Spatial and temporal patterns of shorebird assemblages in select estuaries along the India’s west coast

Abstract

The Indian coast and its adjacent wetlands host large congregations of shorebirds, including winter and passage migrants of high conservation priority, along the Central Asian Flyway. Identifying crucial wintering and stopover sites and seasons is an important step toward conserving shorebirds and their habitats along the Indian coast. We assessed spatial and temporal patterns of shorebird composition from January 2015 to December 2016 at seven estuaries along Maharashtra's Sindhudurg district, which is located on India's west coast, a coastal zone of international importance for shorebirds. Three potential shorebird habitats –mangroves, mudflats, and sandy beaches – were selected at each of the estuaries chosen for the study. We established three vantage points, one each in the mangrove, mudflat, and sandy beach areas, to count birds during low tide. The total count method was followed to count birds, and occasional photograph-based counts were also made when flock size was big or the flocks kept changing. We recorded 31 species of migratory shorebirds, of which 68% wintered and 32% used the Sindhudurg coast as migratory stopover site. We found significantly high richness and abundance of shorebirds during winter and in the mudflats. nMDS was used to determine species composition of shorebird across habitats and months and revealed distinct patterns of composition in five unique phases: arrival, wintering, early departure, departure, and breeding. Our results revealed that the species composition of shorebirds is not homogenous across sites and months, and is largely driven by the habitat heterogeneity of estuaries, seasonality, and anthropogenic disturbances. These results provide baseline information on shorebirds along a stretch of India's west coast and highlight the importance of mudflats and non-protected coastal wetlands for shorebirds.