Natural zone of tropical semi-deserts. Deserts and semi-deserts of russia, animals and plants, climatic zone, characteristics of the zone
You don't have to travel to Africa or Australia to visit the desert. Deserts and semi-deserts are also found on the territory of Russia. The lowest part of the Caspian lowland is occupied by deserts, where flat surfaces alternate with sandy deposits. The climate here is sharply continental: very hot and dry summers, cold winters with little snow. Apart from the Volga and Akhtuba, there are no other sources of water here. There are several oases in the deltas of these rivers.
The strip of semi-deserts of Russia is located in the southeast of the European part of the country, starting in the area of the left bank of the Volga and reaching the foothills of the Caucasus Mountains. These are the western part of the Caspian Sea region and the Ergeni Upland. It also has a harsh continental and dry climate. The waterways of the semi-desert zone are the Volga and Sarpinskie lakes.
On the territory of deserts and semi-deserts, an insignificant amount of precipitation falls - up to 350 millimeters per year. Basically, the soils are sandy and desert-steppe.
The word "desert" suggests that there is no life here. But it is not so.
Climate of deserts and semi-deserts of Russia
The climatic conditions of deserts and semi-deserts influenced the formation of a special flora and fauna. The vegetation in this area is arranged in a mosaic manner. Perennial herbs - ephemeroids - have spread predominantly in semi-deserts. Ephemera also grow here, the life cycle of which is two to three months. In general, the plants are small but have a strong root system. In the region of semi-deserts, black wormwood and hodgepodge, bulbous bluegrass and two-spiked ephedra, camel thorn and fescue grow. Closer to the Caspian Sea, the semi-desert turns into a desert, where vegetation is less and less common. Sometimes you can see here an elmius, wormwood or hairy.
Ecological problems of deserts and semi-deserts of Russia
If we talk about the ecological problems of the deserts and semi-deserts of Russia, then the very intervention of man in the nature of this area is a danger. The very process of desertification - the extreme degree of soil erosion - leads to significant changes, especially under the influence of anthropogenic factors. Another problem of the deserts and semi-deserts of Russia is poaching and extermination of animals and plants in large numbers. And since some rare species live here, human activities cause serious damage to nature. Therefore, it is necessary to protect and preserve the landscapes of the country's deserts and semi-deserts, since this is the wealth of our planet.
Questions to consider:
1. Desert characteristics
2. Desert vegetation
3. Desert fauna
4. Desertification
5. Semi-desert
6. Protection of deserts and semi-deserts
7. Occupations of the population of deserts and semi-deserts
1. Characteristics of the desert.
Desert - a geographic zone with a hot, arid climate and sparse sparse vegetation in the temperate subtropical and tropical zones of the Earth.
The area of deserts is estimated at 31.4 million km 2 (about 22% of the land).
Deserts are found on all continents except Europe, and are located within the borders of approximately 60 countries. In the mountains, the desert forms a high-altitude belt (alpine desert), on the plains - a natural zone.Distributed in the temperate zone of the Northern Hemisphere, subtropical and tropical zones of the Northern and Southern Hemispheres.
Major deserts of the world:
Gobi - Central Asia, Mongolia and northern China
Takla-Makan - borders the Pamirs and Tibet from the north. Central Asia
Sahara - North Africa
Libyan Desert - North of the Sahara
Namib - Southwest African coast
Kyzylkum - between the Syrdarya and Amudarya rivers, Uzbekistan, Kazakhstan
Karakum - Turkmenistan
Atacama - North Chile, South America
Northern mexico
Great Victoria Desert
Great sandy desert
Climatic conditions:
One of the main features of the desert is a lack of moisture, which is explained by the negligible (50- 200 mm per year) by the amount of precipitation that evaporates faster than seeping into the soil. Sometimes it doesn't rain for several years. Most of the territory is endless, and only in places there are transit rivers or lakes that periodically dry up and change their outlines (Lobnor, Chad, Eyr). Some deserts formed within the ancient river, delta and lake plains, others on platform land areas. Deserts are often surrounded by or bordered by mountains.
Over the course of a long geological history, deserts have changed their boundaries. For example, the Sahara - the greatest desert in the world - stretched over 400 500 km south of the present position.
Precipitation 50-200 mm per year
Clear days 200-300 a year
Air temperature + 45 ° in the shade. Surface temperature during the day + 50-60 ° (up to 80 ° and even 94 ° - Death Valley), at night + 2-5 ° (sharp drops)
Dry winds, storms. In winter in Russia frosts with thin snow cover.
Contrary to the prevailing opinion that the desert is an endless monotonous sea of sand, the most common are rocky deserts, or hamads, often located on plateaus or mountain ranges with bizarre outliers. Pebble and rubble deserts, impressive with almost complete lifelessness, stand out among them. Parts of such deserts can be seen in the Sahara, Kyzyl Kum, on the Arabian Peninsula. In conditions of a huge daily temperature range, with periodic moisture and drying of rocks, a characteristic shiny dark crust is formed on their surface, the so-called desert tan, which protects the rock from rapid weathering and destruction. Stony deserts often turn into sandy ones. In Central Asia they are called kumas, in Africa - ergs, in Arabia - nefuds. Sands are easily carried by the wind, forming aeolian landforms: dunes, dunes, safes, etc. Single dunes and dunes not fixed by vegetation can move tens of meters per year. Sometimes sand blown by the wind makes a special sound. In such cases, they speak of singing dunes or dunes (in Dagestan, the singing dune is declared a natural monument). But the bulk of the sand is immobile, as it is held by the long roots of shrubs and grasses, which have adapted to the conditions of a constant moisture deficit. The largest sandy deserts in the world include: Libyan Desert, Rub al-Khali, Nefud, Great Sandy Desert, Great Victoria Desert, Karakum Desert, Kyzyl Kum.
Clay deserts develop on clay deposits of various origins. The largest clay deserts: Ustyurt, Deshte-Lut, Deshte-Kevir Betpak-Dala and others. Takyrs and sors are characteristic of their relief.
Saline deserts form on saline (saline) soils and are scattered in separate patches among other types of deserts.
TAKYR - flat clay surfaces, almost devoid of vegetation, in the deserts of the subtropical belt, an area of several m2 up to tens of km 2 ... In spring they are usually filled with water.
SALMONS - soil types of steppe, semi-desert and desert zones. Contains water-soluble salts, 0.5-10% humus. In the Russian Federation - in the Caspian region.
SORA (blinders), closed depressions in deserts Wed. Asia, covered with a crust of salt or a thick layer of salt dust. Formed in sands due to evaporation and salinization of near-surface groundwater or on the strata of saline bedrock under conditions of effusion water regime with the formation of salt marshes.
