The effect of different coverage of aquatic plants on the phytoplankton and zooplankton community structures: a study based on a shallow macrophytic lake

Understanding the effect of different coverage of aquatic plants on the characteristics of the phytoplankton community structure is beneficial for management of lakes and protection of the aquatic ecosystems. In the present study, the effect of aquatic plants coverage on plankton community structure in a shallow macrophytic lake located in the middle reaches of the Yangtze River was investigated by dividing the lake into low, median, and high coverage habitats. Furthermore, the characteristics of phytoplankton and zooplankton community structures, and physicochemical indexes of lake water in the three habitats were analyzed. The results showed that an increase in aquatic plant coverage effectively reduced total phosphorus and total nitrogen in water and reduce the risks posed by phytoplankton blooms. Phytoplankton populations fluctuated slightly, and cyanobacteria density decreased in the medium coverage habitat when compared to those in the low coverage habitat. The phytoplankton species and quantity increased, and the lake water stability was enhanced in low coverage habitat when compared to those in the high coverage habitat. Zooplankton density, biodiversity index, and Pielou's evenness index of the medium coverage habitat were higher than those of the low and high coverage habitats. Our results suggest that to improve the stability of shallow lake water environment, the coverage of aquatic plants should be maintained at 26.7-33.1% based on the physicochemical properties of water bodies and variations in phytoplankton community structure.