Vol. 4 Year 2004Biodiversity in mangrove ecosystems of India: Status, challenges
and strategiesFaunal resources in mangrove ecosystem
Biodiversity conservation in Indian Sunderban at landscape level: Present
status and strategiesSustainable utilisation of mangrove ecosystem for local community
developmentHeavy metals in mangroves: Methodology, monitoring and
managementMeasuring the effects of salinity stress in the red mangrove,
Rhizophora mangle L.
Bibliography on Mangroves
(2000-2004)
FOREST RESEARCH INSTITUTE
(INDIAN COUNCIL OF FORESTRY RESEARCH AND EDUCATION)
DEHRADUN
PICTORIAL INTRODUCTION TO MANGROVES
FlowersRhizophora apiculata
Lumnitzera littorea
Sonneratia alba
Bruguiera gymnorrhiza
Ceriops tagal Aegiceras corniculatum
Nypa fruticans Phoenix paludosa
Fruits
Xylocarpus granatum Avicennia officinalis
Phoenix paludosa Nypa fruticans
Heritiera littoralis Sonneratia alba
Propagules
Bruguiera cylindrica Ceriops tagal
Rhizophora mucronata
Twin propagules in Rhizophora mucronata Ceriops tagal
Roots
Stilt roots of Rhizophora spp. on muddy substratu Stilt roots of Rhizophora spp. on rocky substratum
Knee roots of Bruguiera spp. Pneumatophores of Xylocarpus mekongensis
Rhizophora mucronata Exposed roots of Xylocarpus granatum
Utility
A walkway made from Phoenix paludosa Edible tender leaves of Acrostichum aureum
Potential area for fisheries
Restoration
A view of mangrove nursery
Plantation of Ceriops tagal Plantation of Rhizophora
apiculata and Bruguiera gymnorrhiza
Plantation of Bruguiera gymnorrhiza
Problems
Indiscriminate felling of mangroves Effect of over-grazing on Avicennia marina
Area infested by Acrostichum aureum Conversion of mangrove area for
aquaculturepreventing better mangroves
Effect of excessive lopping on Bruguiera parviflora Snails feeding on mangroves
Conversion of mangrove area for salt production
Bunding in mangrove area for reclamation
Pest attack on leaves of Rhizophora spp.
Illegal collection of firewood from mangroves
Rare Mangroves
Lumnitzera littorea: Phoenix paludosa
Growing on crab mound
An over-mature tree of Xylocarpus mekongensis Nypa fruticans
BIODIVERSITY IN MANGROVE ECOSYSTEMS OF INDIA: STATUS, CHALLENGES AND STRATEGIES
K. Kathiresan
Annamalai University, Parangipetai - 608 502Introduction
Mangrove forests are among the world’s most productive ecosystems. They enrich coastal biodiversity, yieldcommercial forest products, protect coastlines, and support coastal fisheries (Kathiresan and Bingham, 2001). There may be no other group of plants with such highly developed adaptations to extreme conditions of high salinity, tides, strong winds, high temperatures, and muddy and anaerobic soils. The mangroves create a unique ecological environment that hosts rich assemblages of species. Globally, the mangrove habitats continue to disappear. This paper deals with the present status of mangroves in India, threats faced by them, and strategies responding to the challenges of sustainable development of mangrove resources in this country.
Current Status of Mangroves
Extent of Mangroves
India has a total area of 4,482 km2 under mangroves (Table 1). About 59 per cent are found along the east coast (Bay of Bengal), 23 per cent on the west coast (Arabian sea) and the remaining 18 per cent on the Bay Islands (Andaman & Nicobar Islands in Bay of Bengal) (Fig.1; Table 1).
There are three major types of coastal settings on which mangroves in India exist and they are (i) deltaic, (ii) backwater-estuarine and (iii) insular categories. The deltaic mangroves occur along the east coast (Bay of Bengal) where the mighty rivers (Ganga, Brahmaputra, Mahanadhi, Krishna, Godavari and Cauvery) make the deltas. The backwater-estuarine type of mangroves that exists in the west coast (Arabian Sea) is characterised by typical funnel-shaped estuaries of major rivers (Indus, Narmada, Tapti with delta formation almost absent) or backwaters, creeks, and neritic inlets. The insular mangroves are present in the Bay Islands, where many tidal estuaries, small rivers, neritic islets, and lagoons support a rich mangrove flora.
