CHENNAI: Protecting coastlines from storm damage, tsunami devastation and coastal erosion, acting as nurseries for diverse wildlife, fish species, birds and insects, as carbon powerhouses, filters of sediments and pollutants, and providing ecosystem services to coastal communities. The mangroves have always played a key role in our ecosystem.
However, the habitat-forming species, which can be found in the interface of land, river and sea, have declined rapidly. On the International Day for the Conservation of Mangrove Ecosystem, Xavier Benedict, environmental activist and founder of Art & Architecture Research Development and Education (AARDE) Foundation, walks us through the city’s majestic mangroves, discusses why more awareness about the species and their entwining roots have to be promoted, and the need to restore them.
Excerpts follow:
Tell us about the mangrove ecosystem and its management system in the city?
Mangroves in Tamil are known as Alaiyaathi – Alai (waves) + Aathi (cooling). Within this one word, the environmental management system has been explained in Tamizh. Chennai, about two centuries back, had a large cover of mangroves and wetland ecosystems. Unfortunately, due to encroachment of the wetlands by the administrators during the last two centuries, we have lost all or most of the wetlands ecosystem. Mangroves thrive in such wetlands. However, many high roads were built to cross the wetlands to connect the settlements and subsequently, we built buildings along these high roads and covered them up. Poonamallee High Road, Velachery High Road, and Nungambakkam High Roads are some examples.
What is the current plight of these mangrove forests?
Today, we have a small area of mangrove forests. The Adyar Creek (along Adyar Poonga, Chettinad Palace, and the Leela Palace hotel) and along the borders of Theosophical Society are some. Unfortunately, we have also lost a good number of mangroves — Avicennia Marina in large numbers, which can withstand high pollution levels; Rhizophora stylosa and Rhizophora apiculata, which were thriving along the Madras University Cooum link road. About three years back, it was removed for the Chennai Beautification Project.
Where can one find the remaining mangrove patches here?
Moderately dense mangrove forests can be seen in patches from Pattinapakkam to Thiru. Vi Ka Bridge and the Ennore creek area. Otherwise, it is a sad state of affairs. Urbanisation has killed it. Coastal lagoons and estuaries once dotted the coastal line of Chennai. The Pulicat lagoon, Ennore creek, wetlands of Madras (T Nagar, Vyasarpadi, Pallikaranai), Great Salt Lake, and Muttukadu were some. But we are slowly losing and have lost most of the ecosystem and its biodiversity in the last two hundred years. We’ve never maintained mangrove forests until the Adyar Creek Restoration Project was flagged. We’ve lost plenty of mangroves over time due to ignorance and urbanisation. Recently, we lost the University of Madras’ Canal-Cooum patch too.
What are the features of the mangrove ecosystem in Chennai and Tamil Nadu?
The mangrove ecosystem protects us from tsunamis, heavy winds, and tall waves. The marine ecosystem thrives here, it provides food to migratory birds, fishes, prawns and crabs. Mangroves also protect us from soil erosion and recent research shows that it attracts rain clouds. Our coastal lagoon and mangroves are great ecological and economically productive ecosystems. With high levels of organic matter, the mangrove sustains a diverse community of organisms, ranging from bacteria to fishes, birds and mammals.
What is the vital role of mangroves in conserving biological diversity?
Mangroves can withstand high levels of salinity and pollution. The city’s groundwater can be protected if coastal wetlands and mangroves are present today. Mangroves thrive in places where freshwater and seawater meet — coastal lagoon. When the freshwater is blocked due to dams/embankments, the mangroves vanish. The South East Coast (Coromandel Coast) of India has the major number of lagoons and deltas in India. Unlike the Western Ghats, the east coast depends on lagoons and deltas to attract rain clouds with their moisture during the monsoon. This moisture is higher in the regions where mangroves grow. We need mangroves and wetlands for regular intervals of seasonal rains. However, in the last two decades, the rain patterns have been erratic.
How does it protect the coastline?
The mangroves reduce the speed of the waves and winds. Hence, the coastal settlements get protected. Chennai is protected due to the presence of coastal lagoon, Buckingham Canal, and estuaries. An example is how the area with mangroves cover got protected from the disaster in Nagapattinam, during the Gaja cyclone.
What is their historical significance?
Mangroves of the East Coast of India were brought under intensive management by the colonial authorities during the late 19th century. They were treated as forests rather than as wetlands, and hence management procedures developed for the terrestrial forests were applied to mangroves. Mangrove wood was used as building material (beams and columns, and to make charcoal). This charcoal gives high heat to make lime (building material, before cement). Historically, Vijayanagara rulers and Britishers have exploited the mangroves rather than conserving them.
What threats do the mangrove ecosystem face?
Primarily, it is pollution of various kinds, including ones produced from chemical products like toothpaste and soaps. Industrial population and thermal power plants are the other major threats. Most of our thermal power plants are located on the coastal wetlands and creeks. There is not much legal protection of mangroves or wetlands. Hence, we are in the path of destroying all the wetlands and its ecosystem.
How does the mangrove ecosystem in the Chennai coast provide crucial socio-economic functions?
If the coast is protected from a cyclone’s wrath with the help of mangroves, the economy of the city will not get disturbed every monsoon. So the presence of coastal wetlands and mangroves will make our city sustainable with good water, and a healthier environment. However, mangroves sustain the livelihood of the fishing community and hence stop labour migration.
What steps can be taken by stakeholders including local communities in caring for our mangroves?
In the last decade, we have been seeing good initiatives from the government in promoting mangrove conservation, restoration and sustainable use. NGOs are doing their bit, but without consistent government initiatives, the goodness will not materialise. The Chennai Rivers Restoration Trust has also been doing a good job in and around the Adyar Creek area. The education system needs vernacular thinking. Our universal school system has killed vernacular ecology. We need to create awareness and hands-on experience for the students in their school/college activities.
State Stats
The mangrove cover in the state is 44.83 sq km, which is 0.035 per cent of the state’s total geographical area. The Very Dense mangrove comprises 1.04 sq km of the mangrove cover, Moderately Dense mangrove is 27.24 sq km while open mangroves constitute an area of 16.55 sq km.
Source: www.forests.tn.gov.in