Types of Ecological Succession
Ecological Succession may be of the following two types:
1. Primary succession : When succession begins on an area which has not been previously occupied by a community (e.g. a new exposed rock area, sand dunes, new islands, deltas, shore or recent lava flow) it is known primary succession. The first group of organisms (plants or animals) which become established in such an area is termed the pioneer community.
2. Secondary Succession : When community development is proceeding in an area from which a community was removed and where nutrients and conditions for existence are already favourable e.g. cut over bandoned cropland and ploughed field, it is termed secondary sucession.
Secondary succession is usually more rapid because some s are already present. Moreover, previously occupied territory is receptive to community development than the sterile areas.
Depending upon the predominance of green plants or heterotrophic organisms in the initial serval stage, succession is distinguished into autotrophic succession and heterotrophic succession.
- Autotrophic succession: it is wide spread in nature and begins in predominantly inorganic environment. It is characterized by early and continued dominance by autotrophic organisms (e.g. green plants).
- Heterotrophic succession: It is characterized by early dominance heterotrophs such as fungi, bacteria and animals. It occurs in predominantly lanic environment such as in a stream heavily polluted with sausage, in len log or in small pools receiving leaf bitters in heavy quantities. Energy maximum at the beginning and declines as succession occurs unless .Additional organic matter is imported or an autotrophic community takes place. But in autotrophic succession, energy flow does not usually decline is maintained or increased.
General process of succession
Following steps are found in ground Succession
1. Nudation : Due to human or other natural activities the greenless of rd is called nudation. After nudation the real activity of succession start.
2. Invasion : The seeds collected near the nudation area. The seeds or plants collect first called pioneer. The following steps of invasion are —
(a) Migration: Plant community start at that time when the part of Jamules plants invasion in open area. And the jamules migrate through air, later or animals. Mostly Jamules destroy and those Jamules find according tuation, they raise up and migrate for other places.
(b) Ecesis : After migrate the transfer of new species called Ecesis.
(c) Aggregation : After the colony establish, the seeds become collected. And as a result of it there become start competition for light and place. During competition the strong plants keep alive.
3. Competition and Reaction: Inter specific competition start in plants for light and palace. Strong plants keep alive and start genesis. Plants do action through migration, it is called change in environment. This order is called reaction. Change situation become some little favour towards old plants and more towards new. Thus the new species comes in place of old. Thus the vegetarian plants convert into small and small change into tree.