noun, plural: successions
(b.) A following of things, events, people, or ranks after another in sequence of time, as in a succession of disasters.
Ecological succession has an essential role in changing the composition or structure of a community. For instance, a new community of forest trees introduces shade to its ecosystem, or a previous community of vegetation that changed the fertility of the soil.
Succession may arise from the formation of new, unoccupied habitat (e.g. a lava flow or a severe landslide). This kind of succession in which the sequential development of plant or animal communities in an area where no soil initially exists is called primary succession. Succession may also be initiated by a disturbance of an existing community (e.g. fire, severe windthrow, logging). This kind of succession where communities develop in areas where soil already exists is called secondary succession.