Changes in the areas and quality of wetland habitat makes it imperative to monitor trends in the number of wintering waterbirds and their distribution in the Yangtze River floodplain, the most important waterbird regi...Changes in the areas and quality of wetland habitat makes it imperative to monitor trends in the number of wintering waterbirds and their distribution in the Yangtze River floodplain, the most important waterbird region in eastern China, so that effective science-based action can be taken to ensure the survival and future recovery of the waterbirds of the region. However, obtaining accurate data on the number of waterbirds and distribution, which can be confidently compared across years and sites, is complicated by a number of factors which can affect count quality. It is essential to employ a survey methodology which maximizes count accuracy and precision and minimizes the bias inherent in counting waterbirds;failure to achieve these goals will lead to incorrect results and analytical problems. Recently we developed a systematic waterbird survey methodology which was tested, with promising results, in the winters of 2008/2009 and 2009/2010 at Shengjin Lake, an important wetland in the Yangtze River floodplain. The methodology involves dividing the lake into discrete survey areas, each containing a number of subareas, with clear boundaries, which were surveyed separately. Data, which included information on counts, distributions, the environment and disturbance, were collected in a standardized manner to maximize precision and minimize bias. We use the results from the surveys of the first two winters to provide examples of how the data can be employed to provide detailed information on the number of waterbirds, their distributions and habitat usage. Finally, we discuss the importance of wider application of the methodology throughout the Yangtze River floodplain to underpin a much needed floodplain-wide waterbird monitoring program.展开更多
We studied the waterbird population at Lashihai Lake, Yunnan Province, China, which is a Ramsar Site(Wetland of International Importance), to determine seasonal variation in the species composition and size of the wat...We studied the waterbird population at Lashihai Lake, Yunnan Province, China, which is a Ramsar Site(Wetland of International Importance), to determine seasonal variation in the species composition and size of the waterbird population. The study was conducted at five selected spots along Lashihai Lake at the same time each week from August 2011 to September 2013. In total, 62 waterbird species were recorded, of which 38.71%, 35.48%, 16.13%, and 9.68% were winter migrants, passage visitors, residents, and summer migrants, respectively. We found important seasonal changes in waterbird species composition and population size. Waterbird species richness was highest from September to the following April, with the total species numbers peaking in December. Total individual numbers peaked twice from late November to early December and mid-to-late February. However, waterbird species and individual numbers were comparatively lower from May to August. The change in species composition was determined by the arrival and departure dynamics of winter migrants and passage visitors. Winter migrants primarily caused the periodic changes in population size. Of concern,species and overall waterbird numbers seemed to be lower than the numbers in historical records. The decline of waterbird numbers implies that environmental changes caused by the implementation of the dam upstream of Lashihai Lake may have had adverse effects on this waterbird population. This study confirms the existence of major seasonal changes in species composition and size of the waterbird population at Lashihai Lake. Furthermore, the findings demonstrate that this wetland is of high conservation importance for waterbirds using the Central Asian–Indian and Asian–Pacific migratory routes.展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos.31071941 and 30940010)the Chinese Academy of Sciences Innovation Project (Grant No.KZCX2-YW-QN503)the University of Science and Technology of China Graduate School Educational Innovation Base
文摘Changes in the areas and quality of wetland habitat makes it imperative to monitor trends in the number of wintering waterbirds and their distribution in the Yangtze River floodplain, the most important waterbird region in eastern China, so that effective science-based action can be taken to ensure the survival and future recovery of the waterbirds of the region. However, obtaining accurate data on the number of waterbirds and distribution, which can be confidently compared across years and sites, is complicated by a number of factors which can affect count quality. It is essential to employ a survey methodology which maximizes count accuracy and precision and minimizes the bias inherent in counting waterbirds;failure to achieve these goals will lead to incorrect results and analytical problems. Recently we developed a systematic waterbird survey methodology which was tested, with promising results, in the winters of 2008/2009 and 2009/2010 at Shengjin Lake, an important wetland in the Yangtze River floodplain. The methodology involves dividing the lake into discrete survey areas, each containing a number of subareas, with clear boundaries, which were surveyed separately. Data, which included information on counts, distributions, the environment and disturbance, were collected in a standardized manner to maximize precision and minimize bias. We use the results from the surveys of the first two winters to provide examples of how the data can be employed to provide detailed information on the number of waterbirds, their distributions and habitat usage. Finally, we discuss the importance of wider application of the methodology throughout the Yangtze River floodplain to underpin a much needed floodplain-wide waterbird monitoring program.
基金funded by the“Technology Supporting Programme” of the “State Wetland Conservation Project for Lashihai Wetland”
文摘We studied the waterbird population at Lashihai Lake, Yunnan Province, China, which is a Ramsar Site(Wetland of International Importance), to determine seasonal variation in the species composition and size of the waterbird population. The study was conducted at five selected spots along Lashihai Lake at the same time each week from August 2011 to September 2013. In total, 62 waterbird species were recorded, of which 38.71%, 35.48%, 16.13%, and 9.68% were winter migrants, passage visitors, residents, and summer migrants, respectively. We found important seasonal changes in waterbird species composition and population size. Waterbird species richness was highest from September to the following April, with the total species numbers peaking in December. Total individual numbers peaked twice from late November to early December and mid-to-late February. However, waterbird species and individual numbers were comparatively lower from May to August. The change in species composition was determined by the arrival and departure dynamics of winter migrants and passage visitors. Winter migrants primarily caused the periodic changes in population size. Of concern,species and overall waterbird numbers seemed to be lower than the numbers in historical records. The decline of waterbird numbers implies that environmental changes caused by the implementation of the dam upstream of Lashihai Lake may have had adverse effects on this waterbird population. This study confirms the existence of major seasonal changes in species composition and size of the waterbird population at Lashihai Lake. Furthermore, the findings demonstrate that this wetland is of high conservation importance for waterbirds using the Central Asian–Indian and Asian–Pacific migratory routes.
