Each and every community undergoes a serious changes and a group of organisms is established which can live and reproduce most successful in the area. This is called biotic succession. Succession is a natural process by which different groups of communities colonize the same area over a period of time in a definite sequence.
The physical and chemical natures of a place mainly determine the kind of the community grows and flourishes there.
A specific sequence of development of a community is related to particular set of physical and chemical conditions. This is known as a sere is called climax or a climatic climax.
The succession which starts from a primitive substratum without any previous living matter is known a primitive succession.
It occurs where an early community has been damaged, leaving a few organisms and considerable organic matter. These remnant species along with, some new ones regenerates a new community. A secondary succession however follows a climatic changes / forest fire / flood by which earlier community is damaged.
Forest of primary succession may take, as long as 1000 years where as secondary succession takes considerably less time.
The first plants to appear in an area are called pioneer, such as hydrophate and crustose.
Types of Succession:
Types of succession are quite dependent on the nature of the habitat in which the plant succession begins. There are seven types of succession such as:-
Hydrosphere: Succession starts in aquatic habitat, e.g. Hydrilla, Polygonum, Mentha.
Litho sere: It starts on a bare rock surface.
Xerosere: Succession initiates on a dry barren land, e.g. Lichen, Moss, Rhus.
Psammosere: Initiating in sandy Habitates, e.g. Spinifex and Lpomoea.
Halosere: Starts in saline soil or water. Pioner plants have succulent leaves and stems, e.g. Aeathus, Llicifolius, Chenopodium, Basella.
Serula: Succession of micro-organism and lower plants on dead plants and bodies.
Esoere or Geosere: It is the development of vegetation in area.
Theories of Climax Community:
In a natural process of succession one community continues to follow another, until the stage comes when a type of community cannot be displaced under the prevailing environmental conditions. The final and terminal community that can maintain itself more or less indefinitely in equilibrium and the state is said to be climax.
According to thus theory, there is only one climax community which is mainly controlled by the climate.
To this theory under natural conditions. It is very common to find more time one type of climax community differing widely from one another with same climatic condition.