SAKHEL (Arabic - coast, outskirts) - the name of the transitional strip (width up to 400 km ) from the deserts of the Sahara to the savannas of West Africa. Semi-deserts and deserted savannas prevail. Precipitation 200 600 mm in year; droughts are frequent.
Desert types
According to their position, continental deserts (Gobi, Taklamakan), located inside the continent, and coastal (Atacama, Namib), stretching along the western coasts of the continents, are distinguished.
Deserts are sandy (Sahara, Karakum, Kyzylkum, Great Victoria Desert), clayey (South Kazakhstan, southern Middle Asia), rocky (Egtpet, Israel) and saline (Caspian lowland).
2. Desert vegetation.
Desert vegetation does not form a closed cover and usually occupies less than 50% of the surface, being distinguished by a great peculiarity of life forms and a great sparseness.
Types of plants:
1. Succulents - agave, aloe, cacti
2. The root system reaches the groundwater
(roots 20-30 m ) - camelthorn plant
3. Heat-resistant, able to tolerate dehydration - wormwood
4. Ephemeroids - develop within a short period, then rhizomes or bulbs remain in the soil. - tulip, sedge, bluegrass
XEROPHITES (from the Greek xeros - dry and phyton - plant), plants adapted to life in arid habitats. Several types: succulents - heat-resistant, but do not tolerate dehydration (agave, aloe, cacti); hemixerophytes - do not tolerate prolonged dehydration, the root system reaches groundwater (sage, camel thorn); euxerophytes - heat-resistant, able to tolerate dehydration (wormwood, gray-headed Veronica, some mullein); poikiloxerophytes - when dehydrated, they fall into suspended animation (some mosses).
EPHEMES, annual herbaceous plants, the entire development of which usually occurs in a very short time (several weeks), more often in early spring. Typical for steppes, semi-deserts and deserts (for example, dimorphic quinoa).
EPHEMEROIDS, perennial herbaceous plants, the aboveground organs of which develop from autumn to spring and in summer die off, and underground (bulbs, tubers) persist for several years. Typical for steppes, semi-deserts and deserts (species of tulip, sedge, bluegrass)
Plant adaptations:
root system deeply embedded in the soil;
modified leaves or thorns, scales;
pubescence of leaves - promotes less evaporation;
shedding leaves with the onset of heat;
bloom only during spring.
Sandy deserts of Asia (Karakum, Kyzylkum, mouth of the Volga river)
Herbs, trees, leafless shrubs and semi-shrubs:
white saxaul (5 m),
sand acacia,
chingil silvery - shrub,
juzgun,
ephedra,
camel thorn (genus of dwarf shrubs and perennial grasses of the legume family, eaten by camels, root length 20- 30 m.),
spikelet - cereal,
bloated sedge,
celine (aristida) - cereal
Clay deserts of Asia (South Kazakhstan, lower reaches of the Ural River, south of Middle Asia)
wormwood,
hodgepodge,
black saxaul (12 m ), Wood is used for fuel; green twigs - food for camels and sheep. Good sand fixer
bulbous bluegrass,
desert beetroot,
milkweed.
Asia. Saline deserts (Caspian lowland)
salleros
sarsazan gnarled
Africa
Celine (aristide)
Date palm trees in oases
America
Succulents (agave, aloe, cacti - cereus, prickly pear), yucca
3. Fauna of deserts
Attachments:
protective sand color,
fast run,
go without water for a long time,
hibernate
nocturnal lifestyle,
holes in the sand
bird nests on the ground (on shrubs and trees).
Insects and arachnids: scarab, linger, scorpion, desert locust
Reptiles:swift foot-and-mouth, steppe agama, monitor lizard, round-headed, frilled lizard, land iguana, sand boa, snake arrow, gyurza, efa, steppe viper, Central Asian tortoise, panther turtle (Africa).
Birds:Saja (sand grouse), saxaul jay, desert warbler, field pipit, desert coinage, avdotka.
Rodents:jerboas, fine-toed gopher, gerbils, giant mole rat.
Long-eared hedgehog.
Ungulates:gazelle, antelopes, including gazelles, saiga, wild ass.
Predatory:wolf, fennec fox, striped hyena, house (jungle cat), sand cat, jackal, coyote, manul, caracal, South Russian dressing, honey badger, Cape South African fox.
4. Desertification
The advance of the desert to other parts of the land is called desertification.
Causes:
Overgrazing.
Intensive long-term cultivation of the land.
Drought.
The Sahara, moving southward, annually takes away 100 thousand hectares of arable land and pastures.
Atacama moves with speed 2.5 km per year.
Tar - 1 km per year.
5. Semi-deserts
Semi-desert - areas that combine the nature of steppes and deserts, found in the temperate, subtropical and tropical zones of the Earth (except for Antarctica) and forming a natural zone located between the steppe zone in the north and the desert zone in the south.
In the temperate zone of Asia:
from the Caspian lowland to the eastern border of China.
In the subtropics:
Anatolian plateau, Armenian highlands, Iranian highlands, Karoo, Flinders, Andes foothills, Rocky Mountain valleys, etc.
In the tropics of Africa:
south of the Sahara, in the Sahel zone (deserted savannah)
Plants:
Russia:tulips, sedge, bluegrass, wormwood, mullein, hodgepodge.
America: cacti.
Africa and Australia: bushesand rare low-growing trees (acacia, dum palm, baobab)
Animals:
hares
rodents (ground squirrels, jerboas, gerbils, voles, hamsters), meerkats,
reptiles;
antelopes,
bezoar goat,
mouflon,
kulan, Przewalski's horse
predators: jackal, striped hyena, caracal, serval, steppe cat, fennec fox, house
birds,
many insects and arachnids (karakurt, scorpions).
6. Protection of deserts and semi-deserts
Nature reserves and national parks
Desert:
Semi-desert:
Ustyurt reserve,
Tiger beam,
Aral-Paygambar.
Listed in the Red Book: Dressing, mole rat, gazelle, saiga, saja, caracal, serval
7. Occupations of the population of the desert and semi-desert
Desert:sheep, goat and camel breeding, irrigated agriculture and horticulture only in oases (cotton, wheat, barley, sugarcane, olive tree, date palm).
Semi-desert:grazing and oasis farming are developed on irrigated lands.
Camels live in deserts (one-humped-dromedar in Africa, two-humped-Bactrian - in Asia).
