Climate Change causes dwindle in the number of migratory water birds

Noida: Asian waterbird census (AWC) 2023 at Dhanauri wetland has recorded decreased number of water birds and overall species diversity. Wetlands International’s largest annual waterbird census, the Asian Waterbird Census (AWC) 2023, is currently being carried out across Asia and Australasia from January 7 to 22, 2023. 

This is the fourth time that this census was carried out at the Dhanari Wetland in Greater Noida on January 18. The AWC Delhi State Coordinator and ecologist, T K Roy, along with active conservationist volunteers from Delhi, Noida, and Wetlands International South Asia, reported a decreased number of water birds and species diversity.

The usual decrease in the number of migratory water birds and species diversity is believed to be caused by global climate change, which has resulted in delayed winters, slow and lesser migration of long-distance winter migratory water birds to the wetlands from far Central Asia, North Asia, Russia, and Siberian part, as recorded almost everywhere in northern India.

The Dhanari wetland, which is spread over an area of 101.21 hectares, is a small wetland located in Greater Noida of Gautam Buddha Nagar District, Uttar Pradesh, surrounded by crop fields. It was once a good habitat for water birds and the especially large number of the Threatened & UP state bird - Sarus Crane and winter migratory water birds. However, the wetland’s existence depends on monsoon rainfall, and it dries up in summer and turns into a small pond as it does not have any independent water source.

Despite this, unexpected rainfall in October and November of 2022 did revive the wetland to some extent, and the adjacent dried marshland, which functions as an aquatic ecosystem, attracted a large number of Graylag Geese for feeding as flies here from other wetlands during the day time every day. 

However, the wetland surface was largely covered with water hyacinth, and the small middle part of the wetland surface is open after the water hyacinth was removed by the forest division, but large areas are still choked by water hyacinth. The periphery of the wetland turned into grassy marshland, and some areas were totally dried up, where cattle grazing. There is hardly much space in the wetland to accommodate more water birds, especially ducks and geese species.

The AWC is a citizen-science program that supports the conservation of wetlands and water birds, and it is an important tool of the Ministry of Environment, Forests and Climate Change's (MoEFCC), Govt of India “National Action Plan for conservation of Migratory Birds & their Habitats along the Central Asian Flyway”. The goal of this census is to provide a comprehensive assessment of the status and trends of waterbirds and their wetland habitats in Asia and Australasia, and to promote their conservation and wise use.

During this fourth AWC 2023 at Dhanauri wetland recorded a decreased number of overall water birds and species diversity in comparison to last year.

A total of 35 species diversity and a total number of water birds of 1,861 compared to last year's species diversity was 40 and a total of water birds 2,459. Out of  35 species 18 resident species and 17 migratory species, the least number includes 4 IUCN Red-listed Threatened species in comparison to last year out of a total of 40 species 20 resident and 20 migratory species including 5 species of threatened birds.

TK Roy, Ecologist, and Conservationist says “Until Dhanauri wetland is notified as a protected area under the Wildlife Protection Act, 1972 and Wetland (Conservation and Management) Rules, 2017 under the provisions of Environment (Protection) Act, 1986 and accordingly sustainable management, protection by the concerned forest/wildlife authority it'll be degrading & unsustainable habitat for the water & water dependant birds. Water birds are one of the indicators of wetlands' health and rich species diversity & number indicate the wetland'ss healthiness. The aim of the AWC is the conservation of the wetlands & water birds and to make people aware of the importance of the wetland & waterbirds for our survival.”

Apart from the global climate change impact the other prime reasons for decreased species diversity and the total number of water birds on the wetland:

• Wetland surface is largely covered by water hyacinth
• Periphery of the wetland dries & the wetland turns into a small grassy marshland
• Rest part of the marshland dried up and cattle grazing
• Human disturbance

Three years comparing AWC 2021-2023 Record: 

Among the major winter migratory species that migrated here from central, north Asia including Siberian Part recorded on the wetland:

Common Teal: migrates from north Asia
Northern Shoveler: migrates from north Asia
Northern Pintail: migrates from north Asia
Greylag Geese: migrates from Central Asia
Barheaded Geese: migrates from Central Asia
Gadwal: migrates from north Asia

Among the IUCN Red-listed Threatened Species recorded on the wetland:

Painted Stork: Indian resident species
Sarus Crane: Resident species
Black-headed Ibis: Indian resident species
Common Pochard: migrates from north Asia

The large number of migratory Graylag Geese (631)  mostly on the adjacent wetland and resident species Purple Swamphen (632) on Dhanaruri wetland was recorded this time as interesting species Mallard (5).