Who lives in the savannas and woodlands. Presentation on the theme "savannas and woodlands"
Savannahs are dominated by herbaceous vegetation. Most of the African savanna is located in Africa, between 15 ° N. sh. and 30°S sh. Savannahs are located in countries such as: Guinea, Sierra Leone, Liberia, Ivory Coast, Ghana, Togo, Benin, Nigeria, Cameroon, Central African Republic, Chad, Sudan, Ethiopia, Somalia, Democratic Republic of the Congo, Angola, Uganda , Rwanda, Burundi, Kenya, Tanzania, Malawi, Zambia, Zimbabwe, Mozambique, Botswana and South Africa.
There are two seasons in the African savanna: dry (winter) and rainy (summer).
- The dry winter season is longer, lasting from October to March in the Southern Hemisphere, and from April to September in the Northern Hemisphere. During the whole season, only about 100 mm of precipitation falls.
- The rainy summer season (rainy season) is very different from the dry season and lasts a shorter amount of time. During the rainy season, the savanna receives between 380 and 635 mm of rain per month and it can rain for hours without stopping.
Savannah is characterized by grasses and small or scattered trees that do not form a closed dome (as in), allowing sunlight to reach the ground. The African savanna contains a diverse community of organisms that interact and form a complex food web.
Healthy, balanced ecosystems are made up of many interacting ecosystems called food webs. (lions, hyenas, leopards) feed on herbivores (impalas, warthogs, cattle) that consume producers (herbs, plant matter). Scavengers (hyenas, vultures) and decomposers (bacteria, fungi) destroy the remains of living organisms and make them available to producers. Humans are also part of the biological community of the savanna and often compete with other organisms for food.
Threats
This ecoregion has been significantly harmed by humans in many ways. For example, local residents use the land for grazing, as a result of which the grass dies and the savannah turns into a barren, desert area. People use wood for cooking and create problems for the environment. Some also engage in poaching (hunting animals illegally), which leads to the extinction of many species.
To restore the damage caused and preserve the natural environment, some countries have created nature reserves. The Serengeti National Park and the Ngorongoro Nature Reserve are UNESCO World Heritage Sites.
The African savannah is one of the largest wild habitats in the world, it covers almost half the area of the continent, about 13 million km². If it were not for the efforts made by people to preserve the savannah, a large number of representatives of the flora and fauna of this corner of nature would have already become extinct.
African savannah animals
Most savannah animals have long legs or wings that allow them to migrate long distances. Savannah is an ideal place for birds of prey such as hawks and buzzards. The wide open plain gives them a clear view of their prey, the rising hot air currents allow them to soar above the ground with ease, and the sparse trees provide an opportunity to rest or nest.
The savannah has a large species diversity of fauna: the African savannah has become home to more than 40 different species of herbivorous animals. Up to 16 different herbivorous species (those that feed on tree leaves and grass) can coexist in one area. This is possible due to their own food preferences of each individual species: they can graze at different heights, at different times of the day or year, and so on.
These various herbivores are food for predators such as lions, jackals, and hyenas. Each carnivorous species has its own preferences for living in the same territory and not competing for food. All these animals depend on each other, occupy a certain place in the food chain and provide balance in the environment. Savannah animals are in constant search of food and water. Some of them are listed below:
African bush elephant
The largest land mammal in the world. These animals grow up to 3.96 m at the withers and can weigh up to 10 tons, but most often they measure up to 3.2 m at the withers and weigh up to 6 tons. They have a long and very flexible trunk that ends with nostrils. The trunk is used to capture food and water and carry them to the mouth. On the sides of the mouth are two long teeth called tusks. Elephants have thick, gray skin that protects them from the deadly bites of predators.
This type of elephant is common in the African savannas and grasslands. Elephants are herbivores and feed on herbs, fruits, tree leaves, bark, shrubs, and the like.
These animals have an important job in the savannas. They eat bushes and trees, and thereby help the grass to grow. This allows many herbivorous animals to survive. There are about 150,000 elephants in the world today and they are endangered because poachers kill them for their ivory.
hyena dog
The African wild dog lives in the grasslands, savannas, and open woodlands of eastern and southern Africa. The fur of this animal is short and colored in red, brown, black, yellow and white. Each individual has a unique coloring. Their ears are very large and rounded. The muzzle of the dogs is short and they have powerful jaws.
This species is well suited for chasing. Like greyhounds, they have a slender body and long legs. The bones of the lower front legs are fused together, preventing them from twisting when running. African wild dogs have large ears that help to remove heat from the animal's body. The short and wide muzzle has powerful muscles that allow it to grab and hold prey. The multicolored coat provides camouflage to the environment.
The African wild dog is a carnivore and feeds on medium-sized antelopes, gazelles, and other herbivores. They do not compete with hyenas and jackals for food, as they do not eat carrion. Humans are considered their only enemies.
Black Mamba
The black mamba is a highly venomous snake common in the savannas, rocky and open woodlands of Africa. The snakes of this species grow about 4 m in length and can reach speeds of up to 20 km/h. The black mamba is not actually black in color, but brownish gray, with a light belly and brownish scales on the back. It got its name because of the purple-black color of the inner surface of the mouth.
Black mambas feed on small mammals and birds such as voles, rats, squirrels, mice, etc. A snake can bite a large animal and release it. She will then chase her prey until she is paralyzed. Mamba bites and holds smaller animals, waiting for the action of toxic poison.
Black mambas are very nervous when a person approaches them and try to avoid it in any way. If this is not possible, the snake shows aggression by raising the front of the body and opening its mouth wide. They quickly attack and inject their poison into the victim, and then crawl away. Before antidotes were developed, mamba bites were 100% fatal. However, to prevent death, the drug should be administered immediately. They have no natural enemies and the main threat comes from habitat destruction.
Caracal
- a species of mammal from, widespread in the savannas of Africa. The physique is similar to that of a normal cat, but the caracal is larger and has large ears. Its coat is short, and the color varies from brown to reddish-gray, sometimes even becoming dark. Its head is shaped like an inverted triangle. The ears are black on the outside and light inside, with tufts of black hair at the tips.
They are active at night, mainly preying on small mammals such as rabbits and porcupines, but sometimes large animals such as sheep, young antelopes or deer become their prey. They have special skills for catching birds. Strong legs allow them to jump high enough to actually knock down flying birds with their large paws. The main threat to caracals is people.
bear baboon
Bear baboons live mainly in the African savannah and high mountain meadows. They never stray far from trees or water sources. This species is the largest in the genus of baboons, males can weigh 30-40 kg. They are very hairy animals with olive-grey fur.
Bear baboons do not live in trees, they spend most of their time on the ground. They may climb trees when threatened, for food or to rest. These mainly eat fruits from trees, roots and beetles. Baboons inadvertently feed other animals by throwing or leaving food behind them for others to pick up.
Egyptian mongoose
The Egyptian mongoose is the largest of all mongooses in Africa. Animals are common in scrublands, rocky regions and small areas of the savannah. Adults grow up to 60 cm in length (plus a 33-54 cm tail) and weigh 1.7-4 kg. Egyptian mongooses have long hair, usually gray with brown dots.
