Chinanews.com, Nanchang, August 3 (Wu Pengquan) "From the perspective of this summer's historic high water level, the ecosystem of Poyang Lake wetland will face severe disturbances from floods in the short term." Poyang Lake National Nature Reserve, Jiangxi Province Xu Zhiwen, director of the District Administration Bureau, made a presentation at the press conference of Jiangxi Provincial Flood Control and Drought Relief Headquarters on the 3rd.

　　Since the beginning of July, due to the combined effects of heavy rainfall and the inflow of water from the upper reaches of the Yangtze River, a super-historical flood in the Poyang Lake Basin has occurred in Jiangxi, a province in the middle and lower reaches of the Yangtze River. The Poyang Lake National Nature Reserve was severely affected, and all its 9 sub-lakes and Caozhou were flooded.

A flock of migratory birds is flying in the waters of Maying Lake in Duchang, Poyang Lake, Jiangxi. (Data map) Photo by Fu Jianbin

　　What is the impact of Poyang Lake's high water level on wetlands and wintering migratory birds? Xu Zhiwen believes that the Poyang Lake wetland is a dynamically changing ecosystem, and the impact of water level changes on the wetland system and wintering migratory birds is a complex and comprehensive impact, with both immediate short-term severe disturbances and delayed long-term continuous indirect effects.

　　Specifically, the duration of the high water level, the precipitation in the second half of the year, and the length of the winter ice and snow period will all have an impact on the Poyang Lake wetland ecosystem, which is mainly reflected in the impact of different water levels and climate changes on the growth of different aquatic plants. The impact is significantly different.

October and November will be the time when the summer and winter migratory birds in Poyang Lake will be "changed". (Data Map) Photo by Lei Xiaoyong

　　Xu Zhiwen said that the resuspension of sediments and the input of external nutrients caused by flooding will cause major changes in the nutrient content and transparency of the water body. Decreased water transparency will have a direct impact on the photosynthesis of submerged plants, especially aquatic plants that multiply by tubers and roots. This may lead to white cranes and cygnets that mainly feed on tubers such as bitter grass and winter buds. When the foraging range of overwintering migratory birds expands, a scattered habitat will appear in Poyang Lake. "For birds that feed on moss, fish, benthic animals, etc., the impact may be small."

　　The flood situation in Poyang Lake area this year is severe, and the growth of food that overwintering migratory birds depend on has been greatly affected. In response, the Jiangxi Forestry Department will take five measures, including appropriate artificial feeding when food is in short supply for migratory birds, to ensure the safe overwintering of migratory birds in Poyang Lake.

　　It is worth noting that every migratory bird migration season is a period of frequent epidemics. This year, Poyang Lake was hit by extreme floods, and the protection of overwintering migratory birds is facing tremendous pressure.

　　According to Shen Caizhou, director of the Disaster Prevention and Control Division of the Jiangxi Forestry Bureau, in order to monitor and control the foci and disease of migratory birds in Poyang Lake, Jiangxi has established a three-level prevention and control system at the provincial, municipal and county levels in the Poyang Lake District to ensure that migratory birds are protected from flying and flying. Epidemic monitoring and prevention; strengthen information exchanges among member units of the "East Asia and Australia Fly Zone", grasp migratory bird migration and epidemic dynamics, strictly prevent possible epidemic hazards, and formulate emergency plans to respond to emergencies.

　　Poyang Lake, located in the north of Jiangxi Province and on the south bank of the middle and lower reaches of the Yangtze River, is the largest freshwater lake in China and an internationally important wetland, as well as one of the largest bird sanctuaries in the world.

　　The reporter learned that in view of the fact that the water level at Hukou Station in Jiangxi has receded below 21 meters, and the water levels of the Yangtze River and Poyang Lake have shown a downward trend. In accordance with the "Emergency Plan for Flood Control and Drought Relief in Jiangxi Province", the Jiangxi Provincial Anti-Drought Relief Plan has decided to adjust the flood control emergency response from Level II to Level III starting at 20:00 on August 2. (Finish)