1. What is Mangrove
Group of Plants taxonomically isolated and successfully adapted in colonizing saline intertidal zone at the interface between the land and sea along the deltas, shallow lagoons, bays and back waters in tropical and subtropical sheltered coast lines.
2. Characteristic of Mangroves
Mangrove forest is restricted only along the saline intertidal habitat of sheltered coastline. It is characterized by dark green foliage and negatively geotropic roots. It shows maximum modification in its morphology, physiology and biochemical processes expressing some superficial characters like preumatophores, stilt roots and vivipary for withstanding partly submerged saline conditions.
3. Best growth and limitation of mangrove forests
Best Mangrove formation is found where the tidal regime is normal (2-6 ft/1-3 m) with regular mixing of seawater and fresh water form the rivers, where temperature does not optimally go below 200 C, soil is mostly alluvial in nature with high salt, low oxygen, high hydrogen sulphide, high water contents and rainfall remains 2000-3000 mm per year. Mangrove forest can extend only up to the limit of saline intertidal flow.
4. Role of mangrove ecosystem for sustainable development
a) This ecosystem maintains a very special type of biological diversity and highest biological productivity.
b) Mangrove plants play a vital role in environmental protection and act as a cost-free self-repairing static border security force for saving inland vegetation and life from storm, cyclone and floods.
c) This ecosystem provides atmospheric equilibrium; checks soil erosion, stabilizes coastline by adding new areas and building new islands.
d) Some of the potential resources of this ecosystem are very valuable for sustainable life support system, such as highly efficient fuel energy from the wood of Avicennia, source of good charcoal, tannins, ply-woods, adhesive, alcohol, honey, wax, rayon, oils, fodder, medicines, perfumes, boat and ship building materials, paper pulp and many wild life resources like fishes, crustaceans, shellfishes, reptiles, birds, amphibians, insects and mammals. It is very valuable for many migratory birds, edible crabs, fishes, tiger prawns, reptile’s skin, oysters and the Royal Bengal Tiger.
5. Areawise distribution of Mangroves forests in India
|
Total areas in the world (source : Wacharakitty, 1993) |
1,71091 Sq. km. |
|
Total areas in India (non IRS) |
6756 Sq. km. |
|
Total areas (IRS) India |
4844 Sq. km. |
6. Distribution of Mangrove areas in different states
(The state-wise area covered by mangrove forests (nonIRS & IRS data) are shown in the following charts.)
Areas of Mangroves [Area in Sq. km. (Non IRS)]
Areas covered by Mangroves [Area in Sq. km. (IRS)]
7. Assessment of Species diversity
Except one fern Acrostichum, all trees, shrubs, climbers and herbs in this group belong to the families of Angiosperm. Species diversity is dependent upon the availability of optimum ecological conditions in different areas. Depending upon the relative environmental factors, richness of the species decreases from the East coast mainly the Sunderbans and the Mahanadi delta towards the West Coast and finally form a monotype strand in the Gulf of Kutchh in Gujarat.
a. Diversity of families, genera & species of world mangroves (including orchids)
|
World |
New World |
Old World |
|
|
Families |
31 |
4 |
29 |
|
Genera |
47 |
5 |
42 |
|
Species |
99 |
13 |
82 |
b. Diversity of families, genera & species in Indian mangroves (excluding orchids)
|
India |
E. Coast |
W. Coast |
And. & Nico. |
|
|
Families |
29 |
28 |
20 |
22 |
|
Genera |
43 |
42 |
26 |
32 |
|
Species |
69 |
63 |
35 |
49 |
c. No. of salt marshes & associated species in mangrove areas in India
|
Families |
Genera |
Species |
|
|
Salt marshes |
1 |
8 |
12 |
|
Orchids |
1 |
4 |
7 |
|
Asclepiadaceae |
1 |
1 |
2 |
d. No. of mangrove species endemic, rare/endangered in India
|
No. of Species |
Percentage |
|
|
Endemic |
6 |
8.8 |
|
Endng / Rare |
25 |
36.5 |
e. No. of families, genera and species occur in different states of India
|
S.No. |
State |
Families |
Genera |
Species |
|
1 |
West Bengal |
26 |
40 |
59 |
|
2 |
Orissa |
27 |
40 |
61 |
|
3 |
Andhra Pradesh |
19 |
26 |
33 |
|
4 |
Tamil Nadu |
13 |
16 |
20 |
|
5 |
Kerala |
15 |
21 |
25 |
|
6 |
Karnataka |
19 |
17 |
24 |
|
7 |
Goa |
11 |
15 |
22 |
|
8 |
Maharashtra |
13 |
17 |
25 |
|
9 |
Gujarat |
9 |
10 |
12 |
|
10 |
Andaman & Nicobar Island |
22 |
32 |
49 |
8. Values
Mangroves are the mainteners of near shore marine habitats and simultaneously provide varieties of commercial and economic values to a variety of organism in different trophic levels. Besides the commercial and economic values, mangroves also play a major role in maintaining different types of environmental problems. The economic and commercial values as well as environmental values are shown in the following table:
Economic and Commercial values
|
Firewood and Charcoal |
Adhesive |
|
Timber for house and ship building |
Fish food and fish float |
|
Fishes |
Crocodile skin |
|
Shrimps and prawns |
Perfume |
|
Crabs, shelfish amd crustaceans |
Soft wood industries |
|
Birds |
Oils |
|
Tannin |
Alcohol used as transport fuel |
|
Mammals |
Rayon |
|
Ply wood |
Fibre |
|
Paper pulp |
Amphibian |
|
Fodder |
Condiments |
|
Honey and wax |
Sweet meat |
|
Medicine |
Cigarette wrappers |
Environmental values
Protection from wind, storm, cyclone and act as a cost free self repairing static security guard
Shore line stabilization
Decrease coastal erosion
Protect inland flora and fauna from the effect of sea level rise
Essential habitat for spawning and nursery bed of marine fishes
Sewage and industrial pollutant resistant
Essential habitat for Royal Bengal Tiger
Essential habitat for scarlet eye bees and other endangered migratory birds
Essential habitat for estuarine crocodiles, dugongs, dolphin
Essential habitat for Olive Ridley Turtles
Essential habitat for sea otters
Eco-tourism
Education and Scientific studies
PROBLEMS
Indiscriminate Tree felling and Lopping. Indiscriminate Conversion of Land, Creeks and Channels. Industrial Pollutants. Global Threats Regarding the Rise of Temperature due to Green House Drift and Rise of Sea Level. Encroachments. Ownership of Land. Traditional Method of Fishing. Cattle Pressure. Wood Borers & Pests. Infestation by Barnacles, Oysters, Crabs and Gastropods. Grass Cutting. Mortality of Mangrove Trees.
STRATEGIES
Preservation
(Absolute Protection for Biodiversity)
Conservation
(Human use of the Protected Areas under Biosphere Reserve, National Park & Santuaries)
Use of Mangrove Areas for Various Economic Purposes
(Acquaculture, Mariculture, Fishing, Nagivaion, Eco-Tourism, Water Sports, Salt Production, Sea weed Culture etc.)
Large Scale Plantation in Degraded Mangrove Area
ACTION PLAN
Estuaries, Deltas and adjoining major river system should be conserved as
National Parks, Sanctuaries or Biosphere Reserve for Biodiversity conservation.
Protection of coastal flood, soil erosion and environmental equilibrium through plantation. Productive fishing zone should be conserved for breeding, spawning and nurshing ground. Densely Forested areas regardless to location should be reserved for protection of wildlife,
forest produce and environment. Small and big islands should be conserved for speciation and formation of new land.