Ecological Succession
▪ The sequential, gradual and predictable changes in the species composition in an area are called succession or ecological succession.
▪ The entire sequence of communities that successively changes in a given area are called sere(s).
▪ The individual transitional communities are termed as seral stages or seral communities.
▪ The community that is in near equilibrium with the environment is called a climax community.
▪ The species that invade a bare area are called pioneer species.
▪ The changes that occur in successive seral stages to reach a climax community are:
i. changes in the diversity of species of organisms.
ii. increase in the total biomass.
iii. increase in the number of species and organisms.
▪ Ecological succession is of two types:
i. Primary succession: It begins in areas where no living organisms ever existed. Therefore, the establishment of a biotic community is very slow, e.g., newly cooled lava, bare rock, newly created pond or reservoir.
ii. Secondary succession: It begins in areas where natural biotic communities have been destroyed, e.g., abandoned farm lands, buried or cut forests. Since soil is available, it is a faster process.
