Unfortunately, not many people know what savannas are and where they are located. Savannas are a natural area that is found mainly in the subtropics and tropics. The most important feature of this strip is the humid seasonal climate with pronounced alternations between dry and rainy seasons. This feature determines the seasonal rhythm natural processes Here. This zone is also characterized by ferrallitic soils and herbaceous vegetation with groups of isolated trees.
Savannah localization
Let's take a closer look at what savannas are and where they are located. The most large area Savannah is located in Africa, it occupies about 40% of the area of this continent. Smaller areas of this natural zone are located in South America (on the Brazilian plateau, where they are called campos, and in the Orinoco River valley - llanos), in the east and north of Asia, the Deccan Plateau, the Indo-Gangsai Plain), as well as in Australia.
Climate
Savannah is characterized by monsoon-trade wind circulation air masses. In summer, these regions are dominated by dry tropical air, and in winter by equatorial humid air. The farther away you go, the more there is a reduction in the rainy season (from 8-9 months to 2-3 on the outer borders of this zone). The amount decreases in the same direction annual precipitation(from approximately 2000 mm to 250 mm). Savannah is also characterized by slight temperature fluctuations depending on the season (from 15C to 32C). Daily amplitudes can be more significant and reach 25 degrees. Such climatic features created a unique natural environment in the savannah.
Soils
The soils of the region depend on the duration of the rainy season and differ in leaching regime. Ferrallitic soils have formed near areas where the rainy season lasts about 8 months. In areas where this season is less than 6 months, you can see red-brown soils. On the borders with semi-deserts, the soils are unproductive and contain a thin layer of humus.
Savannahs of South America
In the Brazilian Highlands, these zones are located mainly in its interior areas. They also occupy areas and In Brazil there are typical savannas with red ferrallite soils. The vegetation of the zone is predominantly herbaceous and consists of the legume, grass, and asteraceae families. Woody species vegetation is either not present at all, or occurs in the form of separate species of mimosa with an umbrella-like crown, milkweeds, succulents, xerophytes and tree-like cacti.
In the northeast of the Brazilian Highlands, most of the area is occupied by caatinga (a sparse forest of drought-resistant shrubs and trees on red-brown soils). The branches and trunks of caatinga trees are often covered with epiphytic plants and vines. Several types of palm trees are also found.
Savannah South America also located in the arid regions of the Gran Chaco on red-brown soils. Sparse forests and thickets of thorny bushes are common here. The forests also contain algarrobo, a tree from the mimosa family, which has a curved column and a highly branched, spreading crown. Low forest tiers are shrubs that form impenetrable thickets.
Among the animals in the savannah are the armadillo, ocelot, Pampas deer, Magellan cat, beaver, Pampas cat, rhea and others. Of the rodents, the tuco-tuco and viscacha live here. Many areas of the savanna suffer from locust infestations. There are also many snakes and lizards here. Another one characteristic feature landscape - a large number of termite mounds.
African shrouds
Now all readers are probably wondering: “Where is the savanna in Africa?” We answer that on the black continent this zone practically follows the contour of the tropical rainforest region. In the border zone, forests are gradually thinning out and becoming poorer. Among forest areas there are patches of savannas. Tropical rain forest is gradually limited only to river valleys, and in the watershed areas they are replaced by forests, the trees of which are dry time shed their leaves, or savannahs. There is an opinion that tall grasses tropical savannas began to form due to human activity, as he burned out all the vegetation during the dry season.
In areas with a short wet season, the grass cover becomes shorter and sparse. From tree species Various flat-crowned acacias are found in the region. These areas are called dry or typical savannas. In regions with a longer rainy season, thickets of thorny bushes grow, as well as tough grasses. Such vegetation areas are called desert savannas; they form a small strip in
The African savannah world is represented by the following animals: zebras, giraffes, antelopes, rhinoceroses, elephants, leopards, hyenas, lions and others.
Savannahs of Australia
Let's continue our topic “What are savannas and where are they located” by moving to Australia. Here this natural zone is located mainly north of 20 degrees south latitude. In the east there are typical savannas (they also occupy the south of the island New Guinea). During the wet season, this region is covered with beautiful flowering plants: the families of orchids, ranunculaceae, lilies and various grasses. Characteristic trees- acacias, eucalyptus, casuarina. Trees with thickened trunks, where moisture accumulates, are quite common. They are, in particular, represented by the so-called bottle trees. It is the presence of these unique plants makes the Australian savanna a little different from the savannas that are located on other continents.
This zone is combined with sparse forests, which are represented by different types eucalyptus. Open woodlands of eucalyptus occupy most of the north coast country and a large part of Cape York Island. IN Australian savannah you can find many marsupial rodents: mole, rat, wombat, anteater. The echidna lives in the bushes. The emu, a variety of lizards and snakes can also be seen in these regions.