They are primarily carnivorous, but will also eat fruit if available in their habitat. Their typical diet consists of rodents, fish, birds, reptiles, insects, and larvae. Egyptian mongooses also feed on the eggs of various animals. These fauna can eat poisonous snakes. They prey on birds of prey and large savannah carnivores. Egyptian mongooses benefit the environment by killing animals (such as rats and snakes) that are considered pests to humans.
Zebra Grant
Grant's zebra is a subspecies of the Burchell's zebra and is widely distributed in the Serengeti Mara. Its height is about 140 cm, and its weight is about 300 kg. This subspecies has rather short legs and a large head. Grant's zebra has black and white stripes all over its body, however the nose and hooves are completely black. Each individual has its own unique color.
The main predators of zebras are hyenas and lions. There are about 300,000 zebras left in the savannah and they are endangered.
a lion
They live in the African savannas south of the Sahara. They eat gazelles, buffaloes, zebras and many other small to medium sized mammals. Lions are the only cats that live in family packs called prides. Each pride includes from 4 to 40 individuals.
The coat color of these animals is ideal for camouflage with the environment. They have sharp, hooked claws that they can retract or extend at will. Lions have sharp teeth that are perfect for biting and chewing meat.
They play an important role in the survival of other animals. When this predator kills its prey and eats it, parts or pieces of the carcass are usually left, which are consumed by vultures and hyenas.
Lions are quite interesting and graceful creatures that are interesting to watch, however they are endangered due to over-hunting and loss of habitat.
Nile crocodile
The Nile crocodile can grow up to five meters in length and is common in freshwater swamps, rivers, lakes and other watery places. These animals have long snouts that can capture fish and turtles. The body color is dark olive. They are considered the smartest reptiles on earth.
Crocodiles eat almost anything in the water, including fish, turtles, or birds. They even eat buffalo, antelopes, big cats, and sometimes humans when they get the chance.
Nile crocodiles skillfully disguise themselves, leaving only their eyes and nostrils above the water. They also blend well with the color of the water, so for many animals that come to the pond to quench their thirst, these reptiles are a mortal danger. This species is not endangered. They are not threatened by other animals except humans.
African savannah plants
This habitat has become home to a huge number of wild plants. Many representatives of the flora have adapted to grow in long periods of drought. Such plants have long roots that are able to reach water deep underground; thick bark that can withstand constant fires; trunks that accumulate moisture for use in winter.
Herbs have an adaptation that prevents certain animals from eating them; some are too spicy or bitter for certain species, while others are more than acceptable. The advantage of this adaptation is that each animal species has something to eat. Different species may also consume individual plant parts.
There are many different types of plants in the African savanna and below is a list of some of them:
Acacia Senegal
The Senegalese acacia is a small thorny tree from the legume family. It grows up to 6 m in height and has a trunk diameter of about 30 cm. The dried juice of this tree is gum arabic - a hard transparent resin. This resin is widely used in industry, cooking, watercolor painting, cosmetics, medicine, etc.
Many wild animals feed on the leaves and pods of the Senegalese acacia. Like other legumes, these trees store nitrogen and then enrich poor soils with it.
Baobab
Baobab is found in the savannahs of Africa and India, mostly near the equator. It can grow up to 25 meters in height and live for several thousand years. During the rainy months, water is stored in a thick stem, with roots up to 10 m long, and then used by the plant during the dry winter season.
Almost all parts of the tree are widely used by the locals. The bark of the baobab is used to make cloth and rope, the leaves are used as spices and medicines, and the fruit, called "monkey bread", is eaten pure. Sometimes people live in the huge trunks of these trees, and representatives of the Galagidae family (nocturnal primates) live in the crowns of the baobab.
bermuda grass
This plant is also called pig finger. Bermuda grass is widely distributed in warm climates from 45°N. up to 45°S It got its name from an introduction from Bermuda. Grass grows in open areas (pastures, open forests, and gardens) where frequent disturbances to the ecosystem occur, such as animal grazing, floods, and fires.
Bermuda grass is a creeping plant that forms a dense carpet when it touches the soil. It has a deep root system, and in drought conditions, the roots can be underground at a depth of 120-150 cm. The main part of the root is at a depth of 60 cm.
Pigtail is considered a highly invasive and competitive weed. Few herbicides are effective against it. Before the advent of mechanized farming, Bermuda grass was the worst weed for farmers. Nevertheless, it saved a huge amount of agricultural land from erosion. This plant is highly nutritious for cattle and sheep.
elephant grass
Elephant grass grows in the African savanna and reaches a height of 3 m. It is found along lakes and rivers where the soil is rich. Local farmers feed this herb to their animals.
The plant is very invasive and clogs natural waterways that need to be cleared periodically. Elephant grass grows well in tropical climates and can be killed by a slight frost. The underground parts will remain alive if the soil does not freeze.
This herb is used by the locals in cooking, agriculture, construction and as an ornamental plant.
Persimmon loquat
Persimmon medlar is widely distributed throughout the African savannah. It prefers wooded areas where termite mounds are nearby, and is also found along riverbeds and wetlands. In heavy soils, termite mounds provide the tree with aerated and moist soil. Termites do not eat live trees of this species.
This plant can reach 24 m in height, however, most trees do not grow that tall, but reach a height of 4 to 6 m. The fruits of the tree are popular with many animals and locals. They can be eaten fresh or canned. The fruits are also dried and ground into flour, and beer is also brewed from them. The leaves, bark and roots of the tree are widely used in traditional medicine.
Mongongo
The mongongo tree prefers a hot and dry climate with little rainfall and is common in wooded hills and sand dunes. This plant reaches a length of 15-20 meters. It has many adaptations that allow it to live in arid environments, including: a moisture-retaining trunk, long roots, and thick bark.
This species is widely distributed throughout the southern savannah. Nuts from this tree are part of the daily diet of many Africans and are even used to make oil.
Kombretum krasnolistny
Redleaf combretum prefers a warm and dry climate, and grows near rivers. The tree grows from 7 to 12 m in height and has a dense expanding crown. The fruit is poisonous and causes severe bouts of hiccups. The tree has straight, long roots because it requires a lot of water to grow.
They feed on its leaves in spring. Parts of this tree are used in medicine and the woodworking industry. Good adaptability, fast growth, dense spreading canopy, interesting fruits and attractive leaves make it a popular ornamental tree.
Acacia twisted
Acacia twisted is a tree from the legume family. Its homeland is the African savanna of the Sahel, but the plant can also be found in the Middle East. It is known that the plant can grow in highly alkaline soil, and withstand dry and hot environmental conditions. In addition, trees that reach the age of two are notable for slight frost resistance.
The wood of these trees is used in construction and furniture is made from it. Many wild animals feed on the leaves and pods of the acacia tree. Parts of the tree are used by the locals to make jewelry, weapons and tools, as well as in traditional medicine.
The black locust plays an important role in the restoration of degraded drylands, as the roots of the tree fix nitrogen (the main plant nutrient) in the soil through interaction with symbiotic nodule bacteria.
Acacia sickle-bladed
The sickle-bladed acacia is commonly found in the savannahs of equatorial East Africa, in particular the Serengeti Plain.
This acacia can grow up to 5 m tall and has sharp spikes up to 8 cm long. The hollow spikes can be inhabited by 4 species of ants and they often make tiny holes in them. When the wind blows, the spikes thrown by the ants make a whistling sound.
