When you look at India’s long coastline, the real border between land and sea isn’t just a sandy beach. In some places, it is a thick, green wall of trees. These trees are mangrove forests that form a living shield that covers 4,991.68 square kilometers of shoreline, representing a small but mighty 0.15% of the country’s total geographical area.
The International Day for the Conservation of the Mangrove Ecosystem was established by the United Nations Educational, Scientific and Cultural Organisation (UNESCO) in 2015 and has been observed on July 26 every year since. As we take this day to reflect on our coastal ecosystems, it becomes clear that mangroves are incredibly important to us. Not only do they protect coastlines and support coastal communities, they also provide food security and a home for a huge variety of wildlife. Around the world, these salt-loving forests cover over 15 million hectares, thriving in muddy, shallow waters, bridging the ocean and the land.
The Architectural Wonders
The survival of these forests is astonishing! They have evolved highly efficient mechanisms to manage extreme salt stress. Some species maintain a high salt concentration in their cell sap, while others store excess salt in older leaves or secrete excessive salts through roots (example Rhizophora) or specialised excretory glands present on the leaves (example Avicennia officinalis).
They also have highly efficient root systems, like prop, stilt and pneumatophores. Prop roots grow straight down from the branches until they touch the mud, acting as vertical pillars. Stilt roots, on the other hand, grow outwards and then downwards from the lower trunk at an angle, acting like a tripod to hold the tree straight above the water. The Rhizophora mangrove is the most famous example for having prop and stilt roots. Additionally, species of Avicennia and Sonneratia use an underground network of roots that push finger-like pneumatophores, known as breathing roots, up through the oxygen-starved mud to breathe.
Diversity in Numbers
About 40% of global mangrove cover is found in Southeast and South Asia, and among those countries, India holds about 3% of the total mangrove vegetation. According to the State of Forest Report 2023, India is placed third, following Indonesia and Australia.
Our country is incredibly rich in mangroves, featuring both true and associate species. True mangroves live exclusively in the harsh, muddy area where the ocean meets the land. These species boast a high tolerance for salt, breathe through pneumatophores, and have a unique way of reproducing through ‘live’ propagules rather than traditional seeds. India has 46 true mangroves species! However, nine of these species are facing a high risk of extinction and are considered to be “species of conservation importance”. These are, Sonneratia griffithii, Heritieria fomes, Excoecaria indica, Aglaia cucullata, Aegialitis rotundifolia, Brownlowia tersa, Ceriops decandra, Phoenix paludosa, and Sonneratia ovata.
In contrast, there are other plants known as associate mangrove that are capable of surviving both terrestrial and estuarine conditions. However, they cannot withstand the extreme conditions of the intertidal mud. India has 188 mangrove associated species and includes plants such as Porteresia coarctata (wild rice), and Ipomoea pes-carpae (beach morning glory).
India’s mangrove habitat is divided into three regions: the east coast, which is lined with 40 mangrove species, the west coast, which harbours 27 of them, and the Islands of Andaman and Nicobar and Lakshadweep, with the former having 38 species of mangroves, and the latter supporting three species. The lush diversity of mangrove vegetation on the east coast is fuelled by vast river deltas and expansive intertidal mudflats that are heavily enriched with organic sediments. On the other hand, the mangrove forests on the West Coast are constrained to narrow sea-inlets, small river mouths, lagoons, and backwater systems, which results in less extensive mangrove cover.
Looking at the east coast, West Bengal leads the nation with 2,119.16 square kilometers of mangrove cover. It is home to the world’s largest mangrove forest, the Sundarbans. This massive coastal forest acts as a giant shock absorber against severe storms and cyclones.
Over the west coast, Gujarat features the second largest mangrove cover of 1,164.06 square kilometers. Here, the mangroves are spread across four regions: Kutch, the Gulf of Kutch and Saurashtra, and South Gujarat (including the Gulf of Khambhat). 71.5% of the total mangrove cover of the state is concentrated in Kutch.
