ESTIMATES OF SPECIES EXTINCTIONS FROM SPECIES–AREA RELATIONSHIPS STRONGLY DEPEND ON ECOLOGICAL CONTEXT.

Matias M.G., Gravel D., Guilhaumon F., Desjardins-Proulx P., Loreau M., Munkemuller T. and Mouquet N. (2014).

Ecography 37, 1-12, doi:10.1111/j.1600-0587.2013.00448.x

Key message : In this study, we estimate species loss using a spatially explicit mechanistic simulation model to evaluate three important aspects of ecological context: coexistence mechanisms (e.g. species sorting, competition–colonization tradeoffs and neutral dynamics), spatial distribution of environmental conditions, and spatial pattern of habitat loss. We found that 1) area-based estimates of extinctions (both Species area SAR and endemics area EAR) are sensitive to coexistence mechanisms as well as to the pattern of environmental heterogeneity; 2) there is a strong interaction between coexistence mechanisms and the pattern of habitat loss; 3) SARs always yield higher estimates of species loss than do EARs; and 4) SARs and EARs consistently underestimate the realized species loss. Our results highlight the need to integrate ecological mechanisms in area-estimates of species loss which ignore the ecological context that shapes species distributions.

From modelling species distributions to estimating/measuring species loss. (a) Species distributions are generated by using a mechanistic model which consists in mortality, offspring production and dispersal and competition (b) Empirical SARs and EARs were constructed using a sampling function with increasing quadrat sizes. Species loss were estimated by using: (c) backwards SAR and EAR estimates; or (d) instantaneous measures based on the numbers of species remaining in the landscape directly after habitat loss. (e) Equilibrium species loss was measured by using the mechanistic model to follow community dynamics after habitat loss.

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OTHER TOPICS: Aesthetics of Biodiversity, Biodiversity & Ecosystem Functioning, Biogeography, Macroecology & Ecophylogenetics, Experimental Evolution, Functional Biogeography, Functional Rarity, Metacommunities, Metaecosystems, Reviews and Synthesis, Trophic Biogeography & Metaweb