Analysis of changes in cyanobacterial and algal flora of selected water reservoirs in Wrocław between 1878 and 2010 (south-west Poland)

The paper includes the results of research carried out between 2006-2010 in the city of Wrocław (Poland). The water reservoirs selected for the analysis had previously described phycoflora and these studies were excellent comparative material for the today’s condition of their algoflora. The aim of this research was to conduct detailed studies of the current taxonomic composition of phycoflora in the chosen water reservoirs and to trace the changes which have taken place over time. The research determined the degree of similarity between the different communities in terms of the occurrence of common species and also the changes in their quantity. The study revealed 535 species of cyanobacteria and algae belonging to five phylas. The comparison of the composition of phycoflora from the studied ecosystems from previous years with the current results provided a model study showing the direction and pace of changes in the composition of the flora of cyanobacteria and algae in a given time. The species composition of cyanobacteria and algae in each year is adequate to the trophy of the studied water bodies. The processes in transforming communities of cyanobacteria and algae have led to the stabilization of the current status of the reservoirs as eutrophic.