The desert was and remains an extreme natural environment for human life, although it was in the desert that ancient civilizations originated and existed: Egypt, Mesopotamia, Khorezm, Assyria, etc. Life usually arose near a well, river or other water source. This is how oases appeared, the first "islands" of life, created by human labor. Life in oases and occupations of the population differed significantly from the conditions of the desert proper, where people are doomed to eternal nomadic wanderings under the scorching sun and dusty storms in search of water. Sheep and camel breeding has become a traditional pastime of nomads. Irrigated agriculture and horticulture developed only in oases, where such plants as cotton, wheat, barley, sugar cane, olive trees, date palm, etc. were cultivated for a long time. The rapid influx of population into large oases led to the formation of the first cities.
THE FAMOUS DESERT OF THE WORLD
GOBI (from Mong. Beef - a waterless place), a strip of deserts and semi-deserts in Central Asia, in the south and southeast of Mongolia and in the adjacent regions of China. Bounded in the north by mountainsMongolian Altai and Khangai, in the south - Nanshan and Altintag. Subdivided intoTrans-Altai Gobi , Mongolian Gobi , Alashan Gobi , Gashun Gobiand the Dzungarian Gobi. Area over 1000 thousand km2 .
Plains prevail at an altitude of 900 1200 m mainly composed of rockschalk, Paleogene and neogene... They alternate with more ancient hummocks, ridges and island ridges (up to 1800 m ). The sloping piedmont plains are dissected by numerous dry channels flowing into closed depressions, which are occupied by drying up lakes, salt marshes, or hard clay surfaces; there are also small masses of moving sands.
The climate is sharply continental in the temperate zone (temperature fluctuations from -40 ° C in January to + 45 ° C in July). Precipitation per year falls from 68 mm in the northwest of the Alashan Gobi to 200 mm in the north-east of Mongolia; there is a summer maximum. There are almost no rivers with constant flow, most of the channels are watered only in summer. The soils are gray-brown and brown, often in combination with sandy desert, salt marshes and takyrs. Carbonate, gypsum-bearing and coarse-gravelly soil varieties are characteristic.
Desert vegetation is sparse and sparse. On the plateau and foothill plains, there are small shrub gypsophilous vegetation (barnyard, green leaf, teresken, rheumuria, several species of saltpeter and saltwort). On the salt marshes, in addition to saltpeter and saltwort, there are tamarisks and potash. On the sands there is sandy wormwood, Zaisan saxaul, kopecks, perennial and annual grasses. In the northeast and east of Mongolia, semi-deserts are widespread, where, along with wormwood and saltwort, cereal groups are developed, and rare clumps of dwarf caragana are found. A wild camel, an ass-kulan, a Przewalski's horse, several species of antelope, many rodents and reptiles have survived. Many endemic species of flora and fauna. Big Gobi Nature Reserve (within Mongolia).
Livestock raising (small ruminants, camels, horses, to a lesser extent - cattle). Quite abundant groundwater is of great importance for water supply. Agriculture is developed only along the river valleys.
KYZYLKUM, desert in Wed. Asia, in the interfluve of the Amu Darya and Syr Darya, in Uzbekistan, Kazakhstan and partly in Turkmenistan. OK. 300 thousand km2 ... Plain (height up to 300 m ) with a number of closed depressions and isolated mountain ranges (Sultanuizdag, Bukantau, etc.). Most of it is occupied by ridge sands; there are many takyrs in the northwest; there are oases. Used as a pasture.
SAKHARA, Africa's largest desert in the world. St. 7 million km2 ... The states of Morocco, Tunisia, Algeria, Libya, Egypt, Mauritania, Mali, Niger, Chad, Sudan are located in the Sahara in whole or in part. OK. 80% of the Sahara are plains with a height of 200 500 m ... In the northeast there are drainless depressions: Qattara (133 m), El-Fayyum, etc. In the central part there are mountain ranges: Ahaggar, Tibesti (Mount Emi-Kusi, 3415 m , the highest point of the Sahara). Stony and gravelly (hamads), pebble (regi) and sandy (including ergs) deserts prevail. The climate is tropical desert: precipitation in most of the territory is less 50 mm per year (on the outskirts of 100 - 200 mm ). Average January temperatures are not lower than 10 ° С; an absolute maximum of 57.8 ° C, an absolute minimum of -18 ° C (Tibesti). The daily amplitudes of air temperature are more than 30 ° C, and that of soil - up to 70 ° C. In addition to the transit river. Nile and Niger sections, no permanent watercourses. Dry beds of ancient and modern watercourses (wadis, or ueda) prevail. Underground waters feed numerous oases. The vegetation cover is extremely sparse, sometimes absent. Agriculture (date palm, cereals, vegetables) in the oases. Nomadic and semi-nomadic animal husbandry.
TAKLA MAKAN, a desert in western China, one of the largest sandy deserts in the world. Extension from west to east over 1000 km, width up to 400 km , area of sands over 300 thousand km2 .
It was formed under conditions of long-term accumulation of sediments within the Tarim Basin, which is composed mainly of alluvial deposits (the Tarim River and its tributaries), partially blown over. The surface is flat, gradually decreasing to the north and east from 1200 1300 m to 800 - 900 m ... In the west, single ridges rise above Taklamakan (the highest point is Mount Chongtag, 1664 m ), composed of sandstones.
Most of the territory is covered with sands up to 300 m ... In the southwest, dunes predominate, in the northeast, sandy ridges of complex configuration (including large ones, sometimes stretching for 10 12 km , - the so-called whale backs), sand pyramids (height 150- 300 m ), etc. On the outskirts of Takla-Makan, salt marshes occupy significant areas.
The climate is moderately warm, sharply continental, with negligible (less 50 mm per year) the amount of precipitation. High dustiness of the atmosphere is characteristic. The rivers flowing from Kunlun penetrate into the depths of Taklamakan for 100 200 km gradually drying out in the sands. Only the Khotan River crosses the desert and in summer brings its waters to the Tarim River, which flows along the western and northern outskirts of Taklamakan.
The depth of groundwater in the relief depressions (within the ancient deltas and old speech) 3- 5 m , they are usually inaccessible for plants, therefore, most of the territory is devoid of vegetation, and only in places with a close occurrence of groundwater are rare thickets of tamarisk, saltpeter, and reed. On the outskirts of Takla-Makan and river valleys, there are poplar turanga, elk, camel thorn, annual hodgepodge, saxaul. The fauna is poor (rare herds of antelopes, hares, gerbils, jerboas, voles); in the river valleys - wild boars.
Separate oases (mainly in the valleys of the Tarim and Yarkand rivers). There is no permanent population. Near the southern outskirts of Taklamakan among the sands are the ruins of ancient settlements confined to dry valleys.
