slide1 n.
Skip this Video
Loading SlideShow in 5 Seconds..
G E M PowerPoint Presentation


187 Vues Download Presentation
Télécharger la présentation


- - - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

  1. G E M

  2. Mangroves are one of the coastal natural phenomena seen in river mouth zones in subtropical areas. They can been found on muddy "wetlands" of loose and moist soil. They are among the richest eco-systems in terms of natural resources.

  3. Mangroves are buffers between the land and the sea. Coastlines throughout the world are facing serious problems of coastal erosion and threat of rising sea levels due to global warming have increased the threats by several folds. To control such assault of the sea on land the nature has provided what is called as mangroves, a tropical littoral ecosystem which is more dynamic than the sea itself.

  4. Mangroves are unique because they are able to thrive in areas where the water is poor in oxygen content, in salt water, in fresh water and in brackish water (a mixture of salt and fresh water). Mangroves are fast-growing trees taking several years to reach up to 25 meters when they are fully grown. Of the seven types of mangroves, three are most dominant, the black, red and white types.

  5. Black Mangroves Easily identified by its roots which are specialized to take in oxygen. Roots look like tubular bristles which stick out vertically and trap oxygen for its oxygen-starved root systems. The Black Mangrove is tolerant of high saline conditions and the trees grow in isolated groups or woodland formations. Individual trees are fairly large and may grow up to 20-25 meters in height and 40 centimetres in diameter at breast height.

  6. Red Mangrove This is an evergreen tree, which grows to about 25 meters in height and 40 centimetres in diameter at breast height. These are immediately recognized by their elaborate prop and aerial root system which stabilizes the trees. The roots contain a waxy substance that helps keep salt out. Where salt gets through, salt is deposited in older leaves and the tree then sheds them. The wood can be converted into good quality charcoal and the bark produces high quality tannin which is suitable for leatherwork.

  7. White Mangrove These are the shortest of the three species (reaches 5.6 meters and a diameter of 30 centimetres) and have un-buttressed roots. This species normally grows in the back portion of mangrove swamps, which remains unaffected by tidal inundation, except during spring tides. The bark is light brown to reddish dark brown, and the leaves are ovate. The leaves have adapted to their salty environment by developing special openings (glands) that allow salt to pass from inside the tree to the outside. The leaves are then coated with speckled white salt crystals which are what gives this species its name- white mangrove.

  8. Intrinsic Values of Mangroves 1] Coastal Resilience Mangrove forests provide protection and shelter against extreme weather events, such as storm winds and floods, as well as tsunamis. Mangroves absorb and disperse tidal surges associated with these events – as indicated by Hirashi and Harada (2003), a mangrove stand of 30 trees per 0.01 hectare with a depth of 100 m can reduce the destructive force of a tsunami by up to 90%.

  9. 2] Biodiversity Mangrove forests are rich in biodiversity providing a habitat for wide varieties 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. Many of the fish caught commercially in tropical regions reproduce and spend time in the mangroves as juveniles or adults. Mangroves are also home to many birds and mammals – such as mangrove monkeys in South Asia.

  10. 3] Economic value • Traditional economic activities vary from fishing and gathering of crustaceans to usages of the trees for timber or tannin production. Research by Barbier (2007) concluded that the economic annual value of just one hectare of mangrove forest (by adding the values of collected wood and non-wood forest products, fishery, nursery and coastal protection against storms) is $12,392. In many coastal areas including Gulf of Kutch, mangroves are a substitute for fodder. Thus mangroves reduce pressures from the scarce pasturelands. • Honey collection from the mangrove forest • is a promising business in India. It has been • estimated that Sundarbans mangrove • alone produce 111 tons of honey annually. • Honey collected from Cynometraramiflora • and Aegialitisrotundifolia has a good • market value and is in demand.

  11. 4] Tourism: Given the diversity of life inhabiting mangrove systems, and their proximity in many cases to other tourist attractions such as coral reefs and sandy beaches, it is perhaps surprising that only a few countries have started to tap into the tourism potential of their mangrove forests. Places as diverse as Bonaire and offer snorkelling expeditions in and around mangroves to witness a marvellous variety of baby fish, jellyfish, and urchins against a magical background of interwoven roots delving deep into the sandy substrate. Great potential exists elsewhere for revenue generation in this manner, which values the mangroves intact and as they stand.

