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    Diversity Index

    Diverity Indices...

  • used to describe the complexity of communities or ecosystems;
  • can rely on species, size or pigment (phytoplankton) composition or any other determinant separating one group of organisms from another;
  • Simple Diversity Index introduced by Margaleff (1951):

    S - 1
    D = ------------

    with D = Diversity Index, S = Number of species/groups, N = total number of individuals.
  • Highest diversity: coral reefs, tropical plankton communities, stable enrionments
  • Lowest diversity: plankton blooms, new biotops, unstable envrionments
  • Diversity can be high although only few species occur when total number of individuals is low.

    Thought Experiment: Which population has the higher diversity?

  • Pop1: S = 3, N = 50
  • Pop2: S = 7, N = 84,000

    For more information on diversity indices and introduction of other commonly used indices refer to web page