ATAKAMA (Atacama), a desert in the north of Chile, in the South. America, along the Pacific coast approx., Between 22-27 ° S. w .; precipitation less 50 mm in year. The river is crossed. Loa. Large deposits of copper ores (Chuquicamata, El Salvador), saltpeter (Taltal), sodium chloride, borax.
ADDITIONAL MATERIAL
PRZHEVALSKY HORSE (Equus caballus), equid-hoofed mammal of the genus of horses. Body length 2.3 m , height at withers approx. 1.3 m ... It is quite a typical horse, with a solid build, with a heavy head, thick neck, strong legs and small ears. Its tail is shorter than that of a domestic horse, and its mane is erect and short. The color is sandy-red or reddish-yellow. The mane and tail are black-brown, a black-brown belt runs in the middle of the back, the end of the muzzle is white. In summer the hair is short and close-fitting, in winter it is longer and thicker.
This wild horse was discovered and described in Central Asia by N.M. Przhevalsky in 1878. It was once widespread, but by the end of the 19th century it survived only in the south-west of Mongolia (in Dzungaria), where in 1967-1969 it was seen (in natural conditions) for the last time. Przewalski's horse herds consisted of 5-11 mares and foals led by a stallion. They were very mobile and constantly moved, which was determined by both scarce winter pastures and uneven rainfall in their habitats. Constant migrations have led to the fact that these horses have become very hardy and strong. They always emerged victorious from fights with domestic stallions.
The main reason for the destruction of the population in natural conditions is fishing (hunting, poaching) and competition for watering places with livestock. Almost immediately after the discovery of the animals, the owner of the Askania-Nova park F. Falz-Fein and later the animal dealer K. Hagenbeck began to look for opportunities to get these rare animals. In this struggle, various means were used. Hagenbeck, having learned about Falz-Fein's suppliers in Biysk, bought 28 foals with the help of his agents. Despite the fact that by the beginning of the 20th century, 52 purebred Przewalski horses were delivered to Europe, only three pairs served as a source for breeding. Przewalski's horse is kept in many zoos in the world; several dozen individuals live on semi-free content in the Askania-Nova nature reserve. An international plan has been developed for the reintroduction of the Przewalski horse to its original habitat - to the mountain-steppe zone of Mongolia.
TUSHKANCHIKA (jerboa, Dipodidae) - a family of mammals of the order of rodents; includes 11 genera and about 30 species, including three-toed dwarf jerboas, large jerboa, long-eared jerboa, and uplifted jerboa. jerboas are characterized by a large head with a blunt muzzle, long rounded ears, large round eyes and long vibrissae, a short kurgan body (body length 4- 26 cm ), small front legs, powerful hopping hind legs. Large ears, eyes and long vibrissae indicate a high development of hearing, twilight vision and touch, which are necessary for jerboas when searching for food and protecting from enemies at night. Small front legs are used for grasping and holding food, as well as for digging holes, in which jerboas achieve great skill. The hind limbs are jumping, and in connection with this function they are greatly modified: the foot is lengthened and the three middle metatarsal bones grow together into one common bone called the tarsus. The tail plays an important role in movement: it serves to maintain the balance of the body when jumping, especially when making sharp turns at a fast gallop. A black and white tassel at the end of the tail in many species is called a banner and serves as a signal for intraspecific communication. In addition to gnawing food, the incisors serve to loosen the soil when digging holes, while the limbs are used mainly to shovel off the loosened soil.
Jerboas are distributed from North and North-East Africa, South-East Europe, Asia Minor and Western Asia through the Caucasus, Central Asia, Kazakhstan, the extreme south of Siberia (Altai, Tuva, Transbaikalia) to North-East China and Mongolia. They are mainly found in semi-desert and desert landscapes, only some species inhabit the steppe zone, and some penetrate into the mountains to a height higher 2 km above sea level. Different species have developed adaptations for living on loose or dense soils, and therefore jerboas can be found in sandy, and in clay, and in rubble semi-deserts and deserts.
Jerboas are typically nocturnal animals. Before dawn, they hide in holes that they build themselves. The main run of the jerboa burrow runs obliquely under the surface with one or more blind emergency passages approaching almost to the surface. The main passage for the day is clogged with an earthen plug, which is called a pretty penny. For this pretty penny, which has not yet dried out in the early morning, you can find a burrow of a jerboa. If you start to dig an inhabited hole, then the animal knocks out the ceiling of one of the emergency passages and jumps out through it. In the far part of the main passage, the jerboa digs out a burrow with a rounded living chamber, which is lined with finely gnawed blades of grass. The jerboas spend the winter period in deep hibernation in their burrows.
The seeds of various plants, lily bulbs, which they dig up from the ground, serve as food for jerboas. The diet also includes green parts and roots of plants, and in some species, animal feed (small insects and their larvae) make up a significant proportion of the diet. In the spring and summer, animals breed, the female gives birth to 1-8 cubs (usually 2-5).
Jerboas play an important role in desert biocenoses. They have a significant effect on the soil and vegetation cover, serve as food for desert predators. In many areas, jerboas are background animals. Some species damage sand-hardening plants; they can be carriers of causative agents of a number of infectious diseases of animals and humans.
SANDS (Gerbillinae), a subfamily of mammals of the order of rodents; includes about 100 species, united in 13 genera, including dwarf, small, large, short-eared, fat-tailed gerbils, taters (barefoot gerbils). Outwardly, gerbils resemble rats or mice. Their body length is up to 19 cm , reddish-yellow long tail with a tassel. The back is yellow-sandy, the abdomen is white.
Gerbils are common in the desert steppes and deserts of Africa, Asia and Southeast Europe. They feed mainly on plant foods, but they can also eat small invertebrates. They do not hibernate for the winter, but in cold weather they do not leave their holes for a long time, feeding on prepared supplies. Many breed all year round, with females producing multiple litters ranging from 2 to 12 pups. Gerbils are carriers of the causative agents of the plague, tick-borne typhus, they harm agricultural land. These animals are often kept at home.
JEYRAN (Gazella subgutturosa), an artiodactyl mammal of the true gazelle genus (Gazella) of the subfamily of gazelles (Antilopinae); forms 2-4 weakly expressed subspecies. Body length 95- 125 cm , height at withers 60- 75 cm, weight 18-33 kg ... Males have black and lyre-shaped horns up to 40 cm ... Females are usually hornless. The coloration of the upper body and sides is sandy. The underside of the body, the neck and the inner side of the legs are white. The tail is two-colored: the main part is sandy, the end is black. When the frightened goitered gazelle runs, he lifts him up, and the tail stands out sharply against the background of the white mirror. For this feature, the Kazakhs and Mongols called the gazelle the black tail (kara-kuyryuk, hara-sulte). Young gazelles have a pronounced facial pattern in the form of a dark brown spot on the bridge of the nose and two dark stripes extending forward from the eyes.
