Dictionary > Succession

Succession

Ecosystem Succession

Following a wild fire in a forest land, an ecological succession may ensue.

Definition

noun, plural: successions, word origin: Latin “successio”
1. (general) (a) The act of following in order or sequence; (b) A following of things, events, people, or ranks after another in a sequence of time, as in a succession of disasters.
2. (ecology) The directional and progressive change of communities in a given area over time. There are two types of succession: primary and secondary.

Supplement

In ecology, ecological succession as defined above refers to the progressive succession of ecological communities over time. The idea of ecological succession was credited to Jean-André Deluc (Swiss geologist and meteorologist) and to  Adolphe Dureau de la Malle (French naturalist) in the 19th century.

Two types of ecological succession:

  • Primary succession, wherein a community (typically, lichens and moss) colonizes a land not previously occupied, e.g. newly formed land from lava flows, newly exposed land surface, and glacial tills.
  • Secondary succession,  wherein a new community colonizes a previously inhabited geographical area that was disrupted or destroyed by a disturbance (e.g., fire, flood, tornadoes, hurricanes, epidemic diseases, pest attack, etc.)
Ecological succession: In this diagram, the process begins at a bare rock formed from volcanic eruptions (or from retreating glaciers). The next stage is the pioneer species (lichens and moss) growing on the rock. The death and, subsequently, the decomposition of these species contribute to the soil formation. The next groups of plant colonizers are grasses and herbaceous plants. They are next replaced by shrubs and bushes, then by trees. As the diversity of plant species improves, the animals occupying the area also become diverse. However, since competition for sunlight, space, and nutrients is increased, those that are better adapted and more tolerant survive and thrive, e.g. ‘shade-tolerant trees”.

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