Changes in macrophyte communities in Lake Swarzędzkie after the first year of restoration

Abstract

Lake Swarzędzkie, near Poznań, was a hypertrophic lake because of its high nutrient content, cyanobacteria blooms, and disruptive recreational use, especially swimming, which was popular there. This is why protection measures have been in place since 1991, and a restoration program has been ongoing since fall 2011. The evaluation of the presence and distribution of macrophytes as an important element of lake ecosystem was conducted in August 2012. Nine plant communities were observed: Phragmitetum communis; Typhetum angustifoliae; Nupharo-Nymphaeetum albae; Hydrocharitetum morsus-ranae; Thelypteridi-Phragmitetum; Cicuto-Caricetum pseudocyperi; Acoretum calami; Ceratophylletum demersi; Potametum lucentis. The first three were dominating associations. The presence of submerged vegetation appears to verify the positive impact of the applied conservation and restoration measures. Improvement is confirmed by the significant decrease in concentrations of chlorophyll-a and total nitrogen, as well as the gradual decrease in total suspended solids and increased transparency.