Grasslands of World

Temperate grasslands

Natural Grasslands primarily occur in regions that receive between 500 and 900 mm of rain per year.

Climate plays an important role in the formation of grasslands, Grasslands are dominated by grasses and Grasslike plants.
There are two different kinds of grasslands: Tropical and Temperate.

Grasslands are known by different names in different parts of the world: -
'Steppes' in Asia;
'Prairies' in North America;
'Pampas', 'LIanos' and 'Cerrados' in South America;
'Savannahs' and 'Velds' in Africa; and
'Rangelands' in Australia.

Grasslands in the southern hemisphere tend to get more precipitation than those in the northern hemisphere.Some grasses grow more than 7 feet (2 meters) and have roots extending several feet into the soil.

Tropical grasslands are warm year round, but usually, have a dry and a rainy season.One such tropical grassland, the African savanna.

Temperate grasslands which receive average between 10 and 30 inches (25 and 75 centimetres) of rain per year, have shorter grasses, sometimes just a few millimetres.

Temperate grasslands

(i)THE PRAIRIES

Location

• The temperate grasslands of North America are known as the Prairies.
• The prairies cover parts of United States of America and parts of Canada.

Important Features.

• Prairies are treeless but, near the low-lying plains, flanking river valleys, woodlands can be found. 
• Tall grass, up to two metres high, dominates the landscape. 
• It is actually a “sea of grass.”
• The prairies are bound by the Rocky Mountains in the West and the Great Lakes in the East.

Climate

• The summers are warm with temperatures of around 20°C, while in winter -20°C.
• The annual rainfall is moderate and is ideal for the growth of grass.
• Due to the absence of the north-south barrier, a local wind “Chinook” blows here which helps in the melting of snow, making pasture land available for grazing of animals.

Flora and Fauna

• The Rainfall is very little or unreliable, grasses are short and sparse. 
• These areas are suitable for cattle rearing. Large cattle farms called ranches. Bison or the American Buffalo is the most important animal of this region.

Crops

• The Prairies are also known as the “Granaries of the world,” due to the surplus of wheat production.

Rivers

• In the USA, the area is drained by the tributaries of Mississippi.
• The Canadian prairies are drained by the tributaries of Saskatchewan Rivers.

(ii)THE VELDS

Location

The temperate grasslands of South Africa are called the velds.

Important Features.

• Velds are rolling plateaus with varying heights ranging from 600 m to 1100 m. 
• It is bound by the Drakensburg Mountains on the east and to its west lies the Kalahari desert.
• On the northeastern part, “high velds” are located that attain a height of more than 1600 m, in some places. 

River

• The tributaries of rivers Orange and Limpopo drain the region.

Climate

• The velds have a mild climate due to the influence of the Indian Ocean.
• Winters are cold and dry.
• Temperatures vary between 5°C and 10°C and July is the coldest month.
•  Summers are short and warm.

Flora and Fauna

• Grasses dominate the landscape. Red grass grows in velds.
•  In the high velds acacia and maroola are seen to be growing. 
• The animals of the velds are primarily lions, leopards, cheetah and kudu.
• Sheep rearing is the most important occupation of the people.Merino sheep is a popular species and their wool is very warm.

Occupation

• Gold and diamond mining are major occupations of people of this region.
• Johannesburg is known for being the gold capital of the world. 
• Kimberley is famous for its diamond mines.

Tropical grasslands

Tropical grasslands are located near the equator, between the Tropic of Cancer and the Tropic of Capricorn.

THE SAVANNAS

Location

• They cover Africa as well as large areas of Australia, South America, and India.
• It is confined to the tropics and is best developed in Sudan, hence its name the Sudan Climate.

Important Features.

• The savanna is a rolling grassland with scattered trees and shrubs.
• Savanna has two distinct seasons in regards to precipitation. There is a rainy season in the summer with around 15 to 25 inches of rain and a dry season in the winter when only a couple of inches of rain may fall.

Flora and fauna

• Tropical grasslands are dominated by grasses, often 6 to 12 feet tall at maturity. The elephant grass may attain a height of even 15 feet.
• Many trees are umbrella shaped, exposing only a narrow edge to the strong winds.
• The grasslands are also called as ‘bush-veld’.
• They have deciduous trees, shedding their leaves in the cool, dry season to prevent excessive loss of water through transpiration, e.g. acacias, the baobab tree, and the jackal berry tree.
• Trees usually have broad trunks, with water-storing devices to survive through the prolonged drought.
• As the rainfall diminishes towards the deserts the savanna merges into the thorny scrub.
• The world's greatest diversity of ungulates (hoofed mammals) is found on the savannas of Africa. 
• The savanna is known as the ‘big game country’ as thousands of animals are trapped or killed each year by people from all over the world.

Climate

•  These areas are hot year-round, usually at 64 degrees Fahrenheit.
• Although these areas are overall very dry, they do have a season of heavy rain.
• Annual rainfall is from 20-50 inches per year which is concentrated in six or eight months of the year, followed by a long period of drought.

Soil

The soil of tropical grasslands is porous, with rapid drainage of water.

Farming

• Droughts are long due to unreliable rainfall.
• The Sudan Climate, with distinct wet-and-dry periods, is also responsible for the rapid deterioration of soil fertility.
• During the rainy season, torrential downpours of heavy rain cause leaching of nitrates, phosphates and potash.
• During the dry season, intense heating and evaporation dry up most of the water.
• Many savanna areas, therefore, have poor laterite soils which are incapable of supporting good crops.

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