What plant is typical for savannas? What are savannas and where are they located? Savannahs of South America. Where are the savannas in South America?

Savannas and deserts are huge areas of our planet, sharply different from each other in flora and fauna and similar only in their hot climate. Zones of equatorial forests on Earth give way to savannas, which turn into semi-deserts, and then semi-deserts give way to deserts - with quicksand and a minimum of vegetation. These territories are of great interest to researchers; many expeditions are sent there every year to study the natural diversity of our planet. What are savannas and deserts and how they differ from temperate steppes, you will learn on this page

What are savannas and what plants grow in them?

Savannas are grassy plains located between tropical forests and deserts. They differ from the temperate steppes in that trees and shrubs are found everywhere, sometimes solitary, and sometimes forming entire groves. So savanna can also be called forest-steppe. Acacias, baobabs and cereals grow there. There are savannas in America, where they are called “llanos,” and in Africa and Asia.

The main feature of savannas is that there are clearly distinct rainy and dry seasons.

As you can see in the photo, savannas look completely different in different seasons. Both plants and animals have adapted to months-long droughts. The leaves of savanna plants are usually narrow, they can curl into a tube, and are sometimes covered with a waxy coating. During the dry season, vegetation freezes, and numerous animals - zebras, buffaloes, elephants - make long migrations (transitions from one place to another) in search of water and food. In the rainy season, on the contrary, the savannah is full of life.

Euphorbia candelabra grows only in Somalia and eastern Ethiopia. Its branches resemble a candelabra, that is, a candlestick for several candles. The tree reaches a height of 10 m, and even elephants find refuge in its shade.

When talking about what grows in the savannah, one cannot fail to mention the favorite delicacy of giraffes - acacia. These trees have a wide, flat crown that creates shade for the leaves growing below, protecting them from drying out. These are quite tall trees, and their leaves and branches serve as food for the inhabitants of those places. Giraffes are very fond of acacia - the tallest land animals on our planet. With a height of 6 m, a third of which is the neck, the giraffe finds plant food at a height where it has no competitors. And its long 45-meter tongue allows it to grab the farthest branches.

Perennial savannah grasses have underground shoots and the roots grow to form a woody, tuberous body. It persists through the dry season and produces new shoots as soon as wet weather sets in.

Interesting facts about deserts and desert plants

Deserts occupy almost a fifth of the land. All of them, except the Arctic and Antarctic, arise in a hot, dry climate. Not all desert lands are bare and dull. There are also xerophytic plants, the roots, stems and flowers of which are able to obtain and store water, hide from the merciless sun and capture its life-giving rays. And some of them - ephemerals - grow, bloom and fade in just a few weeks under favorable conditions for life.

The desert plant saxaul can be a shrub or a small tree. Its roots go 10-11 m into the ground. These plants form desert-woody thickets - saxaul forests.

Tamarisk grows along river banks, but also lives in deserts, salt marshes and sand. This plant is widely used for fixing shifting sands in forest plantations and in desert and semi-desert areas, especially on saline soils.

Camel thorn is a thorny subshrub. It is helped to successfully exist in the sand by a long root system that goes to a depth of 3-4 m, where water is located. And the plant itself rises above the ground by no more than 1 m.

Ephedra is found in dry areas throughout the world. Its leaves are small and scale-like, which reduces water loss, and its roots are strong and long. This is a poisonous plant, but medicines for asthma and other diseases have been made from it for several thousand years.

One of the most interesting facts about deserts is the presence of magnificent oases in these seemingly dead territories. An oasis in the desert is a place where underground water comes to the surface and forms a spring or lake. Birds fly there to drink, and they spread seeds, from which trees, herbs and shrubs later grow. As long as there is water, the oasis lives. It could be a small pond with a few palm trees or an entire city with rich agricultural land. This is how life flourishes among the sands.

