Traditional medicine

Environmental problems of South America. North America - environmental issues

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Changing the nature of the continent under the influence of human activity. Human impact on nature in South America began when the indigenous population, engaged in agriculture, burned out areas of forests and drained swamps. However, these changes were not so great in comparison with those that arose with the arrival of Europeans on the mainland. From the 16th century predatory use of natural resources began. Plowing of lands, deforestation, grazing, the emergence of new plants brought from other continents led to the weakening or complete destruction of connections between the components of nature, to big changes natural complexes. For example, much of the pampa is plowed or used for grazing. The pastures are overgrown with weeds.

Pampa has lost its original appearance. It has been turned into endless fields of wheat and corn, and paddocks for grazing cattle. The most valuable forests of araucaria - coniferous trees growing in the east of the Brazilian Plateau - have been almost destroyed. In place of tropical forests and savannas, there have long been coffee plantations, brought here from Africa, and cocoa plantations, wild species which grow in the Amazon forests.

The Amazon forests are being destroyed very quickly. The construction of the Trans-Amazonian Highway (5000 km) opened the way to the jungle. At current rates of use, scientists predict that these forests may disappear by the beginning of the 21st century. But the Amazon forests provide the atmosphere with a lot of oxygen and have a huge number of plant and animal species.

The problem of nature conservation South America arose at the beginning of the twentieth century. But only very recently did they begin to implement it: a program was outlined, lists of animals and plants were drawn up, for the conservation of which it was necessary to take urgent measures.

About a hundred species of mammals and birds are now included in the Red Book. The area of protected areas on the entire continent is only about 1%.

Many countries in South America are creating nature reserves and national parks, which simultaneously serve as tourism centers.

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1. The zone of equatorial forests in South America occupies gigantic areas of the Amazonian lowland, the adjacent foothills of the Eastern Andes, and the northern part of the Pacific coast in the equatorial climate zone. These forests are called selvas, which means “forests” in Portuguese. A. Humboldt proposed calling them gileys (from the Greek “gileion” - forest).

2. Zones of savannas, woodlands and shrubs are located mainly in the subequatorial and partly in the tropical climatic zones. Savannas occupy the Orinoco Lowland, where they are called llanos, as well as the interior regions of the Guiana and Brazilian highlands (campos).

3. The zone of subtropical steppes, which are called pampas here, is located south of the tropical savannas. The soils in the pampa are reddish-black, formed as a result of the rotting of dense vegetation from turf grasses - pampas grass, feather grass, bluegrass, etc. These soils have a significant humus horizon (up to 40 cm) and are very fertile. Fast running animals are typical for natural areas of the pampas - Pampas deer, Pampas cat, llamas. Along the banks of rivers and lakes there are many rodents - nutria, viscacha. At present, the natural landscapes in the pampa have been little preserved: convenient lands are plowed (fields of wheat, corn), dry steppes are divided into huge paddocks for large cattle.

4. The semi-desert zone of the temperate zone predominates in the southern - narrowed part of the continent, in Patagonia. Patagonia is located in the “rain shadow” of the Andes. In conditions of a dry continental climate, open vegetation cover is common on gray soils and gray-brown soils (sometimes saline). It is formed by dense turf grasses (bluegrass, feather grass, fescue) and shrubs that form prickly cushions (low cacti, ephedra, verbena). Among the endemic representatives of the animal world of Patagonia, it is necessary to note the skunk, Magellanic dog (similar to a fox), Darwin's ostrich (southern species of rhea). There are Pampas cats and armadillos, small rodents (tuco-tuco, mara, etc.).

5. The Andes are characterized by high-altitude landscapes. Areas of the Andes lying at different latitudes differ in the number and composition of altitudinal zones. The range of altitudinal zones is most fully represented in the equator region.

6. Zone of deciduous and coniferous forests (this is in the south of Chile)

Along the Pacific coast there is a special change in meridional natural zones: in tropical latitudes, a zone of deserts and semi-deserts of the tropical zone is formed (in the Atacama, a loma formation is formed, which is characterized by bulbous and tuberous ephemeroids); in the subtropical zone between 32-38° south. w. There is a zone of dry hard-leaved Mediterranean forests and shrubs. South of 38° S. w. in the subtropical zone - a zone of permanently moist evergreen forests (hemihyle zone), which extends to the south and into the temperate zone up to 46° S. w. The hemihylea consists of evergreen southern beeches, Chilean araucarias, “Chilean cypresses” and other tree species.

