Question

2) What is the definition of ecological niche? What are the differences between fundamental and realized niche? What abiotic factors might reduce the fundamental niche? (give three examples and a brief characterization of each)

Answer 1

Ecological Niche: It is the position or status that a given species occupies in the community or in an ecosystem on account of its structural adaptations , physiological response ad specific behaviour. It is the profession of an organism.

Fundamental niche: This is the niche utilized by an organism when there is no resource limitations and the conditions are ideal for survival. There is no threat of predation, competition, disease and as a result the organism can exploit the fullest or the resource available.

Realized niche: This is the part of the fundamental niche which an organism actually exploit due to the liiting factors of the environment such as predation, competition, disease etc. This s the actual mode of existence of an organism and it depends on its particular adaptation and ability to survive .

The abiotic factors which reduce the fundamental niche are: availability of light, pH tolerance, Temperature tolerance, salt concentration etc.

examples:

1. The three species of Hemidactylus viz. H.brooki, H. reticularis, H. leschenautte occupy three different niches and they belong to even different trophic level to reduce interspecific competition and thereby coexist in a same environment.

2. the myrtle warbler, the black throated green warbler and the burnian warbler all inhabit the same forest and all have similar feeding habit but each of them feeds in a particular part of he forest canopy which a minimum of overlap.

3. It has been observed that seven species of Millipedes, all of them are detritivorous (belong to same trophic level) and also belong to same habitat but each of them utilize different source of energy and can coexist in the same environment .