Shandong Jining Nansi Lake is the sixth-largest freshwater lake in China and the largest in northern China. The water body, comprising Weishan, Nanyang, Dushan and Zhaoyang lakes, is a unique natural environment with rich biological resources, which has developed into a well-preserved and structurally complete macrophytic wetland ecosystem, the largest north of the Huaihe River. With its rivers and vast expanse of open water and extensive marshes, the Site supports a large variety of flora and fauna. There are 656 species of vascular plants, 148 aquatic plants, 248 planktonic animals, 79 benthic animals, 46 fish, six amphibians, seven reptiles, 205 birds and 11 mammals. It also serves as a wintering and resting site for a variety of migratory birds. Some of these are globally threatened such as the critically endangered Baer’s pochard (Aythya baeri) and Siberian crane (Grus leucogeranus); others are vulnerable such as the swan goose (Anser cygnoides) and white-naped crane (Grus vipio). The Site is also an important water diversion area and transfer channel of the South-North Water Transfer Project (Eastern Route), playing a key role in regulating the runoff and water quality.