User:Margcamkey/Realized niche width

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Realized niche width, is a phrase relating to ecology, is defined by the actual space that an organism inhabits and the resources it can access as a result of limiting pressures from other species (e.g. superior competitors). An organism's niche is determined by the the biotic and abiotic factors that make up that specific ecosystem that allow that specific organism to survive there. The width of an organism's niche is set by the range of conditions a species is able to survive in that specific environment.

Fundamental niche width vs. realized niche width[edit]
The fundamental niche width of an organism refers to the theoretical range of conditions that an organism could survive and reproduce in without considering interspecific interactions. The fundamental niche exclusively considers limiting biotic and abiotic factors such as appropriate food sources and a suitable climate. The fundamental niche width often differs from the realized niche width. (the areas that a species actually inhabits and persists). This differentiation is due to interspecific competition with other species within their ecosystem while still considering the biotic and abiotic limiting factors. A species' realized niche is usually much narrower than its fundamental niche width as it is forced to adjust its niche around the superior competing species.

The physical area where a species lives, is its "habitat." The set of environmental features essential to that species' survival, is its "niche." (Ecology. Begon, Harper, Townsend)

The difference of the realized and the fundamental niche is important in understanding how interactions with a variety of different species in one environment affects the fitness of one species. This is not only important in understanding how a species functions in an ecosystem, but it is also important in determining the potential and realized success of invasive species. Invasive species could thrive or be killed off in an environment where they would theoretically be able to exist based off of the presence or lack of there of different species (Lounibos). To survive, an invasive species first has to successfully. make it to the new area, then they have to be able to survive in that habitat, and they then have to be able to successfully compete and reproduce with the other species already in existence. Considering these factors, not all invasive species are devastating to the new environment they inhabit.

In an organism's niche, the abiotic factors determine the ability of a species chance of survival while the biotic factors of that environment can be changed by that species' existence. A species' impacts on its biotic environment in its niche tend to effect not only that species' ability to survive, but the other species it coexists with. Again, these changes are important in understanding the affects of invasive species in a new habitat. The ability of a new species to change an environments biotic factors can make a previously habitable environment for a species uninhabitable. The disappearance of this species can further change the biotic factors of an environment. Invasive species not only directly effect the biotic environment, but they indirectly effect this environment by changing the different species living in a specific habitat.

Experiment[edit source]
The phenomenon was documented by the ecologist Joseph Connell in his study of species overlap between barnacles on intertidal rocks. He observed that Chthamalus stellatus and Balanus balanoides inhabited the upper and lower strata of intertidal rocks respectively, but only Chthamalus barnacles could survive both the upper and lower strata without desiccation. The removal of Balanus barnacles from the lower strata, resulted in the Chthamalus barnacles occupying its fundamental niche (both upper and lower strata) which is much larger than its realized niche in the upper strata.

This experiment was conducted on the rocky intertidal because of its accessibility and the large amount of previous research done on the species living there. Many of the species that live here are also sedentary or slow moving, making them easier to study. The different species are also more easily manipulated so creating experimental and control groups can be better studied. Connell's experiment meant to determine how much physical and biotic (competition) factors affected community structure in the rocky intertidal ecosystem.