Ecosystem their management and conservation | Environmental Geography | Principle Of Geography

 

Environmental Geography

Principle Of Geography

Geography Complete Study Material

(Paper - I)

Ecosystem their management and conservation

             In nature several communities of organisms live together and interact with each other as well as with their physical environment as an ecological unit. We call it an ecosystem. The term ‘ecosystem’ was coined by A.G. Tansley in 1935. An ecosystem is a functional unit of nature encompassing complex interaction between its biotic (living) and abiotic (non-living) components. For example- a pond is a good example of ecosystem.

Management of Ecosystem

           Ecosystems are complex dynamic system. They perform certain functions. These are:- (i) Energy flow through food chain (ii) Nutrient cycling (biogeochemical cycles) (iii) Ecological succession or ecosystem development (iv) Homeostasis (or cybernetic) or feedback control mechanisms Ponds, lakes, meadows, marshlands, grasslands, deserts and forests are examples of natural ecosystem. Many of you have seen an aquarium; a garden or a lawn etc. in your neighbourhood. These are man made ecosystem.

Types of ecosystems 

Ecosystems are classified as follows: (i) Natural ecosystems (ii) Man made ecosystems

(i) Natural ecosystems 

(a) Totally dependent on solar radiation e.g. forests, grasslands, oceans, lakes, rivers and deserts. They provide food, fuel, fodder and medicines. 

(b) Ecosystems dependent on solar radiation and energy subsidies (alternative sources) such as wind, rain and tides. e.g tropical rain forests, tidal estuaries and coral reefs. 

(ii) Man made ecosystems 

(a) Dependent on solar energy-e.g. Agricultural fields and aquaculture ponds. 

(b) Dependent on fossil fuel e.g. urban and industrial ecosystems.

Functions of Ecosystem

          Food chains and energy flow are the functional properties of ecosystems which make them dynamic. The biotic and abiotic components of an ecosystem are linked through them. 

Food Chain 

Transfer of food energy from green plants (producers) through a series of organisms with repeated eating and being eaten is called a food chain. e.g. Grasses → Grasshopper → Frog → Snake → Hawk/Eagle Each step in the food chain is called trophic level. In the above example grasses are 1st , and eagle represents the 5th trophic level. 

During this process of transfer of energy some energy is lost into the system as heat energy and is not available to the next trophic level. Therefore, the number of steps are limited in a chain to 4 or 5. Following trophic levels can be identified in a food chain. 

(1) Autotrophs: They are the producers of food for all other organisms of the ecosystem. They are largely green plants and convert inorganic material in the presence of solar energy by the process of photosynthesis into the chemical energy (food). The total rate at which the radiant energy is stored by the process of photosynthesis in the green plants is called Gross Primary Production (GPP). This is also known as total photosynthesis or total assimilation. From the gross primary productivity a part is utilized by the plants for its own metabolism. The remaining amount is stored by the plant as Net Primary Production (NPP) which is available to consumers.

(2) Herbivores: The animals which eat the plants directly are called primary consumers or herbivores e.g. insects, birds, rodents and ruminants. 

(3) Carnivores: They are secondary consumers if they feed on herbivores and tertiary consumers if they use carnivores as their food. e.g. frog, dog, cat and tiger. 

(4) Omnivores: Animals that eat both plant and animals e.g. pig, bear and man 

(5) Decomposers: They take care of the dead remains of organisms at each trophic level and help in recycling of the nutrients e.g. bacteria and fungi.

Types of Food Chain 

There are two types of food chains: 

(i) Grazing food chains: which starts from the green plants that make food for herbivores and herbivores in turn for the carnivores. 

(ii) Detritus food chains: start from the dead organic matter to the detrivore organisms which in turn make food for protozoan to carnivores etc. In an ecosystem the two chains are interconnected and make y-shaped food chain. These two types of food chains are:- 

(i) Producers → Herbivores → Carnivores 

(ii) Producers → Detritus Feeders → Carnivores

Important Points:

• An ecosystem is a functionally independent unit of abiotic and biotic components of the biosphere. 
• Climatic regime, inorganic substances, organic compounds, producers, macroconsumers and microconsumers are of structural components of the ecosystem. 
• Functional processes an ecosystem are energy flow, food chains, nutrient cycles, ecosystem development and homeostasis. 
• All the abiotic factors such as light, temperature, pressure, humidity, salinity, topography and various nutrients limit the growth and distribution of animals and plants.

Conservation of Ecosystem

           Natural ecosystems have been misused by the human being as a result of which the biodiversity and wild life has been threatened. Increasing human population, its increasing needs and greed are the root causes of destruction of natural ecosystems. Destruction and loss of any of the natural ecosystem will result in ecological imbalance and the human being (the destroyer) himself will become an endangered species. Hence natural ecosystems need protection.

          Protection of natural ecosystem demands management of human use of the biosphere resources such that they give maximum benefits to the present human generation while maintaining its potential to meet the needs of future human generations. Protection of natural ecosystems to an environmentalist means to protect animals and plants in their natural habitat in totality and not the protection of any one species . It can be achieved by the following methods:-

• Humans should reduce their needs. 
• Introduction of the species from the other parts of the world and the human interference should be reduced to minimum into natural ecosystems. 
• Some of the areas should be earmarked as protected or reserve zones. This can be achieved by making buffer or transitional zones around the protected area. (Buffer zone and transitional zones are where only a few humans are permitted to enter) 
• Species in the detrimental habitats should be shifted to their unexploited natural habitat. Delhi Development Authority along with Delhi University has jointly established a Yamuna Biodiversity park in Delhi to protect and restore natural biodiversity lost from the Yamuna river bank. The same natural habitat is created for the plants and aquatic birds. Within a span of one year after the establishment of wetland the number of migratory birds has increased remarkably.
• Zones of megadiversity and hot spots of biodiversity should be protected. Megadiversity zones are those regions of the world which have largest number of species. 200 global megadiversities have been identified. India is one of the megadiversity countries. Hot spots are the richest and most threatened reservoirs of plant and animal life of the earth. They have maximum number of endemic species. 25 terrestrial hot spots have been identified for the conservation of biodiversity. They occupy 1.4% of the earth’s surface and 20% of worlds the human population lives in these areas. Western ghats and Eastern Himalayas are two hot spots of India. 
• International and national level efforts should be made for conserving natural ecosystems e.g. Earth Summit held in June 1992 at Rio di Janerio , Brazil, it wasresolved to make efforts to protect and conserve biodiversity. 
• Sacred forests and sacred lakes are protected by the tribal communities due to the religious sanctity accorded to these forests. They are most undisturbed by human activity and are known as pristine forests. Chipko movement to protect the forests of Mandal villages a good example of local people’s effort to conserve natural ecosystems.