= The process by which an ecosystem changes over time – the biotic conditions change as the abiotic conditions change.

A pioneer species is the first plant to colonise the bare ground. Only the species that can cope with the extreme conditions will grow and survive. Organic material accumulates, changing the conditions. The development of soil enables the seeds of small shallow-rooted plants to establish. As conditions improve, other plants compete and replace the existing plants. Eventually a stable climax community develops, dominated by trees. This remains unchanged unless conditions in the habitat change.

Primary succession: Takes place in newly formed habitats that has never been colonised before, there has never been a community.

Secondary succession: Takes place where an existing community has been cleared.

Deflected succession: A community that remains stable only because human activity prevents succession.