Geographic zones and natural areas of South America

3.2 Human influence on environment South America

The peculiarities of the history of South America and, as a consequence, the great unevenness in the distribution of the modern population and its relatively low average density have determined the significant preservation of natural conditions in comparison with other continents. Large areas of the Amazonian lowland, the central part of the Guiana Highlands (Roraima massif), the southwestern part of the Andes and the Pacific coast remained undeveloped for a long time. Individual wandering tribes in the Amazon forests, with almost no contact with the rest of the population, did not so much influence nature as they themselves depended on it. However, such areas are becoming fewer and fewer. The extraction of mineral resources, the construction of communication routes, in particular the construction of the trans-Amazonian highway, and the development of new lands leave everything in South America less space, not affected by human activity. The extraction of oil in the thick of the Amazon rainforest or iron and other ores within the Guiana and Brazilian highlands required the construction of transport routes in previously remote and inaccessible areas. This, in turn, led to population growth, destruction of forests, and expansion of arable and pasture lands. As a result, to nature using the latest technology The ecological balance is often disturbed, and vulnerable natural complexes are destroyed (Appendix 2). Development and significant transformations began primarily from the La Plata plain, the coastal parts of the Brazilian Highlands, and the far north of the mainland. Areas developed before the start of European colonization are located deep in the Andes of Bolivia, Peru and other countries. On the territory of the most ancient Indian civilizations, centuries-old human activity left its mark on the desert plateaus and mountain slopes at an altitude of 3-4.5 thousand m above sea level. Now the population of South America is almost 320 million people, with 78% urban. The growth of large cities is causing serious environmental problems that characterize urbanized areas around the world. This is the lack and low quality of drinking water, air pollution, accumulation of solid waste, etc.

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MINISTRY OF EDUCATION AND SCIENCE OF THE RF STATE EDUCATIONAL INSTITUTION OF HIGHER PROFESSIONAL EDUCATION BASHKIR STATE UNIVERSITY FACULTY OF GEOGRAPHY

Department of Physical Geography

COURSE WORK

in the discipline "Physical Geography of Continents and Oceans"

on the topic: “Geographical zones and natural zones of South America”

Introduction

CHAPTER 1. NATURAL AREAS OF THE EQUATORIAL AND SUB-EQUATORIAL BELT

1.1 Equatorial rain forest zone

1.2 Subequatorial forest zone

1.3 Zone of savannas, woodlands and shrubs

CHAPTER 2. NATURAL AREAS OF TROPICAL, SUBTROPICAL AND TEMPERATE ZONES

2.1 Rainforest zone

2.2 Zone of savannas, woodlands and shrubs

2.3 Zone of tropical semi-deserts and deserts

2.4 Subtropical mixed forest zone

2.5 Pampa or subtropical steppe

2.6 Mediterranean dry hardwood forest zone

2.7 Temperate semi-desert zone

2.8 Subantarctic forests

CHAPTER 3. MAN: SETTLEMENT AND INFLUENCE ON THE NATURE OF SOUTH AMERICA

3.1 Human settlement in South America

3.2 Human influence on the South American environment

CONCLUSION

LIST OF REFERENCES USED

INTRODUCTION

South America is a continent crossed by the equator, most of which is located in the Southern Hemisphere. South America is located between the Pacific Ocean and the Atlantic Ocean. It was connected to North America more recently with the formation of the Isthmus of Panama. The Andes, a relatively young and seismically unstable chain of mountains, extend along the western border of the continent; the lands east of the Andes are occupied mainly by tropical forests, the vast Amazon River basin. big country in South America by area and population - Brazil. The regions of South America include the Andean states, the Guyanese Highlands, the Southern Cone and Eastern South America. South America also includes various islands, most of which belong to the countries of the continent. The Caribbean territories belong to North America. The South American countries that border the Caribbean Sea - including Colombia, Venezuela, Guyana, Suriname and French Guiana - are known as Caribbean South America. course work we will look at the natural zones and geographic zones of South America, as well as human settlement and its impact on the nature of South America.

