Northern Andes. The northern part of the Andes belongs to the subequatorial belt of the northern hemisphere; here, as in the subequatorial belt of the southern hemisphere, there is an alternation of wet and dry seasons; precipitation falls from May to November, but the wet season is shorter in the northernmost regions. The eastern slopes are much more humid than the western ones; precipitation (up to 1000 mm per year) falls mainly in summer.
In the equatorial belt, seasonal fluctuations are practically absent; for example, in the capital of Ecuador, Quito, the change in average monthly temperatures per year is only 0.4 °C. Precipitation is plentiful (up to 10,000 mm per year, although usually 2,500-7,000 mm per year) and is more evenly distributed over the slopes than in the subequatorial zone.
Caribbean Andes. Located on the border between the subequatorial and tropical zones, the Caribbean Andes, especially the islands and peninsulas of Paraguana and Goajira, have a drier climate than neighboring areas. Throughout the year they are under the influence of tropical air brought by the northeast trade wind. Annual precipitation does not exceed 1000 mm, but more often they are even lower than 500 mm. Most of them fall from May to November, but in the driest northern regions, the wet period lasts only two to three months. Small short streams flow down from the mountains towards the Caribbean Sea, carrying a large amount of detrital material to the shore; places where limestones come to the surface are almost completely waterless.
Northern Andes. The northern Andes are characterized by a clearly defined system of altitudinal belts. In the lower part of the mountains and on the coastal lowlands, it is humid and hot, there is the highest average annual temperature in South America. At the same time, there are almost no seasonal differences. In the lowlands of Maracaibo, the average temperature in August is + 29 ° С, the average in January is + 27 ° С. The air is saturated with moisture, precipitation falls almost the entire year, their annual amounts reach 2500-3000 mm, and on the Pacific coast - 5000-7000 mm.
The entire lower belt of mountains, called the "hot land" by the local population, is unfavorable for people's lives. High and constant air humidity and sweltering heat have a relaxing effect on the human body. Vast swamps are breeding grounds for various diseases.
Above the lower hot mountain belt is the temperate zone of the Northern Andes, rising to a height of 2500-3000 m. This belt, like the lower one, is characterized by an even temperature course throughout the year, but due to the height there are quite significant daily temperature amplitudes. Strong heat, characteristic of the hot zone, does not happen. The average annual temperature ranges from +15 to +20°C, the amount of precipitation and humidity are much less than in the lower zone. The amount of precipitation is especially strongly reduced in closed high-mountain basins and valleys (no more than 1000 mm per year).
The local population calls the next belt of mountains "cold land". Its upper limit lies at an altitude of about 3800 m. Within this zone, a uniform temperature is maintained, but it is even lower than in the temperate zone (only +10, +11 ° C).
The next altitudinal belt of the Northern Andes is alpine. Among the local population, it is known as "paramos". It ends at the border of eternal snows at an altitude of about 4500 m. The climate is severe within this belt. With positive daytime temperatures in all seasons, there are strong night frosts, snow storms and snowfalls. There is little precipitation, and evaporation is very strong.
Above 4500 m in the Northern Andes begins a belt of eternal snow and ice with a constantly negative temperature. Many massifs of the Andes have large alpine-type glaciers. They are most developed in the Sierra Nevada de Santa Marta, Central and Western Cordillera of Colombia. The high peaks of the Tolima, Chimborazo and Cotopaxi volcanoes are covered with huge caps of snow and ice. There are also significant glaciers in the middle part of the Cordillera de Mérida.
Central Andes. The Central Andes are dominated by desert and semi-desert landscapes. Between 5° and 28° S sh. there is a pronounced asymmetry in the distribution of precipitation along the slopes: the western slopes are much less moistened than the eastern ones. To the west of the Main Cordillera there is a desert tropical climate (which is greatly facilitated by the cold Peruvian current), there are very few rivers. If in the northern part of the Central Andes 200-250 mm of precipitation falls annually, and most of them fall in the summer, then to the south their amount decreases and in some places does not exceed 50 mm per year. In this part of the Andes is the Atacama - the driest desert in the world. At some points east of the Cordillera Coast it never rains. In the coastal zone (up to a height of 400-800 m), the lack of rain is somewhat compensated by high relative humidity air (up to 80%), fogs and dews, which usually occur in the winter season. Some plants are adapted to live on this moisture.
The cold Peruvian current moderates the temperature on the coast. The average January temperature varies from north to south from +24 to + 19°C, and the average July temperature varies from +19 to +13°C.
Soils and vegetation are almost non-existent in the Atacama. Individual ephemeral plants that do not form a dense cover appear during the foggy season. Large areas are occupied by saline surfaces, on which vegetation does not develop at all. The slopes of the Western Cordillera, facing the Pacific Ocean, are also very dry.
Deserts rise in places up to 3000 m above sea level. A few oases are located mainly in the valleys of small rivers fed by the waters of mountain glaciers.
The deserts of the Pacific coast merge with a belt of mountainous semi-deserts known as the dry puna. Dry puna extends to the southwestern part of the internal plateaus, to a height of 3000 to 4500 m, in some places falling even lower. Precipitation in the dry puna is less than 250 mm, with a maximum in the summer. In the course of temperature, the continental climate is manifested. The air is very warm during the day, but cold winds in the warmest season can cause severe cooling. In winter there are frosts down to -20°C, but the average monthly temperature is positive. The average temperature of the warmest months is +14, +15°C. In all periods of the year, there is a great difference in the temperatures of day and night. Precipitation falls mainly in the form of rain and hail, but there are also snowfalls in winter, although there is no snow cover.
At low altitudes, with an extremely small amount of rain, significant (up to 80%) air humidity, so fogs and dews are frequent. The Altiplano and Puna plateaus have a very harsh climate, with average annual temperatures not exceeding 10°C. The large Lake Titicaca has a moderating effect on the climate of the surrounding areas - in the lakeside areas, temperature fluctuations are not as significant as in other parts of the plateau. To the east of the Main Cordillera - a large (3000 - 6000 mm per year) amount of precipitation (brought mainly in the summer by east winds), a dense river network. In the valleys, air masses Atlantic Ocean cross the Eastern Cordillera, moistening its western slope.
Due to the fact that the amount of precipitation increases in the east up to 800 mm, and in the north even up to 1000 mm, the vegetation becomes richer and more diverse, the mountain semi-desert passes into the mountain steppe, which the local population calls "puna".
The Punas occupy vast territories in the Central Andes. In Peru and Bolivia, especially along the shores of Lake Titicaca and in the most humid valleys, before the arrival of the Spaniards, they were inhabited by cultural Indian peoples who formed the state of the Incas. The ruins of ancient Inca buildings, stone-paved roads and the remains of irrigation systems are still preserved. The ancient city of Cusco in Peru at the foot of the Eastern Cordillera was the capital of the Inca state.
Above 5000 m in the south and 6000 m in the north, the temperature is negative throughout the year. Glaciation is insignificant due to the dryness of the climate, only on the Eastern Cordillera, which receives more precipitation, there are large glaciers.
The landscapes of the Eastern Cordillera differ significantly from the landscapes of the rest of the Central Andes. Humid winds bring a significant amount of moisture from the Atlantic Ocean in summer. Partly through through valleys, it penetrates the western slope of the Eastern Cordillera and adjacent parts of the plateaus, where heavy rainfall occurs.
