The phenomenon of transition when one biotic community gives way to the other biotic community is referred to as ecological succession. This transition takes place due to modification in the physical environment so that the area becomes less favorable for present species and more favorable for another species. This process of succession ultimately culminates in ‘climax ecosystem’. Climax ecosystem is the final stage when there appears to be a dynamic balance between all the species and the physical environment.
Process of Ecological/Natural succession
The process of succession takes place in systematic sequential order having following steps:
- Nudation: It is the development of a bare area without any life form.
- Invasion: It is achieved through dispersal or migration when a species establishes itself over a bare area. When the growth and reproduction starts these pioneer species increase in number and form groups or aggregates.
- Competition and co-action: There is competition both inter-specific i.e., between organisms of different species and intra specific i.e., within organisms of same species for nutrients, space etc. co-action is the influence they have on each other.
- Reaction:Due to competition and co-action there is modification of the environment which has a strong influence on the physical environment and is referred to as reaction
- Stabilization:The formation of the climax ecosystem which is in equilibrium with the environment is referred to as stabilization.
Factors of ecological succession:
Topographic factor: volcanic eruption, landslides
Climatic factor: drought, forest fire
Biotic factor: overgrazing, industrial activities
Types of ecological succession:
Primary Succession: It is the initial development of an ecosystem. When a community begins 2develop on a site that is previously unoccupied and then the progression from one biotic community to the next is termed as primary succession.
Secondary Succession: It is the re-establishment of an ecosystem. When an area that has been cleared by fire, flood, and drought or due to biotic factors and then gradually reinvaded through a series of distinct stages is termed as secondary succession.
Aquatic Succession: when lakes or ponds are gradually filled and taken over by surrounding terrestrial ecosystem as the nearby soil is eroded from the land.