Savannah is a vast expanse in the tropical zone, with intermittent precipitation, covered with grassy vegetation with sparsely scattered trees and shrubs. The most common savannas are in central Africa. The main mass of plants of the cereal savannah are cereals, reaching a great height (up to 4 m). The savannahs in the Orinok lowland are called llanos, in.
Savannah is a zonal type of landscape in tropical and subequatorial climatic zones. In this natural zone, the change of the wet and dry seasons is clearly expressed at consistently high air temperatures (from + 15°С to + 32°С). As you move away from the equator, the period of the wet season decreases from 8-9 months to 2-3, and precipitation - from 2000 to 250 mm per year. The violent development of plants in the rainy season is replaced by droughts of the dry period with a slowdown in the growth of trees, grass burning out. Some plants are able to store moisture in the trunks (baobabs, bottle tree). The savannah is characterized by the predominance of grassy cover, among which high (up to 5 m) grasses dominate. Shrubs and solitary trees rarely grow among them, the frequency of which increases towards the equator. Of the woody vegetation on different continents, palm trees, a variety of acacias, tree-like cacti are found here.
The soils of the savannas depend on the length of the rainy season. Closer to the equatorial forests, where the rainy season lasts 7-9 months, red ferrallitic soils form. Where the duration of the rainy season is less than 6 months, typical red-brown savannah soils are common. On the borders with semi-deserts, where scarce rains fall for only 2-3 months, unproductive soils with a thin layer of humus are formed.
The dense and high grass cover provides abundant food for the largest animals, such as elephants, giraffes, rhinos, hippos, zebras, antelopes, which in turn attract such large predators as lions, hyenas and others. The world of birds in the savannas is rich and diverse. A small beautiful bird lives here - a nectary, the largest birds on Earth are ostriches. Of the predatory animals, the secretary bird with long legs stands out for its appearance and habits. She hunts for small rodents, reptiles. There are many termites in the savannah.
Savannahs are located mainly in the Southern Hemisphere from 30 ° to 5-8 ° south latitude. In the Northern Hemisphere, they cross Africa, forming a transition zone directly south of the Sahara - the Sahel. Most of the savannas are in Africa. Here they occupy about 40% of the continent.
Savannahs in the north of South America are called llanos (Spanish llanos - plural of "plain"), and on the Brazilian plateau - campos (port, satro - field). This is an area of intensive animal husbandry in Brazil.
Savannas play a very important role in human economic life. Significant areas are plowed up here, cereals, cotton, peanuts, jute, sugar cane and others are grown. Animal husbandry is developed in drier places. Some species of trees growing in savannahs are used by humans for their own purposes. So, teak wood gives solid valuable wood that does not rot in water.
Tropical zones are limited from the equator by the summer position of the tropical front, from the side of temperate latitudes by the winter position of the polar front. Tropical air is formed in it. which from the subtropical pressure maxima goes to the equator in the form of trade winds. Tropical air is formed in anticyclones from the descending equatorial air, as well as from the polar air of temperate latitudes. Tropical air is the main air mass here all year round.
The air of the trade winds is dry, especially in the trade wind, which occurs over the continents and has a very high temperature in the lower layers. But closer to the equator, the trade winds, which over the ocean approach the eastern shores of the continents, are moistened.
1.Location:
The zone of savannas and light forests is developed in Africa, South America, Asia (Hindostan) and in the north-west of Australia. In Africa, it covers Sudan, East Africa, the watershed plateaus of the Congo - Zambezi and Zambezi - Limpopo, part of the Kalahari Basin; in South America - the Orinoco basin and part of the Guiana massif, as well as the vast territory of the Brazilian massif and the Gran Chaco; in Australia - the northern quarter of the mainland; In Asia - Hindustan south of 22 0 n.
2.Characteristics of temperature regime, precipitation:
The temperature of the coldest month within the zone is from 12 to 20 0 , the warmest 20-35 0 . atmospheric precipitation per year in different areas from 100 to 500 mm (in some places up to 1000 mm). The change of dry and wet seasons is very distinct. The river network is sparse: during the rainy period - violent short floods, during the drought - long shallow water, small watercourses dry up.
3.Soil:
The soils are black, red-brown, brown, gray-brown; in India, in red-brown soils, a compacted horizon of carbonate nodules (kankara) is formed at shallow depths.
4.Vegetation:
Basically, the savannah is a tropical type of herbaceous vegetation, which differs from the steppe one in the presence of xerophilic low-growing sparsely standing trees, many of which have an umbrella crown. The main background of the savanna is created by hard-leaved cereals. Trees growing in the savannah have a long root system, reaching 50-60 m, many trees acquire an umbrella-shaped crown (acacia) to reduce evaporation. In West Africa, large areas are occupied by wet savannahs, in which the height of cereals can reach 5 m. In dry savannahs, the height of cereals is much smaller, powerful deciduous trees - baobabs are often found (height up to 25 m, trunk diameter - 10 m or more, the age of the trees can reach 1000 years). In the savannahs of Australia, eucalyptus trees grow with an admixture of acacias, large spaces are occupied by dense thickets of xerophytic shrubs - scrub. In the llanos of the Orinoco, the main background is made up of various cereals with rare groves of palm trees. In the Brazilian massif there are grass savannahs, savannahs with scattered crooked trees, shrubs, individual palm trees, as well as dry light forest (caatinga) of cacti and trees with barrel-shaped trunks. In the Gran Chaco - palm groves, drying tropical swamps (pantanals), dry-loving quebracho forests. In Hindustan - shrub and grass-shrub savannas, with acacias, thorny bushes, succulents. Biomass in the savannah is 500-1500 c/ha.
5.Animal world:
The fauna of the savannah is exceptionally rich. The abundance of herbs also attracts an abundance of ungulates, many rodents, large and small predators, and reptiles. In the savannas of Africa, ungulates are common, most of them are antelopes. There are rhinos, giraffes, elephants, lions, jackals, hyenas. Various types of kangaroos live in the savannahs of Australia, there are a lot of rodents and insects.
The zones do not form continuous bands everywhere. The boundaries of many zones deviate from parallels, within the same zones there are great contrasts in nature. Therefore, along with zoning, another geographical regularity is distinguished - azonal. Azonality- change of components and complexes associated with the manifestation of endogenous processes. The reason for the azonality is the heterogeneity of the earth's surface, the presence of continents and oceans, mountains and plains on the continents, the peculiarity of local factors: the composition of rocks, relief, moisture conditions, etc. Endogenous relief is azonal; location of volcanoes and tectonic mountains, structure of continents and oceans.
There are two main forms of azonal manifestation - sector geographic zones and altitudinal zonality. Within the geographic zones, three sectors are distinguished - the mainland and two oceanic. Sectorization is most pronounced in the temperate and subtropical geographic zones, and weakest of all in the equatorial and subarctic.
