Unfortunately, not many people know what savannas are and where they are. Savannahs are a natural zone that occurs mainly in the subtropics and tropics. The most important feature of this strip is a humid seasonal climate with a pronounced change in the drought and rainy season. This feature determines the seasonal rhythm of natural processes here. Ferrallite soils and grassy vegetation with groups of separate trees are also characteristic of this zone.
Savanna localization
Let's take a closer look at what savannas are and where they are. The largest area of the shroud is in Africa, it occupies about 40% of the area of this continent. The areas of this natural zone are less 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 (Indochina peninsula, Deccan plateau, Indo-Gangsai plain), as well as in Australia .
Climate
The savannah is characterized by the monsoon-trade wind circulation of air masses. In summer, tropical tropical air dominates in these regions, and in winter equatorial humid air. The farther from the equatorial belt, the greater the decrease in the rainy season (from 8–9 months to 2–3 at the outer borders of this zone). In the same direction, the total annual precipitation decreases (from about 2000 mm to 250 mm). The savannah is also characterized by small temperature fluctuations depending on the season (from 15C to 32C). Daily amplitudes can be more substantial and reach 25 degrees. Such climatic features have created a unique natural environment in the savannah.
The soil
The soils of the region depend on the length of the rain period and differ in leaching regime. Near equatorial forests, in areas where the rainy season lasts about 8 months, ferrallite soils have formed. In areas where this season is less than 6 months old, red-brown soils can be seen. At the borders with semi-deserts, soils are unproductive and contain a thin layer of humus.
Savannas of south america
In the Brazilian Highlands, these zones are located mainly in its inland areas. They also occupy the areas of the Orinok Lowland and the Guiana Plateau. In Brazil, there are typical savannas with red ferrallite soils. The vegetation of the zone is predominantly grassy and consists of families of legumes, cereals, and also asteraceae. Woody species of vegetation are either not present at all, or are found in the form of separate mimosa species with an umbrella-like crown, euphorbia, succulents, xerophytes and tree-like cacti.
In the northeast of the Brazilian Highlands, most of the area is occupied by katinga (sparse forest of drought-tolerant shrubs and trees on red-brown soils). Branches and tree trunks kaatinga often cover epiphytic plants and vines. There are also several types of palm trees.
Savannahs of South America are also located in the arid areas of Gran Chaco on red-brown soils. Sparse forests and thickets of thorny bushes are widespread here. Algarrobo is also found in the forests - a tree from the Mimosa family, which has a curved pillar and a highly branching, spreading crown. Low forest tiers are shrubs that form impassable thickets.
Among the animals in the savannah there are an armadillo, an ocelot, a Pampas deer, a Magellan cat, a beaver, a pampa cat, a nanda and others. Of rodents, tuco-tuco and a viscach live here. Many areas of the savannah suffer from locust invasions. There are also many snakes and lizards. Another characteristic feature of the landscape is a large number of termite mounds.
African shrouds
Now all readers are probably wondering: “Where is the savannah in Africa?” We answer, on the black continent, this zone almost runs along the contour of the region of moist tropical forests. In the border strip, forests are gradually thinning out and becoming poorer. Among the forests there are spots of savannah. The tropical humid forest is gradually limited only by river valleys, and in the watershed area they are replaced by forests, whose trees in the dry time drop leaves, or savannas. There is an opinion that tall grassy tropical savannahs began to form in connection with human activities, as he burned all the vegetation during the dry season.
In areas with a short wet season, the grass becomes less stunted and thinner. Of the tree species in the region, various acacias with a flat crown are found. These areas are called dry or typical savannahs. In regions with a longer rainy season, thickets of thorny shrubs grow, as well as hard grasses. Such vegetation is called desert savannahs, they form a small strip in the northern hemisphere.
The savanna world of Africa is represented by such animals: zebras, giraffes, antelopes, rhinos, elephants, leopards, hyenas, lions and others.
Savannah Australia
We continue our theme “What is the savannah and where are they”, moving to Australia. Here, this natural zone is located mainly north of 20 degrees south latitude. Typical savannas are located in the east (they also occupy the south of New Guinea). During the wet season, this region is covered by beautiful flowering plants: families of orchid, buttercup, lilac and various cereals. The characteristic trees are acacia, eucalyptus, casuarins. Trees with thickened trunks are quite common, where a store of moisture accumulates. They, in particular, are represented by the so-called bottle trees. It is the presence of these unique plants that makes the savannah of Australia a little different from the savannahs that are located on other continents.
This zone is combined with sparse forests, which are represented by different types of eucalyptus. Eucalyptus woodlands 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: mole, rat, wombat, anteater. In the thickets of shrubs echidna lives. In these regions, you can also see emu ostrich, a variety of lizards and snakes.
The role of savannah for man
After we have found out in detail what savannas are and where they are located, it is worth saying that these natural zones play an important role for humans. Peanuts, cereals, jute, cotton, sugarcane are grown in these regions . In arid areas, livestock production is quite developed. It is also worth noting that some tree species sprouting in this region are considered very valuable (for example, teak).
Despite its greater importance, man unfortunately continues to systematically destroy the savannah. So, in South America, as a result of burning fields, many trees die. Large areas of the savannah are cleared from the forest from time to time. Until recently, about 4,800 square meters of land was cleared annually in Australia to provide livestock grazing. km of forest. Now such events are suspended. Many exotic trees (Nile acacia, vaulted 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 savannah. As a result of global warming, woody plants are suffering greatly. I would like to believe that in the near future people will nevertheless begin to protect nature.