The reason why the water surface of Poyang Lake shows the scene change of "a line in winter and a large area in summer" is because there is a linear depression at the bottom of the lake, and the water level changes obviously with the seasons.

The water level of Poyang Lake changes greatly in flood season and dry season every year. From June 5438 to March of the following year, the water fell on the beach, rich in fish, shrimp, snails, mussels and various aquatic plants. It is a paradise for migratory birds to live in winter. There are about 148 species of birds, including 69 species of waterfowl and 20 species of national key protected birds, mainly including endangered species such as white crane, white stork, bustard, pelican and white spoonbill.

Since the establishment of the nature reserve, the research on bird rings, ecological observation, breeding and domestication has been carried out, precious birds have been protected and managed, and the number of various migratory birds has increased significantly. Every winter and spring, swarms of migratory birds fly in, and the spectacular sight attracts the attention of international organizations such as the International Crane Foundation.

Extended data:

The main aquatic plants in Poyang Lake are Sophora alopecuroides, POTAMOGETON POTAMOGETON, green algae and cyanobacteria, with only a small area of reeds. The vegetation in the nearby mountains and hills is the natural secondary forest of evergreen broad-leaved forest, mainly including Castanopsis eyrei, Castanopsis eyrei, Castanopsis eyrei, Cyclobalanopsis glauca, Schima superba and so on.

In addition, there are mixed forests of Chinese fir and bamboo; Mixed forest of Chinese fir, Pinus massoniana and broad-leaved trees; Evergreen deciduous broad-leaved mixed forest and deciduous broad-leaved forest. Plantations are mostly economic forest species such as Chinese fir and Pinus massoniana.