Deserts are not only sandy, but also rocky, rocky, and saline. Their vegetation serves as food for animals, even such large ones as camels. They feed on branches and leaves of saxaul and desert acacia, although the leaves of these plants are small and hard. The main delicacy of the “ship of the desert” is camel thorn. Its branches are prickly and inedible, but the leaves are very juicy and tasty.

Desert cacti plants and their photos

Among the plants of southern deserts and semi-deserts, cacti stand out. They do not have leaves, but they have a thick stem in which reserves of water and nutrients are created. Such plants are called "succulents". Desert cacti are very diverse: among them there are large ones like trees, medium ones like shrubs, and short ones like herbs.

Cacti are native to North and South America, and can be found from Canada to Patagonia. Therefore, cacti are a sign of American deserts and semi-deserts. Cacti in the desert differ from other succulents in that they have areoles, that is, modified buds with scales that have turned into spines and hairs or only spines.

Pay attention to the photo: cacti in the desert sometimes form real cactus thickets, which are not so easy to get through. In Australia they even erected a moth monument. The fact is that there, in the 1920s, a South American cactus multiplied catastrophically, and only a compatriot moth could cope with it.

The desert plant saguaro cactus, or giant carnegia, reaches a height of 1.5 m by the age of 20. But it continues to grow, and cacti 7-8 m high have side shoots that look like hands. The cactus has nowhere to rush, since its average lifespan is 75 years, but there are also 150-year-old centenarians. They grow up to 15-20 m, weigh about 10 tons, and 90% of their weight is water. The saguaro has short roots, but very tenacious, so it is not afraid of any hurricanes.

On the Galapagos Islands, off the coast of South America, you can see tree-like cacti reaching a height of 12 m. Surprisingly, these trees are cacti. These are prickly pears, which most often grow as shrubs on the mainland.

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 of 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 largest shroud zone is 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

The savannah is characterized by monsoon-trade wind circulation of 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 of annual precipitation decreases in the same direction (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 have 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. Tree species of vegetation are either not present at all, or are found 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.

The savannas of South America are 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 characteristic feature of the landscape is 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 the forest areas there are patches of savannas. Tropical rain forest is gradually limited to river valleys, and in the watershed areas they are replaced by forests, the trees of which shed their leaves in dry times, or savannas. There is an opinion that tall grass tropical savannas began to form in connection with 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. Among the tree species in the region, there are various acacias with a flat crown. 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 of New Guinea). During the wet season, this region is covered with beautiful flowering plants: the families of orchids, ranunculaceae, lilies and various grasses. Typical trees are 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 that 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 of eucalyptus. Eucalyptus forests occupy most of the country's northern coast and a large part of Cape York Island. In the Australian savannah you can find many marsupial rodents: moles, rats, wombats, and anteaters. 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 of savannah 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 exotic trees (Nile acacia, vaulting landata, prickly pear and others) also have a detrimental effect on the savannah ecosystem.

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

Savannah represents one of the most popular landscapes on the African continent. Moreover, savanna is present not only in Africa, but also on the South American continent, in Australia and even in Asia - in the subequatorial belt.

Like the inhabitants of the steppe, the inhabitants of the savannas have to adapt to difficult climatic conditions.

Characteristics of the savannah

Its features are as follows:

The life of the flora of the savanna directly depends on weather conditions.
During periods of drought, the landscape loses its color and the grass becomes dry.
Vegetation is adapted to constant heat and lack of moisture.
Grasses grow in tufts.
The leaves covered with a waxy coating are narrow and dry.
Many species contain essential oils in abundance.
The main representatives of the flora - cereals, bushes and trees - are much less common.

Savannah grasses

Herbs of the savannah plant world mostly tough-skinned grasses, there are also perennials, and during rainy periods, when the area is subject to flooding, even sedges grow here. Lichens and mosses are very rare and can only be seen on rocks.