CHAPTER 1. NATURAL AREAS OF THE EQUATORIAL AND SUB-EQUATORIAL BELT

1.1 Equatorial rain forest zone

Moist equatorial forests are evergreen forests, mainly in the equatorial, less often in the subequatorial zones in northern South America, Central America, Western Equatorial Africa, and the Indo-Malayan region. In the Amazon basin they are called helium, selva. Distributed in areas with annual precipitation amounts of more than 1500 mm, relatively evenly distributed over the seasons. Characteristic great variety tree species: from 40 to 170 species are found per 1 hectare. Most trees have straight, columnar trunks, branching only in the upper part. The tallest trees reach heights. 50-60 m, trees avg. tier - 20-30 m, lower - approx. 10 m. Many trees have plank-shaped roots, sometimes rising to a height. 8 m. In swampy forests, trees develop stilted roots. Change of foliage different types The growth of trees occurs in different ways: some shed their leaves gradually throughout the year, others only at certain periods. Blooming young leaves initially hang as if withered, differing sharply in color, which is characterized by a wide range of colors - from white and pale green to crimson and burgundy. Flowering and fruiting also occur unequally: continuously throughout the year or periodically - once or several times a year. Often on one tree you can see branches with fruits, flowers and young leaves. Many trees are characterized by cauliflory - the formation of flowers and inflorescences on trunks and leafless areas of branches. The dense crowns of trees almost do not allow sunlight to pass through, so there are very few grasses and shrubs under their canopy. In equatorial forests there are many vines, mainly with woody stems, less often herbaceous. Their trunks reach a diameter of 20 cm, and the leaves are raised to the height of the tree crowns. Some vines, for example, rattan palms, rest on tree trunks with short shoots or special outgrowths; others, such as vanilla, are anchored by adventitious roots; however, most tropical vines are climbing. There are often cases when the trunk of a vine is so strong, and the crown is so closely intertwined with several trees, that the tree braided with it does not fall after death. Epiphytes - plants growing on trunks, branches, and epiphylls - on tree leaves are very diverse and numerous. They do not suck nutritional juices from the host plant, but use it only as a support for growth. Epiphytes from the bromeliad family accumulate water in leaf rosettes. Orchids store nutrients in thickened areas of shoots, roots or leaves. Nesting epiphytes, e.g. Bird's nest and staghorn ferns accumulate soil between the roots, sconce epiphytes accumulate soil under leaves adjacent to tree trunks. In America, even some types of cacti are epiphytes. Wet equatorial forests have been and continue to be exterminated by predators. To date, their area has already been halved and continues to decrease at a rate of 1.25% per year. St. lives in them. 2/3 of all species of plants and animals on Earth, many of which die without even being discovered and explored by humans. In place of the destroyed primeval forest, low-growing and very species-poor forests of fast-growing trees begin to grow. With regular fires and logging, secondary forests are replaced by savannas or pure grass thickets.

1.2 Subequatorial forest zone

The zone of subequatorial forests is located on the outskirts of the equatorial belt. Subequatorial forests in the inner regions of the subequatorial belt, in the outer regions - savannas. Subequatorial forests are divided into 2 subdivisions: 1. Seasonally wet forests. The dry season is 3.5-4 months, the soils are ferrallite. The main background of forests in the north of the Guiana Plateau.2. Subzone of permanently humid subequatorial forests. Occupies only the North-East of the Guiana Plateau. The dry season is less than two months. The soils are ferralitic and red-yellow.

1.3 Zone of savannas, woodlands and shrubs

Zones of savannas, woodlands and shrubs are located mainly in the subequatorial and partly in the tropical climatic zones. Savannas occupy the Orinoco Lowland, where they are called llanos, as well as the interior regions of the Guiana and Brazilian highlands (campos).

Savannah soils are red ferralitic and red-brown. In the savannas of the northern hemisphere, sparse palm trees and acacias grow among tall grasses. Along the banks of rivers, gallery forests are typical. In the savannas of the Brazilian Highlands, the grass cover, as in the llanos, consists of tall grasses and legumes. But the woody vegetation is much poorer; mimosas, tree-like cacti, and euphorbia predominate. In the northeast of the Brazilian Highlands and the Interior Tropical Plains, in a drier climate (up to 400 mm of precipitation per year), tough grasses, thorny bushes, bottle trees, low-growing woodlands of quebracho grow - a tree with very hard wood (“quebracho” in translated means “break the ax”). In the fauna of the savannas of South America there are few ungulates (small deer); There are baker pigs, armadillos, anteaters, and puma among predators. Subzones:1. Wet savannas. Orinoco Lowland (Llanos). A clear division into the dry period, 3.5-4 months. The soils are red, there are areas of yellow and red-yellow. Vegetation palms and forbs. 2. Dry shrub savannas and woodlands. Central part of the Brazilian Plateau, Northeast Orinoco Lowland. The amount of precipitation is no more than 700 mm, the soils are brown-red. The grass cover is sparse, represented mainly by grasses, and shrubs are typical. This type of savanna is called campos. The dry period is about 5 months.3. Kaatina (desertified woodland subzone). Northeast Brazilian Plateau. There is almost complete absence of grass cover, only shrubs and wax palm grow. The soils are red-brown.

CHAPTER 2. NATURAL AREAS OF TROPICAL, SUBTROPICAL AND TEMPERATE ZONES

2.1 Rainforest zone

It extends along the entire eastern, windward slope of the Brazilian Plateau, receiving 1500-2000 mm of precipitation per year thanks to the southeastern trade winds. The close proximity of the ocean determines an equal maritime climate with temperatures of + 20... + 24 in winter and + 26... + 27 in summer. Therefore, the vegetation is represented by dense multi-tiered evergreen forests, close to the mountain equatorial forests. In these forests there are many species of trees with valuable wood: pau brazil tree, rosewood tree, rosewood, purple tree, zebra tree, ebony tree, etc. There are many palms and ferns. The typical soils of the zone are red-yellow ferrallitic. Divided into two subzones (eastern Brazilian Plateau): 1. Subzone of seasonally wet forests (in the north). Precipitation is no more than 1400 mm, the dry period is about 5 months.2. Subzone of permanently wet (trade wind) forests.