The role of savannas for humans
After we have found out in detail what savannas are and where they are located, it is worth saying that these natural areas play an important role for humans. Peanuts, grains, jute, and cotton are grown in these regions. Livestock farming is quite developed in arid areas. It is also worth noting that some tree species growing in this region are considered very valuable (for example,
Despite its greater importance, people, unfortunately, continue to systematically destroy the savanna. Thus, in South America, many trees die as a result of burning fields. Large areas Savannas are cleared of forest from time to time. Until recently, in Australia, about 4,800 square meters were cleared annually to provide livestock pasture. km of forest. Such events are now suspended. Many people also have a detrimental effect on the savannah ecosystem. exotic trees(Nile acacia, vaulting landata, prickly pear and others).
Climate change leads to changes in the function and structure of the savanna. Woody plants are suffering greatly as a result of global warming. I would like to believe that people will start
11. Physiographic characteristics of the Amazonian lowland and Brazilian plateau.
AMAZON LOWLANDS. Geographical position. The main features of the nature of the Amazon are determined by its flat topography, long-term continental development and equatorial position. This largest region of equatorial climate and tropical rainforests on the planet accounts for most of the basin of the deepest river system Earth.
The boundaries of the Amazon are clearly delineated by the slopes of the Brazilian and Guiana highlands and the eastern foot of the Andes.
Geological structure and relief. The main part of its territory is occupied by the huge alluvial plain of the Amazon, formed from the merging of vast platform syneclises filled with marine and continental sediments. The axis of the region is the Amazon, which carries its waters from the foot of the Andes to the Atlantic Ocean somewhat south of the equator and collects its tributaries from both hemispheres.
Climatic conditions. The middle and western Amazon has a typically equatorial climate, with two periods of particularly heavy rainfall from February to June and October to January. On the northern and southern edges of the Amazon, periods of heavy rainfall merge into one, corresponding to the summer of each hemisphere. The wet season there is very long; during the dry season, precipitation also falls, although its amount is noticeably reduced. Temperatures throughout the Amazon are high and uniform, with little seasonal variation.
There is no very strong heat, but even temperatures are 24... 27 °C. Rain usually falls in the form of heavy and prolonged downpours in the afternoon, and in the evening and at night it begins clear weather. These climatic features favor the development of tropical rainforests with their diverse and lush vegetation.
Zap. Amazonia . The vegetation of the high floodplains (varzea) is similar to the interfluves (ete) and includes especially many palm trees, hevea, sumaumu-ceibu, cocoa tree, etc. The vegetation of the low floodplains (igapo) is very poor. Typical abundance of animals adapted to life in trees: broad-nosed monkeys, sloths, small anteater; Among the terrestrial animals there are the giant armadillo, tapirs, peccaries, etc. There are many birds, reptiles, amphibians, fish, insects and ants.
East Amazonia . The forests contain a significant admixture of deciduous trees. Only strips of Varzea and Igapo on alluvial soils remain evergreen. Animals of open spaces also appear: mazama deer, the average anteater and small armadillos, many rodents, termites.
Population and environmental issues. The Amazonian lowland is very sparsely populated. The main routes of communication are rivers; along which there are small settlements and two large cities: Manaus - at the mouth of the Rio Negro and Belem - at the mouth of the river. Pair; a motorway has been built to the latter from the city of Brasilia. Manganese ores discovered in 1945 are being mined (Serra do Navio in Amapa), deposits have been discovered nearby iron ores, and in the lower reaches of Madeira - oil (Nova Olinda).
Due to ongoing climate change and deforestation, vast areas of the Amazon rain forest may develop into a cerrado, the predominant type of arid savanna in modern Brazil. Over the past few decades, scientists have noted a 70% reduction in forests. Deforestation has negatively impacted the fragile ecological balance of the Amazon forests and led to the extinction of many species of trees, plants and animals. As was previously thought, the Amazon was home to almost a third of all living organisms on the planet, including insects and plants. Since the late 70s of the 20th century, over 70% of all tropical forests in Brazil have been destroyed. In addition, the decomposition of wood and other vegetation residues as a result of logging and burning of forests leads to increased emissions. carbon dioxide into the atmosphere, which, in turn, increases the greenhouse effect.
BRAZILIAN PLATEAU. Geographical position. Between the flat, low-lying plains of the Amazon and Parana basins in the north and west and the Atlantic Ocean in the east, a territory with elevated and dissected relief extends for approximately 5 million km 2.
Relief. Within the highlands there is a wide variety of relief, which combines areas of crystalline plateaus with island uplands composed of sedimentary rocks, volcanic plateaus and blocky ridges formed as a result of Cenozoic faults and uplifts. As a result of the fragmentation and uplift of the East Brazilian shield in the Neogene, ridges or “sierras” were formed, which reach heights of more than 2000 m. They are most clearly expressed in the relief of the Serra do Mar in the southeast and the Serra do Espinhaço north of the South Tropic. The highest point of the highlands - Mount Bandeira (2890 m) - is located within the Caparao National Park. The Parana and its numerous tributaries fall from the steps of the plateau, forming rapids and waterfalls, the energy of which is now being intensively used. The most famous is the grandiose Iguazu Falls (70 m) on the Parana tributary of the same name.