The mangroves are large widespread on the east coast of India due to the nutrient-rich alluvial soil formed by the mighty rivers and a perennial supply of freshwater along the deltaic coasts. But, the deltas with alluvial
Table 1.
State and district-wise cover of mangrove forests in India
S. no. State District-wise area
(km2)State-wise
area
(km2)Total
area
(km2)East coast 1. West Bengal Medinipur 3 24 Parganas North 29 24 Paragnas South 2,093 2,125 43.63 (2081) (46.43) 2.
Orissa Baleshwar 3 Bhadrak 18 Jagatsinghpur 10 Kendarapara 184 215 4.40 (219) (4.89) 3.
Andhra Pradesh Godavari 241 Krishna 104 Guntur 52 397 8.15 (333) (7.43) 4.
Tamil Nadu South Arcot 9 Trichirapalli, Thanjavur, Pudukottai 12 21 0.40 (24) (0.55) Bay Island 5.
Andaman and Nicobar Andamans Nicobar 929 37 966 19.83 (789) (17.6) West coast 6.
Gujarat Bharuch 6 Bhavnagar 25 Jamnagar 140 Kachchh 854 Surat 4 Unagarh 1 Valsad 1 1,031 21.17 (911) (20.33) 7.
Maharashtra Mumbai city 2 Mumbai 32 Thane 24 Raigarh 38 Ratnagiri 12 108 2.22 (118) (2.63) 8.
Goa Goa 5 5 0.10 (5) (0.11) 9.
Karnataka Dakshina Kannada 2 0.06 Uttara Kannada 1 3 (2) (0.05) 10.
Kerala Sparse - Total 4,871 100.00 (4,482) (value in parentheses is the latest cover reported by Forest Survey of India , 2001)
Source: The State of Forest Report, 1999 and 2001, FSI, Dehradundeposits are almost absent on the west coast of India, and in their place is taken by the funnel-shaped estuaries or backwaters (Gopal and Krishnamurthy, 1993). The east coast has a smooth and gradual slope which provides larger area for colonisation of mangroves, whereas the west coast has a steep and vertical slope (Fig. 2).
Floral Species Diversity
Total numbers of floral species present in mangrove forests of India are given in Table 2. Altogether, 879 species of flora, consisting of 559 algae, 104 fungi, 69 bacteria, 32 lichens, 23 actinomycetes, 12 plants of saltmarshes, 11 seagrasses are on record. East and west coasts are represented with about 500 floral species, whereas only 194 species have been recorded from the Andaman and Nicobar Islands. This low number of floral species on the island ecosystem must be due to lack of proper survey conducted so far, as compared to other coastal regions.
Faunal Species Diversity
Total numbers of faunal species that occur in mangrove habitats of India are given in Table 3. Altogether, 3,122 species of fauna consisting of 749 invertebrates,711 insects, 546 fin-fish, 435 birds, 311 molluscs, 139 crabs, 85 reptiles, 71 mammals, 55 prawns, 13 amphibians and 7 fish parasites are on record. East coast is represented by 2,075, a high number of faunal species. This is followed by Andaman and Nicobar Islands with 827 species and by west coast with 728 species. The reasons for the species richness in the east coast of India may be due to the presence of luxuriant mangrove forests and to the proper surveys conducted there, as compared to other coastal regions.
Fig. 1. Mangrove areas of IndiaTotal Biological SpeciesTotal numbers of floral and faunal species reportedly present in mangrove forests of India are shown in Table 4. Altogether, 4001 species of flora and fauna consisting of 879 floral species and 3,122 faunal species are present. Of the total biological species so far recorded, the faunal species occupies 78 per cent and the floral species 22 per cent and thus the faunal species component is about 3.5 fold higher than floral component.
