title: Reducing spatial variation in environmental assessment of marine benthic fauna.
abstract: The Benthic Quality Index, BQI, is widely used for benthic quality assessment. Here, we investigated if spatial variation in the BQI can be reduced by accounting for the environmental factors instead of having different boundaries for different salinity regimes between status classes in the EU Water Framework Directive and Marine Strategy Framework Directive. For this purpose we tested salinity, sediment structure, and depth in a regression model to test their contribution to variations in BQI. The spatial variation in BQI was better explained by depth than by salinity or sediment structure. The proposed assessment method uses the residuals from the regression model between BQI and depth. With this method the variance in BQI between samples was reduced by 50% to 75% in the majority of situations. A method to establish the boundary between good and moderate status and how to derive EQR-values according to the WFD is presented.
authors: Department of Wildlife, Fish, and Environmental Studies, Swedish University of Agricultural Sciences, SE 901 83, Umeå, Sweden. Electronic address: Kjell.Leonardsson@slu.se.
authors: Kjell
authors: K
authors: Leonardsson
authors: Hafok AB, SE 179 61, Stenhamra, Sweden.
authors: Mats
authors: M
authors: Blomqvist
authors: Marine Monitoring AB, Strandvägen 9, SE 453 30, Lysekil, Sweden; Department of Biology and Environmental Sciences - Kristineberg, University of Gothenburg, SE 451 78, Fiskebäckskil, Sweden.
authors: Rutger
authors: R
authors: Rosenberg
mesh_terms: D059001:Aquatic Organisms / Q000254:growth & development*; D017753:Ecosystem; D004784:Environmental Monitoring / Q000379:methods*; D008962:Models, Theoretical; D009792:Oceans and Seas; D012044:Regression Analysis; D012623:Seawater / Q000737:chemistry*; D013548:Sweden; D014876:Water Pollution / Q000032:analysis*
keywords: BQI; Benthic quality index; Depth; Marine Strategy Framework Directive; Salinity; Sediment; Water Framework Directive