Climatic conditions. Due to its location within the subequatorial and tropical zones, the Brazilian Highlands receive a lot of heat throughout the year. In the central part, annual precipitation (1500-1200 mm) falls mainly within 4-6 months. in the summer of the southern hemisphere. average temperature January 25...27 °C, and the average July temperature is about 24 °C.
Significant change climatic conditions observed towards the east. In the north-eastern part of the highlands, the wet season is reduced to 3 months a year and the amount of precipitation is reduced to 1000-400 mm, and their annual amounts fluctuate sharply from year to year. The southeastern trade winds leave the bulk of the moisture on the coast, and relatively dry air currents penetrate into the highlands. Equatorial air does not always reach the northeastern bulge unchanged.
Vegetation and fauna. The Brazilian Highlands are dominated by savannas and tropical woodlands. "Campos" is common name savannah, adopted in Brazil. Campos-limpos are characterized by a complete absence of woody vegetation. The area is a continuous sea of grass and this vaguely resembles the steppes temperate zone. Among the herbs - different kinds feather grass, bearded grass, wheatgrass, as well as representatives of the families Apiaceae, Lamiaceae and legumes. All these plants burn out and turn brown during the dry period, only small cacti and agaves retain their appearance unchanged all year round.
In Campos Cerrados, trees and shrubs grow along with herbs. Trees no more than 3-5 m high usually have an umbrella-shaped crown. Grasses in the shade of trees can reach 1-2m in height and grow so densely that during the wet season the area becomes impassable. Fires are common in savannas, sometimes covering vast areas.
In the forests, even close to settlements monkeys live, causing great damage to gardens and crops; in the savannas there are armadillos, anteaters, as well as the large flightless bird rhea, which resembles an ostrich. There is an abundance of birds everywhere, especially parrots and hummingbirds; Typical predators are pumas and jaguars; snakes and other reptiles are very common.
There are many ants in forests and savannas. Some of them settle near human habitation and cause great trouble to people. An integral feature of the savannah landscape is termite mounds.
Population and environmental problems. The most populated area is the one adjacent to Atlantic Ocean. The most big cities- Sao Paulo (population 17.7 million people in 2000) and Rio de Janeiro (10.6 million people) - and industrial development. In many large cities, the problem of air pollution, particularly from vehicle exhaust, is so severe that some, such as São Paulo, have imposed restrictions on the use of private cars. Despite adding alcohol to gasoline and reducing carbon dioxide emissions by about 30%, no significant improvement in urban air quality has been achieved.
The largest areas of arable land are concentrated in the Paraná basin, where coffee trees, tobacco, bananas, and grapevines are grown. On irrigated lands river valleys, especially in the north, rice crops are common.
In the humid north, sugar cane and oil palm are grown, and in drier areas, coffee trees are grown. In the northeast, which suffers most often from droughts, cotton is grown on irrigated lands. In internal parts The highlands occupy vast areas of savannah and secondary thickets used as pastures.
Geographical position
Geological structure
Natural areas and flora
Minerals
Bibliography
Geographical position
The Brazilian Plateau occupies most of eastern South America from 3 to 35° S. sh., mainly in Brazil, the south - in Uruguay, in the southwest its edge extends into Paraguay and Argentina. Strongly elevated in the east and southeast above the Atlantic coast. The highest point here above sea level is Pico da Bandeira, the highest peak of the Brazilian Plateau and Brazil. Height 2890 m (Fig. 1). It is located in the Caparao massif, between the lower reaches of the Paraiba and Rio Dosi rivers. Composed of gneisses. The slopes are covered with tropical rainforests. In the north to the Amazonian Lowland and in the southwest to the Laplata Lowland it is gently inclined; in the north-west it breaks off to the depression of the upper Paraguay.
Rice. 1 Pico da Bandeira
Geological structure
The Brazilian plateau consists of ancient crystalline shields and syneclises filled with sedimentary and volcanic rocks.
The ancient Guiano-Brazilian shield, which forms the basis of the Brazilian Plateau, is composed of Precambrian gneisses and crystalline schists, penetrated by granitoids. The shield protrudes to the surface in the form of the West Brazilian and East Brazilian protrusions of the folded basement. They are separated by the Parnaiba (Maranhao) and San Francisco basins. The East Brazilian high corresponds to the Late Proterozoic fold system (Baikalides), in places including older cores. At the beginning of the Cenozoic, the Cretaceous alignment surface here was uplifted, deformed and disrupted, which led to the formation of block mountains. The fault steps formed ledges. On the steep eastern side, they sometimes reach a height of several hundred meters and give the impression of real ridges (“serres”). From the foot of such a serra, the area to the east gradually rises, and then drops steeply down, forming a new serra.