Altitudinal zonality - a natural change of belts from the foot to the top of the mountain. Altitudinal belts are not copies, but analogs of latitudinal zones; their selection is based on a decrease in temperature with height, and not a change in the angle of incidence of the sun's rays. In addition, the spectrum of solar radiation changes in the mountains: the proportion of ultraviolet rays increases. When climbing mountains, the pressure decreases, and there is no change in the length of day and night, as when moving from the equator to the poles. The most important differences between latitudinal zones and similar altitudinal zones are as follows:
1. Among the latitudinal zones there are zones not only of thermal, but also of dynamic origin (for example, areas of subtropical pressure maxima), there cannot be altitudinal belts similar in origin.
2. Temperature changes with height much faster than in the horizontal direction from the equator to the poles. In the SP, the temperature decreases by an average of 0.5 0 for each degree of latitude, in the troposphere vertically - by an average of 6 0 for each kilometer. It is the rapid decrease in temperature with height that predetermines the possibility of altitudinal climatic zonation, provided that the relief of the earth's surface is raised to a sufficient height (the change of belts in the mountains occurs faster).
3. Altitude zonation in the mountains is formed not only under the influence of changes in altitude, but also under the influence of specific forms of land relief. The difference in relief is one of the fundamental ones for the situation in which latitudinal zones and altitudinal zones are formed. Altitudinal zonality is therefore more diverse and variable than zonality, and is much more subject to local factors (in the mountains there is a belt of subalpine and alpine meadows, which is not on the plains).
4. The structure of altitudinal zonality depends very strongly on the exposure of the mountain slope (on the southern and northern, on the leeward and windward slopes, a different spectrum of belts is formed: a forest can grow on the windward slopes, on the leeward, in more arid conditions - a steppe), under the influence of which arises zonality asymmetry, i.e. the difference in heights of the belts of the same name on opposite slopes.
5. Under certain conditions, altitudinal inversion(there is no inversion of latitudinal zones). The most common cause of inversions is the stagnation of cold air in intermountain basins, which rolls down here from mountain slopes and peaks (tundra is located at the bottom of the basin, and coniferous forest is on the slopes).
At the same time, altitudinal zonality has much in common with horizontal zonality: the change of belts when climbing mountains occurs in the same sequence as on the plains when moving from the equator to the poles. Latitudinal zonality determines the type of altitudinal zonality: each zone has its own typical set of belts. The altitudinal zonality always begins at the foot of the mountain range from an analogue of the latitudinal zone on which the mountain foot rests. In the mountains located in the steppe zone, the first altitudinal belt is mountain-steppe. The number of altitudinal belts generally depends on the height of the mountains and the latitude of the place. The simplest spectrum is observed in the mountains of polar latitudes - there is a single belt of glaciers. In temperate latitudes, there are already three to five belts; in the equatorial belt, the most complete range of high-altitude belts develops.
Along with the altitudinal zonation, one can speak of the deep zonation of underwater landscapes. F.N. Milkov identifies shallow-water landscapes of the shelf, bathyal landscapes of the continental slope, abyssal landscapes of the ocean floor, and ultra-abyssal landscapes of deep-sea trenches.
There is no consensus on whether altitudinal zonality is zonal or azonal. F.N. Milkov attributed altitudinal zonality to the manifestation of zonality. He wrote that there are geographical areas of the plains, which are distinguished by a relatively simple structure, and there are geographical areas of mountainous countries, characterized by a more complex structure, changing in horizontal and vertical directions. S.V. Kalesnik believed that altitudinal zonation is azonal. ON THE. Gvozdetsky believed that there are, as it were, two forms of geographical zoning: horizontal - on the plains and high-altitude - in the mountains. A.G. Isachenko came to the conclusion that there are three zonal patterns: latitudinal zoning (latitudinal zoning), sector (meridional zoning) and altitudinal (vertical) zoning.
Amazon river
largest river of South America - Amazon. Most of its basin lies south of the equator. Square of this most extensive river basin in the world over 7 million km2, length river from the main source (Marañon River) is 6400 km. If, however, Ucayali and Apurimac are taken as the source of the Amazon, then its length reaches 7194 km, which exceeds the length of the Nile. Water consumption The Amazon is several times the flow of all the largest rivers in the world. It is equal to an average of 220 thousand m3/s (the maximum flow rate may exceed 300 thousand m3/s). Average annual flow The Amazon in the lower reaches (7000 km3) makes up the majority of the flow of all of South America and 15% of the flow of all the rivers of the Earth!
Main source The Amazons - the Marañon River - begins in the Andes at an altitude of 4840 m. Only after the confluence with the first major tributary - the Ucayali - within the plain, the river receives the name Amazon.
Amazon collects its numerous tributaries(more than 500) from the slopes of the Andes, the Brazilian and Guiana highlands. Many of them are over 1500 km long. The most numerous and largest tributaries of the Amazon are the rivers of the southern hemisphere. The largest left tributary is the Rio Negro (2300 km), the largest right and largest tributary of the Amazon is Madeira (3200 km).
Part of the tributaries, eroding clayey rocks, carry very muddy water (“white” rivers), others, with clear water, are dark from dissolved organic substances (“black” rivers). After falling into the Amazon Rio Negro (Black River), light and dark waters flow in parallel, without mixing, for about 20-30 km, which is clearly visible on satellite images.
Channel width The Amazon after the confluence of Maranyon and Ucayali is 1-2 km, but downstream it increases rapidly. At Manaus (1690 km from the mouth) it reaches already up to 5 km, expands in the lower reaches up to 20 km, and at the mouth the width of the main channel of the Amazon, together with numerous islands during the flood, reaches 80 km. In the western part of the lowland, the Amazon flows almost at the level of the banks, in fact, without a formed valley. To the east, the river forms a deeply incised valley which contrasts sharply with the watershed.
Approximately 350 km from the Atlantic Ocean begins amazon delta. Despite its ancient age, it did not move into the ocean beyond the boundaries of the native shores. Although the river carries out huge masses of solid material (an average of 1 billion tons per year), the process of delta growth is hindered by the activity of the tides, the influence of currents, and the lowering of the coast.
In the lower reaches of the Amazon, a great influence on its regime and the formation of shores is exerted by ebbs and flows. The tidal wave penetrates more than 1000 km upstream, in the lower reaches its wall reaches a height of 1.5-5 m. The wave rushes against the current at great speed, causing strong excitement on sandbanks and banks, destroying the coast. Among the local population, this phenomenon is known under the name of "pororoka" and "amazunu".
The Amazon is full of water throughout the year. Twice a year river water level rises to a considerable height. These maxima are associated with rainy periods in the northern and southern hemispheres. The greatest flow in the Amazon occurs after the rainy season in the southern hemisphere (in May), when the bulk of the water is carried by its right tributaries. The river overflows its banks and in the middle reaches fills a huge territory, creating a kind of giant inland lake. The water level rises by 12-15m, and in the Manaus region, the width of the river can reach 35 km. Then comes a period of gradual decrease in water flow, the river enters the banks. The lowest water level in the river is in August and September, then there is a second maximum associated with the summer rains of the northern hemisphere. On the Amazon, it appears with some delay, around November. The November maximum is significantly inferior to the May one. In the lower reaches of the river, two maxima gradually merge into one.
