Lecture 9: spatial ecology, plant communities, and disturbance. Disturbance: an event that causes rapid or marked change in a population or community often thought of as displacing an ecological system from its equilibrium. ( e. g. Succession: a regular sequence of changes in the species composition of a community in a newly forms or disturbed habitat that progresses to a stable state. Climax community: the end point of a successional sequence, or sere; a community that has reached a steady state under a particular set of environmental conditions. Sere: a series of stages of community change in a successional sequence leading toward a stable state. Primary succession: new substrate created, no pre-existing vegetation. Secondary succession: pre-existing vegetation undergoes a disturbance. Secondary succession in temperate deciduous forest biome: koffler scientific reserve. Old-field succession, stage 3: woody shrubs move in. Old-field succession, stage 5: tree canopy closes in. Old-field succession, stage 6: shrub layer thins out.