The Brazilian plateau is low (from 250-300 to 800-900 m) and has a slightly hilly, almost flat topography. Even the highest outlier peaks are usually smoothed out. Greatest heights reach the eastern regional massifs. They form the Great Escarpment, descending in two large steps to the ocean. Among the ridges of the lower stage, Serra do Mar (1889 m) and Serra dos Organos (2070 m), located north of Gunabara Bay, stand out. Their proximity to Rio de Janeiro and Sao Paulo has made them a favorite holiday destination for wealthy Brazilians and tourists. The second, higher stage of the Great Escarpment is formed by the Serra do Mantiqueira, rising almost a full kilometer above the Serra do Mar. Here are the most high peaks Brazil - Bandeira (Banner Peak), 2890 m and Agulhas Negras (Black Eagles Peak). Along the right bank of the river. In Sao Francisco, the sharp residual Proterozoic ridges of the Serra do Espinhaço rise to 1500-2100 m (Fig. 2). In hot humid climates rocks They quickly collapse: the softer and looser ones are washed away by showers, leaving the hard ones. Individual blocks acquired a cone-shaped shape, for which they received the name “sugarloaf” (Fig. 3). One of them adorns the picturesque bay of Rio de Janeiro. Syneclises (in the states of Maranhão and Piaui, along the rivers of São Francisco and the upper Paraná, etc.) are usually represented by stratified plains, often with erosional ledges of the cuesta type, and in the most elevated areas - remnant sandstone table plateaus with steep ledges - chapadas (they are characteristic and for a non-folded foundation cover); only the Parana depression is occupied by a stepped lava plateau.
Rice. 2 Residual Proterozoic Fig. 3 "sugarloaf" in the bay crests of Serra do Espinhaçu Rio De Janeiro
The further you go to the east, towards the humid breath of the Atlantic, the more the trees close together into a continuous cover of deciduous evergreen forests and the terrain becomes higher and rockier. The eastern edge of the Brazilian Plateau, which breaks down to the ocean, is already mountain ranges, broken into separate huge blocks, soaring steeply above tectonic depressions. The eastern edge of the Brazilian Plateau, which breaks down to the ocean, is already mountain ranges, broken into separate huge blocks, soaring steeply above tectonic depressions.
In the center and north-west, basement plateaus predominate, alternating with high plateaus - chapadas. To the west, the mountainous terrain gives way to the vast plains of the upper reaches of the Parana River - the Parana Plateau. Downstream of the Paraná there are extensive lava plateaus. The ledges of hardened lava make all the left tributaries of the Parana “jump” down, as if on steps, forming numerous rapids and waterfalls (Fig. 5). There are 56 of them on the Tieta River alone. Parana itself falls from a height of 17 m by the Senti Quedas waterfall (Fig. 4).
Rice. 4 Senti Kedas waterfall Fig. 5 waterfall of the left tributary of the Parana River
Natural areas and flora
The Brazilian plateau in the northwest and north is covered with moist evergreen and deciduous evergreen forests.
In the center are shrublands and savannas - campos cerrados, formed on red coarse soils. During the rainy season, they are overgrown with turf-grass vegetation. Campos plants are well adapted to the alternation of dry and wet seasons, which last about six months. Deciduous low-growing trees and shrubs, growing here along with evergreens, are covered with small leaves with a waxy coating. Chaparro-curatella, licheira (“emery wood”), mangabeira, milky juice and the fruits of which are used as food by local residents, I think with fruits (Fig. 6), very rich in vitamins, as well as agaves, cacti and some types of palms.
Rice. 6 I show the fruits
During the dry period, everything burns out, and in some places a dense crust forms in the upper horizons of lateritic soils. In the west, the “Campos Cerrados” transition into the marshy, low-lying Pantanal plain, which is flooded during the rainy season and during drought, which is a combination of swamps and lakes with areas of forests, shrubs and meadows.
In the northeast there is xerophytic-succulent woodland - caatinga (Fig. 7).
Rice. 7 Caatinga (Portuguese caatinga, in the Tupi language - white, light forest)
Poor soils barely cover the rocks, and there is almost no grass. There are prickly shrubs and all kinds of cacti everywhere. And above them are dry-loving shrubs and trees, columnar cacti and tree-like euphorbia. At some distance from each other, like skittles, bottle trees grow (Fig. 8). These thickets are almost devoid of foliage and provide no shelter at all from the burning rays of the sun or from downpours. During the winter-spring dry period, which lasts 8-9 months, precipitation falls less than 10 mm per month. At the same time, the average air temperature is 26-28 C. At this time, many plants shed their leaves. Life comes to a standstill until the autumn rains, when more than 300 mm of precipitation falls per month with an annual amount of 700-1000 mm. As a result of rainfall, the water level in rivers rises rapidly. Floods occur regularly, destroying houses and washing away topsoil from fields.
