Succession

Succession is the act or process of following in order or sequence.

Political succession

In politics, succession is the ascension to power by one politician or monarch after another, usually in a clearly defined order.

 

Ecological succession

In ecology, succession is the replacement of one biological community by another. Succession can be primary or secondary. Primary succession occurs on essentially new substrata: bare rock or soil that has never been colonised before. Examples would be sand dunes and lava flows. Secondary succession occurs on land which has been colonised before, but has been disturbed back to some earlier state. Examples would include a drained reservoir, cleared forest, or ploughed field.

Succession begins with arrival of the pioneer species and leads eventually to establishment of a climax community. In primary successions pioneer species are typically hardy plants that survive under harsh conditions. On English sand dunes, marram grass has deep roots to tap into the water table, rhizomes to bind the soil, and leaves that reduce water loss through transpiration. On lava flows the first plants to colonize are adapted to survive in thin or no soils and possibly little water. The pioneer plants add organic matter to the soil, and help bind soil particles together, eventually allowing other species to colonise the area. This process slowly enhances the soil quality, enabling a sequence of other species assemblages to survive until a climax community is established. Climax communities are those communities of plants, animals, fungi, etc. that will be able to replace themselves with new generations of the same species. The climax community of an area will be determined by the characteristics of an area, such as elevation, soil type, and amount of rainfall. The climax communities most people are familiar with are usually some form of woodland that comes in after a field is abandoned.

Musical succession

In music or musical set theory, a succession is a series of any musical parameters including pitches, pitch classes, or simultaneities (see simultaneity succession). Succession may be thought of as a more general term for any possible progression, as in chord progression or harmonic progression, though not all simultaneity successions are harmonic progressions.