Editing Ecological niche (section)

==Hutchinsonian niche==<!-- Hutchinsonian niche redirects here-->
[[File:Purple-throated carib hummingbird feeding.jpg|thumb|The shape of the [[beak|bill]] of this [[purple-throated carib]] is complementary to the shape of the flower and [[coevolution|coevolved]] with it, enabling it to exploit the nectar as a resource.]]

The Hutchinsonian niche is an "[[N-dimensional space|n-dimensional]] hypervolume", where the dimensions are environmental conditions and [[Resource (biology)|resources]], that define the requirements of an individual or a species to practice its way of life, more particularly, for its population to persist.<ref name=Levin/> The "hypervolume" defines the multi-dimensional space of resources (e.g., light, nutrients, structure, etc.) available to (and specifically used by) organisms, and "all species other than those under consideration are regarded as part of the coordinate system."<ref name=Hutchinson1957>{{cite journal | author = Hutchinson, G.E. | year = 1957 | title = Concluding remarks | journal = Cold Spring Harbor Symposia on Quantitative Biology | volume = 22 | issue = 2 | pages = 415–427 | url = http://artifex.org/~ecoreaders/lit/Hutchinson1957.pdf | access-date = 2007-07-24 | doi = 10.1101/sqb.1957.022.01.039 | archive-url = https://web.archive.org/web/20070926153803/http://artifex.org/~ecoreaders/lit/Hutchinson1957.pdf | archive-date = 2007-09-26 | url-status = dead }}</ref>

The niche concept was popularized by the zoologist [[G. Evelyn Hutchinson]] in 1957.<ref name=Hutchinson1957/> Hutchinson inquired into the question of why there are so many types of organisms in any one habitat. His work inspired many others to develop models to explain how many and how similar coexisting species could be within a given community, and led to the concepts of [[Realized niche width#Niche width vs. realized niche width|'niche breadth']] (the variety of resources or habitats used by a given species), [[Niche differentiation|'niche partitioning']] (resource differentiation by coexisting species), and 'niche overlap' (overlap of resource use by different species).<ref name=Chase2>{{cite book |author1=Jonathan M. Chase |author2=Mathew A. Leibold |title=Ecological Niches: Linking Classical and Contemporary Approaches |url=https://books.google.com/books?id=Ssmcl_ubQUQC&pg=PA11 |page=11 |isbn=9780226101804 |year=2003 |publisher=University of Chicago Press}}</ref>

[[File:Resource allocation.png|thumb|Where three species eat some of the same prey, a statistical picture of each niche shows overlap in resource usage between three species, indicating where competition is strongest.]]

Statistics were introduced into the Hutchinson niche by [[Robert MacArthur]] and [[Richard Levins]] using the 'resource-utilization' niche employing histograms to describe the 'frequency of occurrence' as a function of a Hutchinson coordinate.<ref name=Levin/><ref name=MacArthur>{{cite journal |author=Robert H. MacArthur |title=Population ecology of some warblers of northeastern coniferous forests |journal=Ecology |volume=39 |issue=4 |year=1958 |pages=599–619 |url=http://people.biology.ufl.edu/troutinthemilk/IGERT/MacArthur_1958.pdf |doi=10.2307/1931600 |jstor=1931600 |bibcode=1958Ecol...39..599M |access-date=2014-05-18 |archive-url=https://web.archive.org/web/20140519002134/http://people.biology.ufl.edu/troutinthemilk/IGERT/MacArthur_1958.pdf |archive-date=2014-05-19 |url-status=dead }}</ref> So, for instance, a [[Normal distribution|Gaussian]] might describe the frequency with which a species ate prey of a certain size, giving a more detailed niche description than simply specifying some median or average prey size. For such a bell-shaped distribution, the ''position'', ''width'' and ''form'' of the niche correspond to the ''mean'', ''standard deviation'' and the actual distribution itself.<ref name=Putnam>{{cite book |chapter-url=https://books.google.com/books?id=NCpkrNG6xFkC&pg=PA107 |page=[https://archive.org/details/principlesofecol00putm/page/107 107] |author1=Rory Putman |author2=Stephen D. Wratten |title=Principles of ecology |chapter=§5.2 Parameters of the niche |isbn=9780520052543 |year=1984 |publisher=University of California Press |url-access=registration |url=https://archive.org/details/principlesofecol00putm/page/107 }}</ref> One advantage in using statistics is illustrated in the figure, where it is clear that for the narrower distributions (top) there is no competition for prey between the extreme left and extreme right species, while for the broader distribution (bottom), niche overlap indicates competition can occur between all species. The resource-utilization approach postulates that not only can competition occur, but that it ''does'' occur, and that overlap in resource utilization directly enables the estimation of the competition coefficients.<ref name=Schoener1986>{{cite book |last1=Schoener |first1=Thomas W. |date=1986 |chapter=The Ecological Niche |editor1-last=Cherret |editor1-first=J. M. |title=Ecological concepts: the contribution of ecology to an understanding of the natural world |location=Cambridge |publisher=Blackwell Scientific Publications}}</ref> This postulate, however, can be misguided, as it ignores the impacts that the resources of each category have on the organism and the impacts that the organism has on the resources of each category. For instance, the resource in the overlap region can be non-limiting, in which case there is no competition for this resource despite niche overlap.<ref name=Pocheville2015/><ref name=Chase2/><ref name=Schoener1986/>

[[File:Mistletoe infested tree.jpg|thumb|left|upright=0.75|As a hemi-[[parasitic plant]], the [[mistletoe]] in this tree exploits its host for nutrients and as a place to grow.]]