Towards the west, the tropical belt narrows.

2.2 Zone of savannas, woodlands and shrubs

Distributed in the Gran Chaco plain. The climate of the zone is similar to the subequatorial one, but differs from it in its significant continentality and large amplitudes of seasonal temperatures. This is where the “heat pole” of South America is located - + 47 C. The duration of the dry period is 9-10 months, which causes the complete drying of water bodies in winter time. The soils are brown-red and even red-brown. The vegetation cover is dominated by dry woodlands, represented by gnarled Quebracho, Algarrobo, and Chañar trees with an admixture of succulents. Animal world very poor, similar in species composition to the fauna of the savannahs of the subequatorial belt. As the climate changes, that is, with the advent of the dry season, tropical rainforests in South America are turning into savannas and tropical woodlands. In the Brazilian Highlands, between savannas and tropical rainforest, there is a strip of almost pure palm forests. Savannas are distributed over a large part of the Brazilian Highlands, mainly in its interior regions. In addition, they take large areas in the Orinoco Lowland and in the central regions of the Guiana Highlands. In Brazil, typical savannas on red ferrallitic soils are known as campos. Their herbaceous vegetation consists of tall grasses of the genera Paspalum, Andropogon, Aristida, as well as representatives of the legume and Asteraceae families. Woody forms of vegetation are either completely absent or occur in the form of individual specimens of mimosa with an umbrella-shaped crown, tree-like cacti, milkweeds and other xerophytes and succulents. In the dry northeast of the Brazilian Highlands, a significant area is occupied by the so-called caatinga, which is a sparse forest of drought-resistant trees and shrubs on red-brown soils. Many of them lose their leaves during the dry season, others have a swollen trunk in which moisture accumulates, for example, cottonweed (Cavanillesia platanifolia). The trunks and branches of caatinga trees are often covered with vines and epiphytic plants. There are also several types of palm trees. The most remarkable caatinga tree is the carnauba wax palm (Copernicia prunifera), which produces vegetable wax, which is scraped or boiled from its large (up to 2 m long) leaves. Wax is used for making candles, polishing floors and other purposes. From the upper part of the carnauba trunk, sago and palm flour are obtained, the leaves are used to cover roofs and weave various products, the roots are used in medicine, and the local population uses the fruits for food, raw and boiled. It is not for nothing that the inhabitants of Brazil call carnauba the tree of life. On the Gran Chaco plain, in particularly arid areas, thickets of thorny bushes and sparse forests are common on brown-red soils. In their composition, the two species belong to different families, they are known under the common name "quebracho" ("break the ax"). These trees contain large number tannins: red quebracho (Schinopsis Lorentzii) - up to 25%, white quebracho (Aspidosperma quebracho blanco) - slightly less. Their wood is heavy, dense, does not rot and sinks in water. Quebracho is being intensively cut down. At special factories, tanning extract is obtained from it; sleepers, piles and other items intended for long-term stay in water are made from the wood. The forests also contain algarrobo (Prosopis juliflora), a tree from the mimosa family with a curved trunk and a highly branched spreading crown. The algarrobo's small, delicate foliage does not provide shade. Low forest layers are often represented by thorny bushes that form impenetrable thickets. The savannas of the northern hemisphere differ from the southern savannas in appearance and species composition of the flora. To the south of the equator, palm trees rise among the thickets of cereals and dicotyledons: copernicia (Copernicia spp.) - in drier places, Mauritia flexuosa - in swampy or river-flooded areas. The wood of these palms is used as a building material, the leaves are used to weave various products, the fruits and the core of the Mauricia trunk are edible. Acacias and tall tree-like cacti are also numerous. Red and red-brown soils of savannas and tropical woodlands differ more high content humus and greater fertility than the soils of humid forests. Therefore, in the areas of their distribution there are major areas of arable land with plantations of coffee trees, cotton, bananas and other cultivated plants exported from Africa. The fauna of the drier and open spaces of South America - savannas, tropical woodlands, subtropical steppes - is different than in dense forests. In addition to the jaguar, common predators include the puma (found throughout almost all of South America and extending into North America), ocelot, and pampa cat. The southern part of the continent is characterized by the maned wolf from the canine family. The Pampa fox is found on the plains and mountainous areas almost throughout the continent, and in the extreme south - the Magellanic fox. Among the ungulates, the small Pampas deer is common. In savannas, forests and arable lands there are representatives of the third American family of partially edentates - armadillos (Dasypodidae) - animals equipped with a durable bony shell. When danger approaches, they burrow into the ground. Among the rodents found in savannas and steppes are the viscacha and the tuco-tuco, which lives in the ground. The swamp beaver, or nutria, is widespread along the banks of reservoirs, whose fur is highly valued on the world market.

