Anseriformes As A Main Focus,Studying The Threats Migration Waterfowl Facing Along The East Asian-Australasian Flyway

East Asian-Australasian Flyway(EAAF),one of the eight migration flyways in the world,supports high waterbird diversity waterbirds.However,this flyway is severely threatened and research and conservation effort on this flyway is largely lacking.In this thesis,investigated and summarized population trends of migratory waterbirds along this flyway and identify the major threats driving the population decline.The results of the thesis are:1.Status of migration waterbirdsin EAAF and major threats to waterbirds:EAAF supports 43%of waterbird species and 27%populations in the world.Population trends of over 50%EAAF waterbird populationsare unknown.Migratory waterbirds are the more threatened than residentiary ones.38%of populations of the Anseriformes and Charadriiformes are declining.Pollution,natural system modifications and biological resource use are the most serious threats in EAAF and affect over 54%of migratory waterbirds.2.The location of China is very important for EAAF waterbirds:As a vital wintering area,breeding area or important staging site,China is very important to waterbirds.93%EAAF migratory waterbirds species and 85%populations are distribute in China,among which 85%of the species and 87%of the populationsare globally threatened.Pollution and natural system modifications affect 84%-90%of migratory waterbirds in China.Biological resource use,human intrusions and disturbance,invasive species also affect over 60%of migratory waterbirds in China.3.Factors affect the habitat selection of Anseriformes in the Yangtze River floodplain:The result shows that the lake area,average water level,absolute amplitude of water level between years,transparency of lake water,average annual temperature,precipitation and the conservation status of the lake affect the habitat choice of geese and ducks.4.Change in distribution and abundance of geese and ducks in the Yangtze River floodplain:We compared recentsurvey data in Poyang,East Dongting and Anhui lakes with historical records between 2004 and 2014,to identify population trends of geese and ducks.Specifically,we tracked changes in distribution and abundance of the Bean Goose in the Yangtze River floodplain.The waterbird abundance in Poyang Lake changed between the two years but showed no significant trend,while in East Dongting and Anhui lakes it was decreasing.The total number of Bean Geese was stable in the Yangtze River floodplain but changes occurred among lakes between years and seasons.Waterbirds in Poyang Lake varied between years,which were potentially caused by drought.It was reported that the intensive sand mining resulting in a wider and deeper outflow channel was the main reason for the drought.Furthermore,the ThreeGorges Dam advanced water level recession for up to one month,which exacerbated the drought in Poyang Lake.This hydrological change caused by Three Gorges Dam is likely to be the main reason for the waterbird decline in East Dongting Lake.The decrease of waterbird abundance in Anhui lakes mainly was caused by aquaculture.