Mangrove Habitat Loss
Hundreds of acres of the Sundarbans mangroves-one of the world's largest such forests-are feared to have been lost due to illegal felling carried out for government schemes aimed at providing housing and farmland to the poor.
• 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 ecotone. They require warm saline water and so they are situated along tropical coastlines.
• Mangroves have a “complex salt filtration system” and complex root system to cope with salt water immersion and wave action. 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 and they cannot bear freezing temperatures.
• Mangroves grow in areas with low-oxygen soil and in this soil slow-moving waters allow fine sediments to pile up. 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.
Threats to Mangroves
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.
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”.
o Cyclones, typhoons and strong wave actions.
o Trampling and over grazing by wildlife and livestock close to mangrove regions.
o Damage by crabs, oysters and pests to the young seedlings of mangroves.
o 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.
o 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.
o 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.
o 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.
Steps to be taken to Conserve Mangrove
Strict implementation of the Environmental (Protection) Act, the Supreme Court’s order banning semi-intensive and intensive aquaculture in the coastal areas, and the Coastal Regulation Zone (CRZ) notification
Scientific management practices are very much essential for conservation and sustainable management of the precious mangrove forests.
Environmental monitoring in the existing mangrove areas should be taken up systematically and periodically.
The participation of the local community should be made compulsory for conservation and management. Floristic survey of mangroves along the coast is to be taken up to prepare biodiversity atlas for mangroves.
The forest department officials should be trained on taxonomy, biology and ecology of mangrove species.
Agro-forestry along the periphery of mangroves in the wastelands can be taken up for providing alternate fodder to the cattle of nearby villages.