An Assessment of the MTR Aquatic Plant Bioindication System for Determining the Trophic Status of Polish Rivers

Mean Trophic Rank (MTR), a new British biological macrophyte-based method for assessing trophic status of rivers was applied in Poland in 2000-2001. The occurrence and abundance of 86 aquatic plant species was recorded at 48 sites on 19 rivers in the lowland part of Poland. Forty-six of these species are MTR scoring taxa used in the British system, but another 40 species were recorded of which 11 species were selected as potential scoring plants for use in Poland. The revision of MTR scoring plants used in Britain was performed and resulted in the proposed elimination of 24 taxa as scoring species for Poland. The habitat conditions of the selected river sites were assessed and their diversity was observed in terms of eutrophication level. The MTR score was evaluated and its correlation with water trophic level was shown. The environmental preferences of the individual plant species according to water chemistry were estimated to give proposals of the MTR scoring species in Poland and the indicated preference was analogous to the original Species Trophic Rank (STR) score used in the UK. The MTR system was recommended for use in biological monitoring programmes.