Correlation Research Between Overwintering Migratory Birds And Environmental Factors In East Dongting Lake

Wetlands are important habitats for wintering migratory birds and have crucial effect to survival of wintering migratory birds.Wetlands provide a lot of food and appropriate habitats,and wetland birds play a great role in promoting energy flow of wetland ecosystems and maintaining stabilization of wetland ecosystems.Community structure,quantity and abundance of wetland birds are important evaluation indicators for wetland quality,and play an important role in wetland conservation.In recent years,owing to human disturbance and natural climate change,kind and quantity of wetland birds in the world show a declining tendency.Decrease of wetland area and destruction of wetland habitat function pose a serious threat to survival of wetland birds.Therefore,protecting ecological functions in wetlands and maintaining normal survival of wetland birds are important issues in wetland ecology.Numerous environmental factors in wetands have a significant impact on normal survival of birds and the study of environmental factors in wetlands is the key of bird conservation.In this paper,firstly,regularities about distribution of different zones in East Dongting Lake wetland and its causes were studied.The results show that the distribution of arbor area,sedge area and reed area has great relationship with water level.The ability to bear water stress of aspen-based arbor is the weakest,so that arbor area distributes on high elevation area in East Dongting Lake;among the three,the ability to bear water stress of reed is medium and that of sedge is the strongest,so that compared to reed area,sedge area is closer to water area.Secondly,change of quantity and diversity of migratory birds were studied.Drought,cryoconite cover,rat disaster,closed fishing,putting many fries into the lake and other factors all influence quantity and diversity of migratory birds.In this paper,the correlation among migratory birds with different feeding habits during winter in East Dongting Lake and 5 kinds of environmental factors,the correlation among 5 kinds of migratory birds with different feeding habits and the correlation between NDVI and water level in 7 sampling points were studied.The results show that in other 6 sampling points except Caisang Lake,NDVI(Normalized Difference Vegetation Index)is positively correlated with water level;other 4 kinds of environmental factors except air temperature is positively correlated with Shannon-Wiener index of migratory birds;water level is positively correlated wit h total quantity of migratory birds and quantity of 5 kinds of migratory birds with different feeding habits;the correlation coefficient among migratory birds with different feeding habits is all positive.Finally,in this paper,RDA(Redundancy Analysis)were used to study the correlation among wintering birds in East Dongting Lake wetland and 5 kinds of environmental factors,the correlation among migratory birds with different feeding habits and the correlation among environmental factors.The results show that the correlation coefficient among 5 kinds of migratory birds with different feeding habits is positive;migratory birds feeding on sedge have strong and positive correlation with migratory birds feeding on seeds;migratory birds feeding on fishes have strong and positive correlation with migratory birds feeding on tubers;NDVI and water level have positive correlation with total quantity of migratory birds,and air temperature,air pressure and sunshine duration have negative correlation with total quantity of migratory birds;NDVI and water level have relatively strong and positive correlation with migratory birds feeding on fishes,migratory birds feeding on tubers and migratory birds feeding on invertebrates;sunshine duration has strong and negative correlation with migratory birds feeding on seeds and migratory birds feeding on sedge;sunshine duration has positive correlation with air temperature,air pressure and NDVI,and has weak and negative correlation with water level;the correlation among air temperature,air pressure,NDVI and water level is positive.In this paper,three aspects of conservation measures including source conservation for rare migratory birds,migratory bird conservation on migratory pathways and migratory bird conservation on wintering habitats were proposed.Thereinto,migratory bird conservation on wintering habitats includes sand excavation roundly prohibited,poaching prohibited,short-term closed fishing and putting fish fries in lake,planting poplars prohibited,throwing food artificially in wintering period,reducing the quantity of shipping lanes,using artificial rainfall to reduce the impact of drought,planting artificially wetland vegetation and controlling water level using pivotal project.The results from this research can provide theoretical basis for wetland conservation and wetland bird preservation in East Dongting Lake and measures proposed from this research could provide references for wetland migratory bird conservation in East Dongting Lake wetland.