Ecosystem

Q.4. Explain the following Ecosystems with case studies: 

(a) Forest

(b) Grassland

(c) Desert

(d) Aquatic

Ans.(a) Forest Ecosystem: Forests are formed by a group of plants which is predominantly and structurally defined by its trees, shrubs, climbers and ground cover A few examples of forest écosystems are protected forest lands, national reserves and wildlife sanctuaries.

Forests types in India include coniferous forests, evergreen forests, broadlea forests, deciduous forests, thorn and mangrove forests.

Forest products can be classified on the basis of: 

(i) Direct Use: Products like fruits, medicinal plants, fuel, bamboo, grass are different products.

(ii) Indirect Use: Products like construction material, paper, gum are indime products.

Case Study: Chipko Movement of 1970s

In the 1970s, an organized resistance to the destruction of forests spread throughout India and came to be known as the Chipko movement. The name of the movement comes from the word 'embrace, as the villagers hugged the trees, and prevented the contractors' from felling them The Bishnoi community of Rajasthan also played its role in saving trees in the 18th century. The original 'Chipko movement was started around 260 years back in the early part of the 18th century in Rajasthan by this community. A large group of them from 84 villages led by a lady called Amrita Devi laid down their lives in an effort to protect the trees from being felled on the orders of the Maharaja (King) of Jodhpur.

Ans.(b) Grassland Ecosystem: Landscapes on which vegetation largely comprises of grass and small annual plants. In such places rainfall is low and sol quality is extremely poor. A few examples of grasslands are the Himalayan pasture belt, teral, shola grasslands etc.

Case Study: Grassland degradation in middle-south Inner Mongolia 

During 1988, the government of Mongolia assessed the quality of grasslands to check the state of their pasture lands. It was analysed that soil quality then was good as the nutrient levels were high. Due to over-grazing activities from the year 2000-2008, the grassland ecosystems degraded. A change in usage patterns of grasslands also brought about a climatic change in the environment. The Government of Mongolia has taken steps for conservation of wildlife and their lands

Ans. (c) Desert Grasslands: Deserts and semi-arid areas are located in Western India and the Deccan Plateau. The climate in these tracts is extremelt dry. For example, the cold deserts of Ladakh, or the hot Thar deserts of Rajasthan These deserts have very little water retaining capacity, so crops like Jowar and Bajra which require less water are grown here.

Case Study: Impact of construction of Indira Gandhi Canal in Rajasthan 

The Indira Gandhi Canal was constructed to rejuvenate the Thar region and it has had many positive socioeconomic impacts. However, the ecological impacts of this new canal water supply have mainly been negative The desert biodiversity of the region is under threat, to the point of extinction of some species. As many as 153 species of plants have disappeared from the irrigated region of the Thar Desert. About 21% of the flora has changed in the Sriganganagar District, where irrigation is being practiced for the past seven decades. This change has been of lesser magnitude (about 12%) in Bikaner, where irrigation is being practiced for the past two decades. This clearly indicates that, with time, the desert species are under great threat with a change in the ecosystem.

Ans. (d) Aquatic Ecosystem: An aquatic ecosystem is an ecosystem in a body of water. Communities of organisms that are dependent on each other and on their environment live in aquatic ecosystems. The two main types of aquatic ecosystems are marine ecosystems and freshwater ecosystems.

Case Study: Threat to Wetlands in Assam (Deepor Beel) 

Deepor Beel is a protected site under the Ramsar Convention on Wetlands, 1971, the area has been suffering from environmental degradation due to continuous encroachment and waste dumping. In fact, the Guwahati Municipal Corporation dumps all its waste in the vicinity. Once spread over 4,000 hectares, the wetland has now shrunk to 500 hectares. It used to be home to over 200 species of migratory birds. In January 2006, nine storks were found dead, which might have been caused by toxic wastes. The site now faces various natural and anthropogenic threats, primarily from the development of industries within the periphery of the site, illegal hunting of wild animals and deforestation.