In concrete jungle, nature scripts a survival story

MUMBAI: For 18 months, a team of researchers led by wildlife experts Sunjoy Monga and Sunetro Ghosal spanned out across the Mumbai region surveying and sampling hundreds of sites for creatures great and small. The result of that study, commissioned by the MMRDA’s Environment Improvement Society, is one of the most comprehensive inventories of the region’s natural riches. The study is now available to the public.
Mumbai is naturally blessed: For an urban agglomeration of over 18 million, — likely more than any other Indian metro. The region is “gifted”, says Monga, in being located at the crossroads of two major biogeographical zones — the Western ghats and the Malabar coastal zone — and fertilized by the monsoon. Yet three of the largest freshwater bodies in the region are man-made: Tulsi, Vihar and Powai lakes were formed by municipal water schemes after the mid-1800s. The regional habitat ranges from forests and coast to freshwater wetlands and urban parks.

Even in cities, nature finds a way: Urban growth can provide ecological niches. While larger mammals like the Indian fox and nilgai seem to have vanished in the region, a couple of smaller ones have adjusted. Some examples of adaptation are appallingly obvious: The leopard hunts for dogs near garbage dumps; rodents are flourishing and so are crows and pigeons. But cattle egrets are also on the rise, the Indian jackal and jungle cat now frequent the mangrove patches of Uran and Vasai-Virar and some bat species have benefited from fruit trees introduced by humans. Fifteen species of snakes have been observed in and around human settlements. Some waders and storks have taken to polluted wetlands.

Protected pockets matter: The island city and suburbs are most built-up yet seem to record high biodiversity, largely because of the Sanjay Gandhi National Park and, to a lesser extent, Aarey Colony, both of which still have abundant diversity including mammals. Coastal regulations have also helped preserve some of the region’s mangroves, another rich habitat.

Much is under threat: Abundance and adaptation can’t take away from the fact that many habitats, including the most bio-diverse forests, are shrinking or degraded. The worst hit are open landscapes with grass and scrub which, together with cultivated land, was once perhaps the most widespread habitat. Some 80% of grass and scrub is thought to have disappeared, especially in Thane and Raigad, where development has intensified in past decades. With the grasslands have gone the larks. Raigad district, including the area around Navi Mumbai up to Alibaug, has some of the healthiest habitats but is under greatest threat from urban projects.

Alien invasion is a worry: Foreign flora is common across the region. While thousands of old-growth native trees have been lost to development, they tend to be replaced, if ever, with ornamental exotics or fast-growing species that don’t attract birds or butterflies as well. At least 25 species of freshwater fish have been introduced purposely or accidentally for ornamental fishery, aquaculture or game-fishing, some as far back as the 1930s.

Powai lake has become a dumping ground for fish, including alien invasives like carp, tilapia and the red piranha, the report says. Exotic species can be strong colonizers and negatively affect native fauna. “Nature’s opportunistic,” says Monga, “but it comes with a cost.”

A guide for planning? Ecological wealth often mirrors economic. Prosperous neighbourhoods are often more leafy and biodiverse than areas that are home to slums, with an average 47 bird species in the former compared to 12 in shanty towns.

Biodiversity reflects what is right and wrong in the city, says Monga.

It is unclear how much this study will influence future development, but the findings make a compelling case for retaining ecological wealth in planning floral diversity for the city, keeping protected areas, and integrating nature in recreation.

“We need to inculcate and integrate an ecological sensibility in planning and development,” says Monga.