Mangroves are salt-tolerant vegetation that grows in intertidal regions of rivers and estuaries. They are trees and shrub species that grow at the interface between land and sea in tropical and subtropical regions of the world, where the plants exist in conditions of salinity, tidal water flow and muddy soil.

As of 2012, mangroves are found in 105 nations globally. Although distributed across 105 nations, the top 10 mangrove holding nations contain approximately 52% of the global mangrove stock with Indonesia alone containing between 26% and 29% of the entire global mangrove stock.

Distribution of major mangrove concentrations:

• Mangroves of the World have been divided into two groups: Eastern group i.e. East Africa, India, Southeast Asia, Australia and the Western Pacific and Western group comprises of West Africa, South and North America and the Caribbean Countries.
• The most extensive area of mangroves is found in Asia, followed by Africa and South America. 
• Four countries (Indonesia, Brazil, Nigeria and Australia) account for about 41 percent of all mangroves.
• The Sundarbans region is the world’s largest area of mangrove forest, spanning approximately one million hectares (2.47 million acres) in India and Bangladesh. 

Role of mangroves in maintaining the ecological balance:

• Basis of a complex marine food chain.
• Help in water quality improvements.
• Mangroves serve as breeding, feeding and nursery grounds for most of the commercial fishes and crustaceans on which thousands of people depend for their livelihood
• They are a natural coastal defence. The sturdy root systems of mangrove trees help form a natural barrier against violent storm surges and floods. 
• River and land sediment is trapped by the roots, which protects coastline areas and slows erosion. This filtering process also prevents harmful sediment reaching coral reefs and sea grass meadows
• They are carbon sinks.  Coastal forests help the fight against global warming by removing carbon dioxide from the atmosphere, most of which is stored within the plant. When mangrove tree roots, branches and leaves die they are usually covered by soil, which is then submerged under tidal water, slowing the breakdown of materials and boosting carbon storage. 
• They are rich in biodiversity and harbour a number of faunal and floral species, both aquatic and terrestrial. Mangroves are regarded as the most productive ecosystems on account of the large amounts of organic and inorganic nutrients that are released by them.

Threats to mangroves ecosystem:

Climate change may reduce global mangrove area by 10-15%, but it is a long term, less significance threat to the current 1-2% annual loss from human activities.

Natural threats:

• Cyclones, typhoons and strong wave actions.
• Trampling and over grazing by   wildlife and livestock close to mangrove regions.
• Damage by crabs, oysters and pests to the young seedlings of mangroves.

Anthropological threats:

• Agriculture: Many thousands of acres of mangrove forest have been destroyed to make way for rice paddies, rubber trees, palm oil plantations, and other forms of agriculture.
• Coastal Development: Coastal development takes many forms but as streams and wetlands are filled by roads and concrete, they can no longer process natural chemicals. Worse still, pollutants that accompany development can damage individual trees or whole tracts of mangroves.
• Shrimp Farming: By far the greatest threat to the world’s mangrove forests is the rapidly expanding shrimp aquaculture industry. Hundreds of thousands of acres of lush wetlands have been cleared to make room for artificial ponds that are densely stocked with shrimp. 
• Charcoal and Lumber Industries: Chopping down mangroves for charcoal and timber is an important cottage industry for many coastal communities. Mangrove wood is used for building material, fencing, and fuel. It also yields valuable, high-quality charcoal. In places where fishing has declined below subsistence levels, many people have turned to charcoal production for their livelihood, which furthers the cycle of habitat loss and fishery decline.

Way forward:

• Stronger Legal and regulatory approaches for protection must be enforced. Example:  Maharashtra Govt ensured ‘Reserved Forests’ status to mangroves.
• Global initiatives like Mangroves for the Future (MFF) by IUCN, global assessment of mangrove status by Mangrove Atlas etc must be encouraged and participative.
• Heightened awareness by people all over the world and preservation methods and knowledge must be imparted effectively.

As countries race to protect their forests, they must also protect the vital mangrove ecosystems along their coastlines. With continued data analysis, conservation, management and restoration, we can halt the loss of the world’s remaining mangrove forests and begin to reverse it.