Study On The Changes Of Waterfowl Habitat In Dongting Lake Over Wintering Period Basing On 3S Technology

In order to study the changes of waterfowl habitat in past twenty years, the study was done based on 3S technology. The details of waterfowl habitat in East Dongting Lake, South Dongting Lake and West Dongting Lake were surveyed respectively. First of all, the main land use types were determined basing on the field investigation and the corresponding relationship between different land use types and remote sensing images were established. Land use types were carried out for different years in each region after remote sensing images were pretreated. At the same time, the waterfowl investigation was done, determining the demands of wintering waterfowl in Dongting Lake. According to the different requirements of different waterfowl habitat, evaluation system of different waterfowl habitat was established. Then waterfowl habitat evaluated was done for different in East Dongting Lake, South Dongting Lake and West Dongting and further changes were gotten for each region. Following conclusions are obtained and the main results are as follows:(1) Reed beach accounted for the largest proportion of land use types in eastern Dongting Lake for recent twenty years. Wintering waterfowl habitat was about 50% in East Dongting Lake. Retention rate of water and reed beach is higher than other land use type during the period of 1989 to 2013. Retention rate of woodland, only 2.34%, is lowest during the period. Waterfowl habitat suitability increased 19.1% and reduced 14.7% of East Dongting Lake. Wintering waterfowl habitat protection achieved good results in eastern Dongting Lake.(2) In the past 20 years, water accounted about 22% in south Dongting Lake. Marsh fluctuated and declined during the period. Retention rate of water and reed beach was higher during 1989 to 2013. Proportion of water, mudflats and marsh land changing into reed beach was 9.3%,63.1% and 45.5% respectively.(3) Proportion of mudflats and water fluctuated in recent nearly twenty years in weatern Dongting Lake. Water reached the maximum in 2002, while mudflats reached the minimum proportion in the year. Marsh was stable at around 15%. Water and reed beach kept the high retention rate in western Dongting Lake.(4) Landscape advantage degree of waterfowl habitat was creasing in recent two decades of Dongting Lake, while patch diversity reduced. Landscape pattern of waterfowl tended to be stable in Dongting Lake.(5) In recent twenty years, the eastern Dongting Lake and the southern Dongting Lake was the same, which increased at first and then decreased. Change trend of wintering waterfowl habitat in western Dongting Lake has been reduced.Research is useful for understanding winter waterfowl habitat changes of Dongting Lake and exploring the change of wetland resources. It can also help to analysis driving factors of wetland change. Study plays an important role in wintering waterfowl protection and wetland management.