Contents - LAC Biosafety

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Ecology of insects in the forest
environment
3.1 The concept and functioning of ecosystem
To understand the status and role of insects in the forest environment,
it is first necessary to briefly discuss the concept and functioning of an ecosystem.
Nature is a highly complex, interconnected system. Links exist not only
between the living components but also between living and non-living
components. The significance of this complex interrelationship has been well
captured by the concept of ecosystem. An ecosystem can be defined as a
functional unit or entity consisting of a community of living organisms and the
physical environment in which they live, interacting with each other so that
there is a flow of energy from plants to the consumer organisms, and the cycling
of some materials between living and non-living components, with all the living
components existing in a dynamically steady state. It denotes a level of
organization above the living community, integrating it with its abiotic environment.
It provides a framework to organize our thoughts, as well as facts observed
from nature. In practical terms, a forest ecosystem consists of the community of
living trees and other vegetation, animals and micro-organisms and their
physicochemical (i.e. abiotic) environment which function together as an
integrated unit or system. It is difficult to delimit the physical boundaries of
an ecosystem because of the continuity of interconnections, but for practical
purposes it can be delimited according to our convenience. Thus we can talk
of a one-hectare patch of tropical forest as an ecosystem, or the entire forests of
Sri Lanka, of Southeast Asia or of the tropical forests as a whole as an ecosystem.
Each of these is itself part of a larger ecosystem. The largest ecosystem on earth is
the biosphere or ecosphere, which includes all the living organisms on the earth
interacting with the physical environment of the earth.
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