Environmental evolution of Lake Liangzi and its driving factors over the past 100 years, Hubei Province

Abstract

The restoration of lake ecosystems requires a good knowledge on the history in the lakes and the driving mechanism of environmental changes. Aimed at current situation of limited study on past environmental changes of macrophyte-dominated lake, Lake Liangzi, located in the middle reach of the Yangtze River, was selected for historical environment study. High-resolution multi-proxy (i.e. diatom, geochemistry and grain size), 210Pb/137Cs dating of a sediment core collected from this lake and documentary data(i.e. population and air temperature) were analyzed to investigate environmental changes during the past one-hundred years. Furthermore, effects of key driver on the evolution of ecological environment were estimated quantitatively using the redundancy analysis. Results showed that total phosphorus and heavy metal element Cu from the sediments were two significant variables, explaining solely 12.7% and 8.5% of the variances in diatom data, respectively. Therefore, anthropogenic nutrient input was the most important factor on the environmental evolution of Lake Liangzi. Meanwhile, heavy metal pollution also imposed an important effect on this lake. The results of this study can provide a baseline of scientific information for environment restoration in the present lake and other similar lakes in the Yangtze floodplain.