The Strategy of Ecosystem Development

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The Strategy of Ecosystem Development

• Alishia Hill

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Ecological Succession

• Development of ecosystems
• Orderly process of community development that is
  reasonably directional and predictable
• Modification of the physical environment by the
  community

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• H. T. Odum and Pinkerton were the first to point
  out that succession involves a fundamental shift
  in energy flow as increasing energy is relegated
  to maintenance
• Maintenance
• community respiration

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Figure 1

• Figure 1 Comparison of the energetics of
  succession in a forest and a laboratory
  microcosm. PG, gross production PN, net
  production R, total community respiration B,
  total biomass

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Bioenergetics of Ecosystem Development

• Rate of primary production exceeds the rate of
  respiration
• P/R ratio is greater than 1 but approaches 1 as
  succession occurs
• Energy fixed tends to be balanced by the energy
  cost of maintenance (community respiration) in
  the mature ecosystem
• P/R ratio should be a good functional index of
  the ecosystems maturity

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Conclusion

• As long as P exceeds R, organic matter and
  biomass (B) will accumulate in the ecosystem
• Net community production in an annual cycle is
  large in young nature and small in mature nature