The Evergreen Rainforest Biome, Temperate Grassland Biome Part 2

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The Evergreen Rainforest Biome

Geographical Background: This biome extends up to 10o latitude on both sides of the equator. It covers the area of Amazon low land of south America, Congo basin of equatorial Africa and South Eastern Asian Islands extending from Sumatra to New Guinea.

This area experiences high temperature throughout the year with range as little as 2oC. However, the daily range of temperature is much higher than the annual range of temperature. This area gets heavy rainfall ranging between 150 cm-250 cm.

It is distributed throughout the year. Rainfall occurs in the afternoon almost on daily basis. This also happens because of huge amount of water vapor reaching in the atmosphere due to high temperature. Hence, this area is considered to be an equable climate as both temperature and rainfall are high for whole of the year.

Evergreen Rainforest Biome

Evergreen Rainforest Biome

Evergreen Rainforest Biome

Natural Vegetation and Animal Life: The combination of heat and moisture make this biome as perfect environment for a great variety of plants and animal species. Most of the trees have buttressed trunks, shallow roots and large dark evergreen leaves. The evergreen rainforest arranged in three levels.

  1. The upper or canopy level where trees lie between about 20 metres to 50 metres. Most of them are hard wood trees like ebony, mahogany, rose wood, sandalwood, cinchona, etc.

  2. The second or intermediary level where trees lies between about 10 meters to 20 meters. Apart from palm trees, epiphytic and parasitic plants are also found in this layer

  3. The third or lower level lies from surface level to about 10 meters of height. Under this category variety of plants are found namely orchids, ferns, mosses, herbs, bananas, pineapples etc. Because of tall and broad-leaved dense plants, sunlight could not reach at the lowest level or surface. Because of poor photosynthesis process at this level, number of plant species are very low.

Like vegetation, evergreen rainforest is inhabited by numerous birds, mammals, insets etc. Some important animals of this biome are Jaguar, lemur, orangutan, elephant, etc. Macaw parrot, sloth and toucan are some of the important birds of this area. Most of the birds are colourful. The water bodies of the equatorial areas are also rich in animal life with alligators, tactless, fishes, frogs, Hippopotamus etc. Because of the impenetrability and high vegetation growth in the lower part, most of the insects, birds and animals resides on the branches of the trees.

Lower Canopies of Vegetation

Lower Canopies of Vegetation

Lower Canopies of Vegetation

It may be pointed out that the rainforest biome represents only 13 % of the total geographical area of the world but this biome accounts for the 40 % of the total productivity of the world.

Human Response: Human being has also started to damage this biologically rich ecosystem through various developmental activities. These activities are construction of large dams and reservoirs, roads and high ways, extraction of timber clearance for pasture or crops, encroachment and clearance by landless peasants etc.

Ecologists argue that if clearance continues at recent rates, all of the world’s undisturbed rainforest is likely to have disappeared or to be damaged by 2020. Rainforests contain about 40% of all known species of plants and animals. Clearance of rain forest causes the loss of valuable natural resources including hard wood trees and tree products such as quinine rubber vegetable gums etc. This loss is just not ecological but also has very significant environmental consequences. The evergreen forest provides various environmental services by helping to regulate global weather patterns, soil erosion, river flooding in the tropics etc.

Temperate Grassland Biome

Geographical Background: Temperate grasslands are located in two typical locations i.e. interior of the continent in the northern hemisphere and margin of the continents in the southern hemisphere. Therefore, the temperate grasslands of the southern hemisphere have moderate climate than their counterparts of the northern hemisphere because of more marine influences as they are closer to the coast. The temperate grasslands of the northern hemisphere are characterized by continental climate wherein extremes of summer and winter temperatures are well marked. Though grasslands in the southern hemisphere are located along the coast, these are located in the rain shadow areas of the high coastal mountains. These locations account for scanty rainfall in all these regions.

In the northern hemisphere, the grasslands are far more extensive. In Eurasia, they are called the steppes and stretch eastwards from the shores of the Black Sea to the plains of Manchuria in China. In North America, the grasslands are quite extensive and they are called prairies. They lie between the foot hills of the Rockies and the Great Lakes. In the southern hemisphere, these grasslands are less extensive. These are known as Pampas in Argentina and Uruguay. In South Africa, these grasslands are sandwiched between Darkensberg Mountains and the Kalahari Desert and are called veldt. In Australia, these grasslands are known as downs and are found in the Murray-Darling basins of South Australia.

The Temperate Grassland Biome

The Temperate Grassland Biome

The Temperate Grassland Biome

Natural Vegetation and Animal Life: The natural vegetation of these regions comprises treeless grasslands. Trees appear only on slopes of mountains where precipitation is more. The height of grass varies from place to place according to the amount of precipitation and fertility of the soil. The appearance of these grasses on these lands varies with the seasons. In springs, the grass beings to appear green, fresh and blooming with small and colourful flowers. In summers, due to the scorching heat and evaporation, the green grass turns yellow and then brown. Towards autumn, the grass withers and dies, but the roots remain alive and lie dormant throughout the cold winter season. These grasslands are natural habitat of a variety of animals. Noteworthy among them are antelopes, wild asses, horses, wolves, kangaroo, emu, and dingo or wild dog.

Human Response: No other biomes have ever undergone so many changes as the temperate grassland biomes. This has happened due to the human activities. Majority of the grasslands have been converted into agricultural lands which have now become famous granaries of the world. The second crucial factor responsible for alteration of this virgin grasslands is pastoralism or domesticated of animals. Large scale hunting of animals has resulted into phenomenal decrease of the population of some animals and disappearance and extinction of some animals. For example, many species of animals such as antelope, Zebra, lions, leopards, hyenas have disappeared from the African Veldts by the mass hunting of animals by the European immigrants.

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