Chilean-Argentine Andes. In the Chilean-Argentine Andes, the climate is subtropical, and the moistening of the western slopes - due to winter cyclones - is greater than in the subequatorial zone; when moving south, the annual precipitation on the western slopes increases rapidly. Summer is dry, winter is wet. The area of distribution of this climate covers the coast between 29 and 37 ° S. sh., the Central Valley and the lower parts of the western slopes of the Main Cordillera. In the north, a transition to semi-deserts is planned, and to the south, an increase in precipitation and the gradual disappearance of the summer drought period mark the transition to the oceanic climate of temperate latitudes.
As you move away from the coast, the climate becomes more continental and drier than on the shores of the Pacific Ocean, and seasonal temperature fluctuations increase. In Valparaiso, the temperature of the coolest month is + 11°С, and the warmest is +17, +18°С, seasonal temperature amplitudes are small. In the Central Valley, they are more palpable. In Santiago, located in the Longitudinal Valley, the average temperature of the coldest month is +7, +8°C, and the warmest is +20°C. Precipitation is scarce, increasing from north to south and from east to west. About 350 mm falls in Santiago, and 750 mm in Valdivia. Farming in these areas requires artificial irrigation. On the western slopes of the Main Cordillera, precipitation is more than in the Longitudinal Valley (but less than on the Pacific coast).
When moving south, the subtropical climate of the western slopes smoothly passes into the oceanic climate of temperate latitudes: the annual precipitation increases, and the differences in seasonal moisture decrease. Strong westerly winds bring a large amount of precipitation to the coast (up to 6000 mm per year, although usually 2000-3000 mm). More than 200 days a year go heavy rains, often descend on the coast thick fogs, the sea is constantly stormy; the climate is unfavorable for living. The eastern slopes (between 28° and 38°S) are drier than the western (and only in the temperate zone, south of 37°S, due to the influence of westerly winds, their moisture increases, although they remain less humid compared to Western). The average temperature of the warmest month on the western slopes is only 10--15°C (the coldest -- 3--7°C)
Southern (Patagonian) Andes. The climate of Southern Chile is humid, with little difference in temperature between summer and winter, and is very inhospitable to humans. The coast and the western slopes of the mountains are under the constant influence of strong westerly winds, bringing a huge amount of precipitation. With an average number of up to 2000-3000 mm in some areas west coast falls up to 6000 mm of precipitation per year. On the eastern slope, leeward of the western air currents, the amount of precipitation decreases sharply. Persistent strong winds and rainfall over 200 days a year, low cloud cover, fog and moderate temperature during a year -- characteristics climate of southern Chile. On the coast itself and the islands, constant storms rage, bringing huge waves ashore.
With an average winter temperature of +4, +7°C, the average summer temperature does not exceed +15°C, and in the extreme south it drops to +10°C. Only on the eastern slope of the Andes do the amplitudes of fluctuations between the average temperature of summer and winter increase somewhat. At high altitudes in the mountains, negative temperatures prevail throughout the year; on the highest peaks of the eastern slope, frosts down to -30°C last for a long time. In connection with these features of the climate, it is snowy, the border in the mountains lies very low: in the north of the Patagonian Andes, at an altitude of about 1500 m, in the south - below 1000 m. Modern glaciation occupies a very large area, especially at 48 ° S. sh., where on the territory of more than 20 thousand km2 there is a powerful ice cover. This is the so-called Patagonian Ice Sheet. Powerful valley glaciers diverge from it to the west and east, the ends of which lie much below the snow line, sometimes near the ocean itself. Some glacial tongues of the eastern slope end in large lakes.
Glaciers and lakes feed a large number of rivers flowing into the Pacific and partly into the Atlantic Ocean. The river valleys are deeply cut into the surface. In some cases, they cross the Andes, and rivers starting on the eastern slope empty into the Pacific Ocean. The rivers are winding, full-flowing and turbulent, their valleys usually consist of lake-like extensions, followed by narrow rapids.
Fire Earth. The climate of Tierra del Fuego is very humid, with the exception of the extreme east. The archipelago is under the constant influence of sharp and humid southwesterly winds. Precipitation in the west is up to 3000 mm per year, and drizzling rains prevail, which go 300-330 days a year. In the east, the amount of precipitation decreases sharply.
The temperature throughout the year is low, and its seasonal fluctuations are negligible. We can say that the Tierra del Fuego archipelago is close to the tundra in summer temperature, and to the subtropics in winter.
The climatic conditions of Tierra del Fuego are favorable for the development of glaciation. The snow line in the west lies at an altitude of 500 m, and the glaciers break directly into the ocean, forming icebergs. Mountain ranges are covered with ice, and only individual sharp peaks rise above its cover.
The flora and fauna of the Andes is as variable and diverse as the relief and climate of this huge mountain system. The cocoa tree and the Antarctic beech grow here, and among the animals you can meet both the monkey and the Chilean deer.
In the equatorial section of the Andes (between 2 ° S and 5 ° N), where the climate is constantly hot and humid, red soils are formed and vegetation develops especially luxuriantly. Here, the lower parts of the slopes of the mountains are occupied by a humid equatorial forest. In this forest, as A. Wallace describes, “first of all, diverse, but generally symmetrical tree trunks are striking, which, without branching, reach a very significant height. Settling quite far apart, they give the impression of some kind of columns supporting a gigantic building.
Above, maybe 150 feet high, the foliage and intertwining branches of these huge trees form an almost continuous green canopy, usually so dense that the sky appears below as some kind of obscure radiance; even the dazzling light of the tropical sun reaches the earth much weakened, in the form of indistinct glare. Some kind of magical twilight reigns, a mysterious silence, and all this together gives the impression of something great, primitive, even boundless.
The trunks of trees in the forest are mostly covered with smooth bark, painted in whitish, green, yellowish, brown, sometimes almost black. Along with smooth trunks, there are trunks that are strongly fissured and wrinkled; in some, the bark is flaky, hanging down in long ribbons. Under the canopy of tall trees there are several tiers of lower trees. In the forest there are plants such as a cocoa tree with flowers located directly on the trunk and large branches, various palm trees. Especially valuable coconut palm: its unripe nuts give a very pleasant juice (coconut milk), coconut oil is obtained from the pulp of ripe nuts, and their shells are used for various small crafts, as they differ great strength. Tree ferns, various creepers, beautiful orchids grow in abundance in the forest. Orchids climb trunks and branches, flourish on fallen trunks, cover rocks and cliffs from top to bottom. Along the banks of the rivers, you can often see groves of graceful bamboos with their swaying foliage and straight, shiny trunks.
Throughout the forest, among palms and other trees, rubber plants - hevea and castilla - are scattered. Hevea is a large tree with a lush deciduous crown. When the bark of a tree is cut, sap flows out of it. If you hold this juice over the smoke of a fire, then it coagulates into a dense elastic brown mass. This is rubber, which Europeans first met when they saw Indian children bouncing balls (balls) upon impact.
There are no huge herds of mammals here, no large flocks of birds, the animals are scattered thick trees, hide in their foliage and give out their presence only with rare and sharp sounds.
A. Wallace describes his impressions of the animals of the rainforest in this way: “The rare cries of birds are melancholic, mysterious in nature and rather increase the feeling of loneliness than bring animation. A sudden cry in the silence puzzles you: it is the cry of some defenseless, fruit-eating animal, seized by a tiger cat or a boa constrictor. In the morning and in the evening, howler monkeys raise a terrifying, heartbreaking roar, in the midst of which it is difficult to maintain complete mental concentration.