In the east there are humid tropical evergreen and summer green forests. There, tropical rainforests stretch along the Atlantic coast, which in the coastal part are largely reduced to plantations of tropical crops. The eastern windward slopes and high mountain plateaus of the Brazilian Plateau are characterized by pronounced altitudinal zonation. Tall-grass evergreen forests, similar in appearance and species composition to Amazonian jungle. Higher up they give way to tree ferns (Fig. 9, 10) and bamboos, and at an altitude of 1800 m deciduous trees and coniferous araucaria appear. Above 2200-2400 m, mountain meadows begin, giving way to peat bogs, mosses and lichens
On South - mixed forests from conifers with evergreen deciduous and treeless savanna - campos limpos; lateritic and chestnut soils are developed under the savannas. On the arid interior plains of the highlands, composed of porous sandstone and, in some places, clayey rocks, treeless grassy savannas (prairies) are common, with gallery forests along river valleys. "Campos-Limpos" are beautiful pastures.
The western leeward slopes of the eastern ridges of the highlands are characterized by seasonally wet deciduous forests.
Fig.8 Bottle tree
Rice. 9 tree ferns
Rice. 10 tree ferns
Climate
The Brazilian plateau lies in the subequatorial, tropical and subtropical climatic zones. Average temperatures in January vary from southwest to northeast from 22 to 29 °C (maximum up to 42 °C), in July - from 12 to 25 °C, minimum - 6 °C (below the tropics). The amount and regime of precipitation within the Brazilian Plateau are very different: in the north and in the center precipitation falls mainly in summer, up to 1400-2000 mm per year (in the northeast less than 500 mm, the driest region), in the east - over 2000 mm, almost without drought, and in the south 1000-1800 mm throughout the year. The low mesas adjacent to the Amazon have a humid and hot tropical climate with heavy rainfall and thunderstorms. No less humid climate and on the slopes of the Serres Grand Escarpment facing the South Atlantic. Annual quantity The precipitation here is about 2000 mm. In the inland areas of the Brazilian Plateau, fenced off on all sides by high serras and chapadas, from 500 to 1000 mm of precipitation falls annually, with about 90% of it falling during the rainy season (January - June). But even at this time, cruel, devastating downpours only wash the earth. The moisture evaporates before the soil has a chance to absorb it. It is not uncommon for the dry season to last throughout the year, causing severe droughts.
BRAZILIAN PLATEAU, in the east of South America, mainly in Brazil (the southern edge is in Uruguay, the southwestern edge is in Paraguay and Argentina). It extends from north to south (from 3 to 35° south latitude) and from east to west (from 35 to 65° west longitude) for more than 3,200 km in each direction. In the east and southeast, it is strongly elevated above the Atlantic coast (height up to 2890 m, Mount Bandeira - highest point Brazilian plateau). In the north it gently descends to the Amazonian Lowland, in the southwest - to the Laplata Lowland; in the northwest it drops steeply to the valley of the upper Paraguay.
Relief and geological structure.
The Brazilian plateau consists of elevated plains 250-900 m high, above which rise mountain ranges (especially in the eastern part) - the so-called serras (Serra da Mantiqueira, Serra do Espinhaçu, Serra do Mar, etc.) and table plateaus with steep slopes - chapadas (for example, on the Mato Grosso plateau). Tectonic troughs and depressions are expressed in relief by stratified plains (the Parnaiba River basin), often with erosional ledges such as cuestas, accumulative plains (the middle reaches of the Araguaia River), and stepped trap plateaus (in the middle reaches of the Parana River). Near the Atlantic coast there are many rounded island mountains that resemble “sugar loaves,” for example, Mount Pan di Azucar (height 395 m; coast of Guanabara Bay). They are formed under humid tropical climate conditions in blocky massifs, broken by cross vertical cracks and composed of rocks that are susceptible to erosion at the top. In the eastern part of the Brazilian Plateau, manifestations of karst and pseudokarst occur. Numerous caves developed in limestones (eg São Mateus Imbira), dolomites, sandstones and quartzites (eg Mina do Chico Rei).
The Brazilian plateau is located within the ancient South American plateau. In the northwestern and southeastern parts it is composed of Archean-Early Proterozoic crystalline rocks of its basement protruding to the surface (Central Brazilian and Atlantic shields), intruded by granites. The territories along the Parnaiba rivers in the northeast and Paraná in the central and southwestern parts of the Brazilian Plateau belong to the development area of the Paleozoic-Mesozoic platform cover, formed by strata of horizontally occurring sedimentary and volcanogenic (Cretaceous plateau basalts) rocks. See also Brazil.