Jeyran is widespread in Front, Middle and Central Asia, South Kazakhstan, as well as in Eastern Transcaucasia. It lives on flat, hilly deserts and cereal-saltwort semi-deserts. As good runners, gazelles prefer areas with dense soil, avoiding free-flowing sands. In summer, they graze in the morning and in the evening, and spend the hottest time on the beds, saving moisture. The beds are located out of the blue near trees, often favorite, and bushes. The geyran moves after the shadow of the tree, hiding from the sun, first of all, its head. Raised from a prone, the gazelle quickly jumps up and rushes at a speed of 55- 60 km / h about 200-300 m , then looks around. In winter, it grazes almost all day.
Jeyrans feed on herbaceous or shrubby plants, in summer choosing the most moisture-saturated herbs: barnyard, onions, feruls. To watering holes with open and flat banks without dense coastal thickets gazelles usually go for 10- 15 km every 3-7 days. They are able to quench their thirst not only with fresh, but also brackish water (including from the Caspian Sea). The herb that gazelles eat can also contain significant amounts of salt.
In spring and summer, animals are kept singly or in small groups of 2-5 heads. In autumn and winter, they gather in herds from several tens to hundreds of heads. Then the rut occurs. The beginning of the rut is preceded by the device by males of rutting latrines. In September, males dig small holes with the hooves of their forelegs and leave their excrement there. Other males, discovering such pits, can throw out old excrement and leave their own there. Obviously, such pits serve as markers of the occupied territory. Pregnancy of females lasts 5.5 months. In May, the female gives birth to one, rarely two cubs. Newborns first days only lie on a bare patch of land. The sandy-brown color of the gazelle merges so much with the soil that you can easily step on the baby without noticing him. The cub begins to follow the mother and feed on its own in two weeks. The main natural enemy of the gazelle is the wolf.
In captivity, the gazelle is well tamed and reproduces, but does not live long. The goitered gazelle population is declining, although work is underway to restore the number of animals. A subspecies from the Arabian Peninsula (Gazella subgutturosa marica) is listed in the International Red Book.
FENEK (Fennecus zerda) is a type of predatory animal of the wolf family. Outwardly it resembles a miniature fox. Body length about 40 cm , tail up 30 cm ; weight 1.5KG ; ears are large (up to 15 cm ) and wide. The coat is long, reddish-cream on top, pale yellow or almost white; the tip of the bushy tail is black. Fenech lives in the deserts of North Africa and Southwest Asia. He is active at night, spends the day in a deep burrow. Huge ears allow the Fenech to catch the slightest rustle. In case of danger, he buries himself in the sand. When hunting, Fenech can jump high and far. It feeds on small rodents, birds and their eggs, lizards, insects, carrion, and plants. Pregnancy in a female lasts 51 days. Cubs (2–5) are born in March – April in a burrow with a nesting chamber lined with grass, feathers and wool.
JACKALS, a group of species of carnivorous mammals of the wolf family. The most common is the Asiatic jackal (Canis aureus), which looks like a small wolf. Its body length is up to 85 cm , tail about 20 cm ; weight 7-13 kg. The color of the coat in winter is pale yellow, dirty yellow, with a noticeable reddish and black tinge, the tail is reddish-brown with a black end. It is found in the south of Eurasia, in North Africa; in Russia mainly in the North Caucasus. The Asian jackal prefers to settle in thickets of bushes and reeds, on plains, near rivers, lakes and seas. Less commonly, it is found in the foothills. The jackal uses natural niches and depressions, crevices among stones, and sometimes abandoned burrows as shelters. The beast is active mainly in the dark, but often during the day. He makes migrations only in search of food.
The jackal is omnivorous, but feeds mainly on small animals: rodents, birds, fish, as well as insects, carrion and the remains of the prey of large predators. He also eats fruits and berries, including grapes, watermelons, melons, and plant bulbs. Living near the villages, he also hunts poultry. When going out to hunt, the jackal makes a loud howl, which is picked up by all its relatives who are nearby. They hunt more often singly or in pairs. The jackal forms pairs for life, the male takes an active part in creating a burrow and raising offspring. The rut takes place from January to February. Pregnancy lasts about 2 months. Usually 4–6, less often 8 puppies are born. The Asian jackal is a carrier of dangerous diseases (rabies and plague). It has no commercial value.
The scooped jackal (Canis mesomelas) and the striped jackal (Canis adustus) live in East and South Africa. In lifestyle and habits, they are similar to the Asian jackal. The Ethiopian jackal (Canis simensis) is found in Ethiopia. Outwardly, he looks like a dog with a fox head. A wide black stripe stretches along the middle of the back, sharply delimited from the red sides and limbs. The belly is white, the tail is long red, with a black end. Ethiopian jackal lives in the mountains at an altitude 3000 m , it feeds on rodents and hares. Its numbers are small and this animal is protected.
COYOTE (meadow wolf, Canis latrans), a carnivorous mammal of the wolf family. Body length about 90 cm , tail - 30 cm ... Erect ears, a long fluffy tail, which he, in contrast to the wolf on the run, keeps down. The coat is thick, long, grayish or reddish-brown on the back and sides, very light on the belly. The end of the tail is black. The coyote is distinguished by a developed higher nervous activity, it is able to adapt to a changing habitat.
Coyote lives in the prairies and steppes of North and Central America. He runs into the woods by accident. His lifestyle has a lot in common with the jackal. It makes a lair in caves, hollows of fallen trees, deep holes. The loud howl of a coyote is an integral part of the prairie flavor. It feeds on rodents, hares, rabbits, birds and lizards, sometimes fish and fruits, and does not disdain carrion. Pets (goats, sheep) are rarely attacked. It hunts both alone and in a pack; destroys a lot of harmful rodents. It is completely safe for humans. Couples are formed for life, rut takes place in January-February. Pregnancy lasts 60-65 days. In a brood there are 5-10, sometimes up to 20 cubs.
CARACAL (Felis caracal), a predatory mammal of the feline family, the genus of cats. Body length 65- 82 cm , tail 20- 31 cm ; weight 11- 13 Kg ... It resembles a lynx in appearance and tassels on the ears. But it has a thinner, slender body, on high thin legs; also has a uniform light red color. There are small black markings on the muzzle and ears, the ends of the ears are decorated with tassels.
