temperature extremes and extreme weather conditions. Plant communities are formed from several ecologically related, species of life, and the formation of a community is associated with weather conditions and the type of a particular site. The most typical for all is the presence of xerophytic grasses, adapted to the arid climate. The northern steppes are characterized by forbs, the southern ones are a community of grasses, and the semi-desert steppes are dominated by shrubs that can overcome strong desert winds.
Traditional steppe vegetation is made up of herbaceous plants, some of them are characteristic only for this area, and some of them can be found in meadows and wooded areas. Features of the color of the leaves and stem (grayish, or gray-green), is associated with their ability to easily tolerate moisture deficit, dry periods, the ability to curl up in a period when there are no precipitation... In the steppes of the temperate zone, you can find plants that are more characteristic of the meadow zone, which is easily explained by the climate in which the humidity is higher.
In addition to the usual steppe plants in the steppe can be represented by those that are of industrial importance. These include: corn, wheat, beets, barley, rye, forage crops that are used for pasture. The herbs that are used in folk medicine, are harvested for medicinal purposes, are used in pharmaceutical preparations, folk remedies for the treatment of diseases are also important to a person. More than 45 species of orchids, 50 species of legumes, 20 species of lily and asteraceae, which disappear due to human activity, are included in the Red Book of Russia. Among them are locust lily (royal curls), dolomite bell, yellow iris (water), yellow water lily.
The steppe, depending on the grasses, is divided into 5 main types of vegetation:
- mountain (cryoxerophilic);
- herb (mesoxeroyl);
- feather grass (xerophilic);
- desertified (haloxerophilic);
- desert (super xerophilic).
The main part of the steppes is located between forest-steppe and semi-desert, and the flora of these zones is represented mainly by cereals. Most widespread in the steppe received different kinds feather grass.
Flowering steppe plants
Steppe plants with flowers are so good that many of them are cultivated for the garden, used in landscape design, for growing in flower beds. Such plants include spring Adonis, Anafalis (three-veined, pearl), Goniolimon (beautiful, Tatar), Kachim (paniculate, Pacific, creeping, holly), Meadowsweet (elm, red, purple, Kamchatka), Hyacinth, Clematis (clematis) , Crocus and Narcissus.
The steppe looks most beautiful in spring. Melting snows fill the soil with water, and the sun is not yet very hot, so in April and May the spring steppe is a sight to behold. indescribable beauty... In early spring, mustard, rapeseed, feather grass, tulips bloom in the steppe. In the northern steppes, due to certain climatic conditions, flowers characteristic of the meadow grow, such as meadow sage, the flowers of which are collected in paniculate inflorescences, visible from afar, due to the intense violet-blue color. Meadowsweet blooms with a beautiful scattering of white-pink flowers that stand out brightly against the background of green spring foliage, Thin-leaved peony growing in the northern steppes is almost more beautiful than its garden counterparts, in natural conditions it has dark crimson flowers. In the northern steppes, Esparcet grows, in which the inflorescence is pale pink, in shape resembling a brush directed upward. It is used as a valuable forage plant.
The vegetation in the southern steppes is not so rich. The ephemeral plants that bloom in the southern steppe in spring are low. The sickle horned head, Veronica spring, and some others have time not only to bloom in a short period, but also to form seeds before the onset of arid summer period... The northern and southern steppes are 2 radically different types of steppe vegetation, and between them there are many different types that combine 2 or more modifications: feather grass steppes with forbs, northern steppes with feather grass, steppes interspersed with forests. A growing carpet of grass and cereals changes greatly appearance steppe, depending on the season.
Tiled Skewer and other healers
Tiled skewer or wild gladiolus usually grows in meadows, but it can also be found in forb steppes. A plant of incredible beauty, which creates whole populations in nature, the so-called gladiolus meadows, but, unfortunately, already belongs to rare species... In the Kursk region, thin skewer blooms with a density of up to 160 plants per 1 m², student expeditions of biologists go to admire its flowering. It is a herbaceous perennial belonging to the corms, with three xiphoid leaves. Spreading bell and grass carnation usually become its companions. Tiled skewer can be found even in the Murmansk region and the Komi Republic, where it survives thanks to its rhizome-tuber with reserves of nutrients for the period of drought and in winter time... It has long been used as a medicinal plant.
