Mangrove Forests
Mangrove forests, also called tidal forests, are found in intertidal zones of coastal areas. They grow in warmer tropical and sub-tropical latitudes 30 degrees usually. Basically, Mangroves are the coastal wetlands of warm regions of the planet. Mangroves are unique salt-tolerant trees with interlacing roots that grow in shallow marine sediments. The mangrove vegetation is adapted to grow in brackish waters of intertidal zones, areas with low-oxygen soil. The salt-tolerant mangrove vegetation is called Halophytic vegetation.
Characteristics features of mangroves
Mangroves are a group of trees, palms, shrubs, vines and ferns that live in waterlogged saline soils. Saline soils mean soils containing different salts. Mangroves cover less than 1% of the world’s surface with a total mangrove area of around 150,000 sq.Km.(Source: World Atlas of Mangroves, 2010). Mangroves are found on tidal mud flats and along freshwater riverbanks.
Characteristics features of mangroves are:
- Mangroves provide valuable ecosystem services. Their roots are the breeding grounds and nurseries for many fish species like shrimp and sea trout.
- The adaptations of mangrove vegetation allow it to survive in brackish waters through its Aerial Breathing roots -Specialized above-ground roots that take up oxygen from the atmosphere.
- Mangrove roots diverge from stems and branches and penetrate the soil some distance from the main stem. Roots also have many pores through which atmospheric oxygen enters into the roots.
- A unique way of mangrove reproduction process is called Vivipary. Seeds germinate into seedlings while being still attached to the parent tree. They photosynthesize while still attached to the mother tree. The parent tree supplies water and necessary nutrients. They are buoyant and float in the water for some time before rooting themselves on suitable soil.
- Mangrove trees stabilize the soil, prevent erosion and provide natural infrastructure to help protect nearby populated areas by absorbing cyclones.
- Mangrove trees either excrete salt from their leaves, roots, or branches And they have succulent leaves, sunken stomata and buttressed roots.
- Mangroves are a crossroad where oceans, freshwater, and land realms meet. They are among the most productive and complex ecosystems on the planet.
- The mangrove ecosystem provides essential habitat for a large number of animal species. They support a wealth of life from flora to fauna to people.
- Mangroves are more effective than concrete barriers in absorbing wave action.
Global Distribution of Mangrove Forests:
Mangroves grow in warmer tropical and sub-tropical latitudes up to latitudes 30 degrees usually. They are found in about 118 countries and territories within tropic and subtropic regions worldwide. Approximately 75% of the global mangroves are found in 15 countries. Asia has the largest amount of the world’s mangroves.
About 41 per cent of the world’s mangroves are found in Asia, with 21 per cent in Africa, 15 per cent in North and Central America, 13 per cent in Latin America, and 11 per cent in Australia and the islands of Oceania.
In the eastern parts of Australia, some species of mangroves grow far south between latitudes 32 and 38 degrees in the Atlantic.
Mangroves in India
Mangroves refer to those forest ecosystems whose vegetation tolerates both high water salinity and regular floods. They are reservoirs of the large number of plant and animal species associated together over a long evolutionary time and are tolerant of the same environmental conditions. The species composition of plants and animals varies from place to place with tidal amplitude, nature of the soil, profile, degree and quality of freshwater input and salinity, time of exposure in between tides, temperature, cloud cover, wind and wave action.
As per the India State of Forest Report 2019, released by the Forest Survey of India, the mangrove cover in the country is 4975 sq. km which is nearly 3.3% of the world’s mangrove vegetation.
India’s contribution is 45.8% of the total mangrove cover in South Asia.
India is also home to the world’s largest mangrove forests of the world -Sundarbans. Sundarban lies in the vast delta formed by the confluence of the Ganges, Brahmaputra, and Meghna rivers and extends across southern Bangladesh and India’s West Bengal State. This region is famous for its charismatic Royal Bengal Tiger. Other threatened species like Ganges and Irawadi dolphins; estuarine crocodiles and endemic river terrapin are also found here. Other species of Sundarrbans are spotted deer, turtles, fishing cats, and numerous bird and insect species.
Significance of Mangroves -
As mangroves are coastal wetlands, they also provide a range of ecosystem services:
Coastal Resilience - mangroves are coastal bio-shields as they provide storm protection against cyclonic storms, hurricanes and tsunamis by reducing their damaging impact on human lives and properties. In areas where mangroves have been cleared coastal damage due to tropical cyclones is very severe. Their protective role has been widely recognised especially after the devastating Tsunami of 2004.
Biodiversity - Mangrove forests are rich in biodiversity providing habitat for a wide variety of animal and plant species. They are dynamic areas, rich in food. Live and decaying mangrove leaves and roots provide nutrients that nourish plankton, algae, fish and shellfish.
Foundation Species - The complex root system facilitates the accumulation of organic detritus and inorganic nutrients, thus acting as nursing and breeding grounds for micro-organisms, birds, and marine and coastal species like reptiles and fishes. As mangrove forests provide habitat for many other species, mangroves are also called Foundation Species.
Shoreline Stabilization- Mangrove forests act as the zone of land accretion due to trapping of fine sediments thereby arresting soil erosion and stabilising coastlines.
Carbon Storage - Mangrove forests are one of the world’s principal stores of Blue Carbon’ thus playing a critical role in climate change mitigation through carbon sequestration. A hectare of mangrove forest sequesters up to four times as much carbon as a similarly sized tract of rainforest.
Economic Signification - Mangroves act as an important source of livelihood for the coastal communities dependent on the collection of honey, tannins, wax and fishing. These also provide timber, firewood and medicinal products.
Next to economic value, mangroves also bear great cultural significance for communities, such as the shellfish gatherers in South America, as their identity is strongly related to the ecosystem they live in.