Of the cereals that are most characteristic of this African landscape, elephant grass. The plant got its name because it is a favorite delicacy of giant elephants. During the rainy season, this grass can grow up to 3 meters in height, and in dry times, the ground shoots dry out and often die from fires. But due to the fact that the root system remains alive, elephant grass grows back in wetter conditions. Local residents often use the shoots of this plant for food.

Bermuda grass (Pigmatum grass) forms a dense carpet, grows in open areas, constantly exposed to threats - floods, animal grazing, fires. However, the plant has adapted well to surviving in difficult conditions: roots up to 1.5 meters long go deep underground, finding life-giving moisture there. The plant is considered a weed, which is very difficult to control without special equipment, but at the same time, it very effectively protects the soil from erosion and serves as food for many animals, including sheep.

Savannah trees

More often than not, savannah trees are stunted and are often entwined with vines.

Most often you can see the famous baobab, a tree with a thick trunk over 29 meters high. It is characterized by a spreading crown. This giant is also called the monkey tree because these primates love to feast on its fruits.

The flowering period takes several months, but the life of each flower is fleeting, just a single night. The plant is pollinated by bats. The thick trunk protects the plant from fires, which are not uncommon in the savanna, and is also capable of retaining moisture accumulated during the rainy season for a long time, like a sponge. The length of the roots of this tree often reaches 10 meters.

Man widely uses baobab in his activities, eating leaves, making paper, fabric and rope from the bark, and the substance obtained from the seeds of the tree is a powerful antidote.

Oil palm- another representative of the savanna plant world, it has a long lifespan, from 80 to 100 years, palm wine is obtained from its juice, and the pericarp pulp is used in the production of soap.

Mongongo. This is a plant of the Euphorbiaceae family, reaching a height of 30 m. It has palmate leaves and flowers collected in inflorescences. The fruits are actively consumed by indigenous people. This tree can live in the savanna due to its long roots that go deep into the soil, as well as the ability of the trunk to absorb and retain moisture.

Acacia. Acacia savannas look amazing, on which several species of this tree grow:

whitish;
Senegalese;
twisted;
acacia giraffe.

The plant has a slightly flattened crown shape, which is why it is often called umbrella-shaped. Thanks to such a flat and wide crown of the acacia, it creates shade under which herbs grow, hiding from the scorching sun. Acacia senegal - a small tree, a representative of the legume family, it reaches a height of no more than 6 m, with a trunk diameter of about 30 cm. This acacia has thorns. The benefits of the tree are great: by accumulating nitrogen, like other legumes, Senegalese acacia enriches poor soils, and its pods and leaves are absorbed by the fauna of the savannah.

Twisted acacia can withstand both heat and drought well. Its wood has found application in furniture production and construction.

Acacia wood is used to make high-quality furniture, which is expensive, and the bark is actively used in industry due to the adhesives it contains.

Persimmon medlar- a representative of the African savanna, this is a plant from the Ebony family, a deciduous tree, the bark of which is colored gray. The average trunk height is no more than 6 meters, but some trees manage to grow up to 25 meters. It has dark green leaves, blooms with cream flowers during the rainy season, fruits appear only on female trees, they gradually ripen, changing color from light yellow to purple.

Combretum red-leaved grows near rivers, the average tree height is from 7 to 10 meters, the crown is dense. The roots are long, the fruits are poisonous. The leaves of the plant are used as food for giraffes, and people use parts of the tree for industry and medicine.

Most often, trees grow alone, less often - in small groups. In the savannas of Brazil you can often find real forests, although they are rare. The herbaceous and semi-shrub cover here is about a meter.

A clear division into two seasons - dry winter and rainy summer - is the main feature of the climate to which savannah vegetation has learned to adapt.

An abundance of tall grasses, gilded by the sun, rare trees and shrubs, more or less common depending on the area - this is the savannah that occupies most of sub-Saharan Africa.