Fig. 2. A cross section from Daman and Cuttack showing the gradients along the east and west coasts of India
(values not to the scale; Redrawn from A.G. Untawale)
Table 2.
Total numbers of floral species occurring in mangroves of east and west coasts and of Andaman and Nicobar Islands of IndiaTable 3. Total number of faunal species reportedly occurring from mangrove habitats along the east and west coasts of India, and from the Andaman and Nicobar Islands
Floral group
East coast Andaman
& Nicobar IslandsWest coast Total Mangroves 63 44 37 69 Salt-marsh vegetation 12 - 10 12 Seagrass vegetation 11 7 2 11 Marine algae
(phytoplankton+seaweeds)265 71 325 559 Bacteria 58 13 10 69 Fungi 58 59 80 104 Actinomycetes 23 - 11 23 Lichens 32 32 32 Total 464 194 507 879
Floral group
East coast Andaman
& Nicobar IslandsWest coast Total Prawns 35 17 29 55 Crabs 91 58 29 139 Insects 371 240 10 711 Mollusks 185 114 81 311 Other Invertebrates 581 76 183 749 Fish parasites 7 0 0 7 Fin fish 331 249 125 546 Amphibians 8 5 0 13 Reptiles 80 7 3 85 Birds 323 53 265 435 Mammals 63 8 3 71 Total 2,075 827 728 3,122 Conservation Status of Biological Species
Conservation status of mangrove speciesMangrove ecosystem as a whole is in vulnerable condition. Hence, all the components of the ecosystem need to be conserved critically. It is necessary to prioritise the rare, endemic and endangered species for immediate conservation measures. My personal field study reveals that 20 mangrove species are either rare or endemic and the species are given in the Table 5.
More widely distributed species such as Aegiceras corniculatum, Acanthus ilicifolius, Avicennia marina, A. officinalis and Excoecaria agallocha, have great ecological amplitude and remarkable ability of vegetative regeneration. Due to high productive values in fuel energy, timber, fodder, boat and house building materials, tannin, paper pulp, and in other sustainable life supports, some common mangrove species of Avicennia, Excoecaria, Bruguiera and Rhizophora may come under the threatened category with the increasing human pressure and if regular regeneration programme through afforestation are not taken up immediately, they may decline in the near future. The Ministry of Environment and Forests, Govt. of India has been taking many efforts to save the biodiversity components of the vulnerable ecosystem.
Conservation status of faunal species
The threatened faunal species that inhabit the mangroves in India are shown in the tables 5 to 10. Of 52 species of marine fish assessed, 9 are vulnerable and 2 are endangered; of 41 invertebrates assessed, 4 species are endangered, 4 species are vulnerable and only one species is critically endangered (Table 6 and 7; Ananda Rao et al., l998). In Sundarbans, 4 reptile , 3 bird and 5 mammal species are extinct, and 10 reptile, 3 bird and 2 mammal species are under threat (Table 8 to 10); Chaudhuri and Choudhury, l994). In Gujarat, 3 birds and 2 turtle species are threatened (Table 11; Wesley Sunderraj and Serebiah, l998).
Threats to Mangroves
The mangroves in India experience some 16 threat factors in different maritime states of our country as shown in the Table 11. Three problems are very common in most of the mangrove ecosystems and they are: 1. over-exploitation of fishery resources, 2. deforestation for firewood, cattle feed, rehabilitation, reclamation and conversion activities, and 3. lack of peoples’ awareness and participation in conservation activities. The most significant threat is of human pressure on mangrove-resources for forestry
Table 4.
Total numbers of floral and faunal species occurring in mangrove forests of India
No. Groups No. of species
Floral group 1. Mangroves 69 2. Saltmarsh vegetation 12 3. Seagrass vegetation 11 4. Marine algae (Phytoplankton + seaweeds) 559 5. Bacteria 69 6. Fungi 104 7. Actinomycetes 23 8. Lichens 32 Faunal group 9. Prawns 55 10. Crabs 139 11. Insects 711 12. Mollusks 311 13. Other invertebrates 749 14. Fish parasites 7 15. Fin fish 546 16. Amphibians 13 17. Reptiles 85 18. Birds 435 19. Mammals 71 Total number of species 4,001 and fishery products. Hence, the Ministry of Environment and forests, Govt. of India has given increasing attention for sustainable management of the mangrove resources, with the local peoples’ participation.
