Migratory Waterbirds in Asan Wetland, Uttarakhand, India: Ecology and Conservation Status of a Ramsar Site

Abstract

The Asan Conservation Reserve, a human-engineered freshwater wetland located in the Shivalik foothills of Uttarakhand, India, has been designated as a Ramsar site since 2020 and serves as an important habitat within the Central Asian Flyway (CAF). The wetland supports over 330 avian species, including globally threatened taxa such as Aythya baeri, Aquila nipalensis, and Haliaeetus leucoryphus, highlighting its international conservation significance. This review synthesizes existing literature and recent datasets to evaluate avian diversity, migration dynamics, and ecological processes at the site. Standardized observations from the Asian Waterbird Census indicate that 5,806 individuals across 126 species were recorded in January 2026, confirming the wetland’s continued importance as a wintering ground for migratory waterbirds. Analysis of recent studies (2023–2025) suggests that waterbird distribution and abundance are closely associated with key environmental variables, including water level fluctuations, nutrient availability, and habitat heterogeneity. However, increasing anthropogenic pressures, such as unregulated tourism, habitat disturbance, and the spread of invasive macrophytes, are altering habitat structure and influencing species composition. Despite improvements in monitoring following Ramsar designation, a gap persists between data generation and effective ecological management. The findings emphasize the need for integrated, science-based conservation strategies that incorporate hydrological regulation, habitat restoration, and long-term ecological monitoring. Strengthening such approaches is essential to maintaining the ecological integrity and functional sustainability of this globally significant wetland within the Central Asian Flyway.