Succession

Primary succession happens when a new patch of land is created or exposed for the first time. This can happen, for example, when lava cools and creates new rocks, or when a glacier retreats and exposes rocks without any soil. Primary sucession begins with lichens and moss (pioneer species) to create soil, eventually reaches climax community.

Succession is a series of progressive changes in the composition of an ecological community over time.

Secondary succession occurs when the severity of disturbance is insufficient to remove all the existing vegetation and soil from a site. Many different kinds of disturbances, such as fire, flooding, windstorms, and human activities (e.g., logging of forests) can initiate secondary succession. Begins with soil, much quicker than primary succession.