Among the insects in this forest, the most common are large, graceful in shape and richly colored butterflies and large ants. If butterflies amaze the observer with their beauty and variety of shapes and colors, then ants usually bake with their importunity. They live everywhere - on trees, in the soil; differing in great gluttony, ants feed on both plants and various insects.
Many birds nest in the dense foliage of trees. First of all, parrots are striking in the abundance and variegation of color. Most parrots are green, but it often fades to blue or dark blue, like some macaws, or yellow and dark orange, like some American wedge-tailed parakeets, or bright carmine, like some lorises. Toucans also stand out - large birds with huge, beautifully colored beaks and delicate chest plumage.
Numerous and varied in the forest are small birds - hummingbirds. Hummingbirds are very small; the largest - no more than a swallow, the smallest - no larger than a bumblebee. They have short legs and small paws, very long sharp wings, a long thin beak and a far protruding tubular tongue. In coloring, their main green tone is combined with blue, purple and various red tones. It can be said that in the plumage of a hummingbird the colors of all precious stones and metals. There are always feather decorations on the head, nape, chest and tail - brightly colored and contrasting with the rest of the plumage. They feed on flower nectar. Quickly rushing through the air, the bird hangs in front of the flower only for a moment, tastes it and rushes with lightning speed to another branch. The weight of a bird can be less than two grams, which is the weight of a bronze coin of 2 kopecks, and tiny testicles, the size of a pea, sometimes weigh only 0.2 grams. Interestingly, hummingbird chicks hatch from eggs blind, and only then begin to see.
In the equatorial Andes, some of the hummingbird species live even near the snow line.
Of the reptiles in the humid equatorial forest of the Andes, there are large iguana lizards that live on trees and feed on plants. These green lizards have a crest on their backs and a very long tail. Of the mammals, chain-tailed monkeys are especially typical - howler monkeys, spider monkeys, marmoset monkeys - small, squirrel-like animals with tufts of hair on their heads.
The humid equatorial forest rises along the western and eastern slopes to a height of 800-1000 m. Above the slopes are covered with mountain forest. The air here is constantly humid, rain, fog, and dampness are common phenomena. In this forest, which covers the mountains to a height of 2500-2800 m, tree fern, bamboo, cinchona grow. Cinchona trees grow sparsely, without forming dense thickets. The trees are intertwined with vines, densely covered with various climbing plants, among which there are especially many bromeliads.
The higher the mountains, the cooler the climate. The nature of the forest is also changing markedly. Tree-like ferns disappear, bamboo becomes lower and smaller, long and thick lianas, twisting around trees to the tops, are replaced by thinner ones, climbing low or even creeping along the ground, deciduous forest becomes lower and rarer, a dense undergrowth of shrubs and grasses appears in it. at an altitude of 3000-3800 m the forest disappears.
Above the forest line in the equatorial Andes lies the paramo belt. This belt occupies the upper slopes of the equatorial Andes, rising to eternal snow and ice. A characteristic feature of the Paramo climate is the lack of expression of the seasons of the year. The average temperature all year round is within 8-10°. But during the day you can experience both the heat of the sun and the chill from the cold wind; get wet in the rain and dry again in the bright sun. The morning is usually clear and calm at first, but then a strong wind rises from about 10 o’clock, and around noon “paramo closes”, as the locals say, that is, everything is covered with a thick cover of fog, which dissipates only in the evening or at night. There are often heavy rains accompanied by snow or snow pellets; sometimes drizzling rains continue for several hours, penetrating everything around with cold and dampness.
The vegetation of this belt is dominated by grasses, the cover of which gives the area a brownish-yellow hue. On an even background of a grassy cereal steppe, tall composite plants - espeletia - stand out as separate specimens or groups. They rise up to 3-5 m in the form of columns, densely dressed with woolly felt and ending at the top with a fan-shaped bunch of hard, fleshy leaves.
To the north and south of the equatorial section of the Andes, the nature of the vegetation changes markedly. North of 5° N. sh. along the low coast of the Pacific Ocean, along the valleys of the Magdalena and Cauca rivers and along the lower parts of the mountain slopes, instead of the evergreen equatorial forest, a summer-green monsoon forest appears. During the dry season, most of the trees in this forest shed their leaves and only plants such as cacti, agaves, and collections remain green. This forest contains many valuable species of trees with very durable wood. Scattered among these trees are groups of palm trees, which stand out for their delicate feathery crown. The trees are intertwined with vines, among which vanilla is found.
For the forest growing on the slopes of the Western, Central and Eastern Cordillera, separated by the valleys of the rivers Magdalena and Cauca, cinchona is characteristic, but tree-like ferns and palm trees are rare there. But thickets of mimosas, agaves with fleshy foliage covered with needles, prickly prickly pear and squat cacti with sharp thorns and large pink flowers. Sometimes on swampy areas of the slopes there are dense thickets of huge bamboo, in which the damp soil is completely covered with a 30 cm high floater.
This mountain forest, gradually thinning, passes with height into shrub thickets and into the paramo belt, which is already torn here into separate sections.
North of 10° N. sh. The Andes enter the savanna zone - a tropical forest-steppe, where the main background is made up of tall grasses and shrubs. Thanks to the pronounced dry winter period here, only sparse vegetation can grow from drought-resistant hard-leaved shrubs, cacti, and a small amount of low-growing tree species. Thickets of shrubs and thorny twisted trees are known in Venezuela under the name chaparral. Areas overgrown with mimosas and cacti are called espinar. Savannah is also characteristic of the Guayaquil Bay area.
The middle part of the Andes, located in the tropical zone, is characterized by a great originality of vegetation cover, where you can find a desert (on the western slopes), and a mountain dry steppe, and a semi-desert (on the intermountain plateaus), and a tropical forest (on the eastern slopes).
The western slopes of the Andes in this part are deserted. In Peru, high candelabra-shaped cacti, leaf-shaped prickly pear and other plants grow on the western slopes. There are also thorny shrubs and semi-shrubs. In Chile, along with cacti, a cactus conifer, one type of feather grass and adesmia bushes with dry, resinous branches grow. Climbing up the western slopes, one can trace how shrubs and rare sods of feather grass gradually disappear and only cacti remain, as if scattered over huge landslides of gray-brown rocks.
Above 3000 m, the upland dry steppe begins - puna, common on the inner plateaus of the tropical Andes.
Pune has rather humid summers and cold, dry winters. During the day in summer it is very hot, but at night it is usually cold (due to the large radiation of heat) and the coastal areas of the lakes are covered with thin ice.
Humid summer brings to life here many plants that bloom and bear fruit. Pillow-shaped shrubs and semi-shrubs predominate, tightly pressed to the ground and adapted to sharp fluctuations in temperature, strong winds, and dry climate. Many evergreen dwarf shrubs with small leaves. Grasses dominate among herbaceous plants: feather grass, fescue, reed grass. In winter, plant growth stops, although many remain green. This time is characterized by considerable severity: temperatures can drop to -16 °, the air is very dry, cold winds often blow, causing dust and sand storms.
On the western edge of the intermountain plateaus between 16 and 30 ° S. sh. puna goes into tola. Tola, the local population calls dwarf evergreen shrubs, tightly pressed to the ground and similar from a distance to lichens. Tola differs from puna in greater dryness and emptiness.
In the fauna of the intermountain plateaus, rodents and ungulates predominate. Rodents get water along with the plants they feed on. Ungulates run long distances in search of water. Of the rodents, mountain viscacha and chinchilla are remarkable, distinguished by fluffy silvery fur; there are mice and shrews. Hunting for rodents, foxes live in the desert mountains. You can often see slender representatives of ungulates from the llama genus: vicuñas and guanacos.
