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5. Development
When an ecosystem reaches the end point of its succession and achieves a state of dynamic equilibrium, it is said to have reached a climax state
There are two theories for natural climax development: monoclimax theory and polyclimax theory. They disagree over whether there can be only one or many ultimate controlling factors of climax communities. These theories may be seen as essentially differing in terms of the time scale by which environmental stability is measured. Given enough time, all other factors will be overcome and a true climatic climax will develop. However, on such a time scale climate can be considered to be constantly changing: "So the condition of equilibrium can never be reached because the vegetation is approaching not a constant climate but a variable one." Krebb,1985.
Modern thinking on this problem has produced what many botanists see as a compromise whereby the stable community that is found on the most widespread soil and terrain combination of the region can be considered as the climatic climax and all other stable communities in the area can be considered edaphic, physiographic or phytographic climaxes.
Monoclimax theory was developed by the American botanist F.E. Clements (1916, 1939). It is based on the idea that climate is the major control on development. The argument is that even though there may be several seres developing within a given climatic region the ultimate result will be convergence to a single climax form of vegetation providing enough time is given and the process is free from interference.
Polyclimax theory was developed following debate over Clements' monoclimax theory. Proponents include Tansley (1939) and Duabenmire (1966). It argues other factors are as important as climate in governing the climax vegetation. These include edaphic climaxes that occur as a result of soil induced factors, and physiographic climaxes that occur as a result of terrain induced factors.
What is a climax state?