SUCCESSION

a universal process of directional change in vegetation, on an ecological time scale. occurs when a series of communities replace one another due to large scale destruction either natural or manmade.

continously -one community replacing another community, until a stable, mature community develops.

The first plant to colonise an area is called the pioneer community. The final stage of succession iscalled the climax community.

The stage leading to the climax community are called successional stages

or seres. characterised by the following: increased productivity, the shift of nutrients from’ the reservoirs, increased diversity of organisms with increased niche development, and a gradual increase in the complexity of food webs.

Primary Succession

In primary succession on a terrestrial site the new site is first colonized by a few hardy pioneer species that are often microbes, lichens and mosses.

The pioneers through their death any decay leave patches of organic matter in which small animals can live.

The organic matter produced by these pioneer species produce organic adds during decomposition that dissolve and etch the substratum releasing nutrients to the substratum. Organic debris accumulates in pockets and crevices, providing soil  in which seeds can become lodged and grow.

As the community of organisms continues to develop, it becomes more diverse and competition increases, but at the same time new niche opportunities develops.

The pioneer species disappear as the habitat conditions change and invasion of new species progresses, leading to the replacement of the preceding community.

Secondary Succession

Secondary Succession occurs when plants recognize an area in which the climax community has been disturbed.

Secondary Succession  is the sequential development of biotic communities after the complete or partial destruction of the existing community.

This abandoned farmland is first invaded by hardy species of grasses that can survive in bare, sun-baked soil. These grasses may be soon joined by tall grasses and herbaceous plants.

These dominate the ecosystem for some years along with mice, rabbits, insects and seed- eating birds.

Eventually, some trees come up in this area, seeds of which may be brought by