Report on Harmonisation of freshwater biological methods

103. For macrophytes only a few methods presented are WFD compliant. This isbecause the methods developed prior to the implementation of the WFD are generallylacking in the definition of stream type-specific reference conditions. This does nothold for schemes specifically designed for WFD monitoring purposes (Austria,Germany, The Netherlands). Sweden and UK intend to implement a predictive habitatapproach (a RIVPACS-type system for aquatic plants) in the near future to modelmacrophyte reference communities.104. For benthic invertebrates, only a small number of methods included in thisoverview fulfill the WFD classification demands at least partially. In particular,recently developed methods of the categories predictive and multimetric assessmentmethods incude stream type-specific evaluation based on reference conditions. Somecountries have modified their traditional methods (e.g. Saprobic System) and/ orcombined them with new assessment methods (e.g. for morphological degradation) tomeet the requirements of the WFD (Rolauffs et al., 2004). Furthermore, it is plannedto adjust the site-specific reference of the UK RIVPACS system by consideration ofstream morphology (Nixon et al., 1997).105. Integrated assessment of all indicative parameters of macrozoobenthoscommunities is done by multimetric indices. Besides the overall appraisal ofecological quality, their modular structure enables indication of the cause ofdegradation by providing individual metric values. Full ecological evaluationaccounting for several biota is carried out by the ecosystem component’s assessmentsystems described above.106. More than 50 percent of the methods present results in five classes of quality.Some of these banding schemes represent recent amendments with respect to thedemands of the WFD. In this context it has to be noted that the numbering of qualityclasses is performed conversely. Some schemes label the highest class with ‘1’ andincrement the number according to increasing deterioration. Other classificationsdenote high quality levels with ‘5’ and count down. This anomaly has to beconsidered and resolved in connection with the exchange and comparison of qualityresults derived by different methods.107. Another 12 percent of the methods use seven classes of water qualityoriginating from the classification of saprobity introduced by Liebmann (1962).26