Climate. Most of The plateau is located in the tropical zone, the northern - in the subequatorial, and the southern - in the subtropical. In the north, average temperatures in January are 24°C (maximum - up to 29°C), in July 22°C, in central regions 24 and 20°C, respectively, in the southern regions - 20 and 11-18°C (frosts down to -8°C are possible). Over most of the plateau, 1200-2000 mm of precipitation falls per year, on the windward slopes facing the Atlantic Ocean - more than 1600 mm (in some places over 2400 mm), in the northeast - in some places less than 300 mm. Precipitation is uneven, except in the extreme south.
Inland waters . The river network is dense, the rivers are high in water, with sharp fluctuations in water flow over the seasons, and many rapids and waterfalls. In the north and northwest, the rivers belong to the basins of the right tributaries of the Amazon River (tributaries Madeira, Tanajos, Xingu, Tocantins with Araguaia), in the northeast and east - to the basins of São Francisco, Parnaiba and other smaller rivers, in the south and south- west - the Parana River basin.
Soils, flora and fauna. Most of the plateau is occupied by shrub savannas (campos cerrados). In the north and north-west there are evergreen and summer-green forests, in the north-east - xerophytic-succulent woodlands (caatinga), in the south - mixed (coniferous with evergreen deciduous) forests and treeless savanna (campos limpos). Gallery forests stretch along river valleys. Ferrozems are developed under savannas, and red ferrallite soils are under forests.
The Brazilian plateau is inhabited by the anteater, the armadillo, the nosoha, the Brazilian tuco-tuco, a variety of rodents, including the largest - the capybara (body length up to 130 cm), deer (swamp and red spitz-horned), among predators - the maned wolf, puma, jaguar . Monkeys, peccaries, and tapirs are found in the forests. There are many birds (rhea ostrich, etc.) and insects, especially butterflies, ants and wasps. IN northern part The plateaus are penetrated by animals of the Amazonian lowland.
The largest protected natural areas within the Brazilian Plateau are the national parks of Aparados da Serra, Brazil, Itatiaia, Caparao, Serra da Bocaina, Serra da Canastra, Serra doz Organs. Add to list World Heritage included the national parks of Iguazu, Chapada dos Veadeiros, Emas, forest reserves of the eastern (“Discovery Coast”) and southeastern Atlantic coast.
Lit.: Lukashova E. N. South America. Physical geography. M., 1958; Vlasova T.V. Physical geography of continents (with adjacent parts of the oceans). North America, South America, Australia and Oceania, Antarctica. 3rd ed. M., 1976.
This area is almost as large in size as. At the same time, it is characterized great variety landscapes. The main features of its nature are determined by the predominance of the relief of plateaus and table plateaus and the dominance of subequatorial and tropical ones. Only at its southern edge does the Brazilian Highlands enter subtropical latitudes.
In a significant part of the highland, crystalline rocks of the ancient base of the platform come to the surface. In its middle part there is a strip of sedimentary deposits, under which the rocks of the crystalline base are hidden. In the southwest, ancient rocks are overlain by diabase lavas. Long-term exposure to erosion processes and recent ones have created a wide variety of relief within the highlands. It combines areas of ancient peneplain with mesas, volcanic plateaus and blocky ridges formed as a result of tertiary faults and uplifts.
The highest parts of the highlands are located near the Atlantic Ocean and are separated from it only by a narrow strip of coastline. Almost everywhere coastline bears traces of recent subsidence. In some places, small lobed bays cut into the coast, representing convenient harbors. On the shore of one of these bays is the largest city -. To the north and south of it, the edge of the highlands recedes somewhat, and wide stripes stretch along the shore of the Atlantic Ocean sandy beaches, partially flooded during high tides.
From the Atlantic Ocean, the eastern and southeastern edges of the Brazilian Highlands appear as high and highly dissected mountain systems. As a result of the fragmentation and uplift of the edge of the highlands in the Tertiary period, a series of ridges or “serres” were formed, which stretch parallel or at some angle to the coast and sometimes reach considerable heights. The highest massif in this area and the entire Brazilian Highlands is Bandeira (2884 m).
The width of the serra strip reaches 300 km, and in some places more than 400 km. In the north of this strip there are rich deposits of iron and manganese ores, radioactive elements, as well as diamonds and gold.
Deeper into the Brazilian Highlands, the serras gradually decline into the flat surface of the high plateau that makes up the bulk of the highlands. In the central regions it is a typical ancient peneplain of crystalline rocks, into which fairly deep river valleys cut. This type of relief is typical for vast plateau Goias.
