Competitive Interaction Effects of Hydrilla verticillata and Vallisneria natans on Phosphorus Concentrations in Water

In the present study, the effects of competitive interactions of submersed plants with different life forms were investigated on phosphorus concentrations in water. Hydrilla verticillata and Vallisneria natans were planted either as single-species monocultures or in a mixed-species pattern. Phosphorus concentrations were lower in the mixed culture of H. verticillata and V. natans than in either monospecific culture. Total phosphorus (TP) concentration, on average, was 0.12 mg l-1 in the mixture and 0.17 mg l-1 and 0.16 mg l-1 for the V. natans and H. verticillata monocultures, respectively. However, no significant differences were found for total soluble phosphorus (TSP) or soluble reactive phosphorus (SRP) concentrations (p>0.05). Thus, competitive interactions between submersed plants of H. verticillata and V. natans can decrease the total phosphorus concentration in water, but do not change the concentration of TSP and SRP.