As for the islands, the Andaman and Nicobar Islands boast over 608.29 square kilometers of lush, highly diverse mangrove forests. Lakshadweep mangroves are only present across a tiny space of 500 square metres in its southernmost ring-shaped Minicoy Island.
Among all coastal states and union territories, the Andaman and Nicobar Islands boast the highest mangrove diversity with 38 species. These pristine islands are an exclusive sanctuary for eight unique species found nowhere else in India, including Lumnitzera littorea, Rhizophora lamarckii, and Sonneratia varieties like S. alba, S. urama, S. gulngai, and S. ovata.
Wilderness in Mangrove
India’s rich mangrove cover creates a unique haven for wildlife, and boasts the highest recorded biodiversity of any such ecosystem globally. It harbors a staggering 4,107 species, comprising 23% floral and 77% faunal life. As you travel across the coastline, each region reveals its own unique wildlife diversity. Let’s look at some of the major mangrove regions:
- The Eastern Coast:
The Sunderbans of West Bengal is the only mangrove habitat in the world where the Bengal tigers are found. Aquatic predators like saltwater crocodiles and river sharks share the habitat with Ganges River dolphins and Irrawaddy dolphins. On land, they reside alongside terrestrial animals like king cobra, python, and spotted deers. The canopy shelters sunbirds, Mangrove pitta, and some endangered raptors like White-rumped vulture and Steppe Eagle.
Odisha’s Bhitarkanika National Park, globally known as the ‘Mangrove Genetic Paradise’, hosts the largest populations of birds and rare albino crocodiles. Nearby, the world’s largest nesting site for olive ridley turtles lies along Odisha’s Gahirmatha coast.
- The Western Coast:
On the western coast, and majorly in Gujarat, the mangroves blend seamlessly into coral reefs and seagrass beds. Beneath the water, these meadows support gentle marine mammals like dugong (sea cow), while ornamental fishes often shelter in the roots. Garden lizards, horn snails, fiddler crabs, green mud crabs, and fishes like spotted scat and green chromide, are some other species found there. The region is also home for a variety of birds like barn owl, Asian openbill, pied kingfisher.
- Andaman and Nicobar Islands:
The archipelago shelters rare invertebrates found nowhere else in India. The island waters support over 200 fish species, alongside hawksbill sea turtles and dugongs. The forest hosts around 150 bird species, like white-bellied sea eagle, the serpent eagle, and the mangrove kingfisher!
Navigating Conservation
Despite their magnificent resilience, this natural wealth remains deeply fragile. The primary driver of mangrove loss is the rapid shift in land-use patterns, specifically, clearing of forests for agriculture and commercial aquaculture, such as shrimp farming.
In the Andaman and Nicobar Islands, mangroves are threatened by wood extraction, encroaching coastal infrastructure, and rising sea levels. Along other parts of the country, these forests suffer extensive damage from agricultural runoff, industrial pollution, and accidental oil spills. Combined, these pressures are pushing this ecosystem to the brink.
Of the mangrove species on the IUCN Red List, India harbours two that are globally threatened: Heritiera fomes and Sonneratia griffithii. These vital species are facing local extinction due to low seed viability and slow growth.
Destroying these forests has global climate consequences as well. Mangroves are one of the planet’s most efficient ‘blue carbon’ sinks, storing 1,000 tonnes of carbon per hectare. Their degradation releases massive greenhouse gas emissions that cause billions of dollars in economic damage annually.
Protecting these living fortresses is an absolute need of the hour. Preserving these ecosystems will also help preserve the wildlife species that rely on them, ensuring that Bengal tiger, sea turtles, and rare bird species will continue to thrive.
By creating a balance with this ecosystem, we can also foster new self-employment avenues, from ecotourism and responsible fishing to beekeeping and cottage industries. Ultimately, securing our mangroves means elevating both the local communities and the wildlife.
For more stories on nature and wildlife, subscribe to our newsletter.
Feature Image: Vineet Singh/ Wildlife SOS
