The Science of the Total Environment, Jan 15, 2012, Vol.415, p.61(8)
To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.scitotenv.2011.05.056 Byline: Ben J. Kefford, Ralf B. Schafer, Leon Metzeling Keywords: Biological traits; Stream macroinvertebrates; Salinization; Suspended sediments; Spatial scale Abbreviations: ANOSIM, analysis of similarity; Br, Breather; EC, electrical conductivity (salinity); JI, Jaccard's Index; PSS, pooled sample sets; NTU, Nephelometric Turbidity Units; NUE, no unacceptable effect; RSF, relative species retention; S.sub.org, sensitivity to organic toxicants; SSD, species sensitivity distribution; UED, unacceptable effect detected Abstract: Ecological risk assessments mostly consider measures of community composition (structure) across large spatial scales. These assessments, using species sensitivity distributions (SSDs) or the relative species retention (RSR), may not be protective of ecosystem functions and services at smaller spatial scales. Here we examine how changes in biological traits, as proxy for ecosystem functions/services, at a fine spatial scale relate to larger scale assessment of structure. We use functional traits of stream insect species in south-east Australia in two habitats (riffle and edge/pool). We find that the protection of community structure in terms of 95% of species over multiple sites against adverse effects of salinity (as electrical conductivity) and turbidity will mostly, but not always, protect traits at smaller scales. Considering different combinations of trait modalities, contaminants and habitat, a mean of 17.5% (range 0%-36.8) of cases would result in under-protection of trait modalities despite protecting species composition (in terms of Jaccard's Index). This under-protection of trait modalities is only because of the different spatial scales that community structure and the traits were considered. We recommend that where the protection of biological traits, ecosystem functions or ecosystem services from stressors is a management goal, protective targets should not be solely set using measures of community structure such as SSDs or RSR. To protect both structural and functional attributes separate risk assessments should be done. Article History: Received 24 February 2011; Revised 6 May 2011; Accepted 8 May 2011
Wildlife Conservation ; Soil Salinity ; Risk Assessment ; Ecosystems ; Electrical Conductivity
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