Reaction - Processes in Succession
This is the most important stage in succession. The mechanism of modification of environment, through the influence of living organisms on it is known as reaction. As a result of reaction, changes take place in soil, water, light conditions, temperature and many other factors of the environment. The environment thus gets modified, and becomes unsuitable for the existing community, and is eventually replaced by another community.
The old occupants are ousted and fresh migrants establish themselves. Thus, through a series of invasions, a sequence of plant communities marked by changes from lower to higher forms establish themselves in the course of time. Each stage of succession plays some part in reducing the extreme conditions in which the sere began. Thus, gradually the conditions of the area are modified by the seral communities to suit the growth of a wider range of species.