From the mouth to the city of Manaus, the Amazon is accessible to large courts. Vessels with a fairly deep draft can penetrate even as far as Iquitos (Peru). But in the lower reaches, due to the tides, the abundance of sediment and islands, navigation is difficult. Deeper and accessible to ocean vessels is the southern branch - Para, which has a common mouth with the Tocantins River. On it stands a large ocean port of Brazil - Belen. But this branch of the Amazon is now connected with the main channel only by small channels. The Amazon with tributaries is a system of waterways with a total length of up to 25 thousand km. The transport value of the river is great. For a long time, it was the only route connecting the interior of the Amazonian lowland with the Atlantic coast.
The rivers of the Amazon basin have large water energy reserves. Many tributaries of the Amazon, when entering the lowlands, cross the steep edges of the Brazilian and Guiana highlands, forming large waterfalls. But these water resources are still very poorly used.
Parana and Uruguay rivers
The second largest river system in South America includes the Parana River with Paraguay and Uruguay, which have a common mouth. its name ( La Platskaya) the system received from the eponymous giant estuary of Parana and Uruguay, reaching 320 km in length and 220 km in width at the mouth. The basin area of the entire system is more than 4 million km2, and the length of the Parana, according to various sources, ranges from 3300 to 4700 km. The sources of Parana - Rio Grande and Paranaiba - are located in the Brazilian Highlands. Many other rivers of the system also begin there. All of them in the upper reaches are full of rapids and form several large waterfalls. The largest waterfalls are Guaira 40 m high and 4800 m wide on the Paran and Iguazu 72 m high on its tributary of the same name. They have a network of hydroelectric stations.
In the lower reaches of the Parana - a typical lowland river. Main maximum discharge occurs in May due to summer rains in the Brazilian Highlands. shipping the importance of the rivers of the La Plata system and La Plata itself is very great.
Orinoco river
The third largest river in South America is the Orinoco. Its length is 2730 km, the basin area is over 1 million km2. The Orinoco originates in the Guiana Highlands. Its source was discovered and investigated by a French expedition only in 1954. The Casiquiare Orinoco River connects with the Rio Negro, a tributary of the Amazon, where part of the water of the upper Orinoco flows. This is one of the most significant examples of river bifurcation on Earth. When it flows into the Atlantic Ocean, the river forms a large delta, the length of which reaches 200 km.
The water level in the Orinoco depends entirely on the rainfall that falls in the northern part of its basin in the summer (from May to September). The maximum for Orinoco, falling on September-October, is expressed very sharply. The difference between summer and winter water levels reaches 15 m.
On the Guiana Plateau, in Venezuela, in the upper reaches of the Churun River (basin of the Caroni River, a tributary of the Amazon) is highest waterfall in the world- Angel.
lakes
There are few lakes in South America. The main genetic groups of lakes on the mainland are tectonic, glacial, volcanic, lagoonal. There are small glacial and volcanic lakes in different parts of the Andes. The largest glacial and glacial-tectonic lakes are concentrated in the west of the Southern Andes.
The largest lake on the continent Titicaca- located on the Andean plateau at an altitude of more than 3800 m, on the border between Peru and Bolivia. Its area is 8300 km2, and the maximum depth is 281 m. Terraces are pronounced on the shores of the lake, indicating a repeated decrease in its level. The lake has a drain into another, shallower tectonic lake - Poopo. The water in Lake Titicaca is fresh, while in Poopó it is highly saline.
On the internal plateaus of the Andes and on the plain of the Gran Chaco, there are many lakes of tectonic origin, shallow, endorheic and saline. In addition, saline marshes and salt marshes (“salares”) are common.
Along the low-lying shores of the Atlantic Ocean and the Caribbean Sea there are large lagoon lakes. The largest of these lagoons is located in the north, in a vast depression between the Andes ranges. It is called Maracaibo and is connected to the Gulf of Venezuela. The area of this lagoon is 16.3 thousand km2, the length is 220 km. The water in the lagoon is almost fresh, but during high tides, its salinity increases markedly.
The lagoons, which have almost lost contact with the Atlantic Ocean, are located in the southeast of the mainland. The largest of them are Patus and Lagoa Mirin.
A significant part of the continent, especially the Out-Andean East, has large reserves groundwater. In the sandy strata, syneclises are not only in the Amazon, but also in the Guiana lowland, Llanos-Orinoco, Gran Chaco, Pampa, and also in other areas, up to 40-50% of the runoff falls on groundwater.
6. Soils and vegetation.
South America is characterized by a large diversity zonal types of soil and vegetation cover and exceptional richness of flora, including tens of thousands of plant species. This is due to the position of South America between the subequatorial belt of the northern hemisphere and the temperate zone of the southern hemisphere, as well as the peculiarities of the development of the mainland, which first took place in close connection with other continents of the southern hemisphere, and later - in almost complete isolation from large land masses, except for connections with North America through the Isthmus of Panama.
Most of South America, up to 40 ° S, together with Central America and Mexico forms Neotropical floristic kingdom. The southern part of the mainland is within Antarctic realm.
Floristic zoning of South America (according to A.L. Takhtadzhyan)
Within the land that connected the South American platform with the African platform, obviously, there was a common for both continents flora formation center savannas and tropical forests, which explains the presence in their composition of some common species and genera of plants. However, the separation of Africa and South America at the end of the Mesozoic led to the formation of independent flora on each of these continents and the separation of the Paleotropical and Neotropical kingdoms. The Neotropics are characterized by great richness and a high degree of endemism of flora, due to the continuity of its development since the Mesozoic and the presence of several large centers of speciation.
The Neotropics are characterized by endemic families like bromeliads, nasturtiums, cannas, cacti. The oldest center for the formation of the cactus family was apparently located on the Brazilian Highlands, from where they spread throughout the mainland, and after the emergence of the Isthmus of Panama in the Pliocene, they also penetrated to the north, forming a secondary center on the Mexican Highlands.
Flora of the eastern part South America is much older than the flora of the Andes. The formation of the latter occurred gradually, as the mountain system itself arose, partly from elements of the ancient tropical flora of the east, and to a large extent from elements that penetrated from the south, from the Antarctic region, and from the north, from the North American Cordillera. Therefore, there are large species differences between the flora of the Andes and the Extra-Andean East.
Within Antarctic realm south of 40°S there is an endemic, not rich in species, but very peculiar flora. It was formed on the ancient Antarctic continent before the beginning of the continental glaciation of Antarctica. Due to cooling, this flora migrated to the north and has survived to this day in small areas of land within the temperate zone of the southern hemisphere. It reached its greatest development in the southern part of the mainland. The Antarctic flora of South America is characterized by representatives of the bipolar flora found on the arctic and subarctic islands of the northern hemisphere.
The flora of the South American continent has given mankind many valuable plants included in the culture not only in the Western Hemisphere, but also beyond. This is primarily potatoes, the ancient centers of cultivation of which are located in the Peruvian and Bolivian Andes, north of 20 ° S, as well as in Chile, south of 40 ° S, including on the island of Chiloe. Andes - the birthplace of tomatoes, beans, pumpkins. Until now, the exact ancestral home has not been clarified and the wild ancestor of cultivated corn is unknown, but, undoubtedly, it comes from the Neotropical kingdom. South America is also home to the most valuable rubber plant - hevea, chocolate, cinchona, cassava and many other plants grown in the tropical regions of the Earth. The richest vegetation of South America is an inexhaustible source of enormous natural wealth - food, fodder, industrial, medicinal plants.
