• Unit 14-Succession

    Key points:
    • Succession is the change in species composition in an ecosystem over time.
    • It may occur on bare ground (primary succession) where soil formation starts the process or where no soil has alreday formed, or where the vegetation has been removed (secondary succession).
    • Early succession, gross primary productivity (GPP) and respiration are low and so net primary productivity (NPP) is high as a bimoass accumulates.
    • In later stages, while GPP may remain high, respiration increases so NPP may approach zero and the production:respiratio ratio is near 1.
    • A climax community is reached at the end of a succession when species composition stops changing.
    • In agricultural systems, succession is often deliberately stopped when NPP is high and crops are harvested.
    • Species biodiversity is low in early stages and increases as succession continues, falling a little in a climax community.
    Key words:
    succession primary succession prisere
    secondary succession seral stages seres
    pioneer community subclimax community climax community
    mineral cycling hydrosphere plagiosere
    plagioclimax psammosere production:respiration

Last Modified on February 23, 2015