In the west of the highlands and in some areas of its central part, crystalline rocks are covered with a thickness of sedimentary deposits of the Lower Paleozoic or Mesozoic. These strata consist of horizontal layers of limestone and sandstone. Rivers divide them into a series of tabletop hills with steep, high slopes. The local population calls these hills “shapads”. A similar relief is characteristic of the Mato Grosso plateau. Over a large area, the surface of the crystalline base is hidden under strata of Triassic lavas, forming the relief of stepped plateaus. The river falls along the steps of these plateaus. with its numerous tributaries, forming rapids and waterfalls, including the famous waterfalls Seti-Kedas, Urabupanga, etc.
The interior regions of the Brazilian Highlands (altitude 500-600 m, rarely exceeding 1000 m) are significantly lower than the outlying parts.
To the west and north, the Brazilian Highlands are bordered by lowlands. Its edges either drop steeply, forming ledges several hundred meters high, or drop rather gently. There are many rapids and waterfalls on the rivers cutting through the edge of the crystalline plateau. Low-lying areas covered with tropical forests extend far into the highlands along river valleys.
The climatic conditions of the region are varied. Almost this entire vast territory is characterized by the division of the year into two periods - wet and dry. Duration of wet and dry periods and annual precipitation amounts in different parts areas are different, which is reflected in the nature of the vegetation cover and the appearance of the cultural landscape.
The climate of the central part of the Brazilian Highlands, as well as the interior, is typical subequatorial with a clear distinction of dry and wet seasons and the predominance of high temperatures. Annual precipitation (1500-2000 mm) falls almost entirely during four to five months of summer southern hemisphere. The average January temperature is approximately 25-27°, and the average July temperature is about 24°C. With such small differences temperature conditions at different times of the year, daily amplitudes can be very significant. In winter, daily temperature changes due to the penetration of cold air from the south can reach 25°. Even in the hottest time of the year, when cold waves appear, temperature drops of up to 15 degrees per day are possible.
The north of the region resembles the south of the Amazon in terms of climatic conditions. The wet period of the year extends over a longer period of time, and temperatures become even more uniform and hardly change throughout the year.
The internal and northern parts of the region are irrigated by tributaries of the river. - Xingu and Tocantins. The river network is very dense, but the river regime is uneven. All watercourses are characterized by autumn-summer floods and a strong drop in level in other seasons. Due to the endless number of rapids and waterfalls, the rivers are not navigable, but the reserves of water energy are large.
A significant change in climatic conditions is observed towards the east. In the northeastern part of the highlands, the wet season is reduced to three months a year and the amount of precipitation is reduced to 100-400 lsh, with annual precipitation amounts fluctuating sharply from year to year. As a rule, this area is bypassed by air currents carrying precipitation. The southeastern trade winds leave the bulk of the moisture on the coast, and penetrate into the highlands already relatively dry. Equatorial air does not always reach the northeastern protrusion of the Brazilian Highlands unchanged. This explains the variability of precipitation in this area and its low annual amounts. At the same time, air temperatures are high, as in other parts of the highlands. The average temperatures of the hottest months reach 28°. The dry climate is not conducive to the development of the water network; there are few rivers in the northeast.” The largest of them, Sao Francisco, has a very unstable regime, but despite this, in certain sections of the flow, free from rapids, it is used for navigation.
Small power plants have been built on rapid sections of the river.
On the slopes of the serra, facing towards, and on the coastal plain, bordering the plateau from the northeast, the amount of precipitation increases sharply and falls almost continuously throughout the year. Only in the north of the eastern edge of the Brazilian Highlands does the maximum precipitation occur in the winter of the southern hemisphere and is created by the southeast trade wind, and to the south the maximum precipitation occurs in the summer, when the coast is exposed to northeastern monsoon winds.
In the south of the region there is a slight decrease in average winter temperatures. There are no frosts here either, only when going up into the mountains there is a significant drop in temperature and sometimes there are frosts.
The Brazilian Highlands are dominated by savannas and sparse tropical forests. Differences in precipitation in different parts of the region lead to significant differences in vegetation cover. The parent rock for the soils throughout the highlands is a thick and ancient weathering crust, so that the bedrock nowhere lies directly on the surface. On the weathering crust in the interior parts of the region, red-brown and red-brown soils are formed, and in the constantly wet areas of the Atlantic coast - red lateritic soils. The two most common types of savanna are campos limpos and campos cerrados. Campos is the common name for savanna. Campos-limpos are characterized by a complete absence of woody vegetation. The area is a continuous sea of grass and thus vaguely resembles the steppes of the temperate zone. Among the herbs are various types of feather grass, bearded grass, wheatgrass, umbellaceae, labiates and legumes. All these plants burn out and turn brown during the dry period of the year, only small cacti and agaves retain the same appearance all year round. Although outwardly similar to the steppe, Kampos-Limpos differs from it in a much greater diversity of species composition. On two or three square meters surface can be counted up to two hundred to two hundred and fifty species of plants.
