In ecology, the final stage of biotic succession attainable by a plant community in an area under the environmental conditions present at a particular time. The species composition of the community remains the same because all the species present successfully reproduce themselves and invading species fail to gain a foothold. Because climatic changes, ecological processes, and evolutionary processes cause changes in the environment over very long periods of time, the climax stage is not completely permanent.
Source: Encyclopaedia Britannica 2002