Overview

Macrophytes are an important component of aquatic ecosystems facilitating the assessment of the general ecologic quality and the monitoring of ecological status. The requirement to use macrophytes in monitoring is inherent in numerous European and national directives (for example, Directive 2000/60/EC of the European Parliament and of the Council of 23 October 2000 establishing a framework for Community action in the field of water policy, 91/217/EEC Directive of the Council of 21 May 1991 urban water treatment, 91/676/EEC Directives of the Council of 12 December 1991 concerning the protection of waters against pollution caused by nitrates from agricultural sources, Austrian Standard ÖNORM M 6232, Loi sur l'eau de 1992 (KKK), Système d'Evaluation de la Qualité des Milieux aquatiques (SEQ), etcetera). In addition to their ecological role, the use of macrophytes as indicators of ecological quality in running waters is based on the fact that certain species and species groups are indicators for specific running water types and are adversely affected by anthropogenic impact. In certain cases the lack of macrophytes is also characteristic for certain types of running water habitats. For example, in deeper rivers macrophytes may be absent due to conditions limiting the habitat such as water depth, water flow velocity, turbidity, etcetera. Therefore, the lack of macrophytes is also characteristic for certain types of running water habitats. A wide range of sampling and survey methodologies has been developed for specific applications aiming at measures for the conservation, drainage impact, water management, ecological habitat enhancement, etcetera. The application of this standard is recommended specifically for the surveying of macrophytes in running freshwaters, of natural, heavily modified and artificial character, for the purpose of determining the ecological status. Furthermore, it can be used as the basis for investigative monitoring of water quality or other applications. This European Standard describes the methodological approach for determining the ecological status of river reaches using aquatic macrophytes. The status of a river reach, or water body with running water, is assessed by surveying representative sites and recording the deviation from the natural conditions of a river reach with similar ecological conditions. Comparison is done with a natural or near-natural reference site. If natural conditions in river reaches serving as background or reference site no longer exist, it is necessary to reconstruct this background upon whatever existing records. This can be effected by modelling or expert knowledge. The presence of aquatic macrophyte taxa in the channels of representative river lengths (that is the representative site) is recorded. Vegetation abundance, the spatial extension of taxa or macrophyte beds (frequency or macrophyte coverage) is assessed by different methods adapted to the scale and purpose of the study. Quantitative descriptions of the macrophyte composition and abundance, taking into account the length of the river surveyed (numerical derivates, metrics) can be used to identify the divergence from type-specific "natural" conditions. This standard differs from DIN EN 14184:2004-02 as follows: a) the scope is applicable to all kinds of running waters; b) requirements have been brought in line with the Water Framework Directive (WFD); c) a further estimator scale to assess aquatic macrophyte abundance has been added in Table 2; d) informative Annex A "Quality assurance - Principles of interlaboratory comparison for macrophyte surveys in running waters - Occurrence and abundance of macrophyte species" has been added; e) the standard has been editorially revised. The preliminary work was carried out by Working Group "Biological methods" (WG 2) of CEN/TC 230, the chairmanship of which was held by BSI (secretariat: United Kingdom). The responsible German committee is NA 119-01-03-05-06 AK "Biologisch-ökologische Gewässeruntersuchung" ("Biological-ecological water examination") of NA 119-01-03 AA "Wasseruntersuchung" ("Water examination") at the Water Practice Standards Committee (NAW). The national revision of this project has been funded by the Länderfinanzierungsprogramm "Wasser, Boden und Abfall" (federal funding programme "Water, soil and waste").

Document: references other documents

Responsible national committee

NA 119-01-03-05-06 AK - Biological-ecological water examination  

Responsible european committee

CEN/TC 230/WG 2 - Biological methods co-ordination group