The vegetation cover of South America is especially characterized by tropical rainforests, which have no equal on Earth either in the richness of species or in the size of the territory they occupy.
Humid tropical (equatorial) forests of South America on ferrallitic soils, named by A. Humboldt hylaea, and in Brazil called selva, occupy a significant part of the Amazonian lowland, adjacent areas of the Orinok lowland and the slopes of the Brazilian and Guiana highlands. They are also characteristic of the coastal strip of the Pacific Ocean within Colombia and Ecuador. Thus, tropical rain forests cover areas with an equatorial climate, but, in addition, they grow on the slopes of the Brazilian and Guiana highlands facing the Atlantic Ocean, in higher latitudes, where there are abundant trade winds for most of the year, and in during a short dry period, the lack of rain is compensated by high humidity.
The hylaea of South America is the richest type of vegetation on the Earth in terms of species composition and density of vegetation cover. They are characterized by high height and complexity of the forest canopy. In areas not flooded by rivers in the forest, there are up to five tiers of various plants, of which at least three tiers consist of trees. The height of the highest of them reaches 60-80 m.
Species richness in the hylaea of South America is huge, more than 300000 plant species are endemic. In this respect, they are superior to the tropical rainforests of Africa and even Southeast Asia. The upper tiers of these forests are formed by palm trees, for example, Mauritia aculeata, Mauritia armata, Attalea funifera, as well as various representatives of the legume family. Of the typical American trees, Bertolettia excelsa, which produces nuts with a high fat content, mahogany tree with valuable wood, etc., should be mentioned.
The South American rainforest is characterized by chocolate tree species with caulifloral flowers and fruits sitting right on the trunk.
The fruits of the cultivated chocolate tree (Theobroma cacao), rich in valuable nutritious tonic substances, provide the raw material for making chocolate. These forests are the birthplace of the Hevea rubber plant (Hevea brasiliensis).
Distribution of some plants in South America
Found in the tropical forests of South America symbiosis some trees and ants, such as several species of cecrops (Cecropia peltata, Cecropia adenopus).
The tropical rainforests of South America are particularly rich in creepers and epiphytes, often brightly and beautifully blooming. Among them are representatives of the family of arroinaceae, bromeliads, ferns and orchid flowers, unique in their beauty and brightness. Tropical rainforests rise up the slopes of the mountains up to about 1000-1500 m without undergoing significant changes.
The world's largest array of virgin forests existed in the north of the Amazon basin and on the Guiana Plateau.
However soil under this richest plant community in terms of volume of organic mass, they are thin and poor in nutrients. Decay products, continuously coming to the ground, quickly decompose in a uniformly hot and humid climate and are immediately absorbed by plants without having time to accumulate in the soil. After clearing the forest, the soil cover quickly degrades, and large amounts of fertilizers are required for agricultural use.
As the climate changes, i.e. with the advent of the dry season, tropical rainforests are moving into savannas and tropical woodlands. In the Brazilian Highlands, between the savannahs and the tropical rainforest, there is a strip of almost pure palm forests. Savannahs are common in a large part of the Brazilian Highlands, mainly in its interior regions. In addition, they occupy large areas in the Orinok Lowland and in the central regions of the Guiana Highlands. In Brazil, typical savannahs on red ferralite soils are known as campos. Their herbaceous vegetation consists of high grasses of the genera Paspalum, Andropogon, Aristida, as well as representatives of the legume and Compositae families. Woody forms of vegetation are either completely absent, or are found in the form of individual specimens of mimosa with an umbrella-shaped crown, tree-like cacti, spurges 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 period of the year, others have a swollen trunk in which moisture accumulates, for example, the cottonwort (Cavanillesia platanifolia). The trunks and branches of Caatinga trees are often covered with creepers 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, rubbing floors and other purposes. Sago and palm flour are obtained from the upper part of the carnauba trunk, the leaves are used to cover roofs and weave various products, the roots are used in medicine, and the local population uses the fruits in raw and boiled form. No wonder the people of Brazil call carnauba the tree of life.
On the Gran Chaco plain, in especially arid regions, on brown-red soils, thickets of thorny bushes and sparse forests. In their composition, two species belong to different families, they are known under the common name "quebracho" ("break the ax"). These trees contain a large amount of tannins: red quebracho (Schinopsis Lorentzii) - up to 25%, white quebracho (Aspidosperma quebracho blanco) - somewhat less. Their wood is heavy, dense, does not rot and sinks in water. Quebracho is heavily cut down. At special factories, tanning extract is obtained from it, sleepers, piles and other items are made from wood, designed for a long stay in water. Algarrobo (Prosopis juliflora) is also found in the forests - a tree from the mimosa family with a twisted trunk and a strongly branching spreading crown. The fine, delicate foliage of the algarrobo leaves no shade. The low tiers of the forest are often represented by thorny shrubs that form impenetrable thickets.
The savannahs of the northern hemisphere differ from the southern savannahs in appearance and species composition of the flora. To the south of the equator, among the thickets of cereals and dicotyledons, palm trees rise: copernicia (Copernicia spp.) - in drier places, winding mauritia (Mauritia flexuosa) - in swampy or flooded areas by rivers. The wood of these palms is used as a building material, the leaves are used for weaving various products, the fruits and core of the Mauritia trunk are edible. Acacias and tall tree cacti are also numerous.
Red and red-brown soil savannahs and tropical woodlands are characterized by a higher humus content and greater fertility than the soils of moist forests. Therefore, in the areas of their distribution are the main areas of plowed land with plantations of coffee trees, cotton, bananas and other cultivated plants exported from Africa.
pacific coast between 5 and 27° S and the Atacama Basin, with their constant lack of rain, have the most typical desert soils and vegetation in South America. Plots of almost barren stony soils alternate with massifs of free-flowing sands and vast surfaces occupied by saltpeter solonchaks. Extremely sparse vegetation is represented by sparsely standing cacti, thorny cushion-like shrubs and ephemera of bulbous and tuberous plants.
subtropical vegetation occupies relatively small areas in South America.
The extreme southeast of the Brazilian Highlands, which receives abundant rainfall throughout the year, is covered subtropical forests from araucaria with an undergrowth of various shrubs, including Paraguayan tea (Ilex paraguaiensis). Paraguayan tea leaves are used by the local population to make a widespread hot drink that replaces tea. According to the name of the round vessel in which this drink is made, it is called mate or yerba mate.
The second type of subtropical vegetation of South America is subtropical steppe, or pampas, characteristic of the eastern, most humid parts of the La Plata lowland south of 30 ° S, is a herbaceous cereal vegetation on fertile reddish-black soils formed on volcanic rocks. It consists of South American species of those genera of cereals that are widespread in Europe in the steppes of the temperate zone (feather grass, bearded vulture, fescue). The pampa is connected with the forests of the Brazilian Highlands by a transitional type of vegetation, close to the forest-steppe, where grasses are combined with thickets of evergreen shrubs. The vegetation of the pampas has been the most severely destroyed and is now almost completely replaced by crops of wheat and other cultivated plants. To the west and south, as precipitation decreases, vegetation of dry subtropical steppes and semi-deserts appears on gray-brown soils and gray soils with spots of salt marshes in place of dried lakes.
