Concept of Ecosystem

Concept of Ecosystem

Intended Learning Outcomes

At the end of this Lecture, students will be able to

• Explain concept of an ecosystem

• Understand ecosystems

• Discuss ecosystem degradation

• Describe resource utilisation

Content

• Concept of an ecosystem

• Understanding ecosystems

• Ecosystem degradation

• Resource utilisation

Concept of Ecosystem

• An ‘Ecosystem’ is a region with a specific and recognizable landscape form such as forest, grassland, desert, wetland or coastal area

• Nature of the ecosystem is based on its geographical features such as hills, mountains, plains, rivers, lakes, coastal areas or islands

• It is also controlled by climatic conditions such as the amount of sunlight, the temperature and the rainfall in the region

• The geographical, climatic and soil characteristics form its non-living (abiotic) component

• The living part of the ecosystem is referred to as its biotic component

• Ecosystems are divided into terrestrial or landbased ecosystems and aquatic ecosystems in water

• Ecosystems have been formed on land and in the sea by evolution that has created species to live together in a specific region

• Thus ecosystems have both non-living and living components

• Some ecosystems are fairly robust and are less affected by a certain level of human disturbance. Others are highly fragile and are quickly destroyed by human activities

• Mountain ecosystems are extremely fragile as degradation of forest cover leads to severe erosion of soil and changes in river courses

• Island ecosystems are easily affected by any form of human activity which can lead to the rapid extinction of several of their unique species of plants and animals

• Evergreen forests and coral reefs are also examples of species rich fragile ecosystems which must be protected against a variety of human activities that lead to their degradation

• River and wetland ecosystems can be seriously affected by pollution and changes in surrounding land use

Understanding ecosystems

• Natural ecosystems include the forests, grasslands, deserts and aquatic ecosystems such as ponds, rivers, lakes, and sea

• Man modified ecosystems include agricultural land and urban or industrial land use patterns

• Each ecosystem has a set of common features that can be observed in the field:

• ‘What does the ecosystem look like?’ One should be able to describe specific features of the different ecosystems in one’s own surroundings

• What is its structure? Is it a forest, a grassland, a water body, an agricultural area, a grazing area, an urban area, an industrial area, etc.?

• What you should see are its different characteristics. A forest has layers from the ground to the canopy. A pond has different types of vegetation from the periphery to its center. The vegetation on a mountain changes from its base to its summit

• What is the composition of its plant and animal species? List the well- known plants and animals you can see. In fact there are so many that they cannot be easily counted

• ‘How does the ecosystem work’? The ecosystem functions through several biogeochemical cycles and energy transfer mechanisms

Ecosystem degradation

• Ecosystems are the basis of life itself

• Natural ecosystems in the wilderness provide a variety of products and are regions in which a number of vital ecological processes are present, without which human civilization would not be able to exist

• Ecosystems are however frequently disrupted by human actions which lead to the extinction of species of plants and animals that can live only in the different natural ecosystems

• Some species if eliminated seriously affect the ecosystem. These are called ‘keystone’ species

• Extinction occurs due to changes in land use. Forests are deforested for timber, wetlands are drained to create more agricultural land and semi-arid grasslands that are used as pastures are changed into irrigated fields

• Pollution from industry and waste from urban settings can also lead to extinction of several species

• The reason for the depletion of natural resources is twofold – our rapidly exploding population that needs to sustain itself on resources and the growth of affluent societies, which consume and waste a very large proportion of resources and energy

• If one thinks before wasting resources such as water, reusing and recycling paper, using less plastics that are non-degradable, ultimately this can have positive implications on the integrity of our natural resource base and conserve the resources that nature provides

• Every region of our earth has different ecosystems based on its climatic conditions and geographical feature

Resource utilisation

• Most traditional societies used their environment sustainably

• In recent times the proportion of ‘rich’ people in affluent societies, grew rapidly

• Inequality thus became a serious problem

• Whereas in the past many resources such as timber and fuel wood from the forest were extracted sustainably, this pattern has drastically changed during the last century

• Economically better off sections began to use greater amounts of forest products, while those people who lived in the forest became increasingly poor

• Similarly the building of large irrigation projects led to wealth in those areas that had canals, while those who hand to remain dependent on a constant supply of water from the river itself, found it difficult to survive.

• The key to this issue is the need for an ‘equitable’ distribution of all types of natural resources

• A more even sharing of resources within the community can reduce these pressures on the natural ecosystems

Summary

• An ‘Ecosystem’ is a region with a specific and recognizable landscape form such as forest, grassland, desert, wetland or coastal area

• Natural ecosystems include the forests, grasslands, deserts and aquatic ecosystems such as ponds, rivers, lakes, and sea

• Most traditional societies used their environment sustainably