Oak Krupka and Siberian Krupka grow in Central Asia, Siberia, and the Caucasus. This is tall plant with a rosette of leaves, blooming with yellowish flowers, has invaluable medicinal properties, used in the treatment of bronchi, whooping cough, as a hemostatic agent, in the form of a decoction is used to treat various skin diseases and rashes.
The northern breakthrough is common in many climatic zones, including in the steppes. Its decoctions have anti-inflammatory and antipyretic effects, and official medicine uses extracts in the composition of contraceptives. Wild Poppy, Tulip, Mullein from the norichnikov family grow in almost all steppes. The composition of biologically active substances contained in its flowers and stems is simply priceless, and, due to the absence of harmful components, is used as a valuable food additive. It is eaten fresh, drinks, salads are prepared from it, the infusion of the flower is useful for diseases of the spleen, liver, intestines, it is part of the chest, expectorant preparations. The natural plant wealth of the steppes is very great.
Wormwood herb
Wormwood carries its specific aroma from early spring to late autumn. After feather grass, this is the most characteristic steppe plant, the smell of which many people associate with the steppe. Essential oils, which are the main wealth of wormwood, make up 3% of the plant's weight. Scientific research useful properties wormwood began several decades ago, but it has been used from time immemorial as a medicinal plant.
This steppe grass since ancient times it has been eaten as a spice, used as a disinfectant, medicinal, tonic, flavoring, and even anthelmintic. Wormwood has more than once helped geologists find mineral deposits, because it changes its color and shape of leaves if it grows in places where natural resources are found.
Plants are a storehouse of natural, useful, invaluable properties, a decorative spring carpet that can destroy human activities for their development. Such natural complexes need to be protected.
Geobotany
Topic 4
Lecture 2
Lecture questions
Steppe zone
Desert zone
Steppe zone.
The steppe zone stretches in a continuous strip along the European part of the country and Western Siberia from the south of Ukraine to the Ob River. In Eastern Siberia, steppes are found only in the form of separate islands among the taiga (Krasnoyarsk Territory, Transbaikalia).
The steppe zone is defined as the territory where the zonal vegetation is the communities of herbaceous xerophytes. It is the xerophilous grasses that tolerate drought well that form the basis of steppe phytocenoses. Currently, within the steppe zone, you can find only relatively small areas of the steppes (for example, in reserves). Huge areas are plowed and natural vegetation has not survived here.
Natural conditions... The climate of the steppe zone is continental. Summers are hot, dry, winters are cold, more or less frosty, with a stable snow cover. Precipitation is 300-500 mm / year, sometimes less. A characteristic feature of the steppe climate is that the amount of precipitation is much less than evaporation. In the warm season, plants almost constantly experience a lack of moisture. The bulk of precipitation falls in the middle of summer, during the heat wave, and in the form of short-term heavy showers. This makes it difficult for plants to use moisture, since water quickly flows down the surface of the soil, and some of it evaporates before it can penetrate into the soil layer. In the open spaces of the steppes, winds almost constantly blow, which intensify the evaporation of water from the aboveground plant organs. At times there are dry winds - hot, drying winds, which are especially dangerous.
Soils of the steppe zone - different varieties chernozems (typical, podzolized, leached, ordinary, southern, etc.). Chestnut soils are widespread in the south of the zone.
Steppe plants... Herbaceous xerophytes dominate in the steppes. Sod (dense bush) grasses with very narrow leaf blades are especially characteristic of the steppes. Among them it is necessary to name, first of all, various types of feather grass ( Stipa). Feather grass grow in rather large dense “bushes” (slide 6). Their leaves are almost always folded lengthwise. The stomata, through which water evaporates, are located on inner surface leaf, which reduces moisture loss (this is important in arid climates). The lower floral scales of feather grass are equipped with a very long awn, which is geniculate and, in many species, covered with hairs (feathery feather grass).
Narrow-leaved turf grasses also include fescue ( Festuca valesiaca) (slide 7) and thin-legged slender ( Koeleria cristata) (slide 8).
In the steppes, there are also some legumes, for example, Sandy Sainfoin ( Onobrychis arenaria) (slide 9), various types of clover ( Trifolium) (slide 10), astragalus ( Astragalus) (slide 11), etc. All of them are quite drought-resistant, tolerate a lack of moisture well.
A significant role in steppe phytocenoses is played by forbs - representatives of various families of dicotyledonous plants (except for legumes). An example is the species of zopnik ( Phlomis), sage ( Salvia), bruise ( Echium) and others (slides 12-14).