Besides the above-mentioned man-made threats, mangrove areas are prone to cyclone, storms and flood. These natural calamities often cause extensive damage to the mangrove ecosystem. There were 366 cyclones, out of which 133 were severe, along the Bay of Bengal, between 1891-1970; on the other hand, only 98 cyclones in the Arabian sea , of which 55 were of severe nature (Koteswaran, l984).
Mangrove ecosystem in India faces many threats in common; but, intensity of the threats varies with different mangrove areas. In general, mangroves in the east coast face more number of threats than the west coast and the Bay Islands. However, Gujarat encounters much problems unlike other mangroves of the west coast. Orissa (Bhitarkanika) faces fewer threats unlike other mangroves of the east coast and hence, the state has the highest species diversity (Table 12). There are area-specific threats, which are discussed below.
Threats in Sundarbans, West Bengal
The major issues identified are: 1. Exploitation of the mangrove forests due to human pressure, 2. conversion of mangrove areas for agricultural purposes, 3. over-exploitation of fisheries especially for seeds of tiger prawns, and 4) loss of flora and fauna (Government of India, l990).
Table 5.
Mangrove species which are rare, endemic and restricted in distribution in India
S.no. Species Rare/Endemic/Restricted distribution 1. Acanthus ebracteatus Restricted to Andaman & Kerala 2. Aegialitis rotundifolia Confined to West Bengal, Orissa & Andhra Pradesh 3. Agalia cuculata Restricted to West Bengal & Orissa 4. Brownlowia tersa 5. Heritiera fomes 6. Heritiera kanikensis Endemic to Bhitarkanika 7. Lumnitzera littorea Restricted to Andaman 8. Merope angulata Confined to West Bengal & Orissa 9. Nypa fruticans Restricted to West Bengal & Andaman 10. Phoenix paludosa Restricted to West Bengal, Orissa & Andaman 11. Rhizophora x annamalayana Endemic to Pichavaram 12. Rhizophora stylosa Confined to Orissa 13. Scyphiphora hydrophyllacea Restricted to Andaman & Andhra Pradesh 14. Sonneratia apetala Rare in several areas 15. S. griffithii Restricted to West Bengal, Orissa & Andaman 16. Tylophora tenuis West Bengal & Orissa 17. Urochondra setulosa Endemic to Gujarat 18. Thespesia populneoides Restricted to West Bengal & Orissa 19. Xylocarpus mekongensis Restricted to West Bengal, Orissa & Andaman 20. Xylocarpus mollucensis Restricted to Andaman
Large scale destruction of estuarine fish and prawn seed resources in the Hooghly- Matlah estuarinesystem of the Sundarban has been reported (Das et al., l987). The seed collectors are interested mostly for the seeds of tiger shrimp as it has trade value and they intend to intensify effort towards collection of tiger shrimp for monitory return. It was estimated that seed collectors destroyed 181.4 million seeds of fin- and shell-fishes after retaining only the seeds of tiger shrimp during the months from January to September (Bhaumik et al., l992). Another report states that about 40,000 shrimp seed collectors annually harvest about 540 million seeds of Penaeus monodon and in this process, about 10.26 billion seeds of other fish and shrimp are killed, which will have a serious impact on future yield of the tiger prawns in the Sundarbans (Chaudhuri and Choudhury, l994).
Other threats to the Sundarban mangroves include 1. acid sulphate soil, 2. pollution, 3. sedimentation and erosion, and 4. embankment constructions. Mangrove soils in many areas are rich in pyrite (FeS
2), which will be converted into sulphuric acid when exposed to air. This soil is extremely acidic and low in fertility. Pollution due to heavy discharge of effluents from many factories has spoiled the water resources, in manyTable 6.
