Two types of succession
Primary
- characteristic of areas NOT previously occupied by organisms.
- Involves sequence of events from exposure of bare rock to establishment of a stable community.
- Usually takes 1000 years in terrestrial habitats
Secondary
- Characteristic of areas previously occupied by organisms, as in an area charred by fire or affected by flooding
- Involves sequence of events from catastrophic event to re-establishment of a stable community.
- Usually takes less time, e.g. Mount Saint Helens of 1980