A special group is made up of steppe ephemeroids - perennial herbaceous plants that develop only in spring, when there is enough moisture in the soil. By summer, their aboveground part dries up completely. An example of this type of plant is the bulbous bluegrass ( Poa bulbosa) (slide 15), different types of tulips ( Tulipa) (slide 16).
Ephemera are also characteristic of the steppe - annual plants that go through their entire life cycle for several weeks. They emerge from seeds in early spring, develop rapidly, move on to flowering and manage to form new seeds before the onset of summer drought. At the same time, the plants themselves completely die off. Among the steppe ephemerals, the crescent horn-head ( Ceratocephala falcata), Black-leaved bedbug ( Lepidium perfoliatum), some types of grits ( Draba), etc. (slides 17-19) These small plants are most abundant in the southern steppes, where the summer drought is especially severe.
In addition to herbaceous plants some shrubs are also found in the steppes. They often form small thickets against the background of steppe vegetation. At the contact of the steppe with the forest, a shrub edge almost always develops. Steppe shrubs include, for example, thorns, or wild plum ( Prunus spinosa), bean, or wild almonds ( Amygdalus nana), various types of spirea ( Spiraea), caragana ( Caragana) (slides 20-23).
Subzones... Consider the subzones in the steppes of the European part of Russia and neighboring states, where they are well expressed. Here, the northern part of the steppe zone, adjacent to broad-leaved forests, is the wettest, while in the south the climate becomes more and more arid. Consequently, the vegetation cover also changes from north to south. The steppe zone in this region is usually subdivided into three subzones.
The first of them, the northernmost, - subzone of meadow, or northern, steppes... It is characterized by the fact that both steppe and oak forest areas are found in watersheds, and steppe vegetation is appearance resembles meadows. Sometimes this strip is also called forest-steppe.
The second, more southern, subzone - forbs-turf-cerealssteppes... Here, on the watersheds, only steppe vegetation absolutely dominates, and a drier version of the steppes is widespread. Forest areas are found only along beams and depressions, where the best moisture conditions are created. The situation is similar in the third, southernmost, subzoneturf-grass steppes... However, an even drier version of the steppes dominates the watersheds.
Variants in the steppes, starting with the wettest.
Meadow, or northern, steppes have a rather high (up to 80-100 cm) and dense grass cover, in which forbs prevail, and feather grass play a subordinate role.
During the flowering period, the meadow steppe is very similar in appearance to a colorful meadow. Here you can find many types of herbs with bright beautiful flowers. Such are, for example, Six-petalled Tavolga ( Filipendula vulgaris), Bruise red ( Echium rubrum), Meadow sage ( Salvia pratensis), Purple goat ( Scorzonera purpurea) and many others (slides 24-27). In addition to herbs, there are also cereals, but mainly broad-leaved - Coastal rump ( Bromopsis riparia), Pubescent sheep ( Helictotrichon pubescens), Wheatgrass medium ( Agropyron intermedium) and others (slides 28-30). On the contrary, there are quite a few typical narrow-leaved steppe grasses. It is mainly Welsh fescue, or fescue. (Festuca valesiaca) and Feather grass ( Stipa pennata) is one of the most moisture-loving feather grass (slides 31-32).
A remarkable feature of the meadow steppes is a very high species richness. So, in the meadow steppe in the Central Chernozem Reserve near Kursk, up to 80-90 plant species can be counted per 1 m. In this respect, the meadow steppe is unique.
The meadow steppe is characterized by a change in the appearance of the vegetation cover during the warm season, the so-called change of aspects. This is because, in the mass, some or other plants are blooming, giving the steppe one color or another (yellow, white, blue, blue, etc.).
A more southern version of the steppe - herb-fescue-feather grass... It is distinguished by a noticeably thinner and lower grass cover. Here, the role of narrow-leaved turf grasses sharply increases. Fescue and various feather grasses dominate, and not the species that are in the meadow steppe, but others, more drought-resistant. At the same time, the role of forbs is quite important. But among this group of plants, more drought-resistant species are also common - wilted sage ( Salvia nutans), Zopnik prickly ( Phlomis pungens) and some others (slides 33-34). The species richness is less than in the meadow steppe.
The southernmost, fescue-feather grass, steppes are even more different from the meadow ones. The grass cover here is especially sparse and low (up to 30-40 cm). Narrow-leaved turf grasses absolutely dominate. In addition to fescue, there are the most drought-resistant feather grass species, for example, Lessing's feather grass, or feather grass ( Stipa lessingiana) (slide 35). There are very few herbs. Between the tussocks of fescue and feathergrass in spring, various ephemeral annuals appear: Bugwort, crescent horned, etc. There are also ephemeral perennials - Bulbous bluegrass, various types of tulips, etc.