Among the birds, in addition to numerous parrots and hummingbirds, rheas (genus Rhea) also live - South American representatives of the ostrich order, some large birds of prey. There are many snakes and lizards in the savannas and steppes. A characteristic feature of the landscapes of South America is a large number of termite mounds. Some areas of South America periodically suffer from locust infestations.

2.3 Zone of tropical semi-deserts and deserts

Deserts and semi-deserts are a natural zone characterized by a complete absence of vegetation and very poor fauna. All this is due to the extremely harsh climatic conditions of the planet where they are located. Deserts, in principle, can form in any climate zone. Their formation is primarily associated with low rainfall. This is why deserts are primarily found in the tropics. Tropical deserts occupy the territory of the western coast of the tropical belt of South America. The natural conditions of deserts are extremely harsh. The amount of precipitation here does not exceed 250 mm per year, and in large areas it is less than 100 mm. Daily temperature ranges reach 30 °C, and very dry winds are constant. All this creates favorable conditions for intense physical weathering and deflation, the accumulation of layers of clastic material in which temporary watercourses dry up. The annual flow does not exceed 50 mm; there is no flow into the ocean. Salt lakes and salt marshes are widespread in depressions. Sparsely developed gravelly or sandy soils are characterized by a very sparse “cover” of desert vegetation, also called puna, of creeping or cushion-shaped herbs and shrubs. The driest desert in the world is the Atacama Desert, where there has been no precipitation for 400 years. The fauna, except birds, is also poor. In the less severe northern and eastern regions, steppes appear on ancient alluvial soils and farming is possible up to an altitude of 4200 m. Mules and especially llamas are also bred here. Coastal deserts and semi-deserts in the western tropical zone of South America are unusually extended in latitude: from 5 to 28° S. w. along the coast and along the western slopes of the Andes. To all their inherent features ( low temperatures coast, waterlessness, intense physical weathering, buried decrepit relief, isolated representatives of xerophytic-succulent vegetation and desert fauna) in South America a special coastal type of vegetation is added - loma (pl. lomas), which grows during the development of heavy fogs and drizzle.

2.4 Subtropical mixed forest zone

To the east of the Andes, not only does the amount of precipitation increase (from 400-500 mm/year in dry steppes to 1000-1200 mm in wet steppes), but also its seasonal distribution evens out - in the east it falls throughout the year. Accordingly, gray-brown soils in the dry steppe subzone are replaced by chernozem-like and reddish-black soils in wet steppes and subtropical savannas. These are areas of intensive agriculture (crops of grain, forage grasses, flax for seed, etc.) and cattle breeding. Almost no natural vegetation has been preserved, and the soil cover is subject to severe erosion. Despite the heavy rainfall, the river network in Pampa is poorly developed and the surface runoff is small. The position and character of the eastern oceanic zone of subtropical mixed forests are very unique in South America. It is expressed on the high lava plateau of Paraná between 24-30° S. latitude, i.e. at lower latitudes than on other continents. The gentle slope of the Brazilian plateau to the south allows deep incursions of cold winter winds from the Pampa - pamperos, causing temperatures to drop to -6 ° C. Average temperatures in July are 12, 13 °C. Due to limited area sushi winter continental monsoon is absent in this area (as in Pampa), frontal rains occur in winter.

