Mumbai’s Mangroves: Forests of Breathing Roots

My foot sinks a few centimetres into the mud. The low tide has left the ground wet and slippery, caking our shoes and the cuffs of our pants with sludge. The tiny mangrove forest in Sewri, a small green lung in the heart of an industrial part of Mumbai city, is several degrees cooler than the traffic-clogged roads that lead to it. All around us, pneumatophores, or ‘aerial roots’ stick out like small spikes. These roots grow above the surface of water, helping dense, submerged root networks breathe when the tide comes in.

Not all shores are the same. Some take the form of sandy beaches and others are dotted with rocky tidepools. And you can go walking on all of these. You glimpse mangroves while commuting across this city, silent patches wilting with debris near the ocean. Mangroves stand as sentries on the peripheries of water and land. They grow along our coastlines, fringing creeks, estuaries, bays and lagoons, and host a mesmerising biodiversity. But there isn’t yet a sufficient understanding of this incredible landscape. While tourism flourishes in the Sundarbans in West Bengal, one of the world’s largest and densest mangrove forests, city mangroves are still not as popular among citizens.

A pity, because the city’s coast has around 20 to 22 species of ‘true mangroves’ or species that thrive exclusively in intertidal environments. A mangrove forest depends heavily on a strong network of roots that hold the forest in place against the ebb and flow of the tide. These roots perform the additional function of hosting microorganisms that break down pollutants in the water. Fresh and saline waters coexist at different times in this soil, so species grow at varying distances from the water, based on their tolerance to salinity. For example, the common grey mangrove (Avicennia marina), stands closer to water and bears small clusters of white and yellow flowers, and fleshy greenish-yellow fruit. On the other hand, the meswak shrub (used in the production of toothpaste), is usually found on the edges, closer to land. These shrubs form a buffer between the flora and fauna of marine and terrestrial zones. Another interesting specimen is milky mangrove or the blind-your-eye mangrove — the bark contains latex that has medicinal uses, but stings badly if it gets in your eye.

Some of these species carry out their own filtration for salt from the soil, and use the distilled fresh water for survival. Mangrove seedlings fall off and are swept away by the tide, only to sink to the muddy bottom somewhere and grow into a new plant. These resilient trees find a way to act as a sponge for the city, increasingly at their own cost. Their aerial roots also invariably (and increasingly) collect garbage that gets entangled in the dense grid.

Numerous marine species thrive in its dense thickets. You will find flatworm, horn snails, telescopium, mud lobster, and fiddler crabs (see video above). Most of these animals play a role in breaking down organic matter and turning the soil. For example, the mounds you see on the soft floor are made by the nocturnal mud lobster. It brings all the nutrients to the surface with its digging. Mangrove systems provide food to 30 to 40 per cent of our coasts. Amphibians, reptiles, and birds form an important part of the food chain.

The term mangrove itself comes from the Senegalese word ‘mangue’, which means ‘into the sea’. In Maharashtra, this ever-shrinking zone acts as a buffer against floods, and protects the land from excessive soil erosion and over salinity. One of the oldest ecosystems, dating back 114 million years, mangrove forests absorb four to eight times the carbon dioxide from the atmosphere than any other kind of vegetation.

For cities, this job description should earn top billing, but mangroves are under threat from mindless reclamation. The floods that wrecked Mumbai’s suburbs in 2005, and killed over a 1,000 people, shone a spotlight on the rampant reclamation of mangrove land and the consequent pinching of the Mithi River’s mouth.Mumbai hosts 40 sq km of mangrove cover in all, which by estimated data, is 30 per cent of what it used to be in the last couple of decades. The city is attempting to fight for these magnificent plants. According to the Mangrove Society of India (MSI), the mangroves in Airoli and Vikhroli are counted among the 12 unique mangrove forests in the country.

Covering an area of 2,000 hectares, Vikhroli’s mangroves form one of the largest private mangrove forests in Maharashtra (managed by the Godrej Foundation since the 1940s). This is home to more than 16 mangrove species, 82 butterfly species, 208 bird species, 13 crab species, 7 prawn species, 20 fish species and several mammals.

The Godrej Foundation has launched a Mangroves App, a visual guide that helps enthusiasts identify different species of mangrove and learn the importance of the critical ecosystem.

The state-run Coastal and Marine Biodiversity Centre in Airoli organises different activities around mangrove ecosystems — including a flamingo-watching boat ride and mangrove trails The Airoli mangroves are spread over 1,690 hectares and visited by over 50,000 flamingos every year. The Mangrove Foundation, an arm of the government’s Mangrove Cell that works to protect these habitats, is dedicated to working with local communities to ensure an enduring public dialogue.

The more you learn about mangroves, the more they seem to be the strongest power in our collective arsenal. Their make-up allows them little rest in the service they inadvertently provide the coasts. And we know how relentless this city can be to all its inhabitants. The least we can do is go say hello, and ensure they remain as dense, numerous and garbage free as possible.

MANGROVE SAFARIS:

Airoli Mangrove Walk and Boat Ride
What: An introductory naturalist-led walk and boat ride that tells you about the mangrove species along our coasts and the biodiversity that lives in and around them.
The walk lasts around two hours
Cost: Rs 330 on weekdays/ Rs 440 on weekends
Contact: 99876 73737

Vikroli Mangrove Walk
What: A walk in the mangrove forest by a naturalist. It navigates local species and information about biodiversity. Pre-book a day in advance for a time slot. Walks are conducted for groups of minimum of 15 people. The walk lasts about two and a half hours.
Cost: Free
Call: 022 67961097
Email: mangroves@godrej.com