  12. 5] cultural value • Next to economic • value, mangroves • also bear great • cultural significance • for communities, • such as the  • Concheras (shellfish-gatherers) in • South America, as their identity is strongly related to the ecosystem they live in.

  13. 6] Carbon Storage Storage of carbon in mangroves takes place through accumulation in living biomass and through burial in sediment deposits. With living biomass typically ranging between 100-400 tonnes/ha, and significant quantities of organic matter being stored in the sediments, mangroves rival the sequestration potential of rainforests.

  14. Worldwide distribution of mangroves Mangroves are found along many of the coasts in the tropics and subtropics, but the total area of mangroves in the world is not well known. Recent estimates range from 16.5 million hectares (FAO, 1994, based on figures from the early and mid-1980s) to 16.9 million hectares (IUCN, 1983), 18.1 million hectares (Spalding, Blasco and Field, 1997) and 19.9 million hectares (Fisher And Spalding, 1993, cited In Spalding, Blasco and Field, 1997). In many of these studies, countries with small areas of mangroves have been excluded.

  15. Mangroves under threat • Globally, half of all • mangrove forests have • been lost since the • mid-twentieth century, • with one-fifth since • 1980 (Spalding et al. 2010). Conversion into shrimp • farms causes 25% of the total destruction, according to UNEP (Botkin and Keller, 2003), happening mostly in Southeast Asia and Latin America. Other drivers of mangrove destruction are wood extraction, climate change and industrial development such as harbours and tourism.

  16. Mangroves in India Surrounded by the Indian Ocean, the Arabian Sea and the Bay of Bengal, India has over 7,500 kilometers of coastline that spans 13 maritime mainland States and Union Territories (UTs). India is home to a variety of coastal and marine ecosystems that are storehouses for biodiversity. From an economic perspective, these coastal and marine ecosystems are of great importance in that they provide a wide range of ecosystem goods and services.

  17. India has a long tradition of mangrove Forest Management. The concern of the Government of India for the conservation of forests and wildlife was clearly demonstrated by a 1976 amendment to the Indian Constitution, which states that it shall be the duty of every citizen of India to protect and improve the natural environment including forests, lakes, rivers and wildlife.

  18. On the basis of the National Mangrove Committee's recommendation, 15 mangrove areas were identified for conservation. The Government of India has provided guidance and financial assistance to States and Union territories for the preparation and implementation of Management Action plans for the conservation and development of these mangrove ecosystems. Most of these plans are now being implemented. The plans broadly cover survey and demarcation, natural regeneration in selected areas, afforestation, protection measures, fencing and awareness programmes.

  19. To protect the mangrove ecosystem, government of India has passed various legislations like The Forest Conservation Act, 1980, the Environment (Protection) Act, 1986 etc. These acts prohibits the diversion of forest areas for non-forestry purpose and prohibits the industrial and other activities such as discharge of untreated water and effluents, dumping of waste, land reclamation and bunding are restricted in order to protect the coastal environment. Mangroves are included in the most ecologically sensitive category.

  20. Mangrove conservation and development efforts undertaken by the Government of India, the Government of Goa and the Andaman and Nicobar Islands Administration have so far been successful in reducing the degree of problems, but there is scope for further improvement.

  21. Some suggested actions include the following: 1] People's involvement in mangrove management on public lands and related benefits 2] Programmes to raise people's awareness of the importance of mangroves, e.g. through films, exhibitions, newspapers, magazines, posters, stickers, brochures, banners, seminars, nature camps etc 3] Bird watching and study tours in the mangrove forests. 4] Establishment of mangrove parks in the mangrove areas close to towns 5] Celebration of Mangrove Conservation Day, with essay competitions, debates and drawing competitions 6] Incentives for sustainable management of mangroves on private and village community land 7] Enforcement of environmental protection laws 8] Research on problems related to pests and diseases and on appropriate management of the mangrove ecosystem 9] Restoration and rehabilitation of degraded mangrove areas.

  22. This educational PowerPoint Presentation (editable) is prepared by GEM Team (courtesy: internet). For other similar GEM PowerPoint Presentations on various environmental issues see next slide. These PPTs may be downloaded from our website Or visit GEM FACEBOOK