Feathered predators hover over the mountain slopes: condors, kites, falcons. Less commonly, hummingbirds fly here. Lizards can often be found among sandy areas and stony placers, but no snakes.
The eastern slopes of the Andes in the tropical zone, characterized by a more humid climate, are covered with forest vegetation. In the northern half of the eastern slopes between 5 and 20 ° S. sh. a mountain forest is widespread, consisting of a cinchona tree, numerous lianas and other climbing plants (epiphytes). Unlike the montane forest of the equatorial zone, this tropical montane forest is not as dense and humid, especially during dry winters, when some trees shed their leaves.
South of 20°S sh. cinchona, tree ferns and bamboos are being replaced by others deciduous trees, among which alder is the most common. Most of the trees lose their leaves in the dry winter, and only the evergreen myrtles enliven the overall tone of the forest with their fine, glossy foliage. Trunks and branches of trees are also entwined with vines and epiphytes, and there are many herbaceous ferns in the undergrowth.
Subtropical Andes, located between 30 and 40 ° S. sh., differ markedly in the nature of the vegetation from the tropical area. On the coast, the slopes of the Coastal Mountains on the western slopes of the Andes, up to a height of 1500 m, evergreen trees and shrubs of the Mediterranean type are common. Shrubs and undersized, gnarled trees predominate. Closer to the coast, the remains of forest vegetation are still preserved: teak forests with epiphytes, ferns and mosses.
But these forests have not been preserved over large areas, and now instead of them gardens are growing green, in which lemons, oranges, quinces, figs, peaches, apples, pears, cherries, plums grow.
Further from the coast and along the western slopes of the Andes, thickets of evergreen shrubs are visible, among which there are cacti, as well as herbaceous bulbous plants - lilies, irises, amaryllis.
On the eastern slopes of the subtropical Andes, the vegetation has a more dry-loving character, since the climate there is much drier than on the western slopes. Up to a height of 1500 m and even higher, shrubs and semi-shrubs dominate, usually having a spherical shape. Among the hard half-meter bushes of barberry and other shrubs there are cacti, you can often see bare soil with salt efflorescence on the surface.
Above 1500 m, along the western and eastern slopes, a belt of mountain forest extends, which continues south of 40 ° S. sh. within the temperate zone. On the western slopes this forest is more varied and richer than on the eastern.
The species of the southern beech are most common in the forest - in the upper part of the slopes they are undersized, in the lower part they are tall. Along with beech forests, there are areas of coniferous ones: araucaria forests with straight trunks and umbrella-shaped crowns resemble pine forests from a distance. There are also coniferous forests from firzroy - evergreen trees up to 40-55 meters high. In the lower part of the western slopes one can find evergreen beeches and sphagnum bogs, which are also widespread in the vicinity of lakes wedged between volcanoes.
The well-known botanist I. M. Albov, who worked in the southern Andes and Tierra del Fuego, describes these swamps as follows: belts."
On the eastern slopes, the mountain forest belt consists almost entirely of southern beech, and only in its lower part is coniferous beech found - esedro.
Above 2000 and 2200 m, the upper parts of the slopes of the subtropical Andes are occupied by a belt of alpine meadows, which continues south into the temperate zone. This belt is not continuous and is often interrupted by rocks, glaciers, and deep gorges. Alpine (alpine) plants grow in the meadows, low, tightly pressed to the ground, but with bright flowers. These are red geranium, yellow ranunculus, white saxifrage, blue-yellow primrose, valerian, etc. In swampy areas, plants form dense moist cushions, on stony placers to screes, shrubs and semi-shrubs appear instead of grasses (barberry, currant, etc.).
The southern margin of the Andes is included in the temperate zone (south of 40 ° S). Here, in a cooler and more humid climate, other species of plants and animals appear. Along the Pacific coast and on the western slope of the Andes, moist, humus-rich soils are brown and brown, in places they become grayish due to leaching of humus and salts deep into the soil layer (podzolic soils).
In the forests, heat-loving plants are fancifully combined with cold-resistant ones. Evergreen magnolias and myrtle trees grow. Dense thickets are formed by low bamboo, at the foot of the trees, fuchsias, ferns, and barberries grow luxuriantly. Here and there, dense bunches of small berries or small bright flower buds turn red from under the thick of dark green shiny leaves. A carpet of beautiful grasses with yellow, blue and pink flowers spreads under the bushes. Of the conifers, slender araucaria, similar to pines with an umbrella-shaped crown, are typical;
In the picturesque beech forests, in addition to the evergreen beech, there is also a beech with falling leaves, which colors the forest in autumn with all shades - from red to pale yellow. Beech forests give a wonderful construction material. They constitute one of the main natural resources of the southern Andes. Forests rise along the western slopes up to 1200 m (near 40° S) and up to 400-500 m on Tierra del Fuego. The upper border of the forest is formed by thickets of southern beech bushes. Above, the belt of alpine meadows immediately begins.
The eastern slopes of the Andes in the temperate zone in its lower part are covered with low-growing forests and grass-shrub vegetation. On Tierra del Fuego, up to a height of 300-500 m, subantarctic forests grow from evergreen and deciduous beech, alternating with peat. Higher up the slopes, the forest gives way to an alpine meadow, some parts of which alternate with rocks, snow fields and glaciers.
In the forests of the Southern Andes, you can meet the Chilean deer, which are hunted by puma, wild cats. Sometimes a fluffy tail of a fox will flicker between the trees or a skunk (American stinker) will quickly run, defending itself from pursuit with a jet of a sharp-smelling liquid. Otters, beavers, viscachas live along the river valleys. Condors and kites soar high in the sky above the mountain slopes. In the forest, among the dense foliage, the squeak and whistle of finches, thrushes, starlings, owls, falcons does not stop, otherwise suddenly in the dark green thicket a hummingbird flashes like a bright spark or a sharp cry of a parrot is heard.
The flora and fauna of the Andes are remarkable not only for their diversity, but also for the fact that they gave the world many cultural species that successfully spread to other continents.
The most important local cultivated plant Chilean Andes is a potato that C. Darwin found growing wild on a sandy coast in the Chonos archipelago. The Chonos Archipelago, as well as Fr. Chiloe and other islands of the southwestern coast of South America, is a remnant of the southern Andes, separated from the mainland by sea straits.
In the middle part of the Andes, namely on the plateaus of Peru and Bolivia, plants such as quinoa millet, beans, tomatoes have their homeland, and in the forests of the lower part of the mountain slopes, pineapple and cherimoya are native plants, which are distinguished by a pleasant taste and refreshing effect on the body. The name tomatoes comes from the ancient Inca word "tomatl". Exported to Europe from Peru, tomatoes were not eaten for a long time. These golden yellow, orange or bright red fruits were displayed in flower beds among flowers or in pots on windows among others. indoor plants. In Europe, they received a different name - the golden apple (pomo doro - in Italian), and now we call them tomatoes.
In the northern part of the Andes, in the mountain forests of the eastern slopes, cinchona grows, the bark of which contains quinine, a good remedy against malaria. This evergreen tree, 3 to 20 m high, has straight branches, small dark green leaves with red veins and pale red panicle flowers. In the mountain forests of the Andes, a coca shrub grows, delivering a therapeutic agent - cocaine. This tall shrub (human height) with light green delicate leaves, at the same time is covered with buds, flowers, semi-ripe brown and ripe red fruits. In a tropical rainforest on the slopes of the Colombian Andes, a cocoa tree grows, 5-6 m and even 13 m high, with a lush dark green crown. Flowers and fruits are located directly on the trunk and branches of the tree, its fruit has the form of a pod 10-16 cm in size, yellowish or reddish in color and contains beans arranged in five longitudinal rows.
