User:Leonardlauryn/Ecological niche

The author writes from a neutral point of view and includes the three broad views of niches (Grinnellian, Eltonian, and Hutchinsonian). All claims are properly cited from verifiable sources. The portion covering Hutchinsonian niche is much more developed than Ginnellian and Eltonian, so these latter sections may need additional revisions. Topics that were not covered were niche shifting, could be mentioned in the "see also" section.

Grinnellian niche
Grinnellian niches can be defined by non-interactive (abiotic) variables and environmental conditions on broad scales. Variables of interest in this niche class include average temperature, precipitation, solar radiation, and terrain aspect which have become increasingly accessible across spatial scales. Most literature has focused on Ginnellian niche constructs, often from a climatic perspective, to explain distribution and abundance. Current predictions on species responses to climate change strongly rely on projecting altered environmental conditions on species distributions. However, it is increasingly acknowledged that climate change also influences species interactions and an Eltonian perspective may be advantageous in explaining these processes.

Eltonian niche
Eltonian niches focus on biotic interactions and consumer-resource dynamics (bionomic variables) on local scales. Because of the narrow extent of focus, data sets characterizing Eltonian niches typically are in the form of detailed field studies of specific individual phenomena, as the dynamics of this class of niche are difficult to measure at a broad geographic scale. However, the Eltonian niche may be useful in the explanation of a species' endurance of global change. Because adjustments in biotic interactions inevitably change abiotic factors, Eltonian niches can be useful in describing the overall response of a species to new environments.

* Insert image of beaver/dam*

Hutchinsonian niche
Clarification of fundamental niche and realized niche

Niche and Geographic Range
The geographic range of a species can be viewed as a spatial reflection of its niche, along with characteristics of the geographic template and the species that influence its potential to colonize. The fundamental geographic range of a species is the area it occupies in which environmental conditions are favorable, without restriction from barriers to disperse or colonize. A species will be confined to a its realized geographic range when confronting biotic interactions or abiotic barriers that limit dispersal, a more narrow subset of its larger fundamental geographic range.

* insert picture of fundamental vs geographic range*

An early study on ecological niches conducted by Joseph Connell analyzed the the environmental factors that limit the range of a barnacle (Chthamalus stellatus) on Scotland's Isle of Cumbrae. In his experiments, Connell described the dominant features of C. stellatus niches and provided explanation for their distribution on intertidal zone of the rocky coast of the Isle. Connell described the upper portion of C. stellatus's range is limited by the barnacle's ability to resist dehydration during periods of low tide. The lower portion of the range was limited by interspecific interactions, namely competition with a cohabiting barnacle species and predation by a snail. By removing the competing B. balanoides, Connell showed that C. stellatus was able to extend the lower edge of its realized niche in the absence of competitive exclusion. These experiments demonstrate how biotic and abiotic factors limit the distribution of an organism.

See Also:
Niche shifting

Geographic range

Distribution and Abundance