HISTORICAL INFORMATION ON AQUATIC VEGETATION REVEALED BY SEDIMENTARY DIATOMS: A CASE STUDY ON LIANGZI LAKE

Aquatic vegetation is one of the most important ecological characteristics of shallow lake ecosystems. Understanding its evolution is crucial for lake ecological restoration. In this study, Liangzi Lake, a representative lake from the Yangtze floodplain, was chosen because of the high abundance of aquatic vegetation. To reconstruct the historical evolution of aquatic vegetation, a sediment core from its deepest area was analyzed with radiometric dating (210Pb/137Cs) and sedimentary diatoms. The reconstructed aquatic vegetation information by sedimentary diatom records reflected the succession of aquatic vegetation in historical period in comparison with the monitoring aquatic vegetation records since 1950s. We also reconstructed the coverage of aquatic vegetation over the past 200 years for Liangzi Lake. Based on the data from reconstructed historical aquatic vegetation information and the historical environmental data from its catchment, this study revealed that flood was one of the main factors affecting aquatic vegetation development in Liangzi Lake. This study demonstrated that diatoms can be used for the reconstruction of the amount of historical aquatic vegetation in such shallow lakes, which can provide the scientific basis for the aquatic vegetation protection and important guidance of the lake for the ecological restoration.