15-12-2012, 06:33 PM
Forest Ecosystem (Terrestrial Ecosystem)
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Forest Ecosystem:
A forest is an area with a high density of trees.
World’s total land area is 13,076 million hectares - (Source: FAO; 1989)
Of which total forests account for about 31% of the world’s land area.
In India, the forest cover is roughly 19% of the total land area.
The forest ecosystem are of great concern from the environmental point of view.
It provides numerous environmental services like;
Nutrient cycling,
Maintaining biodiversity
Providing wildlife habitat
Affecting rainfall patterns
Regulating stream flow
Storing water
Reducing flooding
Preventing soil erosion
Reclaiming degraded land & many more….
Grassland Ecosystem(Terrestrial Ecosystem)
Grasslands (also called Greenswards) are areas where the vegetation is dominated by grasses and other herbaceous (non-woody) plants.
Grasslands occupy about 24% of the earth’s surface.
Grasslands occur in regions too dry for forests and too moist for deserts
The annual rainfall ranges between 25- 75 cm, Usually seasonal
The principal grasslands include:
Prairies (Canada, USA)
Pampas (South America)
Steppes (Europe & Asia)
Veldts (Africa)
Aquatic Ecosystems:
Aquatic ecosystems deal with biotic community present in water bodies.
In terrestrial ecosystem, carbon dioxide & oxygen are present in gaseous form whereas in aquatic ecosystem, these are available in dissolved state.
Depending upon the quality and nature of water, the aquatic ecosystem are categorized into:
Freshwater Ecosystem and
Marine Ecosystem.
Freshwater Ecosystems:
Freshwater ecosystems cover 0.8% of the Earth's surface and contain 0.009% of its total water.
Freshwater ecosystems contain 41% of the world's known fish species.
Aquatic ecosystems perform many important environmental functions. For example:
They recycle nutrients, purify water, attenuate floods, recharge ground water and provide habitats for wildlife.
Aquatic ecosystems are also used for human recreation, and are very important to the tourism industry, especially in coastal region.
There are three basic types of freshwater ecosystems:
Lentic: slow-moving water, including Pools, Ponds, and Lakes.
Lotic: rapidly-moving water, for example Streams and Rivers.
Wetlands: areas where the soil is saturated with water or inundated for at least part of the time