Published online by Cambridge University Press: 05 June 2012
Strategic response to competition, disturbance and stress
The concept that living organisms display ecological ‘strategies’ has advanced rapidly in recent years. The r–K continuum of MacArthur and Wilson (1967) made an important early contribution in contrasting the opportunistic r-species (with rapid rates of population growth), which exploit temporary habitats, with the equilibrium K-species of stable habitats in which competitive ability and survival of the individual is more important than population growth. In the same way that differing species of organism have gradually evolved over long periods of time (Darwin, 1859), such strategies arose through the exertion of competitive natural selection upon varied populations in which differences from the previous norm constantly arose. The CSR model of Grime (1974, 1979) – standing for Competitor–Stress tolerator–Ruderal – made an important further advance in adding the stress-tolerators, organisms capable of exploiting continuously unproductive environments or niches. The competitors are equivalent to the K-species and the ruderals (living on disturbed sites) approximate the r-species. This theory also recognizes that in plants there is a separation of the established (adult) and regenerative (juvenile) strategies and they may respond differently to their environment. This theory has been very thoroughly applied over a long period of time in a number of ecosystems, and with the publication of Plant Strategies, Vegetation Processes and Ecosystem Properties (Grime, 2001), is becoming a major tool in the manipulation of vegetation and ecological prediction.