Succession In Ecosystems

Succession is the change of one community of organisms into the other. Primary succession occurs when area previously devoid of life is colonised by communities of organisms for instance after the eruption of a volcano which lead to formation of a rock surface. The area is first colonised by the pioneer species such as lichens which are adapted to survive in such harsh conditions. As organisms die, they are decomposed by microorganisms thus adding humus, this in turn leads to formation of soil which makes the environment more suitable for more complex organisms. Over time, the soil becomes richer in minerals thus enabling larger plants such as shrubs to survive. Eventually, a climax community is established which is the final seral stage of succession, a self-sustaining and stable community of organisms. Secondary succession occurs in a previously colonised area in which an existing community has been cleared. This type of succession can occur after events such as forest fires. As a soil layer is already present, succession begins at a later stage.

Deflected succession- A community that remains stable only because human activity prevents succession from running its course.

This happens all the time, for example, sheep grazing prevents grassland from developing into woodland.

Many places need to be actively managed in the battle against succession, for example, golf courses need to be mowed all the time