In the Andes, llamas and alpacas were first tamed by the Incas, which are now used for transporting goods and for shearing wool. Lama is a camel-like animal with a long neck. It loves the sandy areas of puna and paramo and has long been used as a beast of burden. Lama can carry loads up to 60 kg. The alpaca, which is very similar to the llama, is valued for its fine wool and is not used as a beast of burden.
Closely related to these animals are also vicuñas and guanacos, which are completely untamed. Vicuña is a graceful, agile, shy animal with a very fine brown coat, which is used for dressing the most expensive woolen fabrics. A very fast and unpretentious guanaco is found mainly in the southern part of the Andes and, like the vicuña, is the subject of hunting by the Indians.
Of the small animals, the chinchilla is highly valued - a rodent that lives at high altitudes from 2000 to 3500 m. The ninshilla is valued for its beautiful fluffy bluish-silver fur and is now almost exterminated due to predatory hunting.
In the Andes, three largest areas can be distinguished, forming separate landscape areas. A landscape area is a natural area in which the connection between the relief, climate, rivers, soil and vegetation cover and the animal world is especially clear and forms a unique whole. These are the Southern Andes, the Middle Andes and the Northern Andes.
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The Andes are the longest mountain system on Earth (9000 km). They were created mainly by alpine mountain building, which continues there to this day. Faults, volcanism, and recent uplifts played an important role in the formation of their folded-block structures; in terms of the activity of volcanic phenomena, only the chains of Southeast Asia are comparable with them. The Andes also have glacial features due to both ancient and modern glaciation. Stretching meridionally, the Andes are located in six zones: equatorial, two subequatorial, tropical, subtropical and temperate. They are the best way on Earth to trace the relationship between latitudinal zonality and altitudinal zonality. The orographic plan of the Andes is much more complex than the Cordillera of North America. The coastal Cordillera is not represented throughout. Orographically almost continuous is the Western Cordillera, created in the Cretaceous and Tertiary times and composed mainly of the Mesozoic effusive "Andean" strata, sometimes called the Maritime in the Central Andes, the Main Andes in the Chilean-Argentine, and Patagonian in the south. Further to the east rise ridges with ancient Paleozoic and even Precambrian cores, raised a second time in the Neogene. They are represented by the Central Cordillera of Colombia, the Eastern Cordillera of Ecuador (with eastern massifs separated from it) and the Central Cordillera of northern Peru (east of Mara-no "on). In southern Peru, this belt includes the Cordillera Wilca-Bamba, Vilcanota and Karavaya in Bolivia - the Cordillera Real and the Central Cordillera, in northwestern Argentina - the Eastern Cordillera, and in the Chilean-Argentine Andes - the Frontal (Frontal).In the north of the Andes, the Eastern Cordillera of Colombia is also distinguished, which bifurcates into the Sierra de Perija and the Cordillera de -Merida, covering the Maracaibo basin.They are similar in structure to the previous zone, differing only in that in the Cretaceous they were deeply submerged and were in geosynclinal conditions.In the northeast they pass into the young fold chains of the Caribbean Andes, and in the northwest separated from the Sierra de Perija by the ancient horst massif of the Sierra Nevada de Santa Marta The main structures of the Andes are bordered from the east, especially in Peru, Bolivia and in northwestern Argentina (as far as Tucumán), the young and low echelon ranges of the Subandian Cordillera, which are shown on the maps of the Atlas of the World as the Cordillera Oriental of northern Peru and the Cordillera Oriental of Bolivia. The combination of the main morphostructural zones in individual segments of the Andes is different. In the Caribbean Andes - two narrow single-rise ridges, in the North-Western - a fan of three different Cordilleras diverging north with the addition of the Coast and the Sierra Nevada de Santa Marta massif, In Ecuador, the entire system, consisting of two main ridges, narrows to 100 km.
In the transverse profile of the Central Andes, up to 750 km wide, all closely compressed structures can be traced. On the Chilean-Argentine segment, only the Coastal and Main Cordillera remain with the Longitudinal Valley of Chile separating them and with the Precordillera attached from the east, and in the Patagonian, these last ancient structures also wedged out. Differences in height, width, division, of course, are reflected in the nature of latitudinal zonality and the manifestation of altitudinal zonality. The position of the Andes on the western outskirts of South America determines the differences in their nature and on the meridional segments; the western slopes have a western oceanic nature of landscapes, the high, closed intermountain plateaus of the Central Andes are inland, and on the eastern slopes the patterns inherent in eastern oceanic landscapes are expressed over a considerable distance. Each latitudinal geographic zone, each meridional strip has its own spectrum of altitudinal zones. However, the deep tectonic-erosive division of the Andes and the exposure of the slopes sometimes cause sharp contrasts in the landscapes of the windward and leeward slopes, even on the same ridge. However, there are some general patterns that are inherent in large stretches of the Andes. These include the structure of the altitudinal zonality of the eastern slopes at low latitudes, the position of the snow line throughout the Andes, and the presence of a vast desert belt in the West. Eastern slopes of the Andes from the Cordillera de Merida to 17-18 ° S sh. lie in low latitudes, receive a significant amount of solar heat and moisture, and mountain forests can develop on them. In the east of the Andes, the lower belt, the tierra caliente, is the least homogeneous. The relief of the foothill and low-mountain strip is very diverse: the Eastern Cordillera of Colombia breaks off steeply in the east, separate massifs rise in front of the Eastern Cordillera of Ecuador, and in the Central Andes, Subandian ridges stretch one after another. In the constantly wet equatorial belt, differences in the relief of the ke cause changes in the mountain hylaea. Increased moisture condensation on mountain slopes causes the promotion of humid forests and more high latitudes, in the Central Andes they are adjacent to the Mamore savannas. Even further south, in the Yungas of Bolivia, where a long dry period is already pronounced, mesophytic forests appear even on the windward slopes, longitudinal valleys and slopes lying in the "rain shadow" are distinguished by aridity, xerophytic vegetation and a less developed, rubbly cover of red-brown soils. . Accordingly, different economic use these lands. In the hard-to-reach wet hylaea, the Indian tribes carry out only consumer agriculture and partly logging.
In the tierra caliente of Colombia, Venezuela and the Central Andes, cocoa, sugar cane and bananas are cultivated under favorable moistening conditions, and in drier areas, on porous soils, cotton and coca are cultivated. In addition, oil deposits are confined to the Subandian belt. Tierra templada is distinguished by greater uniformity and greater length of the forest belt in latitude due to lower temperatures and maximum moisture condensation at these altitudes (from 1000-1500 m to 2000-2800 m). The mountain hylaea extends from the Sierra de Perija to 23-24°S. sh., i.e., 10-12 ° more than the humid forests of Tierra Caliente. The relief of this belt is dominated by steep slopes and narrow gorges; The gently sloping areas are characterized by coffee plantations (particularly in Venezuela and Colombia), as well as corn. The forest belt of tierra fraa is best expressed in equatorial latitudes. To the north and especially to the south, temperature amplitudes increase, precipitation decreases, and the upper limit of forests drops to 2800 m, in Bolivia even to 1700 m, and under 22-24 ° S. sh. the forest belt wedges out. These forests of fogs (nephelogilea) cover the steepest slopes and are poorly mastered by man. The Tierra Fria belt includes the Andean plateaus. Due to their isolation and large area, the boundaries of zonal landscape types approximately coincide with the boundaries of geographical zones. The paramos belt (tierra elada) located on the ridges is usually raised above the intermountain basins to a height of 3000-3400 m to 4500 m. southern Ecuador). The upper part of the tierra elada belt is represented by mosses, lichens, bare rocks and, finally, eternal snows. The geographical position of South America in low latitudes and the aridity of the western part of the Andes are not very favorable factors for the development of modern glaciation in one of the most powerful mountain systems in the world. In the Andes of Colombia, Ecuador and northern Peru, average monthly temperatures at an altitude of 3000 m (in temperate countries this is often the height of the snow line) are 10-12 ° C. Abundant precipitation, although occasionally falling here in the form of snow, can maintain a permanent snow cover only above 4700-4800 m. Further south, in the Central Andes, winter temperatures decrease - at an altitude of 4000 m, the minimum temperatures are -15 °, -18 ° . At the same time, summer and especially spring temperatures are very high, which is typical for the continental climate.