The subtropical vegetation and soils of the Pacific coast are similar in appearance to the vegetation and soils of the European mediterranean. Thickets of evergreen shrubs on brown soils predominate.
The extreme southeast (Patagonia) is characterized by vegetation dry steppes and semi-deserts of the temperate zone. Gray-brown soils predominate, salinization is widespread. The vegetation cover is dominated by tall grasses (Roa flabellata, etc.) and various xerophytic shrubs, often pillow-shaped, undersized cacti.
In the extreme southwest of the mainland, with its oceanic climate, insignificant annual temperature differences and an abundance of precipitation, moisture-loving evergreen subantarctic forests, multi-tiered and very diverse in composition. They are close to tropical forests in the richness and diversity of plant life forms and the complexity of the forest canopy structure. They abound with vines, mosses, lichens. Along with various tall coniferous trees of the genera Fitzroya, Araucaria and others, evergreen deciduous species are widespread, for example, southern beeches (Nothofagus spp.), Magnolia, etc. There are many ferns and bamboos in the undergrowth. These moisture-soaked forests are difficult to clear and uproot. They are still one of the most important natural resources Chile, though heavily affected by logging and fires. Almost without changing their composition, the forests rise along the slopes of the mountains to a height of 2000 m. Forest burozems develop under these forests. To the south, as it gets colder, the forests become depleted, creepers, tree ferns and bamboo disappear. Conifers (Podocarpus andinus, Austrocedrus chilensis) predominate, but evergreen beeches and magnolias remain. Beneath these depleted subantarctic forests, podzolic soils form.
Under the influence economic activity human vegetation has undergone significant changes. In just 15 years, from 1980 to 1995, the area of forests in South America decreased by 124 million hectares. In Bolivia, Venezuela, Paraguay and Ecuador, the rate of deforestation over this period exceeded 1% per year. For example, in 1945, in the eastern regions of Paraguay, forests occupied 8.8 million hectares (or 55% of the total area), and in 1991 their area was only 2.9 million hectares (18%). In Brazil, about 15 million hectares of forests were destroyed between 1988 and 1997. It should be noted that after 1995 there has been a marked decrease in the rate of deforestation.
main reason deforestation in the Brazilian Amazon, there remains an expansion of agricultural land, mostly permanent pasture. The destruction of forests leads to the destruction of the upper soil horizon, the development of accelerated erosion and other processes of soil degradation. Due to deforestation and pasture overload, soil degradation processes have affected almost 250 million hectares of land.
7. Animal world.
No less rich than the vegetation cover, the fauna of South America is also characterized. The modern fauna, like the flora of the mainland, was formed starting from the end of the Cretaceous period. in isolation and little climate change. The antiquity of the fauna and the presence in its composition of a large number of endemic forms are associated with this. In addition, there are some common features of the fauna of South America and other continents of the southern hemisphere, which indicates a long-standing relationship between them. An example is marsupials, preserved only in South America and Australia.
All the monkeys of South America belong to the broad-nosed group, which is absent from the fauna of the Old World.
A feature of the fauna of South America is also the presence in its composition of three endemic families of edentulous, united in one order. A large number of endemic species, genera and even families are found among predators, herbivores and rodents.
The very rich and peculiar fauna of South America (together with Central America) belongs neotropical region and is included within its two subregions - Brazilian and Chile-Patagonian.
Tropical rainforests
The greatest originality and wealth are characterized by tropical rainforests, animals there hide in dense thickets or spend most of their time on tall trees. Adaptation to an arboreal lifestyle is one of the features of animals in the Amazonian forests, as well as animals in the forests of the Congo Basin in Africa or the Malay Archipelago in Asia.
American (broad-nosed) monkeys live in the tropical forests of South America, divided into two families - marmosets and cebids. Marmoset monkeys are small. The smallest of them reach a length of no more than 15-16 cm, limbs equipped with claws help them to stay on tree trunks. Many cebids are characterized by a strong tail, with which they cling to tree branches, it acts as a fifth limb. Among them, a genus of howler monkeys stands out, which received its name for the ability to make far-audible cries. Spider monkeys with long, flexible limbs are widespread.
Of the representatives of the order of edentulous in tropical forests live sloths(Bradypodidae). They are sedentary and spend most of their time hanging in trees, feeding on leaves and shoots. Sloths climb trees confidently and rarely fall to the ground.
Distribution of some animals in South America
Some are also adapted to life on trees. anteaters. For example, it freely climbs tamandua trees; the small anteater, which has a tenacious tail, also spends most of its time in trees. The large anteater is common in forests and savannahs, leads a terrestrial lifestyle.
In tropical forests there are predators from the family feline: ocelots, small jaguarundis, as well as large and strong jaguars. Of the predators belonging to the family canine, an interesting little-studied forest, or bush, dog living in the rainforests of Brazil, Suriname and Guyana. Tree-hunting woodland animals include the coatfish (Nasua) and the kinkajou (Potos flavus).
Ungulates, few in South America, are represented in the forests by only a few genera. Among them are the tapir (Tapirus terrestris), the small black peccary pig, and the small South American pointed deer.
Characteristic representatives rodents in the forests of the Amazonian lowland and other regions of South America - arboreal chain-tailed porcupines coendu (genus Coendou). Agoutis (Dasyprocta agouti), which are found in the forests of Brazil, cause great damage to plantations of tropical crops. Almost throughout the mainland, especially in the Amazonian forests, the capybara capybara (Hydrochoerus hydrochaeris) is common - the largest representative of rodents, whose body length reaches 120 cm.
Several species live in the forests of South and Central America. marsupial rats, or opossums. Some of them are equipped with a tenacious tail and climb trees well. The Amazon forests are teeming with bats, among which there are species that feed on the blood of warm-blooded animals.
Reptiles and amphibians are very richly represented in the forests. From reptiles the anaconda water boa (Eunectes murinus) and the terrestrial arboreal dog-headed boa (Corallus caninus) stand out. Many poisonous snakes, lizards. There are crocodiles in the rivers. From amphibians many frogs, some of them lead an arboreal lifestyle.
There are many different types of forests birds, especially brightly colored parrots. The largest of the parrots, the macaw, is the most typical. In addition, small parakeets and beautiful, brightly feathered green parrots are widespread. The most characteristic representatives of the avifauna of South America, in particular tropical forests, are hummingbirds. These small colorful birds that feed on the nectar of flowers are called insect birds.
Also found in the forests hoatzins(Opisthocomus hoatzin), whose chicks have claws on their wings to help them climb trees, sun herons and shuttle-billed herons, harpies are huge birds of prey that prey on young deer, monkeys and sloths.
One of the features of the tropical forests of the mainland is a large number insects, many of which are endemic. Diurnal and nocturnal butterflies, various beetles, ants abound. Many butterflies and beetles are beautifully colored. Some beetles glow so brightly at night that you can read near them. Butterflies are huge; the largest of them is agrippa, its wingspan reaches almost 30 cm.
Savannas, woodlands and steppes
Fauna more dry and open spaces South America - savannas, tropical woodlands, subtropical steppes - different than in dense forests. Of the predators, in addition to the jaguar, the cougar (found almost throughout South America and entering North America), the ocelot, and the pampa cat are common. The southern part of the mainland is characterized by a maned wolf from the canine family. On the plains and in mountainous regions, the pampa fox is found almost throughout the mainland, in the extreme south - the Magellanic fox. Of the ungulates, a small pampas deer is common.
