Lake Macrophyte Nutrient Index of standing waters in Serbia (LIMNIS)

The aim of this study was to derive a Macrophyte Nutrient Index for standing waters in Serbia, based on the LEAFPACS method and to correlate it against existing Lake Typology. le data matrix of 46 species and 1463 sample quadrats was compiled from two datasets: a revised phytocenological database given according to Braun-Blanquet Cover Abundance Scale and a database of sample quadrats collected during the summer months of 2009, 2010 and 2011 at 31 lakes in Serbia. The nutrient indices (MSI) for 46 lake hydrophytes were calculated using the Reprediction Algorithm on N-Ellenbergʹs values. A Macrophyte Nutrient Index (LIMNIS) was calculated as the weighted average of MSI values for Serbian lakes. Correlation between rescaled MSI and original N-values was strong (0.82), and the same applies to the root-mean-square error value (0.75). Moderate LIMNIS values were derived for meso-oligotrophic lakes, as well as for eutrophic swamps and fens of the Danube floodplain. In the same manner, lakes classified as eutrophic showed the relatively higher LIMNIS values, and those recognised as potential conservation resources were characterised by moderate or low LIMNIS scores. LIMNIS values of six Lake Groups differed by less than one unit, which confirmed the similarity of the previously given Lake Types.