Threatened species of fish along the Indian mangrovesSource: Ananda Rao et al., l998
S.no. Species Family IUCN status 1. Arius subrostratus valenciennes Ariidae Vulnerable 2. Boleophthalmus boddarti Cuvier Gobiidae Vulnerable 3. Boleophthalmus dussumieri Cuv. Val Gobiidae Endangered 4. Scartelaos viridis Ham. –Buch. Gobiidae Endangered 5. Periophthalmus koelreuteri Bl. Schn. Gobiidae Vulnerable 6. Dasyatis uarnak (Forsskal) Trygonidae Vulnerable 7. Elops machnata (Forsskal) Elopidae Vulnerable 8. Leiognathus splendens (Cuvier) Leiognathidae Vulnerable 9. Muraenichthys schultzei (Bleeker) Muraenidae Vulnerable 10. Psammaperca waigiensis (Cuvier) Centropomidae Vulnerable 11. Secutor ruconius Ham. - Buch. Leiognathidae Vulnerable Table 7.
Threatened species of invertebrates along the Indian mangroves
S.no. Species Family IUCN status 1. Cardisoma carnifex (Herbst) Gecarcinidae Critically endangered 2. Gelonia erosa (Solander, l786) Geloindae Endangered 3. Macrophthalmus convexus Stimpson l858 Ocypodidae Endangered 4. Meretrix casta (Chemnitz) Veneridae Vulnerable 5. Penaeus canaliculatus (Oliver, l811) Palaemonidae Vulnerable 6. Penaeus japonicus Bate, l888 Palaemonidae Vulnerable 7. Pilodius nigrocrinitus Stimpson, l858 Xanthindae Endangered 8. Sesarma taeniolata Grapsidae Vulnerable 9. Uca tetragonon (herbst, l790) Lanchester, l900 Ocypodidae Endangered Source: Ananda Rao et al., l998
places (Chaudhuri and Choudhury, l994). Erosion is a serious problem along the estuarine mouths due to severe tidal wave actions in the Sundarbans. The erosion of embankments especially during monsoon results in flooding of human dwellings, which is a perennial problem. Besides this, construction of embankments to prevent entry of water in to the human dwellings, and a number of artificial drainage systems has changed the pattern of water movement and tidal inundation.
Due to reduction in freshwater inputs, the freshwater loving species like Nypa fruticans and Heritiera fomes get reduced in population density.
Threats in Orissa
In the Bhitarkanika, mangrove destruction is due to human pressure, conversion of paddy cultivation etc. In Mahanadi, the destruction of mangroves is due to heavy human pressure, indiscriminate felling, decrease of wildlife particularly endangered species and fishes; and, conversion for different land uses (India, Ministry of Environment and Forests, l990).
Chadha and Kar (l999) detailed the degradation issues. There is a heavy pressure on forest resources of Bhitarkanika for fodder, firewood, house and other constructions, due to large human and cattle populations. This is a problem specifically after the harvest of agriculture crops, when the people are unemployed during the period between December to May. An estimated 70,000 cattle are found within the sanctuary.
Table 8.
Threatened and extinct reptile species in Sundarbans*Extinct species
S.no. Name of species Family 1. Crocodilus porosus Crocodilidae 2. Varanus bengalensis Varanidae 3. V. salvator " 4. V. flavescens " 5. Chelonia mydas* Chelonidae 6. Eretmochelys imbricata* " 7. Lepidochalys olivacea " 8. Caretta caretta* " 9. Demochelys coriacea* " 10. Lissemys punctata Trionychidae 11. Trionyx gangeticus " 12. T. hurun " 13. Batagur baska Emydidae 14. Python molurus Boidae
Source: Chaudhuri and Choudhury, l994.Table 9.