In Campos Cerrados, trees and shrubs grow along with herbs. Trees no more than 3-5 m high usually have an umbrella-shaped crown. Grasses in the shade of trees can reach 1-2 m in height and grow so densely that the area becomes almost impassable during the wet season of the year.
Fires are common in savannas, sometimes covering vast areas. After fires, the savanna is covered with a peculiar grass called copingodura, which has reddish panicles and leaves containing oil. This cereal is a valuable feed for livestock. It grows strongly after the destruction of other plants.
The entire territory covered by savannas, in different directions intersected by dark green forest strips stretching along river valleys and ravines. These forests are somewhat poorer than typical tropical rainforests, but still have a truly tropical appearance. They contain cecropia and some types of palm trees. The tree trunks are so entwined with vines that even a cut tree does not fall to the ground, supported by the natural ropes entwining it. In the northeast of the region, which is very dry, typical savanna gradually turns into a kind of tropical forest - caatinga, where the vegetation, to an even greater extent than the vegetation of the savannah, is adapted to withstand prolonged drought. Vegetation cover in caatinga it consists of a combination of trees and shrubs, with an almost complete absence of herbs, especially grasses and asteraceae. Many trees have swollen trunks and soft, porous wood that retains large amounts of moisture. The trunks of other trees are thin, and the crown is very spreading. Most of the trees and shrubs are equipped with spines. All this makes the terrain difficult to pass, although individual plants stand at quite significant distances from each other. Of the most typical plants of Caatinga, the numerous cacti of the most interesting various forms, prickly pears and euphorbias. Among the latter are rubber plants. Several types of palm trees are also found. The most remarkable caatinga tree is the carnauba wax palm (Copernicia cerifera), which produces vegetable wax, which is scraped or boiled from its large (up to two meters in length) 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 fruits are used by the local population as food, raw and boiled. It’s not for nothing that the people of Brazil call carnauba “the tree of life.”
With the onset of rains, the caatinga changes its appearance very quickly. Travelers write that after long period drought, you can fall asleep in the evening in a forest scorched by the sun, devoid of leaves and flowers, and after a night of rain you can wake up in a completely different environment: within a few hours, many plants become covered with leaves and bloom. bright flowers and the whole appearance of the caatinga changes completely.
Tropical rainforests grow along the eastern edge of the highlands, along the slopes of the Serres and on the hilly coastal plain. From the sea itself they begin as a wide strip of mangroves, which then turn into a typical flood-free forest, very reminiscent of the Amazon forest. It contains cecropia, palm trees, tree ferns, vines, including a unique bamboo vine, and various epiphytes. On the mountain slopes facing the ocean, changes in the composition of the forest and its appearance with increasing surface. At altitudes of 1800-2000 m, palm trees and tree ferns gradually disappear, some types of vines are replaced by others, woody vegetation thins out, but herbaceous vegetation becomes richer, and they begin to appear more and more often deciduous plants, since winter temperatures here are already quite low. At an altitude of 2100-2200 m, at the upper limit of tree vegetation, evergreen plants disappear completely. Higher up are alpine meadows, and then a tundra-like landscape with extensive peat bogs, characterized by sphagnum mosses, various lichens and sundews. In winter, at high altitudes of the Brazilian Highlands, windy weather prevails, there are snowfalls and at night the temperature can drop to 5-7° below zero.
In the extreme southeast of the region, along the border with subtropical latitudes near the coast of the Atlantic Ocean, forests of Brazilian araucaria (Araucaria brasiliensis) with an undergrowth of (Ilex paraguaiensis) grow on red earth soils. These forests are being intensively cut down due to valuable wood araucaria.
The fauna of the Brazilian Highlands is diverse, as it combines different types of landscapes. Forests, even close to populated areas, are inhabited by numerous monkeys, bringing great harm gardens and crops, armadillos, anteaters, and rhea ostriches live in savannas. Common predators are pumas and jaguars. Birds abound everywhere, especially parrots and hummingbirds, and there are a lot of snakes and other reptiles. Number of people bitten poisonous snakes, in Brazil reaches 15 000 per year, and about a third of them die due to poor medical care.
The numerous termite structures are very interesting. There are a lot of different ants in forests and savannas. Many of them settle near human habitation and cause great trouble to people.
The territory of the Brazilian Highlands is unevenly populated and developed. Therefore, the degree of preservation of natural landscapes in different parts of the region is different. The most populated area is the area adjacent to the Atlantic Ocean. The largest cities and the largest areas of arable land are located there, on which valuable tropical crops are grown. Large areas are occupied by coffee plantations, sugar cane, orange groves and banana plantations, which play a huge role in the nutrition of the population.
In the northeast of the region, cotton crops are common on irrigated lands.
Natural vegetation in the Atlantic strip has been severely destroyed, with tropical rainforests suffering the most. In the interior of the region there are vast areas of virgin savannah, used only to a small extent for cattle breeding.
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