In addition, the position in the subtropical maximum belt and the orographic isolation of the Central Andes determine the extreme dryness of the air. Insolation and wind speed are also very high. Such a combination of climatic factors cannot contribute to the development of glaciation, and the snow line in Pune rises to 6000-6300 m. Favorable conditions are created in the Chilean-Argentine Andes. Here they reach great heights, and the increasing amount of precipitation towards the south quickly reduces the snow line; valley glaciers appear. The combination of all the factors that determine the development of glaciation reaches its optimum in the Patagonian Andes. The peaks do not exceed 3000-4000 m, but in temperate latitudes at such an altitude, negative temperatures are observed throughout the year. Constant westerly winds bring a huge amount of moisture, and the mountains are covered with thick snow and glaciers, the snow line descends to 1200-1000 m. Another zonal phenomenon characteristic of high mountains and other continents in low latitudes should be noted. On the firn fields of the Ecuadorian volcanoes, as well as between 29-35 ° S. sh. you can observe "repentant snows". Under the combined ablative action of insolation, wind, rain, erosion of melt water, regular rows of firn pyramids up to 5 m high are formed, elongated and tilted towards the sun. They resemble kneeling figures, hence their name. If the eastern slopes of the Andes are covered for a very large extent by wet mountain hylaea, and the southern Andes are almost buried under eternal snow and ice, then the western slopes between 5-28 ° S. sh. are desert. The regularity of the existence of deserts in the west of the tropical zone can also be traced on other continents. In South America, the West is not only within the scope of the subtropical anticyclone; it is completely isolated by high mountains from the influence of the humid East. In addition, the steepness of the western continental slope of South America contributes to the rise of cold deep waters, lowering the temperature of the lower layers of the troposphere; configuration coastline and the course of the Andes are parallel to the prevailing winds. Therefore, the zonal western coastal desert extends in South America for 23° in latitude. The Andes also protect the east of the mainland from the drought of the West. At a distance of only 400 km from the coastal desert, the hylae of the Amazon are spread.
The Andes is the longest (9000 km) and one of the highest (Mount Aconcagua, 6962 m) mountain systems of the Earth, bordering all of South America from the north and west; southern part of the Cordillera. In some places, the Andes reach a width of over 500 km (the greatest width - up to 750 km - in the Central Andes, between 18 ° and 20 ° S). The average height is about 4000 m. The Andes are a major interoceanic watershed; to the east of the Andes flow the rivers of the Atlantic Ocean basin (the Amazon itself and many of its large tributaries originate in the Andes, as well as the tributaries of the Orinoco, Paraguay, Parana, the Magdalena River and the Patagonian rivers), to the west - the rivers of the Pacific Ocean basin (mostly short). The Andes serve as the most important climatic barrier in South America, isolating the territories to the west of the Cordillera Main from the influence of the Atlantic Ocean, to the east - from the influence of the Pacific Ocean. The mountains lie in 5 climatic zones (equatorial, subequatorial, tropical, subtropical and temperate) and are distinguished (especially in the central part) by sharp contrasts in the moistening of the eastern (leeward) and western (windward) slopes.
Due to the considerable length of the Andes, their individual landscape parts differ significantly from each other. By the nature of the relief and other natural differences, as a rule, three main regions are distinguished - the Northern, Central and Southern Andes.
The Andes stretched through the territories of seven states of South America - Venezuela, Colombia, Ecuador, Peru, Bolivia, Chile and Argentina.
According to the Italian historian Giovanni Anello Oliva (1631), the eastern ridge was originally called the "Andes or Cordilleras" ("Andes, o cordilleras") by the European conquerors, while the western one was called the "sierra" ("sierra"). Currently, most scientists believe that the name comes from the Quechuan word anti (high ridge, ridge), although there are other opinions.
Geological structure and relief
Andes - revived mountains erected by the latest uplifts on the site of the so-called Andean (Cordillera) folded geosynclinal belt; The Andes are one of the largest Alpine folding systems on the planet (on the Paleozoic and partly Baikal folded basement). The formation of the Andes dates back to the Jurassic. The Andean mountain system is characterized by troughs formed in the Triassic, subsequently filled with layers of sedimentary and volcanic rocks of considerable thickness. Large massifs of the Main Cordillera and the coast of Chile, the Coastal Cordillera of Peru are Cretaceous granitoid intrusions. Intermountain and marginal troughs (Altiplano, Maracaibo, etc.) formed in the Paleogene and Neogene times. Tectonic movements, accompanied by seismic and volcanic activity, continue in our time. This is due to the fact that a subduction zone passes along the Pacific coast of South America: the Nazca and Antarctic plates go under the South American one, which contributes to the development of mountain building processes. The extreme southern part of South America, Tierra del Fuego, is separated by a transform fault from the small Scotia plate. Beyond the Drake Passage, the Andes continue the mountains of the Antarctic Peninsula.
The Andes are rich in ores, mainly of non-ferrous metals (vanadium, tungsten, bismuth, tin, lead, molybdenum, zinc, arsenic, antimony, etc.); the deposits are confined mainly to the Paleozoic structures of the eastern Andes and the vents of ancient volcanoes; in Chile - large copper deposits. There is oil and gas in the forward and foothill troughs (in the foothills of the Andes within Venezuela, Peru, Bolivia, Argentina), and in the weathering crusts - bauxites. In the Andes there are also deposits of iron (in Bolivia), sodium nitrate (in Chile), gold, platinum and emeralds (in Colombia).
The Andes consist mainly of meridional parallel ranges: the Eastern Cordillera of the Andes, the Central Cordillera of the Andes, the Western Cordillera of the Andes, the Coastal Cordillera of the Andes, between which lie internal plateaus and plateaus (Puna, Altiplano - in Bolivia and Peru) or depressions. The width of the mountain system is mainly 200-300 km.
Orography
Northern Andes
The main system of the Andes mountains (Andean Cordillera) consists of parallel ridges stretching in the meridional direction, separated by internal plateaus or depressions. Only the Caribbean Andes, located within Venezuela and belonging to the Northern Andes, stretch sublatitudinally along the coast of the Caribbean Sea. The northern Andes also include the Ecuadorian Andes (in Ecuador) and the Northwestern Andes (in western Venezuela and Colombia). The highest ridges of the Northern Andes have small modern glaciers, and eternal snows on volcanic cones. The islands of Aruba, Bonaire, Curaçao in the Caribbean are the peaks of the continuation of the Northern Andes descending into the sea.