Inhabits the deserts of Africa and Asia, including the south of Turkmenistan. It hunts mainly at night, and during the day it takes refuge in abandoned burrows. Caracal hides prey and overtakes it in large (up to 4.5 m ) by jumping. It mainly feeds on rodents: gerbils, jerboas, ground squirrels, as well as tolai hares; less often birds, small antelopes, hedgehogs, porcupines. Can hunt livestock and poultry.
Cubs (1 to 4) are born in early April. In ancient times, caracals were trained to hunt antelopes, hares and birds. It has no commercial value. Small in number. Caracal is listed in the International Red Book. Protected in the Repetek Nature Reserve.
KULAN (onager, Equus hemionus), equid-hoofed mammal of the genus of horses. Body length 2.0- 2.4 m , height at withers 110- 137 cm , weight 120- 127 kg ... In appearance, the kulan is slender and light. The head is relatively heavy, the ears are longer than those of a horse. The tail is short, with a black-brown brush at the end, like donkeys and zebras. Coloring sandy-yellow in various shades. The belly and inner parts of the legs are white. From the withers to the croup and along the tail there is a narrow black-brown stripe. The mane is low.
Kulan is distributed in the Front, Middle and Central Asia. However, the once large area has been significantly reduced. The number is restored only in reserves, including in the south of Turkmenistan (Badkhyz reserve). The kulan was brought to the Barsakelmes island and to the foothills of the Kopetdag. Habitats depend on territorial characteristics. The animal can inhabit hilly plains or foothills, deserts and semi-deserts. With the exception of spring, when the pastures are covered with young succulent grass, kulans need daily watering and do not move further from water bodies than 10- 15 km ... In case of danger, they can reach a speed of 60- 70 km / h without slowing down the pace for several kilometers. There are no strictly defined periods of grazing and rest.
The kulan treats most animals, except for sheep, peacefully, often grazing with gazelles and herds of horses. These animals have developed mutual communication, should the gazelles be on the alert, or anxiously shout to the birds, as the kulan darts off the spot. The angry kulan is very ferocious.
Kulans have well-developed eyesight, hearing and smell. Approach the kulan unnoticed at a distance of 1- 1.5 km impossible. However, he can walk past a motionless person at a distance. 1.5 m , and this is due to the peculiarities of his visual apparatus. Kulans hear the camera click in the distance 60 m ... They are silent animals. With a cry reminiscent of a donkey, but more deaf and hoarse, the male calls the herd.
The rut takes place from May to August. During the rutting period, the male starts prancing in front of the females, holding his head high. Often he runs around the herd, jumps, screams, rolls on his back, tears with his teeth and throws up bundles of grass.
Even before the start of the rut, adult males drive out young kulans from the herds. During this period, there are serious fights between males. Baring their mouths and pressing their ears, they, with their eyes filled with blood, rush at each other, trying to grab the hock. If one manages to do this, then he begins to twist the opponent in a circle on the axis and gnaw his neck.
Pregnancy of females lasts 331-374 days, on average 345. Kulanits are born from April to August. The first hours they lie motionless, but already on the first day they begin to graze with their mother. The grown up kulanok becomes very active. When he is hungry, he walks around his mother, digs the ground with his foot near her belly, throws his legs around her neck. The male protects the young from possible attacks of young kulans. In captivity, animals breed. Kulans are universally protected, two subspecies - Syrian (Equus hemionus hemippus) and Indian kulan (Equus hemionus khur) are included in the International Red Book.
CAMELS (Camelus), a genus of mammals of the family of camelids of the order of calluses; includes two types: dromedar (one-humped) and bactrian (two-humped). Length up to 3.6 m ... Camels are characterized by signs: they do not have hooves - their legs end in two toes with blunt claws, and the lower surface of the foot is protected by an elastic callous pillow. They are common in the deserts of Central Asia (Bactrian), as well as in Africa, Arabia, Asia Minor, India (dromedar).
Camels feed on shrub and semi-shrub hodgepodge, tree leaves, and bulbs. The well-known ability of camels to do without water for a long time is due to the fact that they can tolerate a slight increase in body temperature without increased moisture yield. This feature allows you to spend less moisture on cooling. In addition, moderate dehydration in a camel is not accompanied by thickening of blood and impaired circulation, as in mammals that are not adapted to desert conditions. Camels are able to drink quickly and a lot (they drink about 130-135 liters of water in 10 minutes).
The rut takes place in winter. Usually one, rarely two cubs are born. Only the Bactrian survived in the wild. Dromedar is domesticated and used as a pack and draft animal, as well as for milk, meat and wool.
BACTRIAN is a domesticated bactrian camel, not much different from the wild bactrian camel. Many zoologists do not distinguish between the two-humped camel and the Bactrian. Domestic camels have more humps, wider feet, and well-developed calluses on the knees of the forelegs. The proportions of the skull of domesticated and wild have small but consistent differences. The color of the coat of domestic camels is variable - from light, sandy-yellow to dark brown, while wild ones have a permanent reddish-brown-sandy color. The bactrian camel was domesticated over a thousand years BC. As an animal resistant to low temperatures and anhydrous conditions, it spread in Mongolia, North China and Kazakhstan. There are several breeds of domestic bactrian camels - Kalmyk, Kazakh, Mongolian.
DROMEDAR (dromedary, one-humped camel; Camelus dromedarius), a mammal of the genus of camels of the order of calluses. Length approx 2.1 m , height at withers 1.8- 2.1 m ... Unlike Bactrian, it has one hump and a shorter and lighter coat. The one-humped camel was domesticated in ancient times, probably in Arabia or North Africa. Does not occur in the wild. It is widespread in Africa, Arabia, Asia Minor and Central Asia, India, introduced to Mexico and Australia. Several breeds are known: high-speed riding mahari (North Africa), riding Indian Rajputan, pack Turkmen dromedary.
The way of life is similar to the Bactrian. Better tolerates heat, but worse - frost. Up to 10 days can do without water. Passes under the saddle in a day 80 km with speed up to 23 km / h ... However, in the caravan, the dromedar passes no more than 30 km , since it must graze for a long time. Herbivorous. The rut takes place in winter. When crossed with Bactrian, it produces fertile offspring (the so-called bunks), which are superior in endurance to their parents. But the offspring when crossing hybrids turns out to be weak.
Deserts and semi-deserts of Eurasia stretch from the Caspian lowland to China. In Russia, this occupies the territory of the southeastern regions of the country. The Arctic desert is located in the north. A distinctive feature of deserts and semi-deserts is the high fluctuation in winter and summer temperatures. Semi-deserts are located in the northern part of the natural area. The climate here is milder, so they are characterized by a steppe landscape. Closer to the south, where it becomes arid, and the vegetation cover practically disappears, there is a desert zone.
