Ecological Niche & Ecological Equivalents

The ecological niche is a fundamental concept in ecology that describes the role and position of a species within its environment. Ecological equivalents refer to the species that live in different ecosystems but have similar niches and functions.

What is an Ecological Niche?

Charles Elton and others use the term ecological niche to the status of an organism in a community. Ecological Niche is the position or status of an organism within its community and ecosystem as well as the functional role of an organism in its community, ie, how it transfers energy, behavior, response to modify other species, etc.

The niche includes all the physical, chemical, physiological, and biological factors that the organism requires for its life. The habitat of an organism is the place where it lives. However, ecological niche, on the other hand, is the position or status of an organism within the community. It may be said that habitat is the address and niche in the profession of an organism.

Thus the term ecological niche is a more inclusive term because it includes not only the physical space occupied by an organism but also its functional role in the community or its trophic position.

Different parts of the world with similar physical environments will have taxonomically different but ecologically similar species occupying the same niche. Thus grass species in a temperate grassland in India are different from those in a similar environment in North Europe, America, Australia, etc.

But they all perform the same basic function in their ecosystem, that of the primary producers. Likewise, the grazing kangaroos are the predominant herbivores in Australia but it is cows, buffaloes, and goats in India.

Since the kangaroos, cows, and buffaloes have the same functional position, they occupy the same niche, even though they are all taxonomically different.

Another Interesting ecological generalization was that the same species may function differently or occupy different niches in different habitats or geographical regions. Humans are a good example, which is carnivores in some areas and herbivores in others.

Ecological Equivalents

In some cases, it is seen that different animals in widely separated ecosystems occupy similar niches and perform similar functions. Such animals are called ecological equivalents. Mountain lions of North America feed on deer whereas the lions of Africa feed mainly on antelope and wild beasts.

It’s important to note that the concept of the ecological niche has evolved, and some different interpretations and models have been proposed to describe niche dynamics, such as the Grinnellian niche, Eltonian niche, and Hutchinsonian niche. These models provide different perspectives on how species’ niches are defined and how they influence species distribution and community dynamics.

Types of Ecological Niches

These niches are different models or perspectives of ecological niches. Each niche focuses on different aspects of the ecological niche and provides different insights into how species interact with their environment.

Grinnellian niche or habitat niche includes the abiotic factors. It gives importance to the interaction of the biotic factors to its physiological facts as well.
Eltonian niche also known as functional niche or occupation niche focuses on the functional role of the species in its habitat. It includes trophic interactions, position in the food web, its role as a predator, feeding habits, etc, of the species.
Hutchinsonian niche, also known as the multidimensional or hypervolume niche includes the environmental variables and other dimensions of the environment. It includes any factor that has a direct or indirect influence on the species.

References

Shukla, R.S. and Chandel, P.S. (2001) Plant Ecology. S. Chand and Company Ltd., New Delhi.
Verma, P.S., Agarwal, V.K. (1999). Cell biology genetics molecular biology evolution and ecology. New Delhi: S.Chand Co.(Pvt) Ltd.
Khatibi, Mina., Sheikholeslami, Razieh. (2016). Ecological Niche Theory: A Brief Review, The International Journal of Indian Psychology. Volume 3, Issue 2, No.2. https://oaji.net/articles/2016/1170-1452245952.pdf
Evidence of niche partitioning among small mammals in the Eastern Mojave Desert from scat distribution.