Ecological Succession

Ecological succession is the gradual, orderly, and reasonably predictable change in the species composition of a given area over time, driven by the changing environmental conditions that the organisms living there themselves progressively help to create. It is a community-level process, unfolding over years, decades or even centuries, rather than a change observable within a single generation of any one organism.

Succession begins with the establishment of a small number of hardy species -- the pioneer species -- in an area that is initially bare or largely unoccupied, and proceeds through a series of transitional plant and animal communities, each of which modifies the local environment (soil depth, moisture retention, shade, nutrient availability) in ways that make conditions progressively less suitable for the current occupying species and more suitable for a different set of species to invade and eventually replace them. Each of these transitional communities is called a seral community or seral stage, and the entire sequence of seral communities that occupies a given site from the very first pioneer stage through to the final stable community is together called a sere. …