Representatives of the third American family of edentulous are found in savannahs, forests and arable land - armadillos(Dasypodidae) - animals equipped with a strong bone shell. When danger approaches, they burrow into the ground.
From rodents in the savannahs and steppes there are viscacha and tuko-tuko living in the land. The swamp beaver, or nutria, is widespread along the banks of reservoirs, the fur of which is highly valued on the world market.
From birds in addition to numerous parrots and hummingbirds, there are also rhea (genus Rhea) - South American representatives of the ostrich-like order, some large birds of prey.
In the savannahs and steppes there are many snake and lizards. A characteristic feature of the landscapes of South America is a large number termite mounds. Some areas of South America periodically suffer from locust invasions.
Andes
The mountain fauna of the Andes is distinguished by peculiar features. It includes many endemic animals not found in the eastern part of the mainland.
South American representatives of the camelid family - llamas - are common throughout the mountainous region. There are two types of wild llamas - vigogne and guanaco. In the past, the Indians hunted them for their meat and wool. Guanaco was found not only in the mountains, but also on the Patagonian plateau and in the Pampas. Now wild llamas are rare. The Indians in the Andes breed two domestic species of llamas - the llama itself and the alpaca. Llamas are large and strong animals, used as pack animals on difficult mountain roads, their milk and meat are eaten, and coarse fabrics are made from wool. Alpaca (Lama pacos) is bred only for its soft fur.
Also found in the Andes spectacled bear, some marsupials. Small endemic rodents used to be widespread chinchillas(Chinchilla). Their soft, silky gray fur was considered one of the finest and most expensive furs. Therefore, at present, the number of chinchillas has decreased to a large extent.
Birds are represented in the Andes by endemic mountain species of the same genera and families that are common in the east of the mainland. Of the carnivores, the condor (Vul griphus) is interesting - the largest representative of this order.
The fauna is unique volcanic Galapagos Islands, in its composition the main place belongs to large reptiles- gigantic land turtles and sea lizards (iguanas). There are also many different birds, among which there are representatives of both tropical and Antarctic avifauna (parrots and penguins brought by the cold current, cormorants, etc.). Among the few mammals are eared seals, some rodents and bats. Domestic animals (goats, dogs, pigs) were brought to the islands and ran wild.
As a result of habitat destruction, the number of many species of animals decreased. Currently in South America Endangered there are 161 species of mammals, 269 species of birds, 32 species of reptiles, 14 species of amphibians and 17 species of fish.
For the protection of animals, plants and ecosystems in general, reserves and protected areas other categories. In 2002, there were 706 protected areas in the five IUCN categories in South America, covering an area of almost OUT of million hectares. Among the most famous national parks are Los Glaciares in Argentina, Iguazu in Brazil and Argentina, Itatia in Brazil, Vicente Perez Rosales in Chile, and others. A biosphere reserve was also created on the Galapagos Islands.
Similar information.
47 Savannah and woodland zone
1.Location:
The zone of savannas and light forests is developed in Africa, South America, Asia (Hindostan) and in the north-west of Australia. In Africa, it covers Sudan, East Africa, the watershed plateaus of the Congo - Zambezi and Zambezi - Limpopo, part of the Kalahari Basin; in South America - the Orinoco basin and part of the Guiana massif, as well as the vast territory of the Brazilian massif and the Gran Chaco; in Australia - the northern quarter of the mainland; In Asia - Hindustan south of 220 N.S.
2.Characteristics of temperature regime, precipitation:
The temperature of the coldest month within the zone is from 12 to 200, the warmest is 20-350. atmospheric precipitation per year in different areas from 100 to 500 mm (in some places up to 1000 mm). The change of dry and wet seasons is very distinct. The river network is sparse: during the rainy period - violent short floods, during the drought - long shallow water, small watercourses dry up.
The soils are black, red-brown, brown, gray-brown; in India, in red-brown soils, a compacted horizon of carbonate nodules (kankara) is formed at shallow depths.
4.Vegetation:
Basically, the savannah is a tropical type of herbaceous vegetation, which differs from the steppe one in the presence of xerophilic low-growing sparsely standing trees, many of which have an umbrella crown. The main background of the savanna is created by hard-leaved cereals. Trees growing in the savannah have a long root system, reaching 50-60 m, many trees acquire an umbrella-shaped crown (acacia) to reduce evaporation. In West Africa, large areas are occupied by wet savannahs, in which the height of cereals can reach 5 m. In dry savannahs, the height of cereals is much smaller, powerful deciduous trees - baobabs are often found (height up to 25 m, trunk diameter - 10 m or more, the age of the trees can reach 1000 years). In the savannahs of Australia, eucalyptus trees grow with an admixture of acacias, large spaces are occupied by dense thickets of xerophytic shrubs - scrub.
5.Animal world:
The fauna of the savannah is exceptionally rich. The abundance of herbs also attracts an abundance of ungulates, many rodents, large and small predators, and reptiles. In the savannas of Africa, ungulates are common, most of them are antelopes. There are rhinos, giraffes, elephants, lions, jackals, hyenas. Various types of kangaroos live in the savannahs of Australia, there are a lot of rodents and insects.
48 Deserts of the globe.
Deserts are common in the temperate zone northern hemisphere, subtropical and tropical belts of the Northern and Southern hemispheres. They are characterized by moistening conditions (the annual amount of precipitation is less than 200 mm, and in extra-arid regions - less than 50 mm; the moisture coefficient, which reflects the ratio of precipitation and evaporation, is 0-0.15). In the relief - a complex combination of uplands, hillocks and island mountains with structural layered plains, ancient river valleys and closed lake depressions. erosional the type of relief formation is strongly weakened, eolian relief forms are widespread. For the most part, the territory of the deserts is drainless, sometimes they are crossed by transit rivers ( Syrdarya, Amu Darya, Nile, Huanghe and others); many drying lakes and rivers, often changing their shape and size ( Lopnor, Chad, Air), characterized by periodically drying watercourses. Groundwater is often mineralized. Soils are poorly developed, characterized by the predominance of water-soluble salts in the soil solution over organic matter, salt crusts are common. The vegetation cover is sparse (the distance between neighboring plants is from several tens of cm to several meters or more) and usually covers less than 50% of the soil surface; practically absent under extraarid conditions.
Sandy deserts are inhabited from plants mainly by thorny bushes, from animals - reptiles and small steppe animals. In sandy deserts above the places where groundwater occurs, oases- "Islands" with dense vegetation and reservoirs. The snowy deserts are mostly found above the Arctic Circles and are inhabited by cold-hardy animals.
By the nature of soils and soils:
sandy - on loose deposits of ancient alluvial plains;
loess - on loess deposits of piedmont plains;
loamy - on slightly carbonate cover loams of the plains;
clay takyr - on the piedmont plains and in ancient river deltas;
clayey - in the lowlands, composed of salt-bearing marls and clays,
pebble and sand-pebble - on gypsum plateaus and piedmont plains;
gravelly gypsum - on boards and young piedmont plains;
stony - in low mountains and small hills;
solonchak - in saline depressions of the relief and along the sea coasts.