A mangrove is a shrub or small tree that grows in coastal saline or brackish water. The term is also used for tropical coastal vegetation consisting of such species.
Mangroves are a variety of species of broad-leaved trees (10–40 feet high) lying in muddy creeks and tidal estuaries. They are located on the intermediate zone between the land and the sea and represent one of the best examples of ecotone. They require warm saline water and so they are situated along tropical coastlines. Mangrove plants survive in the saltwater zones between water and land.
- Mangroves have a “complex salt filtration system” and complex root system to cope with salt water immersion and wave actio They are also adapted to the low oxygen conditions of waterlogged mud. Mangroves occur worldwide in the tropics and subtropics, mainly between latitudes 25° N and 25° S. They require high solar radiation to filter saline water through their roots. Hence, mangroves are confined to only tropical and sub-tropical coastal waters.
- It has been found that there are about 80 different species of mangrove trees. Mangroves grow in areas with low-oxygen soil and in this soil slow-moving waters allow fine sediments to pile u Mangrove forests only grow at tropical and subtropical latitudes near the equator as they cannot bear freezing temperatures. Mangrove forests serve an important role in stabilizing and reinforcing coastlands. In this way, they protect these coastlands from erosion that results from action of waves and tides that occur regularly. They act as a shield against storms. This capability of the mangrove forests has saved valuable property and countless lives around the world from imminent destruction.
- Mangrove plants have several unique adaptations that allow them to survive in harsh environments. Mangroves are extremely important to the coastal ecosystems they inhabit. Physically, they serve as a buffer between marine and terrestrial communities. They protect coastlines from damaging winds, waves, and floods. Mangrove has an important role in improving water quality by filtering pollutants and trapping sediments from the land. They reduce coastal erosion.
- Ecologically, they provide habitat for a diverse array of terrestrial and marine organisms. The area of mangroves has greater species diversity as it is the junction of terrestrial and marine ecosystems. They have very high salt tolerance and so some species which require this ambience also thrive upon mangroves. According to one of its oft-quoted definition, “Mangroves represent a characteristic littoral (near the sea shore) forest ecosystem and they are mostly evergreen forests that grow in sheltered low lying coasts, estuaries, mudflats, tidal creeks backwaters (coastal waters held back on land), marshes and lagoons of tropical and subtropical regions”.
- Mangrove environment is very vital and robust. The mangrove species are adapted to deal with these severe environmental conditions in multifarious ways.
- Breathing roots: Oxygen for the purposes of respiration is needed by the underground tissue of any plant. As far as the mangroves are concerned, oxygen in the soil is in very limited supply. This means that the mangroves take up oxygen from the atmosphere. For this purpose, mangrove species have specialized above ground roots called breathing roots or pneumatophores. These roots have numerous pores through which oxygen enters into the underground tissues. In some plants buttress roots function as breathing roots and also provide mechanical support to the tree.
- Stilt roots: In some mangrove species, roots emerge from stems and branches. Such roots get into the soil some distance away from the main stem as in the case of banyan trees. These stilt roots are endowed with many pores through which atmospheric oxygen enters into the roots.
- Vivipary: It is postulated that “saline water, unconsolidated saline soil with little or no oxygen is not a conducive environment for seeds to germinate and flourish. To overcome this, mangrove species have a unique way of reproduction, which is generally known as vivipary”. This is a very unique method of reproduction. In this method, seeds germinate and develop into seedlings while the seeds are still attached to the parent tree. These seedlings are normally known as propagules. They photosynthesize while still attached to the mother tree. The parent tree supplies water and necessary nutrients. They remain buoyant and float in the water for sometime before rooting themselves on suitable soil.
- “About 40% of [the] world’s mangrove cover is found in South East Asia and South Asia… India has about 3% of the total Mangrove cover in South Asia”
- There are 15.9 million hectares of mangrove forests in the warm waters of tropical oceans all over the world. Along the Atlantic coast they are found from Florida till Argentina in a vast expanse. Mangroves grow on both the western and eastern coasts of Africa. They stretch into India, Burma, and south-east Asia. Mangrove forests are also common in New Zealand and Australia.
Mangroves distribution in India
- “Mangrove cover in the country has increased by 54 sq km (1.10%) as compared to the previous assessment.”
- “The current assessment shows that mangrove cover in the country is 4,975 sq km [(1.2 million acres)], which is 0.15% of the country’s total geographical area.”
- They are found in the following states and Union Territories in India: West Bengal, Odisha, Andhra Pradesh, Tamilnadu, Andaman and Nicobar Islands, Kerala, Karnataka, Goa, Maharashtra and Gujarat.