Threatened and extinct bird species in Sundarbans
S.no. Name of species Family 1. Pelecanus philippinensis Pelecanidae 2. Theskiornis melanocephalus Threskiornithidae 3. Leptoptilos javanicus* Ardeidae 4. Ardea goliath " 5. Sarkiodornis melanotus* Anatidae 6. Cairina scutulata* * Extinct species
Source: Chaudhuri and Choudhury, l994.Table 10.
Threatened and extinct mammal species of Sundarbans
S.no. Name of species Family 1. Panthera tigris Felidae 2. Muntiacus muntjac* 3. Bubalis bubalis* 4. Rhinoceros sondaicus* 5. Cervus deruchea* Cervidae 6. Axis porcinus* 7.
Platanista gangetica Platinistidae *Extinct species
Source: Chaudhuri and Choudhury, l994.Table 11.
Threatened species in mangroves of Gujarat
S.no. Name of Species Family Birds 1. Platelia leucorodia 2. Pelecanus philippensiscrispus Pelecanidae 3. Pelecanus philippensis Turtle 4. Chelonia mydas 5. Lepidochethys olivacea Source: Wesley Sunderraj and Serebiah, l998
During cropping season, from June to November, these cattle depend mainly on the forests for fodder. Avicennia, an excellent fodder is under intense pressure due to heavy grazing by buffaloes in the Bhitarkanika, Mahanadi Delta, Balasore coast and Jagatshinghpur district (Chadha and Kar, l999). The average fuel used per household is about 14 kg per day, out of which 12 kg would be in the form of firewood obtained from mangrove forests. About 1,10,000 people depend on the natural firewood of the protected area. About 20,000 people are engaged in collecting firewood from the forests on daily basis. There is a huge gap in demand and the sustainable supply from the forests. Most of the households are constructed by using mangroves: Phoenix stems are used for construction of walls and leaves for thatching, Heritiera for making doors and windows, besides Lumnitzera, Xylocarpus and Avicennia, etc. (Chadha and Kar, l999).
The Orissa mangroves have a serious problem of encroachments. The growing population expands agriculture by encroaching more of the forestlands. Aquaculture in the area had created resentment among the local fishermen. Large areas of mangroves were cleared in the Hatamundia reserved forest for aquaculture purposes (Indian Space Research Organisation, l992).
Poaching of animals like spotted deer, wild-boar, python, cobra, crocodile, migratory birds, occur occasionally in the sanctuary.
The mangroves often exhibit some disease problems. Heritiera fomes dies from the bottom stem; reason for which is not known. Sonneratia apetala shows tip drying disease probably due to high salinity especially during summer.
Threats in Andhra Pradesh
In Andhra Pradesh, natural factors and man-made stresses threaten the mangroves. Occasionally the
cyclonic floods damage the mangroves and associated human beings. Other physical factors that damage the mangroves are vast low-lying areas, funnel-shaped configuration of the river mouth, siltation and shallowness of seawater inlets, and flooding of the rivers with fresh water (Banerjee et al., l998). Kakinada Bay has only about 5 feet depth during high tides, due to heavy siltation, which may result in the changes of water movements and in the formation of mudflats. The Coringa is now separated by a coastal sandy spit, which makes the entry of seawater into the channel very difficult. In general, the mangrove islets are seen well-elevated with sharp vertical peripheral margin due to tidal wave action. The highly elevated lands lack regular tidal flushing and hence, the area is colonised with saltmarsh vegetation of Suaeda species. However, certain blank spaces are also found on the middle area of the elevated lands. This may be due to high salinity.
The mangroves are often affected by disease and pest problems. For example, Avicennia and Sonneratia are infected by the black rust especially at their basal trunks; seedlings of Rhizophora apiculata are damaged by crabs; Avicennia is found defoliated and even killed by lepidopterous larvae; Bruguiera parviflora is damaged at their basal trunks by the larvae of cerambycid beetles; and, Rhizophora mucronata shows browning by a fungus (Cryptospora), starting from the middle of the hypocotyls (Banerjee et al., l998).