2.5 Pampa or subtropical steppe

Pampa is a steppe in the subtropical zone of South America. The winters here are warm and there are rarely frosts; there is little precipitation of only 500 mm per year. These steppes are devoid of trees due to repeated dry periods and highly dense clay soils. Grasses suffer less from grazing and fires. Trees are found only on the slopes of terraces along river valleys. A characteristic feature The pump is the presence of drainless lakes, many of which dry up in the summer. The water in them has an alkaline reaction, as soda accumulates in them. Today, the pampa is densely populated; the bulk of Argentina's inhabitants live here. Livestock breeding and agriculture are well developed. The soil is plowed and the indigenous vegetation is almost gone, and there are no nature reserves. You can find some native vegetation in the alienated zones along the banks of rivers, roads and railways. The landscape of the pampas has changed, alternating arable lands (corn, wheat), sown pastures and strips of exotic trees. The former richest flora had about 1000 species of grasses and the same number of herbs. The rider could easily hide in this huge green sea. Grains predominated mainly: pearl barley, bromegrass, bearded grass, feather grass, bluegrass, and in the south tuesok. The fauna was also rich, with many species of rodents; only one representative of the South American Vizcachi family has survived to this day. Most animals and birds are on the verge of extinction, for example, the Pampian deer. The Argentine Pampa is a flat desert area stretching from the Atlantic Ocean to the foothills of the Andes, from the La Plata River to the Rio Negro. “Pampa” means plain, translated from the language of the Quechua Indians. The landscape is deserted and monotonous at times, as if out of nowhere the mountains rise in front of the traveler, like an island in the sea. The pampa covers about 80 thousand sq. km of territory; such a long extent of the pampa arose due to the accumulation of loose rocks destroyed rocks Andes. The rivers brought to the pampa by mountain streams and the wind played a role in driving small particles of destroyed rocks here. Sedimentary strata thick up to 300 m are found near Buenos Aires, and in some places they completely cover ancient landforms. There are no slopes, thereby impeding the flow of water, thus the pampa was formed due to the gigantic forces of nature itself, sculpting the relief and redoing the work of its creation many times. Today, the Argentine Pampa is similar to the Indus-Gangetic Plain, but natural conditions South Asia is different from Argentina. There are no slopes, and rainwater does not roll down and rivers do not form. Rainwater accumulates in clayey areas in depressions and forms Lagunas - swamp lakes. Most rivers originate in the Pampian Sierras, but the further they go into the valley they lose their strength and most of them dry up. The river course often changes, leaving behind flood waters that become swampy over time. The difference in climate between the eastern and western parts explains the difference in the composition of their soils. In the western part there is a hot, arid climate - low-growing vegetation, most of the lands are completely bare. Eastern s a large number precipitation - dense vegetation.

2.6 Mediterranean dry hardwood forest zone

In the subtropical zone in the west of the continent between 32-38° S., latitude. (central part of middle Chile), as on all other continents, there is a zone of dry hard-leaved Mediterranean forests and shrubs, the transition to which from tropical semi-deserts occurs through subtropical semi-deserts (28-32° S). It is most typically represented on Beregovaya Cordillera, where brown soils and maquis-like thickets of hard-leaved shrubs are common. A zone of subtropical shrub steppe with brown soils extends south through the arid Central Valley. On the Main Cordillera, a spectrum of altitudinal zones characteristic of the Mediterranean zone is expressed. At the bottom there are hard-leaved shrubs, in the middle zone there are evergreen deciduous forests with an admixture of conifers, in the upper zone there are mountain steppes, and in the wetter south there are alpine meadows. Since precipitation falls mainly in winter, and summer is rainless, the river regime is uneven, floods occur in winter and in spring and summer, when snow and glaciers in the mountains melt. In the relief, along with water-erosive forms, glacial ones play an increasingly important role towards the south. The river valleys in the mountains and the Central Valley are the most important agricultural regions of Chile.

2.7 Temperate semi-desert zone

In the extreme south of the continent, in the temperate zone, a natural zone of semi-deserts and deserts, which is not very characteristic of these latitudes, has formed. This is the only zone of deserts and semi-deserts in the world that faces the ocean coast within the temperate zone. In conditions of low rainfall (about 200 mm per year), cereals, cacti and cushion-shaped shrubs grow on gray and brown soils. The fauna is poor, only rodents and reptiles are numerous. Coastal deserts and semi-deserts extend in a narrow strip (from 5 degrees to 28 degrees S) on the western coast of South America. The proximity of the ocean causes high air humidity here, the shores are shrouded in fog for a significant part of the year, and there is little precipitation. It happens that there is no rain for 10 - 20 years. The reason for this is not only the prevailing air masses, but also the cold Peruvian Current. The driest part of the natural area is the coastal Atacama Desert. On its predominantly sandy surface, single drought-resistant plants, in particular cacti, are occasionally found. The Atacama rises along the slopes of the Andes up to 3000 m, where it turns into a high-mountain desert. South of the coastal deserts on the western coast of the mainland and the island of Tierra del Fuego, there are temperate forests where coniferous trees appear: Chilean cedars, cypresses and araucarias.

2.8 Subantarctic forests

The slopes of the Patagonian Andes are covered with moisture-loving subantarctic forests, consisting of tall trees and shrubs, among which evergreen species predominate: at 42 S. latitude. there is an array of araucaria forests, and to the south there are mixed forests. Due to their density, abundance of species, multi-layered nature, diversity of vines, mosses and lichens, they resemble forests of low latitudes. The soils under them are of the brown soil type, in the south they are podzolic. There are many swamps in flat areas. The main representatives of the flora of the forests of the Southern Andes are evergreen and deciduous species of southern beeches, magnolias, giant conifers of the genus Fitroja and Libocedrus, bamboos and tree ferns. Many plants have beautiful fragrant flowers, especially decorating the forest in spring and summer. The branches and trunks of trees are entangled in vines and covered with a lush moss and lichen cover. Mosses and lichens, along with leaf litter, cover the surface. As you rise into the mountains, forests become thinner and their species composition becomes poorer. In the extreme south they are gradually replaced by tundra-type vegetation. On the eastern slope of the mountains, facing the Patanon Plateau, precipitation falls significantly less than in the west. Forests are less dense and poorer in species composition compared to the coast Pacific Ocean. The main forest-forming species are southern beeches with an admixture of some conifers. At the foot of the mountains, the forests turn into dry steppes and shrubs of the Patagonian Plateau.