In terms of species richness, the southern steppes are significantly inferior to other variants of the steppes. Here at 1 m you can find no more than 10-15 species.
For southern steppe characteristic plants, which are called "tumbleweed". They belong to different families of flowering plants, but have a fairly similar appearance. Their aerial part is a loose tangle of branches, which has more or less spherical shape... In autumn, this ball easily breaks off the soil and rolls with the wind across the expanses of the steppe. An example of such plants can be Kachim paniculata ( Gypsophila paniculata), Plain Enegolovnik ( Eryngium campestre), Goniolimon Tatar ( Goniolimon tataricum) and others (slides 33-34).
Ctepe located in the Asian part of Russia and neighboring states.
The steppes of the south of Western Siberia (Barabinskaya steppe) in appearance somewhat resemble the meadow steppes of the European part of the territory under consideration, but differ from them in noticeable swampiness and soil salinity. As a result, the species composition of plants is quite specific here (many halophytes, etc.). In terms of plant composition, the steppes of Kazakhstan have much in common with the steppes of the south of the European part of Russia and neighboring states. Here, as in the European part of the country, they distinguish subzones of forb-sod-cereal and sod-cereal steppes.
In Eastern Siberia, only a few steppe islands are widespread, most often located among the taiga. Their vegetation is very distinctive.
The flora of the steppes of Eastern Siberia is very different from the flora of the steppes of the European part of the country. Here, for example, special Mongolian elements are widespread. However, there are also common plants, especially some cereals: Welsh fescue, or fescue (Festuca valesiaca) and Slim Legged ( Koeleria cristata), Feather-hair and others (slide 39-41).
It is noteworthy that in the eastern Siberian steppes, even the most southern ones, there are no or very few ephemeral perennials (such as tulips, poultry farms, crocuses, etc.). Ephemeral annuals, which are so widespread in the southern Russian steppes, are extremely rare. The basis of the herbage is made up of perennial grasses and forbs.
Desert zone
The desert zone is located south of the steppe zone. It stretches in the form of a continuous strip from the extreme southeast of the European part of the country (the lower reaches of the Terek, Volga and Urals) to the eastern limits of Central Asia and Kazakhstan. There is also a small array of deserts in Transbaikalia, on the border with Mongolia and China.
The zonal vegetation of the deserts is unique. The most drought-resistant xerophytes, most often half-shrubs, dominate, and the vegetation cover is more or less sparse and unclosed. Sparse vegetation is one of the most characteristic features of deserts.
Natural conditions... The desert climate is sharply continental, even hotter and drier than in the steppes. Temperature fluctuations throughout the year are very large. Long hot summers give way to frosty winters with snow cover. The average July temperature reaches 25 ° C. In winter, however, the thermometer can drop significantly below zero. Temperature fluctuations are very large throughout the day in the summer. An unbearably hot day gives way to a rather cold night. All this is typical for a sharply continental climate.
In deserts in summer, the soil surface heats up to 60-70 ° C. Only the most heat-resistant plants can tolerate such temperatures. High temperatures are dangerous for plants not only in themselves, but also because transpiration is sharply increased. Moisture loss is also facilitated by strong winds common in the desert.
Deserts are characterized by an extremely dry climate. Annual precipitation does not exceed 200-300 mm, and evaporation is several times higher. In summer, in extreme heat, plants receive almost no moisture at all, experiencing acute water starvation.
Desert soils usually more or less saline, which is unfavorable for the existence of many plants. The deserts are characterized by gray soils and gray-brown desert soils.
With regard to the nature of the substrate, sandy, clayey, saline and stony (gravelly) deserts are distinguished. Each of these edaphic types of deserts has a special, distinctive vegetation cover. The most widespread in Russia and neighboring states are sandy deserts, the areas of clayey deserts are quite large. Other types are less common.
Distinguish between two climatic types of deserts: deserts, where precipitation falls little by little, more or less evenly over the seasons, and deserts, where the bulk of precipitation falls in spring. These types of deserts differ sharply in vegetation cover.
