Delhi’s rich bird diversity highlights importance of small urban wetlands in Indian cities

A small body of water littered with city trash and sewage is animated by painted storks – large, bald birds with bright pink tails and long, downward-curving yellow beaks. Three individuals stand in the murky waters of the roughly 2.5-hectare Sardar Patel Lake, surrounded by a dense carpet of houses and roads, northwest of Delhi.

The National Capital Territory of Delhi is home to over 400 species of birds. According to a 2021 to studyOn birds wintering in Delhi’s ponds, the researchers recorded 37% of the city’s bird species in its ponds, which they defined as bodies of water smaller than five hectares.

Avocets wade through the waters of Accidental Pond, a waterlogged site next to a flyover construction project in Delhi. The unusual upward-curving bird travels from Central Asia and Europe to the Indian subcontinent.

Sheltered from morning walkers passing near a pond in a park, a greenish warbler twirls in the vegetation around the pond. The little migrant go down in Delhi during the winter, year after year.

Birds in urban water bodies are a common sight but are often overlooked.

Migratory avocet in a small Delhi wetland. The Nation’s Capital ponds are home to a variety of resident and migratory birds. Photo credit: Prakhar Rawal

Motivated by the lack of research on the ecology of urban ponds in India, Prakhar Rawal, the study’s lead author, decided to take a closer look. The capital’s wetlands are under threat due to encroachment, real estate activities, dumping of solid waste and untreated sewage.

“The first objective was to understand the potential of these sites as bird habitats in megacities like Delhi and to see what kind of bird diversity was being sustained at these sites,” Rawal said.

Of the total wetland area of ​​India, 15.26 million hectaresit is estimated that nearly 8% is likely to be located in urban sprawls. While 3.64% of the country’s wetlands are less than 2.25 hectares, the only National Wetlands Database designates them as dots on a map with no defined boundaries or shapes.

Since a detailed map of Delhi’s wetlands was not readily available to the authors, they analyzed Google Earth images taken over ten years to plot the city’s wetlands. Of the resulting 574 wetlands, they conducted surveys in 39 ponds of varying sizes up to 5 hectares.

“Even though the ponds made up 0.5% of Delhi’s land area, we ended up with more than 170 bird species estimated for Delhi’s ponds,” said KS Gopi Sundar, a scientist at the Nature Conservation Foundation and co – author of the study. “This constituted 37% of Delhi’s known bird diversity and one of the highest known diversities of any urban wetland system, let alone urban ponds.”

How Authorities and Communities Managed Delhi’s Ponds affecting the diversity and number of birds at each location. Sundar explained that the popular notion of “beautifying” a body of water by adding concrete to its periphery is bad for birds like sandpipers which need the natural muddy edge for food. Additionally, activities such as planting trees and manicured shrubbery, often not native to the region, attract birds that would not have been there naturally. “Almost 50% of the birds we found in the ponds were birds that used edge vegetation,” he said.

On the other hand, researchers found that artificial pond islands such as metal fountains also increased species diversity.

highway for the birds

Both waterfowl and landbirds cross international borders to arrive in the Indian subcontinent during winters. For some birds on this flight path, Delhi’s ponds are pit stops and refueling stations on their long journey. For others, the ponds are the destination.

During the study, Rawal’s favorite moment was recording migratory ducks such as shovelers and waders such as band-tailed godwits in an unnamed pond near an industrial area to the west. from Delhi. They would have flown along the Central Asian Flywayone of the world’s nine migratory routes for birds.

India plays a vital role in the Central Asian Flyway, which spans much of Eurasia between the Arctic and Indian Oceans. It provides critical stopovers, mainly wetlands, for more than 90% of bird species known to use this migratory route. Furthermore, a large majority of migratory waterbirds arriving in India use urban landscapes and other human-dominated landscapes. beyond national parks and shrines. Their annual range is increasingly hampered by habitat loss and degradation.

According to Sundar, nearly 30 to 40 percent of the birds observed during their study were migratory. “That’s a huge proportion and number of birds using ponds inside a city,” Sundar said. “We didn’t know before that urban ponds are also a very important place for so many migratory species. The Delhiites are therefore very lucky in the sense that this ancient phenomenon of migration is still happening around them.

Monica Kaushik, who has studied the role of urban green spaces for bird conservation in the Himalayan city of Dehradun, said: “It is important not to think of green spaces or urban biodiversity only in the local context. Kaushik, who was not associated with the Delhi pond study, said that with climate change leading to loss of habitats and affecting wildlife movement patterns, the disappearance of green and blue spaces could wipe out the migration links for birds.

During their study, Rawal and the team did not have historical bird checklists for the selected sites. Citizen science platforms that collect information from bird watchers have also revealed negligible data on the ponds. Kaushik, who participated in a pioneering effort to analyze citizen science data for the State of India’s Birds Report 2020, believes that sites far from roads and lesser-known areas often become a “black hole” in the data. If present, the information can help us better understand birds.

Kaushik, a visiting assistant professor at the School of Human Ecology at Delhi’s Ambedkar University, pointed to another reason for conserving nature in cities. “There is a permanent alienation from nature called ‘the extinction of experience’. We want younger generations to experience it [the natural world] first hand too.

The 39 ponds studied by the researchers had negligible historical data and observations recorded through citizen science platforms. Map by Technology for Wildlife

Smaller wetlands

In addition to harboring biodiversity, smaller wetlands can also recharge groundwater, control flooding and regulate local temperatures. Quite a concern in Delhi and Indian cities in general.

Ritesh Kumar, director of Wetlands International South Asia, explained that the term “small” could be misleading. “A half-acre wetland might have a low [groundwater] recharge value, but a system of 20 weird wetlands in a landscape would have a huge contribution to hydrology, ecology and everything.

While Delhi is known for deteriorating air quality, the NCR has also lost 38% of its wetlands to conversion by construction activities, encroachment and pollution between 1970 and 2014. Kumar said smaller wetlands appear to be the most vulnerable habitats in a growing city. Although blocking the water inlet or outlet and extracting excess groundwater are some ways to kill a wetland, the opportunities for rejuvenation are also the highest due to their size, he added.

In a first attempt at mapping Delhi’s wetlands, which began in 2020, the Delhi Wetland Authority listed and assigned unique identification numbers to 1,043 wetlands of all sizes. The aim is to officially notify bodies of water as wetlands, which provides legal protection under the Wetlands Protection Rules 2017 against encroachment, dumping of solid waste and other threats .

Delhi’s wetlands are under continuous pressure from encroachment, conversion by construction activities and dumping of solid waste. Photo credit: Prakhar Rawal

KS Jayachandran, Member Secretary, Delhi Wetlands Authority, said Mongabay-India, “Our goal is long-term conservation, and we prioritize notifying larger, higher-risk wetlands.” As of January 5, the authority had mapped 1,014 water bodies on a geographic information system platform and ten wetlands were being notified.

Delhi’s water bodies are owned by 16 different land agencies, creating a governance and conservation challenge. Jayachandran added that a guideline for local agencies to follow ecological methods of managing urban wetlands would soon be released.

After being notified, the authority will create an integrated management plan and apply for funds from the government for wetland restoration, including the removal of encroachments and invasive species.

Sundar and Kaushik echo the need to focus on and fund urban ecology studies to help inform policy and guide local authorities.

“It might not be possible for a city planner to create new green spaces, but it would certainly be possible for him to manage those existing green spaces or wetlands in a way that they could accommodate higher biodiversity,” Kaushik said.

This article first appeared on mongabay.

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