- The major concentrations of mangroves are in the Sunderbans delta and Andaman & Nicobar Islands. However, the mangroves are also found in the deltaic areas of Mahanadi, Godavari and Krishna river basins.
- The Government of India formed an Indian Mangrove Committee in 1976. M.S. Swaminathan Research Institute, Chennai is also engaged in management of mangroves in states of Tamil Nadu, Andhra Pradesh and Odisha.
- 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.
- They are destroyed for the conversion of the area for agricultural purposes, fuel, fodder and, salinization, mining, oil spills, aquacultural (shrimp farming), use of chemical pesticides & fertilizers, industrial purposes.
- From seas – Sea level rise, cyclones and tsunami, coastal erosion, oil spills
- From rivers – Polluted water
- From Communities– Destroyed for fuel, fodder
- Plastic bags and other waste is a major threat for mangroves.
- Goats can destroy mangrove seedlings and damage mature trees.
- Mangroves are immensely beneficial but unfortunately half of the world’s mangroves (about 32 million hectares) have already been cleared or destroyed and the remaining ones are also facing grave threat.
- The mangrove forests are important for food, carbon storage and sequestration, coastal protection, tourism and water purification. Hence, there are efforts made to halt further losses as well as to increase mangroves through restoration.
- Mangroves are faced with a lot of threats. For example, a large part of land has been cleared for establishing shrimp farms in Latin America and Southeast Asia which have adversely impacted mangroves. Climate change, changing land-use patterns and tourism also affect the future of the mangrove plant.
- A serious impediment to the unhindered growth of mangroves is prompt and mostly unregulated coastal development. Although India has framed laws to protect its coastline, they are breached quite often. According to a research by the Indian Institute of Science, “India has lost 40% of its mangrove area in the last century, mainly due to agriculture, aquaculture, tourism, urban development and overexploitation”.
- The State of Forest Report, released by the Forest Survey of India, says that “the mangrove cover in the country is increasing only marginally in the past two decades”. These facts very clearly illustrate that there is a lot to be done as far as the sustainable management and conservation of mangroves is concerned. There is an urgent need to restore degraded mangroves by governmental action as well as participation of local communities.
- Many countries have realized the immense value of mangroves to the overall environmental sustainability. They have adopted mangrove restoration and conservation programs. Strict legislation to protect mangroves is in place in many countries. For example, Indonesia has 25 percent of the world’s mangrove population. Coastal fish farmers on the Indonesian island of Java are given 4–5 hectares of land. However, the rider is that these farmers are required to plant mangroves on 20% of this land. Seeds are gathered from budding sprouts and planted 6 to 9 feet apart. This sort of reforestation improves the environment, while feeding people and encouraging the economy. This is a sustainable long term solution devised in Indonesia.
- Many Mangroves sites are protected under the Ramsar convention at the global level. The IUCN and The Nature Conservancy have laid down a global scientific map for the purpose of mangrove restoration. It is being held that two billion hectares of deforested and degraded lands worldwide have the potential for forest landscape restoration and this well-calibrated potential for restoration is related to climate change adaptation and mitigation – including priority areas for mangrove restoration.
- The organizations like the Global Mangrove Watch are working tirelessly towards mangrove conservation. It is providing mangrove extent at multiple points of time from the mid-1990s to the present day. It is being postulated that “this time series of mangrove extent will allow us to identify areas of recent mangrove loss, with the assumption that recently converted areas are more restorable than those that were lost long ago”.
- The organization has outlined the following factors contributing towards mangrove degradation: Urbanisation and industrial development, Conversion to agriculture and aquaculture ponds, Deforestation for fuelwood or timber, Rapidly changing patterns of freshwater regimes, Pollution and coastal erosion.
- Scientific studies have found that large areas in Southeast Asia were converted into shrimp cultivation ponds but they were later abandoned. The Global Mangrove Watch in its study has found that these ponds can be major areas of mangrove restoration.
The State Forest Report 2019 mentions the following conservation techniques for Mangroves:
-The state of Gujarat uses direct seed sowing, raised bed plantations, and fishbone channel plantations to restore degraded mangroves.
-State of Andhra Pradesh has established Eco-DEvelopment Committees and Van Samrakshan Samithi to implement conservation projects in mangrove areas.
-The state of Maharashtra has been implementing restoration, protection, regeneration, and maintenance techniques to conserve mangroves.
