GIS Based Approach to Determine the Changes of Water Hyacinth (Eichhornia crassipes) Cover and Relation with Lesser Whistling Teal (Dendrocygna javanica) Assemblage at Santragachi Wetland, West Bengal

Abstract

The present investigation is conducted to study the year wise (2011 to 2018) changes of water hyacinth (Eichhornia crassipes) cover at Santragachi Lake a Wetland under National Wetland Conservation Programme of India. Further the relationship between water hyacinth cover and the most abundant migratory waterbirds of Satragachi, Lesser Whistling Teal (LWT; Dendrocygna javanica) is assessed because this bird species is fully depended on water hyacinth mat for their roosting. The study comprises of eight satellite images procured from Google earth (2011 to 2018) to explore this relationship. A marked decline in the number of LWT at Santragachi wetland is observed in the year of 2017 and 2018. It is very interesting fact that from 2017-2018, the water hyacinth mat of this wetland is almost cleared before winter and the result of cluster analysis supports this fact. Significant positive correlation is also observed within LWT number and water hyacinth cover area (r = 0.7481 at p< 0.05) along with the total perimeter (r = 0.8648 at p< 0.05) of the water hyacinth islands at Santragachi wetland. However, open water area is also needed for diving, swimming, food searching for the LWT and other waterbirds. Therefore, more study is needed to optimize the clearing operations, focused on optimizing the shape and size of water hyacinth islands for proper management of the waterbirds habitat.