Succession in Ecosystems
Succession (Primary Succession) is the gradual and orderly process of change in an ecosystem over time, brought about by the progressive replacement of one community of living organisms by another until a stable climax community is established. Successions include the lithosere (succession from a bare rock surface) and the hydrosere (succession in a pond, a lake or on a river bank).
Secondary Succession occurs on a site where an existing plant community has been disrupted, often by human activity. This type of succession occurs when agricultural fields are taken out of use or when forested areas are subjected to felling or severe fires that destroy all vegetation. In both cases the top soil remains for the regrowth of natural plant communities