People have long perceived mangroves as malodorous swamps without any utility or value. Often infested with mosquitoes, with the particularity of being flooded or prone to flooding by the sea and inland waters, these forests found along the coasts of tropical regions suffer a poor reputation. Yet they are one of the richest and most productive ecosystems of the planet.
The tangled roots of the mangrove trees provide a precious refuge for vulnerable species and serve as a nursery for young fish, where they are sheltered from predators. Growing between land and sea, these amphibious forests are also home to many terrestrial animals: birds, monkeys, reptiles, deer, and in Bangladesh, the Sundarbans, the largest mangrove forest in the world, is one of the last refuges of the Bengal tiger, far from man.
With one foot in the sea and the other on land, the mangroves also function as a shield and protect the coastline from erosion and natural disasters. The dense tangle of mangrove tree roots prevents sediment carried down by rivers from emptying into the sea and stabilises the shore, while the trunks and branches serve as a breakwater, reducing the force of the waves. A study carried out in Thailand showed that the regions where mangroves had been destroyed or damaged by human activities were among those most affected by the tsunami of December 2004.
Essential for thousands of coastal communities, mangroves have lost a quarter of their surface area in under 20 years, that is 3.6 millions hectares, primarily in Asia. Today, man appears to have become better aware of their environmental, economic and social value. In Bangladesh, their surface area is even increasing, but this remains an exception.
Extrait du livre « Des forêts et des hommes » rédigé par la rédaction de GoodPlanet à l’occasion de l’année internationale des forêts et disponible aux éditions de la Martinière.