An organism free of interference from other species could use the full range of conditions (biotic and abiotic) and resources in which it could survive and reproduce which is called its '''fundamental niche'''.<ref name=Griesemer>{{cite book |title=Keywords in Evolutionary Biology |author=James R. Griesemer |page=[https://archive.org/details/keywordsinevolut00harv/page/239 239] |editor=Evelyn Fox Keller |editor2=Elisabeth A. Lloyd |chapter=Niche: Historical perspectives |isbn=9780674503137 |year=1994 |publisher=Harvard University Press |chapter-url=https://books.google.com/books?id=Hvm7sCuyRV4C&pg=PA239 |url-access=registration |url=https://archive.org/details/keywordsinevolut00harv/page/239 }}</ref> However, as a result of pressure from, and interactions with, other organisms (i.e. inter-specific competition) species are usually forced to occupy a niche that is narrower than this, and to which they are mostly highly [[adaptation|adapted]]; this is termed the [[Realized niche width|'''realized niche''']].<ref name=Griesemer/> Hutchinson used the idea of competition for resources as the primary mechanism driving ecology, but overemphasis upon this focus has proved to be a handicap for the niche concept.<ref name=Chase2/> In particular, overemphasis upon a species' dependence upon resources has led to too little emphasis upon the effects of organisms on their environment, for instance, colonization and invasions.<ref name=Chase2/>

The term "adaptive zone" was coined by the paleontologist [[George Gaylord Simpson]] to explain how a population could jump from one niche to another that suited it, jump to an 'adaptive zone', made available by virtue of some modification, or possibly a change in the [[food chain]], that made the adaptive zone available to it without a discontinuity in its way of life because the group was 'pre-adapted' to the new ecological opportunity.<ref name=Schluter>{{cite book |title=The Ecology of Adaptive Radiation |chapter=§4.2: The ecological theory |author=Dolph Schluter |page=69 |isbn=9780191588327 |publisher=Oxford University Press |year= 2000 |chapter-url=https://books.google.com/books?id=Q1wxNmLAL10C&pg=PA69}}</ref>

Hutchinson's "niche" (a description of the ecological space occupied by a species) is subtly different from the "niche" as defined by Grinnell (an ecological role, that may or may not be actually filled by a species—see [[vacant niches]]).

A niche is a very specific segment of ecospace occupied by a single species. On the presumption that no two species are identical in all respects (called Hardin's 'axiom of inequality'<ref name =Hardin>{{cite journal |author=Garrett Hardin |title=The competitive exclusion principle |journal=Science |volume=131 |pages=1292–1297 |issue=3409 |year=1960 |url=http://www.esf.edu/efb/schulz/seminars/hardin.pdf |doi=10.1126/science.131.3409.1292 |pmid=14399717 |bibcode=1960Sci...131.1292H |access-date=2014-05-19 |archive-date=2017-11-17 |archive-url=https://web.archive.org/web/20171117235048/http://www.esf.edu/efb/schulz/seminars/hardin.pdf |url-status=dead }}</ref>) and the [[competitive exclusion principle]], ''some'' resource or adaptive dimension will provide a niche specific to each species.<ref name=Griesemer/> Species can however share a 'mode of life' or 'autecological strategy' which are broader definitions of ecospace.<ref name="SahneyBentonFerry2010LinksDiversityVertebrates">{{cite journal | author=Sahney, S., Benton, M.J. and Ferry, P.A. | year=2010 | title=Links between global taxonomic diversity, ecological diversity and the expansion of vertebrates on land | journal=Biology Letters | doi=10.1098/rsbl.2009.1024 | volume=6 | pages=544–547 | pmc=2936204 | issue=4 | pmid=20106856 }}</ref> For example, Australian grasslands species, though different from those of the [[Great Plains]] grasslands, exhibit similar modes of life.<ref>[https://web.archive.org/web/20041010205937/http://collections.ic.gc.ca/abnature/glossary.htm Glossary for the Nature of Alberta]</ref>

Once a niche is left vacant, other organisms can fill that position. For example, the niche that was left vacant by the extinction of the [[Equus ferus ferus|tarpan]] has been filled by other animals (in particular a small horse breed, the [[konik]]). Also, when plants and animals are introduced into a new environment, they have the potential to occupy or invade the niche or niches of native organisms, often outcompeting the indigenous species. Introduction of [[non-indigenous species]] to non-native [[habitat]]s by humans often results in biological pollution by the exotic or [[invasive species]].

The mathematical representation of a species' fundamental niche in ecological space, and its subsequent projection back into geographic space, is the domain of [[environmental niche modelling|niche modelling]].<ref>On the logic of the relation between the niche and the corresponding geographic environment, see: {{cite journal|doi=10.1111/0029-4624.00151|url=http://ontology.buffalo.edu/smith/articles/niches.pdf|title=The Niche|journal=Noûs|volume=33|issue=2|pages=214–238|year=1999|last1=Smith|first1=Barry|last2=Varzi|first2=Achille C.}}</ref>