CHAPTER 3. MAN: SETTLEMENT AND INFLUENCE ON THE NATURE OF SOUTH AMERICA

3.1 Human settlement in South America

equatorial forest savannah environment

South America has been unevenly developed by humans. Only the outlying areas of the continent are densely populated, mainly the Atlantic coast and some areas of the Andes. At the same time, the interior regions, for example, the forested Amazonian lowland, remained virtually undeveloped until recently. The question of the origin of the indigenous population of South America - the Indians - for a long time caused controversy. The most common point of view is that South America was settled by Mongoloids from Asia through North America approximately 17-19 thousand years ago (Appendix 1). But, based on some anthropological similarity between the Indian peoples of South America and the peoples of Oceania and the presence of the same tools among them, Some scientists expressed the idea of settling South America from the Pacific Islands. However, few share this point of view. Most scientists are inclined to explain the presence of Oceanian traits in the inhabitants of South America by the fact that representatives of the Oceanian race could also penetrate through northeast Asia and North America with the Mongoloids. Currently, the number of Indians in South America is significantly larger than in North America, although during the period of colonization of the mainland by Europeans it greatly decreased. In some countries, Indians still make up a significant percentage of the population. In Peru, Ecuador and Bolivia there are about half of the total number, and in some areas they even significantly predominate. Most of Paraguay's population is of Indian origin, and many Indians live in Colombia. In Argentina, Uruguay, and Chile, the Indians were almost completely exterminated during the first period of colonization, and now there are very few of them there. Brazil's population is also steadily declining. In the Andes and on the Pacific coast, strong Indian states emerged, characterized by high level development of agriculture and cattle breeding, crafts, applied arts and the beginnings of scientific knowledge. The agricultural peoples of South America produced such cultivated plants as potatoes, cassava, peanuts, and pumpkin. In the process of European colonization and the fierce struggle against the colonialists, some Indian peoples completely disappeared from the face of the Earth, others were pushed out of their ancestral territories into uninhabited and inconvenient lands. Some Indian peoples continue to live in areas of their former habitat. There are still tribes living in isolation that have retained the level of development and way of life at which they were caught by the European invasion. In the interior of Brazil there are still remnants of tribes of the Zhe language family. By the time Europeans arrived on the mainland, they inhabited the eastern and southern parts of Brazil, but were pushed back by the colonialists into forests and swamps. These people are still at a level of development corresponding to the primitive communal system, and are characterized by a wandering lifestyle. The inhabitants of the extreme south of South America (Terra del Fuego) were at a very low stage of development before the arrival of Europeans. They protected themselves from the cold with animal skins, made weapons from bone and stone, and obtained food by hunting gunakos and sea fishing. The Fuegians were subjected to severe physical extermination in the 19th century; now there are very few of them. Before the arrival of Europeans, the main occupation of the tribes living in the Argentine Pampa and Patagonia was hunting. The Spaniards brought horses to the mainland, which later went wild. The Indians learned to tame horses and began to use them to hunt gunakos. The rapid development of capitalism in Europe was accompanied by the ruthless extermination of the population of colonial lands. In Argentina in particular, the Spaniards pushed local residents to the extreme south of Patagonia, to lands unsuitable for grain farming. Currently, the indigenous population in Pampa is almost completely absent. Only small groups of Indians have survived, working as farm laborers on large agricultural farms. The highest socio-economic and cultural development before the arrival of Europeans was achieved by the tribes that inhabited the high plateaus of the Andes within Peru, Bolivia and Ecuador, where one of the oldest centers of irrigated agriculture is located. The most numerous modern Indian people - the Quechua - inhabit the mountainous regions of Peru, Bolivia, Ecuador, Chile and Argentina. On the shores of Lake Titicaca live the Aymara, one of the most high-altitude peoples in the world. A significant part of the population, especially in the Atlantic regions (Brazil, Guiana, Suriname, Guyana), are blacks - descendants of slaves brought to South America at the beginning of colonization, when a large and cheap labor force used on plantations was needed. The blacks partially mixed with the white and Indian populations. As a result, mixed types were created: in the first case - mulattoes, in the second - sambo. Fleeing from exploitation, black slaves fled from their masters into the tropical forests. Their descendants, some of whom mixed with the Indians, still lead a primitive forest lifestyle in some areas. Before the declaration of independence of the South American republics, that is, until the first half of the 19th century, immigration to South America from other countries was prohibited. But subsequently, the governments of the newly formed republics, interested in the economic development of their states and the development of empty lands, opened access to immigrants from different countries Europe and Asia. Especially many citizens arrived from Italy, Germany, Balkan countries, partly from Russia, China and Japan. Settlers of a later period usually kept themselves apart, maintaining their own language, customs, culture and religion. In some republics (Brazil, Argentina, Uruguay) they form significant groups of the population.

