Primary succession, type of ecological succession (the evolution of a biological community’s ecological structure) in which plants and animals first colonize a barren, lifeless habitat. Species that arrive first in the newly created environment are called pioneer species, and through their interactions they build a simple initial biological community. This community becomes more complex as new species arrive. Primary succession is distinguished from secondary succession, which is the recovery of an existing biological community after a disturbance sets back the community’s ecological structure to an earlier stage.
