IMPLEMENTATION AND ADAPTATION OF MACROPHYTE INDICATION SYSTEM: ASSESSMENT OF ECOLOGICAL STATUS OF RIVERS IN BULGARIA ACCORDING TO THE WATER FRAMEWORK DIRECTIVE

The legal requirements stated in the EU Water Framework Directive (WFD) have led to increased activity concerning macrophyte indicator metrics in Europe. Nevertheless in Bulgaria such indexes are still under consideration because of the lack of official methodologies. The macrophyte surveys undertaken as a part of two EU-funded projects are a unique resource allowing aquatic plant communities to be studied. The Reference Index (RI) was chosen as macrophyte assessment method since classifies rivers by using regional approach and reflects different kinds of environmental pressures. RI was implemented on 73 sampling sites in Bulgaria. On the basis of this dataset, our attempt to redesign the RI by the addition of further species, and the re-grouping of existing species, resulted in a considerable improvement in relation with regional conditions. The chosen macrophyte method can be applied at Bulgarian rivers in order to assess their ecological status.