In the Northwestern Andes, fan-shaped diverging north of 12 ° N. sh., there are three main Cordillera - Eastern, Central and Western. All of them are high, steeply sloping and have a folded-block structure. They are characterized by faults, uplifts and subsidences of modern times. The main Cordilleras are separated by large depressions - the valleys of the rivers Magdalena and Cauca - Patia.
The Eastern Cordillera has its highest altitude in its northeastern part (Mount Ritakuwa, 5493 m); in the center of the Eastern Cordillera - an ancient lake plateau (the prevailing heights are 2.5 - 2.7 thousand m); are generally characteristic of the Eastern Cordillera large surfaces alignment. In the highlands there are glaciers. In the north, the Eastern Cordillera is continued by the Cordillera de Merida (the highest point is Mount Bolivar, 5007 m) and the Sierra de Perija (reaches a height of 3,540 m); between these ridges in a vast low-lying depression lies Lake Maracaibo. In the far north - the Sierra Nevada de Santa Marta horst massif with altitudes up to 5800 m (Mount Cristobal Colon)
The valley of the Magdalena River separates the Eastern Cordillera from the Central, relatively narrow and high; in the Central Cordillera (especially in its southern part) there are many volcanoes (Huila, 5750 m; Ruiz, 5400 m; and others), some of them are active (Kumbal, 4890 m). To the north, the Central Cordillera drops somewhat and forms the Antioquia massif, strongly dissected by river valleys. The Western Cordillera, separated from the Central Valley of the Cauca River, has lower altitudes (up to 4200 m); in the south of the Western Cordillera - volcanism. Further to the west is the low (up to 1810 m) Serraniu de Baudo ridge, which passes in the north into the mountains of Panama. North and west of the Northwest Andes are the Caribbean and Pacific alluvial lowlands.
As part of the Equatorial (Ecuadorian) Andes, reaching up to 4 ° S, there are two Cordilleras (Western and Eastern), separated by depressions 2500-2700 m high. Along the faults that limit these depressions (depressions) - one of the highest volcanic chains (the highest volcanoes are Chimborazo, 6267 m, Cotopaxi, 5897 m). These volcanoes, as well as those of Colombia, form the first volcanic region of the Andes.
Central Andes
In the Central Andes (up to 28 ° S), the Peruvian Andes (spreading south to 14 ° 30′ S) and the Central Andes proper are distinguished. In the Peruvian Andes, as a result of recent uplifts and intensive incision of rivers (the largest of which - Marañon, Ucayali and Huallaga - belong to the system of the upper Amazon), parallel ridges (Eastern, Central and Western Cordillera) and a system of deep longitudinal and transverse canyons were formed, dismembering the ancient leveling surface . The peaks of the Cordillera of the Peruvian Andes exceed 6000 m (the highest point is Mount Huascaran, 6768 m); in Cordillera Blanca - modern glaciation. Alpine landforms are also developed on the blocky ridges of the Cordillera Vilcanota, Cordillera de Vilcabamba, Cordillera de Carabaia. To the south is the widest part of the Andes - the Central Andean Highlands (up to 750 km wide), where arid geomorphological processes predominate; a significant part of the highlands is occupied by the Puna plateau with heights of 3.7 - 4.1 thousand m. Pune is characterized by drainless basins (“bolsons”) occupied by lakes (Titicaca, Poopo, etc.) and salt marshes (Atacama, Koipasa, Uyuni, etc. .). To the east of Pune - Cordillera Real (Ankouma peak, 6550 m) with powerful modern glaciation; between the Altiplano plateau and the Cordillera Real, at an altitude of 3700 m, is the city of La Paz, the capital of Bolivia, the highest mountain in the world. East of the Cordillera Real - Subandian folded ranges of the Eastern Cordillera, reaching up to 23 ° S. The southern continuation of the Cordillera Real is the Central Cordillera, as well as several blocky massifs (the highest point is Mount El Libertador, 6720 m). From the west, Pune is framed by the Western Cordillera with intrusive peaks and numerous volcanic peaks (Sahama, 6780 m; Lullaillaco, 6739 m; San Pedro, 6145 m; Misti, 5821 m; etc.), which are part of the second volcanic region of the Andes. South of 19° S the western slopes of the Western Cordillera go to the tectonic depression of the Longitudinal Valley, occupied in the south by the Atacama Desert. Behind the Longitudinal Valley there is a low (up to 1500 m) intrusive Coastal Cordillera, which is characterized by arid sculptural relief forms.
In Pune and in the western part of the Central Andes there is a very high snow line (in some places above 6,500 m), therefore, snow is noted only on the highest volcanic cones, and glaciers are found only in the Ojos del Salado massif (up to 6,880 m high).
Southern Andes
In the Southern Andes, extending south of 28 ° S, there are two parts - the northern (Chile-Argentine, or Subtropical Andes) and the southern (Patagonian Andes). In the Chilean-Argentinean Andes, tapering to the south and reaching 39 ° 41′ S, a three-membered structure is pronounced - the Coastal Cordillera, the Longitudinal Valley and the Main Cordillera; within the latter, in the Cordillera Frontal, there is the highest peak of the Andes, Mount Aconcagua (6960 m), as well as the large peaks of Tupungato (6800 m), Mercedario (6770 m). The snow line here is very high (at 32°40′ S - 6000 m). East of the Cordillera Frontal are the ancient Precordillera.
South of 33°S (and up to 52 ° S) is the third volcanic region of the Andes, where there are many active (mainly in the Main Cordillera and to the west of it) and extinct volcanoes(Tupungato, Maipa, Limo, etc.)
When moving south, the snow line gradually decreases and under 51 ° S.l. reaches a mark of 1460 m. High ridges acquire the features of an alpine type, the area of \u200b\u200bmodern glaciation increases, and numerous glacial lakes appear. South of 40°S the Patagonian Andes begin with lower ridges than in the Chilean-Argentine Andes (the highest point is Mount San Valentin - 4058 m) and active volcanism in the north. About 52° S the heavily dissected Coastal Cordillera plunges into the ocean, and its peaks form a chain of rocky islands and archipelagos; The longitudinal valley turns into a system of straits reaching the western part of the Strait of Magellan. In the area of the Strait of Magellan, the Andes (here called the Andes of Tierra del Fuego) deviate sharply to the east. In the Patagonian Andes, the height of the snow line barely exceeds 1500 m (in the extreme south it is 300-700 m, and from 46 ° 30′ S. glaciers descend to ocean level), glacial landforms predominate (below 48 ° S - powerful Patagonian ice sheet) with an area of over 20 thousand km², from where many kilometers of glacial tongues descend to the west and east); some of the valley glaciers on the eastern slopes end in large lakes. Young volcanic cones (Corcovado and others) rise along the shores, strongly indented by fjords. The Andes of Tierra del Fuego are relatively low (up to 2469 m).
Vegetation and soils
The soil and vegetation cover of the Andes is very diverse. This is due to the high altitudes of the mountains, a significant difference in the moisture content of the western and eastern slopes. Altitudinal zonality in the Andes is clearly expressed. There are three altitudinal belts - tierra caliente, tierra fria and tierra elada.
