Report on Harmonisation of freshwater biological methods
Report on Harmonisation of freshwater biological methods
Report on Harmonisation of freshwater biological methods
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expressed in classes. For most <strong>methods</strong> the number <strong>of</strong> classes and the defined rangesdeviate.37. The numerical evaluati<strong>on</strong> <strong>of</strong> macrophyte compositi<strong>on</strong> and abundance is d<strong>on</strong>e inassessment <strong>methods</strong> <strong>of</strong> France, Germany, Latvia, The Netherlands and UnitedKingdom. Quality appraisal is mainly based <strong>on</strong> a single biotic index integratingindicator species and their abundance. Most indicator species included in the indices<strong>of</strong> the French and British schemes are sensitive to the trophic state <strong>of</strong> the water andthe sediment. In Latvia macrophytes are part <strong>of</strong> the Saprobic System to detect organicpolluti<strong>on</strong>.38. Multimetric assessment based <strong>on</strong> macrophytes is d<strong>on</strong>e by Germany and TheNetherlands. Dependent <strong>on</strong> the stream type assessed by the German method, mossesand phanerogams are separately evaluated, or further metrics (e.g. evenness,percentage <strong>of</strong> Sparganium emersum etc.) are added to the results <strong>of</strong> the main index.Besides the assessment <strong>of</strong> general degradati<strong>on</strong>, the method comprises modules for thedetecti<strong>on</strong> <strong>of</strong> acidificati<strong>on</strong> in base-poor mountain streams. The Dutch method c<strong>on</strong>sidersthe percent coverage <strong>of</strong> plant growth forms and the abundance <strong>of</strong> stream type-specificindicator species to assess general stream degradati<strong>on</strong>. In both <strong>methods</strong> the overallquality <strong>of</strong> the watercourse is derived <strong>on</strong> the basis <strong>of</strong> the analysis <strong>of</strong> the entire aquaticflora including phytobenthos.39. The number <strong>of</strong> quality classes, in the <strong>methods</strong> discussed ranges from four toseven. The quality classificati<strong>on</strong> for sites analysed by the British method is indicatedbut a three class system has been proposed based <strong>on</strong> MTR. Here, <strong>on</strong>lyrecommendati<strong>on</strong>s for the interpretati<strong>on</strong> <strong>of</strong> the index value are given.BENTHIC INVERTEBRATESA. Summary <strong>of</strong> the nati<strong>on</strong>al assessment <strong>methods</strong> for rivers usingbenthic invertebrates40. The overview <strong>of</strong> <strong>biological</strong> assessment <strong>methods</strong> using benthic invertebratescomprises 44 schemes applied in 32 European countries. Besides <strong>methods</strong> which willbe used in WFD-compliant m<strong>on</strong>itoring programmes by the EU Member Statesadditi<strong>on</strong>al assessment <strong>methods</strong> <strong>of</strong> specific interest have been included. The range <strong>of</strong>75