Savannah — the sea of grasses with occasional Islands of trees with the canopy of the umbrella. Vast areas of these amazing natural communities are in Africa, while the savanna in South America, and Australia, and India. A distinctive feature of the savannas is the alternation of arid and wet seasons that lasts for about half a year, one after another. The fact that subtropical and tropical latitudes, where there are savannas, characterized by the change of two different air masses humid Equatorial and tropical dry.
Significantly influence the climate of savannas monsoon winds that bring seasonal rains. Because these landscapes are located between the very humid Equatorial areas with natural forests and very dry areas of deserts, we are constantly influenced by those and others – approx. But the moisture is present long enough in the savannas, there grew tiered forest and dry “winter” in 2-3 months do not allow Savannah to become a harsh desert.
The annual rhythm of life of the Savannah is associated with climatic conditions. During wet periods a riot of grass vegetation reaches a maximum — the space occupied by savannas, turning into a living carpet of herbs. The picture was broken only by the low, gnarled trees — acacia and baobab trees in Africa, fan palm, ravenala in Madagascar, cacti in South America and in Australia — the bottle tree and eucalyptus. The fertile soil of the savannas. In the rainy period, when dominated by the Equatorial air mass, and the earth, and the plants get enough moisture to feed the numerous animals that live here.
Savannah in Africa
But the monsoon goes away, and its place is occupied by dry tropical air. Now it’s time to start testing. Grown in human growth dried grass, trampling by many animals, moving from place to place in search of water. Grasses and shrubs are very susceptible to fire, which often burns a large area. This “help” the natives, huntress: specially burning the grass, they chase their prey in the direction of. So did the people for many centuries and greatly contributed to the fact that the vegetation of the Savannah acquired modern traits: an abundance of fire-resistant trees with thick bark, like baobab trees, wide spread of plants with strong root system. The area of savannas is quite wide, so on their southern and Northern borders of the vegetation varies – approx. from geoglobus. Savannah bordering the desert zone in the North zone in Africa, rich in low drought-resistant grasses, euphorbias, aloe and acacia trees with highly branched roots. To the South they are replaced by moisture-loving plants, and river banks in area of Savannah enter gallery forests with evergreen shrubs and vines, similar to humid Equatorial.
In the rift valley of East Africa is the largest lake of the continent — Victoria, Nyasa, lakes Rudolf and albert, Tanganyika. Savannahs on their banks interspersed with wetlands, planted with papyrus and reeds.
In African savannas there are many famous nature reserves and national parks. One of the most famous is the Serengeti, situated in Tanzania. Part of its territory occupies the crater highlands is a famous plateau with the ancient craters of extinct volcanoes, one of which is the Ngorongoro has an area of about 800 hectares! Savannah of South America have traditionally called “Llanos” and “campus”. From typical African Savannah they are characterised by numerous thickets of shrubs and cacti.
Australian eucalyptus savanna woodlands and Bush frame the Central desert area of the continent. Intermittent streams in winter (screaming) in the summer is the wet season can turn into lakes and swamps.
YEAR IN SAVANNAH
Winter is dry and relatively cold period lasting two or three months. During this time the trees shed their leaves, the grasses shrivel and dry up, and sometimes burn out. The contrast in temperature between day and night reaches 15-18°C. Many rivers in this period, dry, shallow, and the groundwater level is lowered. “Winter” gives way to “spring”, begins flowering when still leafless trees and shrubs. “Summer” period is the most humid and rainy is continuing, as a rule, four or five months – approx. The temperature drops and the humidity increases, accounting for almost 90%. At this time, the trees reveal the leaves, grass grow luxuriantly, and the soil is filled with water. The river becomes full-flowing. Before the next winter comes for a short autumn, when the crops and fruit trees, evaporation decreases. Nature is prepared for a new arid period.
Savannah in South America