In the Andes of Venezuela, deciduous grow (for a while winter drought) forests and shrubs on mountainous red soils. The lower parts of the windward slopes from the northwestern Andes to the Central Andes are covered with mountainous equatorial and tropical forests on lateritic soils, as well as mixed forests of evergreen and deciduous species. The appearance of equatorial forests differs little from appearance these forests in the flat part of the mainland; various palms, ficuses, bananas, a cocoa tree, etc. are characteristic. Higher (up to altitudes of 2500-3000 m), the nature of the vegetation changes; Bamboos, tree ferns, coca shrub (which is the source of cocaine), cinchona are typical. Between 3000 m and 3800 m - alpine hylaea with stunted trees and shrubs; epiphytes and creepers are widespread, bamboos, tree-like ferns, evergreen oaks, myrtle, heather are characteristic. Above - predominantly xerophytic vegetation, paramos, with numerous Compositae; moss swamps on flat areas and lifeless rocky spaces on steep slopes. Above 4500 m - a belt of eternal snow and ice.
South, in the subtropics Chilean Andes - evergreen shrubs on brown soils. In the Longitudinal Valley there are soils resembling chernozems in composition. The vegetation of the alpine plateaus: in the north - mountain equatorial meadows of paramos, in the Peruvian Andes and in the east of Pune - dry alpine-tropical steppes of halka, in the west of Pune and in the entire Pacific west between 5-28 ° south latitude - desert types of vegetation (in the Atacama Desert - succulent vegetation and cacti). Many surfaces are saline, which hinders the development of vegetation; in such areas, mainly wormwood and ephedra are found. Above 3000 m (up to about 4500 m) - semi-desert vegetation, called dry puna; grow dwarf shrubs (tholoi), grasses (feather grass, reed grass), lichens, cacti. To the east of the Main Cordillera, where there is more rainfall, there is steppe vegetation (puna) with numerous grasses (fescue, feather grass, reed grass) and cushion-shaped shrubs. On the humid slopes of the Eastern Cordillera, tropical forests (palm trees, cinchona) rise to 1500 m, stunted evergreen forests with a predominance of bamboo, ferns, and vines reach up to 3000 m; at higher altitudes - alpine steppes. A typical inhabitant of the Andean highlands is polylepis, a plant of the Rosaceae family, common in Colombia, Bolivia, Peru, Ecuador and Chile; these trees are also found at an altitude of 4500 m.
In the middle part of Chile, the forests are largely reduced; once forests rose along the Main Cordillera to heights of 2500-3000 m (mountain meadows with alpine grasses and shrubs, as well as rare peat bogs, began higher), but now the mountain slopes are practically bare. Nowadays, forests are found only in the form of separate groves (pines, araucaria, eucalyptus, beeches and plane trees, in the undergrowth - gorse and geraniums). On the slopes of the Patagonian Andes south of 38°S. - subarctic multi-tiered forests of tall trees and shrubs, mostly evergreen, on brown forest (podzolized to the south) soils; there are many mosses, lichens and lianas in the forests; south of 42°S - mixed forests (in the region of 42 ° S there is an array of araucaria forests). Beeches, magnolias, tree ferns, tall conifers, and bamboos grow. On the eastern slopes of the Patagonian Andes - mostly beech forests. In the extreme south of the Patagonian Andes - tundra vegetation.
In the extreme southern part of the Andes, in Tierra del Fuego, forests (from deciduous and evergreen trees- for example, southern beech and canelo) occupy only a narrow coastal strip in the west; above the forest border, the snow belt begins almost immediately. In the east and in places in the west, subantarctic mountain meadows and peat bogs are common.
The Andes are the birthplace of cinchona, coca, tobacco, potatoes, tomatoes and other valuable plants.
Animal world
Animal world the northern part of the Andes is included in the Brazilian zoogeographic region and is similar to the fauna of the adjacent plains. The fauna of the Andes south of 5 ° south latitude belongs to the Chilean-Patagonian subregion. The fauna of the Andes as a whole is characterized by an abundance of endemic genera and species. The Andes is inhabited by llamas and alpacas (representatives of these two species are used by the local population for obtaining wool and meat, as well as pack animals), chain-tailed monkeys, a relic spectacled bear, pudu and gaemal deer (which are endemic to the Andes), vicuña, guanaco, Azar fox , sloths, chinchillas, marsupial opossums, anteaters, degu rodents. In the south - the blue fox, the Magellanic dog, the endemic rodent tuco-tuco, etc. There are many birds, among them hummingbirds, which are also found at altitudes of more than 4000 m, but are especially numerous and diverse in the "foggy forests" (the tropical rainforests of Colombia, Ecuador , Peru, Bolivia and the extreme northwest of Argentina, located in the fog condensation zone); endemic condor, rising to a height of up to 7 thousand meters; and others. Some species (such as, for example, chinchillas, which were intensively exterminated in the 19th and early 20th centuries for the sake of obtaining skins; wingless grebes and the Titicaca whistler, found only near Lake Titicaca; etc.) are endangered.
A feature of the Andes is a large species diversity of amphibians (over 900 species). Also in the Andes, there are about 600 species of mammals (13% are endemic), over 1,700 species of birds (of which 33.6% are endemic) and about 400 species of freshwater fish (34.5% are endemic)
Information
- Countries: Venezuela, Colombia, Ecuador, Peru, Bolivia, Chile, Argentina
- Length: 9000 km
- Width: 500 km
- highest peak: Aconcagua
Source. wikipedia.org
Or the South American Cordillera, a mountain system stretching in a narrow strip on the western outskirts. The ridges of the Andes, when crossing with each other, form peculiar nodes with the highest peaks. There are many active and extinct here.
Andes
The Andes are composed of meridional ridges. Due to the huge length from north to south, the Andes are located in several. In the mountains, altitudinal zonation is clearly manifested. The sequence of changes in altitudinal zones depends on the position of the foothills of the Andes in a particular natural zone, as well as on the height, width and direction of the slopes of the ridges. Many intermountain valleys and slopes have long been inhabited and mastered by man. Here are the highest mountainous cities in the world - (3690 m), Sucre (2694 m).
Northern Andes
They consist of several ridges separated by deep troughs. There are more than 30 active and many extinct volcanoes, among which the most famous are Cotopaxi and Chimborazo.
In the altitudinal zone of humid tropical mountain forests at an altitude of 1 to 3 km, where average monthly temperatures (+16 - +22 ° C) are lower than on neighboring plains, most of the population of the Northern Andes lives. Here, at an altitude of more than 2500 m, are the cities of Santa Fe de Bogota and. Coffee, corn, and tobacco are grown on gentle mountain slopes.
Central tropical Andes
The widest part of the mountain system. There are internal high plateaus bordered on the east and west by mountain ranges.
The plateaus have long been inhabited by Indian tribes. On one of them is an ancient city - the capital of the state of the Incas. In the Western Cordillera there are large active volcanoes, including Llullalyaco, with a height of 6723 m.
In the southern part of the Central Andes, the Coastal Cordillera is separated from the Western Cordillera by a narrow depression. It stretches for 1000 km. In this depression is one of the most arid - Atacama. It receives less than 100 mm of precipitation per year, and heavy rains occur 2-4 times in 100 years. In Atacama it is much colder than in other areas located at the same latitude: the average annual temperatures are much lower than +20°C.
Southern Andes
Two ridges are well expressed in the relief: the Main Cordillera with the top of Aconcagua and the Coastal Cordillera. Between 33 and 55 °S is the third volcanic region of the Andes.
The slopes of mountain ranges in the subtropical zone up to a height of 2.5 km were once covered with heat-loving forests. At present, almost all of them have been cut down, and wherever the steepness of the slopes allows, subtropical crops are grown: olive trees, grapes, citrus fruits. The western slopes of the Andes in the temperate zone are covered with moisture-loving forests of beeches, magnolias, conifers, with bamboo, ferns and lianas.
