TOWARDS A EUROPEAN STREAM TYPOLOGY.

H.E. Vlek. Department of Ecology and Enviroment, Alterra Green World Research, Wageningen, the Netherlands

The EU Water Framework Directive (WFD) defines a framework for assessing waterbodies in the future. Therefore, there is a strong demand for “new” assessment systems fulfilling the demands of the EU WFD. The aim of the AQEM project is to develop such an assessment system for European streams using benthic macroinvertebrates. For this purpose over 900 streams are sampled in Austria, the Czech Republic, Germany, Greece, Italy, the Netherlands, Portugal, and Sweden. Twenty-eight European streamtypes, which are supposed to be representative for larger geographic regions, have been selected. The selected sample sites range from high ecological status (reference state) to bad ecological status. Data collected on some relevant environmental factors and macroinvertebrate species composition were examined using Detrended Correspondence Analysis (DCA) and Detrended Canonical Correspondence Analysis (DCCA). The results of the analyses will show whether streamtypes really differ in macroinvertebrate species composition and which environmental factors explain the variance in species composition best.