Ecological Niche

Ecological Niche

Ecological Niche

Ecological niche refers to the functional role and position of a species in relation to other species in the given ecosystem. In a natural ecosystem, several species of plant and animal communities perform different roles in getting food and thus each community is confined to certain locality having certain functions. Such locality having ideal environmental conditions for the survival of a species is called niche. The species of a given niche may not service in other niches. The ecosystem stability depends upon diversity of a niche. Greater the niche diversity, greater the stability of ecosystem. The ecosystem becomes unstable if one or more species are eliminated because then niche becomes empty and other species which were dependent on the eliminated species food now become vulnerable to elimination.

Biotic Succession / Ecological Succession

The progressive replacement of one vegetation community in a given habitat by the other is called ecological succession. Succession implies sequential replacement of one plant community or the ecosystem by the other. A plant community is group of plants which are already adapted to a given habitat. In other words ecological succession is an evolutionary sequence of development of ecological community or ecosystem. The biotic succession continues through different phases called as ‘sere’ until a mature and equilibrium community called as climax community is formed.

Features of ecological succession

(1)    It has a particular direction.

(2)    It results from modification of physical environment by the community .Thus it is community controlled even though the environment sets the pattern and rate of change and often sets the limits as to how far development can go.

(3)    It ends in a stabilized ecosystem in which maximum biomass and symbiotic function between organisms are maintained per unit of available energy flow.

(4)    With succession following changes occur---

(a)    Diversity of species increases

(b)   Complex food chains develop

(c)    Biomass increases

(d)   Energy flow increases

(e)   New habitat niche are created

(f)     The climax or stable community controls or becomes buffer against physical forces like temperature, moisture, wind, light, etc.

The first organisms to become established in an ecosystem undergoing succession are known as pioneers. The stable community that is formed at the end of succession is called as climax community. The intermediate stages such as grassland, scrub, shrubs are called sere.