Population Trends and Spatiotemporal Changes to the Community Structure of Waterbirds in Birbhum District, West Bengal, India

摘要

Waterbird assemblages on five important wetlands of Birbhum district, West Bengal, were studied for 13 years to examine the changes in the community composition of the waterbirds and to quantify their population decline during the period between 1998 and 2010. The spatiotemporal analyses revealed that the waterbird communities of these wetlands maintained high spatial but low temporal variations in their structure. Such within-wetland homogeneity was attributed to a relatively static distribution of some key resources. The spatiotemporal variations in the abundance and community structure were associated with a shift in distribution of some important winter migrants from a disturbed and deteriorating wetland to a newly built well protected one. Twenty-one species of waterbirds acted as significant indicators in structuring the waterbird communities of these wetlands, revealing their species rich nature. However, comparisons between data collected for these wetlands in 1998 and 2010 showed that notable changes in these waterbird communities have occurred over longer periods of time, with 16 of the 25 most common and important species having declined in this period indicating an overall decline by 38%. These wetlands still regularly support globally important populations of four waterbird species.