- Mangrove forests give sturdy support to the coastline by minimizing erosion from storm surges, currents, waves, and tides. The intricate root system of mangroves is unique as they allow them to shelter fish and other organisms in an ecologically benign environment. For example, the area of Sunderbans is the world’s largest mangrove forest and they have wider species diversity. This biodiversity hotspot is home to 180 species of trees and plants growing within its marshy boundaries, the Gangetic dolphin, estuarine crocodiles, river terrapins, hawksbill turtles, horseshoe crabs and the famous Bengal tiger. They are a World Heritage site and the biggest carbon-sink in South Asia. They have an important role in carbon sequestration and hence climate management.
- Mangroves are the first line of defence against cyclones and rising seas. They also support coastal communities in multiple ways.
TSUNAMI & MANGROVES Case Study
Pichavaram mangrove forest protected hamlets namely, T.S.Pettai, Vadakku Pichavaram, Therkku Pichavaram, Meenavar Colony, MGR Nagar and Kalaingar Nagar against the fury of tsunami. Total families in these hamlets are about 1228 and total population is about 6191. These hamlets are located between 100 m to 1000 m from mangroves. In these hamlets seawater has not entered into the village and there is no loss of property. However, 4 women belonging to MGR Nagar, who were fishing nearby the sea were washed away and died. It is seen that mangrove trees in rows located close to the sea got uprooted due to the impact of the tsunami and beyond that there is no damage. It seems mangrove forest reduced the impact of the tsunami by two ways: a) velocity of the tsunami water greatly reduced after it entered into the mangroves due to friction created by thick mangrove forest and b) volume of water reaching a point is greatly reduced since tsunami water, after entering into the mangroves, is distributed to all the canals and creeks that are present all over the mangroves. A number of fishers who were fishing in the nearby the sea but moved into mangrove water after seeing huge wave of about 10 to 15 feet coming to the beach experienced these. One of the fishers said, “we saved the mangroves by restoring them and it saved our life and property by protecting us” of about 10 to 15 feet coming to the beach experienced these.)
- Mangroves provide important nesting and breeding sites for fish and shellfish, migratory birds and sea turtles. This underscores their importance to coastal fishing communities. According to a global research, an estimated 80% of the global fish catch relies on mangrove forests either directly or indirectly.
- About 20 percent of India’s population lives on the coast. There are many big cities including Mumbai, Chennai, Puducherry, Thiruvananthapuram, Kochi etc. which lie on the sea shore. A robust and dense cover of mangrove forests can protect these areas, which are vulnerable both to sea level rise and to the more intense and frequent weather events caused by climate change.
- Mangroves also act as great carbon sinks. Some researchers at the global level have postulated that mangroves “isolate carbon at two to four times the rate of tropical forests like the Amazon and store three to five times more carbon per equivalent area than tropical forests”.
- Mangroves are used for timber, mining, agriculture, harbour development and human settlements. Mangrove areas were used earlier for commercial shrimp farming. However, using mangrove areas for shrimp farming has proved to be unsustainable now-a-days.
- Mangroves are an ecosystem with multi-dimensional use. It is held that they are the “best form of coastal bioshield” as they perform a “critical role in reducing the impact of cyclonic storms, hurricanes and tsunami on human lives and properties”.
- It controls/reduces soil erosion. It magnifies fishery productivity of the adjacent coastal waters. This occurs as they act as a nursery ground for commercially important fish, prawn and crabs. Additionally, they supply organic and inorganic nutrients. They are also rich in biodiversity and act as habitats for wildlife.
- It is being held that “the physical environment lays the foundations and draw limits for how and where mangroves thrive, as ‘ecosystem engineers’ mangroves themselves are partially responsible for shaping their physical environment”.
- The highly intricate and very structured roots of mangroves promote the trapping of sediments (i.e. from rivers) and organic debris helping them to adjust with the sea level rise, making them invaluable in promoting climate resilient coasts.
- Mangroves create an excellent diverse habitat as they combine animal species of terrestrial and marine environment in a single ecosystem. Major groups range from insects, molluscs and crustaceans to fish, reptiles, birds and mammals. Mangroves are rich in food and provide shelter to offshore species which use their complex structures as nurseries. Mangroves also provide terrestrial habitat for many species. For example, the vast mangroves of the Sundarbans currently host the largest intact tiger population in the world.
- Mangroves have a seminal role in the ecosystem as they nurture and nourish biodiversity as nursery grounds for many coastal and marine species and support fisheries.