The Stratiotes aloides L. stand as a habitat in oxbow lake Bużysko

The impact of Stratiotes aloides L. (water soldier) on the accumulation and concentration of nitrogen and phosphorus, seston concentrations and provision a habitat for planktonic crustaceans was studied in a Polish oxbow lake during 2002–2004. The Stratiotes stand and the open water differed in the concentrations of mineral nitrogen and chlorophyll a. Stratiotes accumulated significantly more nitrogen in spring. The lower TN:TP ratio, concentrations of mineral nitrogen and chlorophyll a in stands of the water soldier may suggest nitrogen limitation in the littoral of the oxbow lake. The decrease of phytoplankton biomass in the Stratiotes stands may also result from shading and/or allelopathy. The plants did not reduce seston concentrations in the littoral but did affect the abundance and diversity of planktonic and bentho-planktonic crustaceans and probably provided a daytime refuge for Ceriodaphnia and older stages of Cyclopoida but not for Daphnia.