The process of succcssion involves the following steps

The process of succcssion involves the following steps:

(i) Xudation:

This is a process by which a bare area is created. The reasons behind the creation of a bare area may be topographic (soil erosion, landslide, volcanic activity); climatic (glaciers, storms, frost, fire etc.), or biotic (anthropogenic activities like industrialisation, agriculture, etc.).

(ii) Invasion:

This is the process in which new specics reach and establish themselves in the bare areas. There are three substages of invasion.

(a) Migration:

This is the entry of propagules like seeds or spores by agents like air or water into the new area.

(b) Ecesis:

Once the propagules reach the new area, they germinate as they are to survive in the new environment. Most plants fail to survive. The process of successfully es- tablishing in the new envi- ronment is called ecesis. The first species that establishes itself is called the pioneer.

(c) Aggregation:

Increase in the number of individuals after ecesis is called aggregation.

(iii) Competition and coaction:

There is always a competition among or within the species for nutrition and space. Due to competition, there is coaction in which one influences the other leading to survival of the fittest.

(iv) Reaction:

The organisms that have established themselves and are competing for nutrition and space influence the environment and bring in a change in the sur- roundings. Such a process is called reaction. Reaction causes a change or destruction of one community and establishment of another. Each such stage that appears due to reaction is called serai stage.

(v) Stabilisation or climax:

It is the final stage in which the community that has developed is not replaced and is called the climax community.

A climax community, according to Clements (1916) shows three characteristics- unity, stability and phylogenetic relationship.