Savannah vegetation corresponds to the hot climate with long dry periods that prevails in tropical places. That is why savanna is widespread in different parts of the world, including South America and Australia. But it occupies the most extensive territories, of course, in Africa, where it is represented in all its diversity.

In the south, on the border with equatorial tropical forests, a transition zone begins - the forest savanna. There are not very many grasses there; trees grow thickly, but they are small. Then comes the sparsely forested savanna - vast spaces covered with tall grasses, with groves or isolated trees. The baobab tree predominates here, as well as palm, spurge and various types of acacia. Gradually, trees and shrubs become more and more sparse, and grasses, especially giant grasses, become denser.

And finally, near deserts (Sahara, Kalahari), the savannah gives way to a parched steppe, where only tufts of dry grass and low-growing thorny bushes grow.

Deserts

Deserts are those areas where precipitation is extremely rare. However, some plants have adapted to such conditions. Some have a very fast vegetation cycle: a small willow tree is enough for them to produce seeds within ten days. Others have a developed mainly root system: after rain they immediately produce several leaves, and then flowers appear. Cereals can also be found in the Sahara and several types of gorse. Finally, some plants survive drought by storing water in their stems and leaves. These are the well-known cacti, especially common in desert areas of Central and North America.

The roots of some shrubs, for example Saharan acacia, go very deep into the soil, sometimes even more than 20 m, in order to reach the underground reserves of the moisture they need.

Tuareg drinn

keeps the leaves folded in a groove at all times. Its very long roots, protected by a sand muff, extract moisture at great depths.

Baobab It has a huge trunk, the fibers of which contain a lot of moisture.

Euphorbia ("chandelier")

The Euphorbiaceae family has more than 300 genera: some of them are tree-like, like this plant, others resemble cacti.

Prickly pear("Indian fig tree")

Although this plant belongs to the cactus family, it is very similar to a tree with a hard and branched trunk, sometimes more than 3 m high.

Thanks to their succulent stems and leaves, cacti (below) "cocker boom" from South Africa) tolerate drought well.

Saguaro or “giant candle”, is a huge cactus (up to 10-15 m) from the desert regions of America.

It is directly dependent on the weather. During each period of drought, the savannah loses its brightness and turns into a sea of dried grass and sultry gloom. And after a few days of rain, nature becomes unrecognizable.

Savannah vegetation has adapted to the dry continental climate and long droughts and has a strongly xerophytic character. All grasses usually grow in tufts. The leaves of cereals are dry and narrow, hard and covered with a waxy coating. The foliage on the trees is small, protected from excessive evaporation. Many species are characterized by a high content of essential oils.

Elephant grass (Pinnisetum purpureum, P. Benthami) is typical of savannah grasses. It got its name because elephants love to eat its young shoots. In areas where the rainy season lasts longer, the height of grasses can reach three meters. During drought, the above-ground part of the shoot dries out and is often destroyed by fires, but the underground part of the plant is preserved and gives new life after rains.

The hallmark of the savannah is the baobab tree (Adansonla digitata). The height of the tree reaches 25 meters, it is characterized by a thick (up to 10 meters in diameter) trunk and a huge spreading crown. And recently, a giant baobab was discovered in Africa, 189 meters high and with a trunk diameter at the base of 44 meters. These are long-lived trees, some reaching 4-5 thousand years old.

The baobab blooms for several months, but each flower lives only one night. Flowers are pollinated by bats. Baobab is also called the “monkey tree” because its fruits are a favorite food for monkeys. A person in a baobab uses everything: he makes paper from the inner layer of the bark, eats the leaves, and gets a special substance adansonine from the seeds, which he uses as an antidote for poisoning.

Acacia savannas are also common in Africa. More common are Senegalese, whitish, giraffe acacia and other species (Acacia albida, A. arabica, A. Giraffae). Due to its crown, which has a flattened shape, the acacia is called umbrella-shaped. The adhesives contained in the bark are widely used in industry, and the wood is used to make high-quality expensive furniture.