- The organization Global Mangrove Alliance (GMA) is supporting the target of increasing mangrove coverage by 20 percent over current extent by 2030.
- Mangroves for the Future (MFF) is an initiative co-chaired by IUCN and the United Nations Development Programme (UNDP). It is held that the organisation is “running mangrove restoration and sustainable development projects with gender integration as a core strategy in several Asian countries. Participatory, community-based project approaches ensure that women’s and men’s voices are considered equally and aim to improve women’s social and economic empowerment”.
- Case Study The Guyana Mangrove Restoration Project is another bright example. It saw women take a central leadership role with their efforts to increase the resilience of Guyana’s coasts against flooding and coastal erosion. Women were most severely impacted upon by coastal flooding and erosion of Guyana’s coast. Women were provided with resources for economic empowerment and capacity building trainings. As a result of these positive measures, women got positively involved with various activities like honey production, tourism activities and mangrove cultivation. The active participation of women catalysed the formation of a women-led volunteer organisation for mangrove awareness and restoration as well as the ‘Mangrove Cooperative Society’ to support other women with training and resources on activities like beekeeping.
Nurturing and nourishing mangroves helps fulfil multiple objectives like improving the life of aquatic animals, reducing poverty and hunger, enhancing the quality of life of coastal communities etc. The importance of restoration and protection of mangroves is amply reflected in Sustainable Development Goal (SDG) 14 (which focuses on sustainably governing our oceans and coasts and recognises mangroves’ immense value to local communities). But restoring mangrove forests also supports the achievement of many other SDGs like:
- Eliminating poverty and hunger (SDG 1 and SDG 2),
- Ensuring livelihoods and economic growth (SDG 8),
- Taking actions against climate change impacts (SDG 13) and
- Halting biodiversity loss (SDG 15).
They do so in numerous ways. The mangroves have very rich species diversity. For example, India’s mangroves are home to 4,011 species (the highest in the world). The mangroves give sufficient and nutritious food to local coastal communities. This becomes particularly useful to poor and vulnerable populations. Various income-generating opportunities are offered by mangroves. The sustainable harvest of mangrove products meant for market sales present business opportunities for local communities. This benefits women, native tribes, farmers, pastoralists etc. These local income opportunities can be enhanced through the creation of management and planning jobs involved in restoration projects. Mangrove forests are important in climate management as they are “carbon-rich protective buffer zones between land and sea”. The restoration of mangrove forests is directly related to goals which are in sync with climate adaptation and mitigation. The mangroves should be restored in order to promote the resilience of coastal communities from various climate-induced threats. It is held that “mangrove restoration sites can also be strategically placed to contribute to upgrading infrastructure with greater adoption of environmentally sound technologies through applying infrastructures for coastal protection”. In this way, the resilience of coastal communities can be magnified by minimizing their exposure to climate-induced environmental shocks and disasters. It has been acknowledged time and again that mangroves are extremely “efficient carbon sinks”. Hence, well-calibrated actions meant for mangrove restoration efforts help in adapting to adverse impacts of climate change. Various scientific studies have attested the importance of restoration of mangroves in smart climate management. There is a need for an integrated approach to mangrove restoration. By this approach the local coastal communities can emerge as participatory stakeholders in the process of mangrove restoration. The local people can have sustainable development lifestyles in harmony with nature and can also help the government in promoting sustainable tourism. This will also enhance eco-friendly business opportunities for local communities in multiple ways.
- In 1976, the National Mangrove Committee was set up under the Environment Ministry.
- In 1979 it recommended focus on areas like mapping of mangroves using remote sensing, land surveys, etc., to determine degradation rate, assessing sites for establishing reserve forests, conservation program, afforestation, R&D etc.
- Several legislations like Environment (Protection) Act, Indian Forest Act, Wildlife Protection Act, Forest Conservation Act, etc. are sources of protection (though mangroves are not specifically mentioned in all of these).
- In 2018, the High Court called the destruction of mangroves an offence to the fundamental rights of the citizens under article 21 of the Constitution. Since then, the government has been undertaking efforts to conserve the mangroves.
- In 2018, India along with 7 other countries of the Bay of Bengal region came together to protect the mangroves under the BOBLME (Bay of Bengal Large Marine Ecosystem) project. The UN Food and Agriculture Organisation leads this project. The GEF (Global Environment Facility) approved a grant of 15 million USD for this project.
Question 2) While mangrove forests play a major role with more valuable ecological services, scientific management of the same is the need of the hour not only for the wellbeing of the mankind but also for coastal biodiversity. Discuss.