Desert Plants... In deserts, there are various life forms of plants: shrubs, shrubs, perennial and annual grasses, and even trees. Semi-shrubs are especially characteristic. In these plants, the lower part is lignified, perennial, and the shoots current year die off by winter almost throughout. Semi-shrubs are represented in the deserts of the territory under consideration by various types of wormwood and plants from the Marev family. True shrubs are found mainly in sandy deserts. Herbaceous plants include, first of all, ephemeral perennials (for example, some grasses and sedges) and ephemeral annuals. Of the trees in the deserts, only some species of saxaul are widespread (slide 42).
Many of the most common desert plants belong to the Marev family. This is characteristic feature flora of the deserts of Russia and neighboring states. In the vegetation cover of all other natural zones of our country, the species of this family do not play a large role.
Almost all desert plants are capable of tolerating prolonged and severe drought well. Different plants have different ways of adapting to drought.
One of these devices is leaflessness (aphylia). In this case, the leaves either do not develop at all, or look like barely noticeable scales. The functions of photosynthesis are performed by thin green stems of the current year (for example, in saxaul). The absence of true broad leaves greatly reduces the total evaporating surface of the plant, thereby reducing moisture loss.
Another adaptation to drought tolerance is the dropping of the current year's shoots and leaves with the onset of the summer heat (this phenomenon is observed, for example, in some wormwoods). This also greatly reduces evaporation.
Succulents adapt in a peculiar way to the transfer of drought: they accumulate water reserves in their aboveground part (a special aquiferous tissue serves for this).
A special way of adaptation is observed in ephemerals and ephemeroids. They, developing in spring, seem to "escape" from the summer drought. These plants transfer the unfavorable dry season in the form of seeds or dormant underground organs located in the soil (rhizomes, bulbs, etc.). By their nature, both ephemerals and ephemeroids are mesophytes.
Phreatophytes (pumping plants) form a specific group of desert plants. They develop normally only if their roots reach the water table. Phreatophytes do not suffer at all from summer drought, as they are always provided with moisture. They turn green and bloom in the midst of summer. An example of this type of plant is the Camel thorn dwarf shrub ( Alhagi pseudalhagi), the roots of which are able to penetrate into the ground to a depth of 10-15 m (slide 43).
Desert plants are characterized by the fact that their above-ground part by its mass is many times less than the underground one. Desert plants are mostly submerged in the soil.
Among the plants found in deserts, there are quite a few more or less salt-tolerant plants that can grow on saline soils. There are also true halophytes that can tolerate severe salinity.
Subzones... Within the desert zone, three subzones are distinguished: semi-deserts, northern clay deserts, and southern clay deserts.
Semi-desert subzone- the northernmost. It is a transitional strip between the steppe and the desert. Phytocenoses are formed by both steppe narrow-leaved turf grasses (for example, feather grass) and desert dwarf shrubs (sagebrush species, etc.). Both grow together.
However, the vegetation cover on positive and negative forms of microrelief is very different. On microhills, where the soils are drier, semi-shrubs predominate and phytocenoses characteristic of the desert are formed. In microdepressions, where the soils are more humid, sod grasses dominate and steppe phytocenoses develop. With a well-defined microrelief, the vegetation cover has a mottled character. Spots of semi-desert, desert and steppe vegetation alternate with each other, forming a variegated mosaic.
Northern argillaceous subzonedeserts characterized by the fact that precipitation falls here little by little and more or less evenly throughout the year. The vegetation cover is sparse, the surface of the soil, not covered with plants, is visible everywhere. Dominant shrubs growing in the form of low, squat pillows of a rounded shape. This group of plants is represented by various sagebrush and species of the family of haze (they are called "hodgepodge"). Of the wormwood, the wormwood of the white earth is especially common ( Artemisia terrae- albae), growing in the form of dull grayish-greenish pillows (slide 44).
In the group of hodgepodge one can call the gray-haired Lebeda, or kok-pek ( Atriplex cana), Anabasis saline, or biyurgun ( Anabasis salsa), Anabasis leafless, or itsegek ( Anabasis aphylla) (slides 45-47). These plants also grow in the form of pillows. In some of them, the leaves look like small scales or are not developed at all, and the functions of photosynthesis are performed by young green stems. Solyanka are good fodder plants, they are eagerly eaten by livestock (sheep and camels). According to the characteristics of the vegetation cover, the northern clay deserts are called wormwood-saltwort. Deserts of this type are widespread in southern Kazakhstan.
