The gradual evolution of a series of plants within a given area. This occurs in a roughly predictable order, while the habitat changes. Primary succession is ‘ecosystem development on barren surfaces where severe disturbances have removed most biological activity’ (L. Walker and R. de Moral 2003). Secondary succession is the replacement of a community after a disturbance; see Halpern et al. (1997) Ecology 70 for a summary of the variables influencing secondary succession. In autogenic succession the plants themselves are the genesis of change (Ellis and Coppins (2006) J. Biogeog. 33, 9); in allogenic succession the changes are driven by forces outside the ecosystem. The two are not mutually exclusive; see Francis (2006) Area 38, 4.