3.2 Human influence on the South American environment

The peculiarities of the history of South America and, as a consequence, the great unevenness in the distribution of the modern population and its relatively low average density have determined the significant preservation of natural conditions in comparison with other continents. Large areas of the Amazonian lowland, the central part of the Guiana Highlands (Roraima massif), the southwestern part of the Andes and the Pacific coast remained undeveloped for a long time. Individual wandering tribes in the Amazon forests, with almost no contact with the rest of the population, did not so much influence nature as they themselves depended on it. However, such areas are becoming fewer and fewer. Mining, the construction of communication routes, in particular the construction of the trans-Amazonian highway, and the development of new lands are leaving less and less space in South America unaffected by human activity. The extraction of oil in the thick of the Amazon rainforest or iron and other ores within the Guiana and Brazilian highlands required the construction of transport routes in previously remote and inaccessible areas. This, in turn, led to population growth, destruction of forests, and expansion of arable and pasture lands. As a result, with the use of the latest technology, the ecological balance is often disrupted and vulnerable natural complexes are destroyed (Appendix 2). Development and significant transformations began primarily from the La Plata plain, the coastal parts of the Brazilian Highlands, and the far north of the mainland. Areas developed before the start of European colonization are located deep in the Andes of Bolivia, Peru and other countries. On the territory of the most ancient Indian civilizations, centuries-old human activity left its mark on the desert plateaus and mountain slopes at an altitude of 3-4.5 thousand m above sea level. Now the population of South America is almost 320 million people, with 78% urban. The growth of large cities is causing serious environmental problems that characterize urbanized areas around the world. This is the lack and low quality of drinking water, air pollution, accumulation of solid waste, etc.

CONCLUSION

LIST OF REFERENCES USED

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2. Vlasova T.V. Physical geography of parts of the world / 2nd edition, revised and expanded. - M.: Education, 1966. - 640 p.

3. Galai I.P., Zhuchkevich V.A., Rylyuk G.Ya. Physical geography of continents and oceans. Part 2. - Mn.: Iz-vo Universitetskoe, 1988. - 357 p.

4. Zhuchkevich V.I., Lavrinovich M.V. Physical geography of continents and oceans. Part 1. - Mn.: Iz-vo Universitetskoe, 1986. - 222 p.

5. LUKASHOVA E.N. South America. - M.: 1958.

6. Pritula T.Yu., Eremina V.A., Spryalin A.N. Physical geography of continents and oceans. - M.: Vlados, 2003. - 680 p.

7. Physical geography of continents and oceans / Ed. Ryabchikova A.M. M.: Higher School, 1988. - 588 p.

8. Finarov D.P. Geography: Continents, oceans and countries / D.P. Finarov, S.V. Vasiliev, E.Ya. Chernikhova - M.: Astrel, AST; S-P.: SpetsLit, 2001. - 300 p.

Human influence on the South American environment

The peculiarities of the history of South America and, as a consequence, the great unevenness in the distribution of the modern population and its relatively low average density have determined the significant preservation of natural conditions in comparison with other continents. Large areas of the Amazonian lowland, the central part of the Guiana Highlands (Roraima massif), the southwestern part of the Andes and the Pacific coast remained undeveloped for a long time. Individual wandering tribes in the Amazon forests, with almost no contact with the rest of the population, did not so much influence nature as they themselves depended on it. However, such areas are becoming fewer and fewer. Mining, the construction of communication routes, in particular the construction of the trans-Amazonian highway, and the development of new lands are leaving less and less space in South America unaffected by human activity. The extraction of oil in the thick of the Amazon rainforest or iron and other ores within the Guiana and Brazilian highlands required the construction of transport routes in previously remote and inaccessible areas. This, in turn, led to population growth, destruction of forests, and expansion of arable and pasture lands. As a result, with the use of the latest technology, the ecological balance is often disrupted and vulnerable natural complexes are destroyed (Appendix 2). Development and significant transformations began primarily from the La Plata plain, the coastal parts of the Brazilian Highlands, and the far north of the mainland. Areas developed before the start of European colonization are located deep in the Andes of Bolivia, Peru and other countries. On the territory of the most ancient Indian civilizations, centuries-old human activity left its mark on the desert plateaus and mountain slopes at an altitude of 3-4.5 thousand m above sea level. Now the population of South America is almost 320 million people, with 78% urban. The growth of large cities is causing serious environmental problems that characterize urbanized areas around the world. This is the lack and low quality of drinking water, air pollution, accumulation of solid waste, etc.