Within outlying mean indexes: refining the OMI analysis for the realized niche decomposition

The ecological niche concept has regained interest under environmental change (e.g., climate change, eutrophication, and habitat destruction), especially to study the impacts on niche shift and conservatism. Here, we propose the within outlying mean indexes (WitOMI), which refine the outlying mean index (OMI) analysis by using its properties in combination with the K-select analysis species marginality decomposition. The purpose is to decompose the ecological niche into subniches associated with the experimental design, i.e., taking into account temporal and/or spatial subsets. WitOMI emphasize the habitat conditions that contribute (1) to the definition of species' niches using all available conditions and, at the same time, (2) to the delineation of species' subniches according to given subsets of dates or sites. The latter aspect allows addressing niche dynamics by highlighting the influence of atypical habitat conditions on species at a given time and/or space. Then, (3) the biological constraint exerted on the species subniche becomes observable within Euclidean space as the difference between the existing fundamental subniche and the realized subniche. We illustrate the decomposition of published OMI analyses, using spatial and temporal examples. The species assemblage's subniches are comparable to the same environmental gradient, producing a more accurate and precise description of the assemblage niche distribution under environmental change. The WitOMI calculations are available in the open-access R package "subniche."

Keyword(s)

Biological constraint, Niche dynamic, Marginality, Community, Spatio-temporal, Subniche, Habitat

Full Text

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Publisher's official version
171 Mo
Within Outlying Mean Indexes Calculations. Mathematical description of the WitOMI parameters.
4103 Ko
WitOMI results and specie’s code. Tables S1 and S2 are the results of the OMI analysis, the value of the WitOMI parameters and their respective P values, for species of both ecological examples...
488 Ko
How to cite
Karasiewicz Stephane, Doledec Sylvain, Lefebvre Sebastien (2017). Within outlying mean indexes: refining the OMI analysis for the realized niche decomposition. Peerj. 5. 1-17. https://doi.org/10.7717/peerj.3364, https://archimer.ifremer.fr/doc/00389/49999/

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