Geographical location and natural conditions
Arctic desert, as well as deserts and semi-deserts on the map of Russia
In the area of the left bank of the Volga, deserts and semi-deserts extend to Kazakhstan. The lands from the right bank of the river extend to the foothills of the Caucasus. The territories lie on the Caspian lowland, which is a flat area. Millions of years ago there was a seabed here. Most of the deserts are flat ground, and only in the west are steep slopes.
Climate
The natural zone is located in an area of sharply continental climate. Rains and snows are infrequent, which is why the climate is dry but harsh. Most of the rainfall occurs in spring and summer. The evaporation rate exceeds the amount of precipitation.
Strong daily and annual temperature ranges are observed in the desert. During the day, the temperature difference can reach thirty degrees Celsius. In winter, the thermometer drops to -30 ° C, the winds are raging. Their gusts blow off the snow cover from the soil, which makes it black. Summer temperatures exceed + 40 ° C. It rarely rains, but dust storms and dry winds often occur.
Vegetable world
The soils on the territory of the semi-deserts are saline, since they are based on ancient marine rocks. On the territory of semi-deserts, wormwood-cereal vegetation grows. The lands contain little humus, and as a result of human economic activity they turn into mobile sands, therefore they are infertile. Nevertheless, the vegetation cover of the natural zone is variegated. Sarepta feather grass, fescue, white wormwood, black wormwood, desert wheatgrass, viviparous bluegrass grow here. From April to November, semi-desert lands are used as pastures. In June, with the onset of the dry period, vegetation disappears and the semi-desert becomes desert-like.
Closer to the south, the climate becomes arid, and the land turns into a real desert. It is customary to divide it into two subzones: northern and southern. In the northern part, the climate is mild. It is dominated by semi-shrubs: salt marsh barnyard, gray quinoa, krasheninnikovia. adapt to the conditions of existence, many of them are leafless in order to reduce moisture evaporation. Vegetation in one form or another is found throughout the desert. In the southern part there are small trees and shrubs: sandy acacia, Richter's hodgepodge, white saxaul. These areas also serve as pastures.
Animal world
In the zone of semi-deserts and deserts, there are many who have adapted to the harsh conditions. Animals dig deep holes to wait out the heat of the day in them. The optimal conditions for existence in the harsh conditions of the natural zone have developed jerboas, ground squirrels, mice and voles.
During the polar night, which lasts 90 days, winter sets in. Summer comes with a polar day. There are no transitional seasons. Winter temperatures are low, down to -60 ° C. Little precipitation falls. The winds blow off the snow cover from the soil. Summer is short-lived. The air temperature in July is + 3 ° C. During the polar day, the sun does not warm the air well. Snow does not melt 300 days a year, and winter comes overnight.
Trees and shrubs are completely absent. The lands are covered with lichens and mosses in summer. Sedge and grasses grow on stony ground. In the Arctic desert in summer you can find green oases with polar poppies, saxifrage, buttercup and arctic pike.
The soil thaws by 40 cm. Iron oxides accumulate in the upper part, which gives the earth a brown hue. There is sand and stones on the surface. Spherical formations, spherulites, are a landmark of cold deserts.
The fauna is scarce. The animals that live in the arctic desert feed on seafood. Polar bears, leading a semi-aquatic lifestyle, breed off the coast of Chukotka, on Franz Josef Land. In the Arctic reserve "Wrangel Island" dens have been created for them. Arctic foxes, lemmings, hares, and reindeer come from for the summer. Seals and walruses arrange their rookeries on the coast. Birds are considered the most numerous class. Bird markets are organized by eiders, gulls, tundra partridges, guillemots, and terns. When the polar day comes, white geese, geese, plovers and black-throated goose rush to the Arctic.
Ecological problems of deserts and semi-deserts of Russia
The main threat to the transformation of deserts into wastelands is human intervention. Recent scientific research has shown that these zones contain oil and natural gas deposits. Due to technological progress, the need for them is constantly growing. Oil production pollutes the surrounding areas more than others. Getting "black gold" into it entails an ecological catastrophe.
The zone of deserts and semi-deserts of Russia is home to many different species of animals, some of which are listed in the "Red Book". Poaching puts the existence of valuable animals into question for survival. The desertification process itself is damaging agriculture. The number of pastures is decreasing.
Due to anthropogenic influence in the Arctic, ice is melting, as a result of which the zone of the Arctic deserts itself is shrinking. If it is gone, a large number of flora and fauna will disappear from the face of the Earth. Snowmobiles and other land vehicles are polluted by exhaust emissions. Ozone holes negatively affect the life of animals. destroys mining, waste,. Large fish species are threatened with extinction. Their food, small fish and seafood, is caught by humans on an industrial scale.
Deserts and semi-deserts need our protection. Already today there are reserves in the territories, but this is not enough. The work on the protection of natural zones must be monitored at the state level. Every effort should be made to resolve existing problems so that new ones do not arise.
natural zone forest-steppe tundra
The semi-desert zone enters the Russian Plain only in the southeast, occupying the Ergeni Upland and the northern half of the Caspian Lowland. Its southern border to the west of the Volga runs at a distance of about 150 km from the coast of the Caspian Sea; in the Volga-Ural interfluve, it moves further from the sea and passes here along the line: Lake Baskunchak - Lake Aralsor - the mouths of the Small and Big Uzen - the Ural River south of Kalmykov.
The location in the southeast of the Russian Plain in the interior of the Eurasian continent determines the sharply continental, dry climate of this zone. Summer in semi-deserts is sultry and sunny. The average July temperature reaches 23-25 °, in the city of Novouzensk during the warm period 85 days are dry winds. Winter is as cold as on the Kola Peninsula: the average January temperature is -7-8 ° in the south-west of the zone and -13-14 ° in its northeast. The snow cover is thin - from 10 to 30 cm. The total annual precipitation is 300-200 mm; this is three to four times less than the volatility value. For example, in the city of Novouzensk, the annual precipitation is 250 mm, and the evaporation rate is 910 mm.
Surface runoff in the semi-desert is negligible, so its own river network is not developed in it. The groundwater is saline and mostly not potable.
In addition to the climate, the strongest impact on the landscape of the zone is exerted by the geological and geomorphological features of the territory - low absolute height, flatness, weak erosional dissection, the presence of saline bedrock and Quaternary rocks. There are few ravines and beams in the zone. Instead of these erosional forms, closed hollow-depression forms are widespread - steppe depressions, estuaries, sores, etc. Their genesis is different - from suffusion-subsidence to karst and tectonic (some estuaries).