Subzone of southern clay deserts characterized by the fact that the bulk of precipitation falls here in spring, while in summer it does not happen at all for 3-4 months. Winter in this subzone is relatively warm, sunny, and usually snowless. The vegetation cover is dominated by ephemeroids - some perennial grasses and sedges. They only develop in spring when the soil is moist enough. At this time, the desert resembles a green lawn. Plants form a continuous, but rather low cover. This is an excellent pasture for livestock. With the onset of summer drought, the aboveground part of the plants dies off and the soil is exposed. In summer, no plants are seen here. In a desert of this type, the grasses of Bluegrass bulbous and Sedge are especially widespread. (Carex pachystylis) (slides 48-49) . Both plants are rather small and short. During the summer drought, only underground organs located shallow in the soil remain alive. The southern clay deserts are called ephemeral. They are distributed only in the extreme south of Central Asia, and in a relatively small area.
A very special, peculiar type are sandy deserts... They occupy a very large area (Karakum, Kyzylkum, etc.) and are located in those areas where most of the precipitation falls in spring. The sandy desert is a set of large dunes covered with bushes. The thickets of shrubs are relatively dense and often reach the height of human growth. Sands in desert conditions contain more moisture than loamy and clayey soils, as a result of which the flora is especially rich here.
Among the shrubs of the sandy desert, representatives of the genus Juzgun ( Calligonum). All of them have extremely poorly developed leaves resembling very small scales, and the original fruits are loose reddish balls (slide 50).
In addition to juzgun, various other shrubs and small trees are also found in the sandy desert, such as sand acacia (Ammodendron conollyi), Chingil (Hcdimodendron halodendron) , eremosparton (Eremosparton flaccidum) and others (slides 51-53)
A real tree also grows in the sandy desert - White Saxaul (Haloxylon persicum). The appearance of saxaul is very peculiar (slide 54). Its trunk is twisting, knotty, the crown is very loose and consists mainly of thin green twigs hanging down freely like lashes (therefore, the tree gives almost no shadow).
In the spring, in the sandy desert, a continuous green cover of grasses develops on the soil. The bloated sedge is especially abundant here. , or sludge (Carex physodes), is a relatively small plant. A distinctive feature of this sedge is large oval-shaped reddish-brownish sacs located in a small group at the end of the stem (slide 55). Bloated sedge is an ephemeroid. It turns green only in spring, and by summer its aboveground part dries up. This plant has an important forage value.
In the sandy desert, there are also annual ephemerals, for example, the cereal Mortuk Bonaparte ( Eremopyrum bonaepartis), Malcolmia large-colored ( Malcolmia grandiflora), Crescent horn-head ( Ceratocephala falcata), Veronica bow-legged ( Veronica campylopoda) (slides 56-59). All these plants dry up with the onset of summer, completing their life cycle and scattering the seeds.
This is, in general terms, the flora of the sandy desert. It should be emphasized that it was only about motionless, fixed sands, where the vegetation cover is in its natural state. When livestock is grazed too much, the plant cover breaks down and the sand starts to move. The final stage of this process is exposed free-flowing sands blown by the wind. Over time, some specific pioneer plants settle on such mobile dunes, which contribute to the fixation of sand, for example, the Celine cereal ( Aristida karelinii) (slide 60). However, the restoration of vegetation is very slow and with great difficulty.
In our country, are also common saline or succulent solyanka deserts that do not take up large areas. They develop on highly saline moist soils in depressions, drainless basins, etc. Succulent halophytes from the haze family dominate here: Sarsazan ( Halocnemum strobilaceum), Soleros ( Salicornia europaea), potashnik ( Kalidium caspicum), some types of Sveda (Suaeda) and others (slides 61-64). These plants are called juicy hodgepodge. The vegetation cover of the saline desert is usually rather dense and continuous. However, it is formed by only a very few species (usually two or three, and sometimes even one). Plants here are constantly provided with moisture and vegetate from spring to late autumn. They die off only with the onset of frost.
Seminar questions
Vegetation cover of Russia and neighboring states
I.1. Steppe zone:
1.1. Zonal vegetation;
1.2. Natural conditions;
1.3. Soils of the steppe zone;
1.4. Steppe plants.
1.5. Subzones:
1.5.1. Meadow, or northern, steppes (forest-steppe);
1.5. 2. Forbs-turf-grass steppes;
1.5. 3. Sod-grass steppes.
I.6. Features of the steppes of the Asian part of Russia and neighboring states
II.1. Desert Zone:
1.1. Natural conditions;
1.2. Desert soils;
1.3. Climatic types of deserts.