Mangroves under threat -
In India and elsewhere, mangroves are fast disappearing due to coastal development, logging and shrimp aquaculture. mangroves are disappearing at a global loss rate of 1.38% per year. As per Global Forest Watch (an online forest monitoring platform that relies on satellite data for forest surveys), the world lost 192000 hectares of mangrove cover from 2001 to 2012. The rate of tropical deforestation from 2000 to 2012 was about 4.9% or 0.41% annually.
Major causes of mangrove deforestation:
Deforestation - Clearing of mangroves due to urban development, shrimp aquaculture, over-exploitation of timber, agriculture expansion, rice and palm oil cultivation
River changes - Dams and irrigation systems reduce the amount of freshwater reaching mangrove forests, changing the salinity level of water in the forest. If salinity becomes too high, the mangroves cannot survive. Freshwater diversions can also lead to mangroves drying out.
Aquaculture and Tourist activities - The Mangrove ecosystem has suffered from loss of habitat and pollution. This is harming the mangrove greatly. This also disturbs the ecological balance of mangroves. Aquaculture and tourist activities have decreased the mangroves.
Climate Change - causes sea level rise and altered rainfall, thereby causing mangrove loss.
Pollution- Fertilizers, pesticides, and other toxic man-made chemicals carried by river systems from sources upstream can kill animals living in mangrove forests, while oil pollution can smother mangrove roots and suffocate the trees
Many mangrove belts along the coasts of Latin America, Africa and Asia are severely degraded or have completely disappeared. Shrimp farms in Asia, in particular, have already cleared large tracts of mangroves and coral reefs along the coastal and marine environment. Urban development, pollution, over-harvesting of wood in the coastal forests and dynamite fishing are also taking their toll.
Mangroves for the Future (MFF)
Mangrove for the Future is a unique partner-led initiative, established in 2006 to promote investment in coastal ecosystem conservation for sustainable development. It provides a collaborative platform among the many different agencies, sectors and countries who are addressing challenges to coastal ecosystem and livelihood issues, to work towards a common goal.
Established to continue efforts after the 2004 tsunami -
The devastation caused by the Indian Ocean tsunami of December 2004 revealed the vital link between coastal ecosystems, resilience against natural disasters and human livelihood. The devastation was much less in regions with dense mangrove forests.
Understanding these linkages, the International Union for Conservation of Nature (IUCN) and the United Nations Development Programme (UNDP) developed Mangroves for the future.
Countries Associated with Mangroves for the Future (MFF)
India, Bangladesh, Cambodia, Indonesia, Maldives, Myanmar, Pakistan, Sri Lanka, Thailand and Vietnam are Member Countries, Malaysia is the Outreach Country, Kenya and Tanzania are Dialogue Countries.
Long-term sustainable coastal ecosystem management -
Mangroves are the flagship of the initiative, but MFF is inclusive of all types of coastal ecosystems, such as coral reefs, estuaries, lagoons, sandy beaches, seagrass and wetlands. The goal is conservation, restoration and sustainable management of the coastal ecosystem as a key natural infrastructure that supports human well-being and security.
Its long-term management strategy is based on identified needs and priorities for long-term sustainable coastal ecosystem management.
These priorities emerged from extensive consultations with over 200 individuals and 160 institutions involved in coastal management in the Indian Ocean Region.
MFF seeks to achieve demonstrable results in influencing regional cooperation, national programme support, private sector engagement and community action.
This will be achieved using a strategy of generating knowledge and empowering institutions and individuals to promote good governance in coastal ecosystem management.
Frequently Asked Questions (FAQs)
Question: What are mangroves?
Answer - Mangroves are a group of trees and shrubs that are found in intertidal zones (that is the zone between the high tide line and low tide line) of coastal areas. They are also called Tidal Forests
Question: Why is it called a mangrove tree?
Answer - The word mangrove came from the Portuguese word ‘Mangue’ which means "Tree: and the English word grove is used for trees and shrubs which are found in shallow, muddy areas.
Question: Why mangroves are important?
Answer - Mangroves are coastal bio-shields as they provide storm protection against cyclonic storms, hurricanes and tsunamis by reducing their damaging impact on human lives and properties. In areas where mangroves have been cleared coastal damage due to tropical cyclones is very severe.
Question: Where are mangroves found in India?
Answer - West Bengal has 42.5% of India’s mangrove cover, followed by Gujarat (23.5%) and Andaman & Nicobar Islands (12%)
Question: Which is the largest mangrove site in India?
Answer - India is also home to the world’s largest mangrove forests of the world - Sundarbans. These are named after the dominant mangrove species locally known as Sundari, economically valued for its timber.
Question: What is the Global loss of mangroves?
Answer - mangroves are disappearing at a global loss rate of 1.38% per year. As per Global Forest Watch, the world lost 192000 hectares of mangrove cover from 2001 to 2012.
Major causes of mangrove deforestation are:
- Deforestation - Clearing of mangroves due to urban expansion, shrimp aquaculture, over-exploitation of timber, agriculture expansion etc.
- Climate Change - Causes sea level rise and altered rainfall, thereby causing mangrove loss.
- Pollution - Pesticides, Fertilizers, and other man-made chemicals carried by river systems can kill animals living in Mangrove forests.
Question: What is the Global Mangrove Alliance?
Answer - The Global Mangrove Alliance is a partnership amongst Conservation International, The International Union for the Conservation of Nature (IUCN), The Nature Conservancy, Wetlands International and World Wildlife Fund (WWF).
The target of the Alliance is to increase the global area of mangrove habitat by 20% over the current extent by the year 2030. This target underpins and helps deliver objectives, including climate change, climate mitigation sustaining biodiversity and improving human well-being.
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