The continental climate, flat relief and saline soils contribute to the accumulation of salts, including easily soluble salts, in the soils of semi-deserts. Salt licks are as characteristic of semi-deserts as light chestnut soils, which are zonal here. Lack of moisture and soil salinity lead to discontinuous, curtain, distribution of vegetation. The abundance of hollow-depression forms causes an extraordinary variegation, complexity of the vegetation and soil cover. With a lack of moisture, even the smallest depressions - 10 - 20 cm deep - lead to dramatic changes in soil and vegetation. We can say that the semidesert is a zone of complexes, in which the grassy steppe is closely intertwined in depressions, the wormwood-saltwort desert on salt licks and the fescue-chamomile semidesert itself on light chestnut soils.
In the animal kingdom of semi-deserts, an outstanding role belongs to rodents. Among them, by their abundance and impact on the landscape, ground squirrels stand out, represented here by two species - the small ground squirrel living on loamy plains, and the yellow ground squirrel inhabiting the sands. The occurrence of gophers is very high. In some places, one hectare can count up to 740-750 gopher burrows. Emissions of ground squirrels create a tubercle microrelief characteristic of the Caspian region, which further enhances the complexity of the soil and vegetation cover.
In addition to ground squirrels, common rodents in the semi-desert are jerboas, gerbils, voles, steppe pieds, and mice. The saiga antelope, which previously inhabited the steppe and forest-steppe zones of the Russian Plain, is found within the zone. In some places, a wild boar is found along the reed thickets of river valleys. Of the predators, the wolf, the corsac fox, and the steppe polecat are common.
The composition of birds (steppe eagle, harrier, larks), reptiles and insects is also quite diverse.
Most of the semi-desert area is used for pasture. In some places estuary and irrigated agriculture is developed.
The southern third of the Caspian lowland belongs to the desert zone. Due to the small size of the territory and the uniformity of geological and geomorphological conditions, the desert zone on the Russian Plain belongs to one landscape province - the province of sandy and clayey-saline deserts of the Caspian region. The dry and continental climate, characteristic of the southeast of the Russian Plain, reaches its maximum in the desert zone. The annual amount, precipitation in deserts is less than 200 mm. In the city of Astrakhan, an average of 170 mm of precipitation falls per year, with an evaporation rate of 936 mm. Winter is extremely snowy, even by the end of its depth the snow cover does not reach even 10 cm. For this reason, the Caspian desert, especially west of the Volga (Black Lands), where winters are warmer, is a good winter pasture.
Surface runoff in deserts is so insignificant (less than 0.5 l / sec) that not a single local river crosses the territory of the province.
Geologically, the territory of the Caspian Desert is very young; its coastal parts have recently become dry land. In contrast to the semi-desert, the desert zone in the Quaternary was flooded with all three transgressions of the Caspian Sea, including the Khazar one. Almost the entire territory of the province lies below sea level.
Huge areas in the desert are occupied by sands of marine (late Khvalynian Sea) and alluvial-deltaic origin. The area of the Volga-Ural sands alone is about 50 thousand km3.
On the coast of the Caspian Sea, and especially near the Volga delta and to the west of it, there are Baer hillocks. More precisely, these are low (6-20 m) and long (from several hundred meters to 5-6 km) sandy ridges, mainly in the latitudinal direction. First described by Academician K.M.Ber, the hillocks have then more than once served as an object of special study. A variety of hypotheses have been put forward regarding their genesis - eolian, tectonic, water-erosional, water-accumulative and many others. Most likely, their formation should be associated with the accumulation and movement of sediments by the waters of ancient sea basins retreating to the south. Later, part of the hillocks underwent aeolian reworking. Brown desert-steppe soils appear in the soil cover of deserts; salt marshes stretch along the shores of the Caspian in a wide strip. Vegetation is closely dependent on soil. On saline clayey soils, there are wormwood-saltwort groups. The vegetation of sandy deserts, characterized by a shallow bed of fresh groundwater, looks more diverse. It is formed by cereal-wormwood groups with the participation of bluegrass (Poa bulbosa), Siberian wheatgrass (Agropyrum sibiricum), prutnik, and milkweed. In the north-west of the Volga-Ural sands in the Urdinsky sands, rich in fresh water, small groves of poplar and aspen have survived, orchards and melons are cultivated.
Deserts are used as pastures and grasslands. Horticulture, horticulture and melon growing are developed in the wide Volga-Akhtuba floodplain. The area of floodplain land used for agriculture is still small and can be successfully increased many times over.
Natural semi-desert zones are land areas characterized by a dry climate with significant daily temperature drops and low average annual precipitation (about 150 mm / year). These territories are arid, characterized by scarce surface water runoff, which determines the increased content of salts in the soil. Often water bodies and rivers in these areas tend to dry up; during a drought period, their bottom is covered with a layer of salt. In the semi-desert zone, vegetation mainly consists of grasses and low-growing shrubs.
Characteristics of the natural semi-desert zone.
Semi-deserts are located on all continents, except Antarctica, in three climatic zones: temperate, tropical and subtropical. They are dominated by landscapes formed as a result of the action of strong winds; the steppe relief is interspersed with stone mounds or hills.
Another map showing the location of the semi-deserts.
The semi-deserts of the temperate zone in Eurasia stretch from the Caspian lowland to the borders of China. In North America, this zone is located in the foothills of the Rocky Mountains and in the lowlands of the Great Basin. In South America, it is located east of the Andes. Climate characterized by low winter temperatures (up to -25 degrees) and high summer temperatures (up to +30 degrees). Soil brown and light chestnut (Fig. 1 (1)), with a low humus content (about 2%), they include gypsum and a large amount of salts, in some places saline soils and salt marshes are common (Fig. 1 (2, 3)), which can be used for agricultural use only under the condition of artificial irrigation and a decrease in salinity.
The tropical semi-desert zone in Africa combines features of savannah and desert, located to the south of the Sahara, in the humid zone of the Namibian desert, in the northeast of the Kalahari Desert, it is also located in India and Pakistan, on the Arabian Peninsula, in South America on the Brazilian Highlands, in Australia. The maximum summer temperatures reach 50 degrees, the minimum winter temperatures are about 12-15 degrees above zero. Red-brown clayey soils, prone to erosion processes, prevail. (Fig. 2)
The subtropical semi-desert zone is located in the mountains of North and South America, Australia, the Iranian Highlands, North and South Africa. The climate is moderately continental with summer temperatures up to 25 degrees, winters are characterized by a drop in temperatures to 0 degrees with rather rare snowfalls. The soils are sparse, gray-brown and sierozem with rubble inclusions. (fig. 3)
Salt Lake.
Semi-desert in the foothills of the Colorado Plateau.
