ECOSYSTEM & ECOLOGY

Ecosystem

An ecosystem is a fundamental functional unit of ecological study. An ecosystem is a system – ecological system – in which organisms interact with each other and with their environment in a given and unit-time. In other words an ecosystem is a biotic community together with its physical environment considered as an integrated unit. Implied within this definition is the concept of a structural and functional unit, unified through life processes.

An ecosystem is broadly composed of two components:

(1)   Biome – All the plants, animal and microorganisms, in fact all the living beings in a given spatial unit. These are biotic elements.

(2)   Habitat – The Physical environment i.e. a biotic elements such as air, water and land.

Both these components are integrated by the continuous flow of energy and matter between them. We can call Energy as the third component of the ecosystem.

In other words each organism (including humans) is affected by and interacts with its environment. That environment is formed from a combination of interactive nonliving and living elements. When we consider both forms of elements and their interactions as a single entity we have an ecosystem at same level of organization.

Ecosystem can be viewed as an open system in which physical, chemical and biological processes form interactive subsystems. These processes called as biogeochemical cycle operate in such a way that the system is kept in relatively stable and dynamic equilibrium. The ecosystem has its own productivity also. As seen in the definition an ecosystem has both spatial dimension (well defined area) and temporal dimension (viewed in a given time period). Thus an ecosystem becomes a functional and structural unit of ecology.

About the size of ecosystem of scale dimension, an ecosystem varies from microscopic size to the largest one comprising whole biosphere. Ecosystems are hierarchical i.e. there are larger ecosystems comprising smaller ones. So an ecosystem can be a leaf or a branch of tree, the whole tree or a forest including microorganisms, insects, birds, etc. living there. It can also be a river and its tributary or even the Western Ghats or Himalayan ecosystem.

Ecosystems are scale dependent, meaning that their properties and characteristics- everything we can describe about them - may be different when we look at them at different scales. So practically however we define the ecosystem, there is always one unit larger than the existing ecosystem. Thus spatial boundaries of ecosystem too become imaginary or existing ecosystem. Thus spatial boundaries of ecosystem too become imaginary or transitional one, as they all are integrated. It is we humans who impose such boundaries for the convenience of our study and management.