Habitat selection of wintering cranes (Gruidae) in typical lake wetland in the lower reaches of the Yangtze River, China

Shengjin Lake is a typical lake wetland in the lower reaches of the Yangtze River. It is one of the most important wetlands in the world. It is also an important habitat for wintering cranes in China. Environmental factors play an important role in habitat selection of cranes of wetland ecosystem. In this paper, we analyzed land-use types and the four kinds of winter cranes in the Shengjin Lake from the years 1986 to 2015. Also, we adopted grey relational analysis and power function model to analyze the relevance between crane population and land-use types, and the main habitat types of cranes were obtained. We used principal component analysis method to analyze the main influence factor for habitat selection of crane. The results indicated that the main habitat type of four species of overwintering crane was reed-flat; the main factors affecting the habitat selection of cranes were water level, planktonic biomass, and distance to settlement. Among them, the weight of water level factor was the highest, which showed that water level was the most important factor affecting the habitat selection of cranes, followed by planktonic biomass, and the third was the weight of distance to settlement. The average values of them were 0.37 m, 9.47 mg L−1, and 1.25 km, respectively.