An ecological niche describes the functional position and role of an organism within its environment

An ecological niche will be comprised of various components, including:

  • The habitat in which the organism lives
  • The activity patterns of the organism (e.g. periods of time during which it is active)
  • The resources it obtains from the environment (e.g. food source, territorial boundaries, etc.)
  • The interactions that occur with other species in the region (e.g. competition / predator-prey relationships)

Types of Niches

Some species may not be able to occupy their entire niche due to the presence or absence of other species

  • The fundamental niche is the entire set of conditions under which an organism can survive and reproduce (i.e. where it can live)
  • The realised niche is the set of conditions actually used by a given organism after interactions with other species are taken into account (i.e. where it does live)

Fundamental versus Realised Niche

fundamental vs realised niche

Niche Differentiation

Niche differentiation describes the way by which competing species use the environment differently in order to exist

If two species with identical niches compete, two distinct outcomes are possible:

  • Competitive exclusion:  One species will use the resources more efficiently and drive the other species to local extinction
  • Resource partitioning:  Two species will alter their use of the niche to avoid direct competition, allowing for co-existence

Niche Differentiation

          Term:             Niche                    Resource Partitioning                     Competitive Exclusion