Succession

Ecological succession is the process by which the structure of a biological community evolves over time, typically following a disturbance or the initial colonization of a new habitat. The classical model — primary succession on bare rock, secondary succession after fire — described a deterministic trajectory toward a stable 'climax community' shaped by climate. This model has been progressively dismantled by evidence that succession is path-dependent, historically contingent, and often non-equilibrium. The same starting conditions can produce different end states depending on the order of species arrival, a phenomenon known as priority effects. Succession is not the unfolding of a predetermined program but a dynamical process in which early colonists modify the environment for later arrivals, creating feedback loops that can lock in or shift trajectory. From a systems perspective, succession is the visible form of self-organization in ecosystems — the spontaneous emergence of structure from local interactions without global design.