Ecological Niche

The ecological niche is a theoretical concept of the Écologie. It translates at the same time:

  1. the “position” occupied by a organization, a Population or more generally a Species in a ecosystem,
  2. the sum of the requirements to a viable population of this organization.

The description of such a “niche” comprises two types of parameters:

  1. of the parameters physico - chemical characterizing the Environment where the organization evolves/moves,
  2. of the biological parameters , including the relationships to the neighbouring species and the modification of the medium by the organization and the community of species in which it fits.

G.E. Hutchinson (1957) defines an ecological niche as a Hypervolume where each dimension of space is a resource (food, space: seal, etc) environment.

In theory, two species cannot occupy the same ecological niche durably. Indeed, it results from it a competition and the principle of the Natural selection tends to support that which “is adapted the most” to the niche (i.e. that which can reproduce most effectively).

However, of the different species can occupy of the functionally identical but geographically separate niches.

Two species can occupy the same territory, but in different niches. Two species can also occupy of the ecological niches overlapping in space and/or time, i.e. only part of dimensions of the hypervolume of Hutchinson are occupied in a simultaneous way. One speaks then about covering, and if it is not too important, the two species can nevertheless cohabit. It results from it all the same a competition which reduces the manpower of each of the two populations compared to that they would only have by occupying all dimensions.


L' écotone delimiting two different habitats can be an ecological niche for the typical species of this écotone, while episodically accommodating typical species of the adjaçants mediums. These last see there however generally their fitness (chances of survival) decreased.

An organization can occupy successively various ecological niches, according to its developmental stage or of the evolution of its environment (For example, certain organizations Saproxylophage S live in communities which move in a trunk at the rate/rhythm of its decomposition, of which they are the agents).

The species pionnières can occupy of the ecological niches which they find and which are adapted to them, or more often, they take an active part in their construction and maintenance. Many species build their ecological niche; thus the Sphaigne S by storing the ions calcium acidify the medium for their benefit and the detriment of other species, except those which can develop in an acid medium and Oligotrophe. The digestive tract of an animal can be the ecological niche of many neutral species, symbion or parasite with regard to their host.

The very specialized species are more dependant on a reduced ecological niche, but which they exploit a priori better.

See too

External bonds

  • teaching Card of the University of Montpellier
  • illustrated Explanation, with species of wetlands

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