In ecology, a niche refers to the match of a species to a specific environmental condition. It describes how an organism or population responds to the distribution of resources and competitors and how it, in turn, alters those same factors. A niche is a very specific segment of ecospace occupied by a single species. The concept of ecological niche is central to ecological biogeography, which focuses on spatial patterns of ecological communities.

Some key points about niches include:

• A niche is the functional role that an organism plays within an ecosystem.
• It is determined by the biotic factors, which include the distribution of resources and competitors.
• The niche of an organism within an ecosystem depends on how the organism responds and reacts to the distribution and abundance of these factors, and in turn, how it alters the factors.
• A niche can be advantageous for an organism to occupy a very specific niche, as this way, they will encounter less interspecific competition.
• Specialist species that occupy a very narrow or highly specialized niche encounter problems when there is a sudden decline or change in biotic or abiotic factors.

In summary, a niche is a specific role that a species plays within an ecosystem, and it is determined by the distribution of resources and competitors.