Diversity and assemblage of birds in tropical wetlands of Eastern Ghats, India: a call for conservation prioritisation

Abstract

Wetlands are one of the productive ecosystems and are important for water birds in terms of food, nesting and rearing of the young ones. We evaluated bird species richness and abundance in four tropical wetlands (two lentic and two lotic) from October 2016 to September 2017 located in the Central Asian Flyway in Koraput District in the southern part of Odisha state, Eastern Ghats, India. Using diurnal surveys and point count method in three seasons (pre-monsoon, monsoon, and winter), 40 species of aquatic birds with maximum waders belonging to seven orders and 15 families were recorded of which 28 and 12 species are resident and winter migrant birds respectively. Oriental Darter (Anhinga melanogaster) is considered Near Threatened as per IUCN Red list, while Anatidae and Ardeidae are the two most speciose (17.5% each) families recorded. Species richness and abundance of birds were significantly higher (p < 0.05) in the winter season with a large influx of migratory birds, mostly Anseriformes. The two lentic water bodies accounted for higher species richness compared to lotic ones, serving as good wintering grounds for the migrants. The satellite-derived images and their corresponding indices revealed seasonal change in water bodies and their surroundings for the pre- and post-rainy seasons indicating potential habitats for bird population. This study demonstrated the importance of seasonality on the bird assemblages for resting, feeding, and roosting, particularly for winter visitors in wetlands of the Indian Eastern Ghats. Situated along the Central Asian Flyway, these wetland habitats deserve conservation to serve as better functional ecosystems.