Man-made problems are mostly in the reclamation of mangrove lands for agriculture and prawn culture practices, tree felling for firewood, house and boat constructions and developmental activities such as establishment of fertilizer factory nearer to the mangroves (Banerjee et al., l998). There is an over-exploitation of fishery resources especially for the seeds of the tiger prawns. The gastropods like Cerithidea cingulata and Telescopium telescopium and the bivalves such as Anadara granosa and Meritrix species are exploited for lime preparation.
The mangroves are excellent feed for cattle. The buffaloes, goats and cows are left among mangroves during the summer months and they graze Avicennia leaves and grasses (Porteresia coarctata, Myriostachya wightiana, Aleuropus lagopoides). Local people in large quantities to feed their cattle also collect the leaves. It is believed that the buffaloes when fed with Avicennia leaves produce more milk.
The mangroves are used as firewood as they have high calorific value. A ton of mangrove firewood is approximately equivalent to 2 to 5 tons of Indian coal and it burns with high heat without producing any smoke (Banerjee et al., l998). Other threats are due to salt manufacturing, replacement of mangroves by Casuarina plantation by farmers (Jayasundaramma et al., l987) and sea level rise (Prasad et al., l997).
Threats in Tamil Nadu
Cattle grazing, dwindling of fishery resources, siltation, tree felling, heavy human pressure, hyper-salinity etc., are important problems.
Anthropogenic pressure is a major threat especially in the Pichavaram mangrove forest. It is surrounded by 11 villages at a distance of 1 to 3 km from the forest area, colonized by around 2000 families with a total population of 10,000. The fishermen community face three major issues: 1. decline in fishery resources and fishers income; 2. poor fodder supply; and, 3. inadequate firewood availability. The decline in fishery resources is mainly due to narrowing of the river mouth due to siltation. This interferes with the entry of fish juveniles from the Bay of Bengal to mangrove water bodies, which results in decline of fishery resources (Kathiresan, 2000). A similar problem also exists in the Muthupet. The local people have felt seriousness of the problem.
The fodder requirement is about 7 tons/day for feeding 1800 cattles and goats, which utilise mostly the mangrove and adjoining areas of the Pichavaram for grazing especially on Avicennia species. This problem of grazing is very serious especially during monsoon. The propagules especially of Avicennia spp. produced during the season are damaged by the grazing cattle resulting in poor regeneration, especially in Muthupet areas. The firewood requirement is about 6 tons per day for 2,000 families in the Pichavaram. Satisfying the needs of the local people is a prerequisite for sustainable management of mangrove resources.
Pichavaram mangrove forests have already lost 75 per cent of its green cover within the last century and of the existing forest area, only 10 per cent has dense vegetation, while the remaining 90 per cent of the area has been degrading. Kathiresan (2002) has identified that the causes of the natural degradation of mangroves are mainly due to high salinity, low level of available nutrients, and poor microbial counts in the soil substrates. The M.S. Swaminathan Research Foundation, Chennai has identified the problem of poor tidal flushing as an important cause for mangrove degradation. Poor supply of tidal waters as well as that of fresh water from terrestrial sources adds to the problem of mangrove degradation especially in the Pichavaram. The former results in poor flushing and the latter leads to poor supply of sediments, and these have lead to poor sprouting of mangrove propagules. To alleviate these issues, suggestions have been made on flushing of hypersaline soil with tidal water by trenching or by harvesting rainwater. The forest departments in Tamil Nadu and Andhra Pradesh states have been constructing trenches in the hypersaline soil so as to allow the soil flushed with tidal waters and then raising mangroves successfully.
The Gulf of Mannar faces a major problem of high deposition of suspended sediments. The suspended load moves from Vedaranyam towards Rameshwaram Islands, which ultimately damages coral reef and seagrass ecosystems (Shanmugaraj, l998). It is necessary to explore possibility to prevent the suspended sediments by strengthening the mangrove vegetation along the coastal areas from Vedaranyam to Rameshwaram.
Threats in Andaman and Nicobar Islands
In Andaman and Nicobar Islands, degradation occurred only in very small pockets up to 2,379 m
2 within 7 years (Ramachandran et al., l998). However, the mangroves are less disturbed as compared to other mangroves along the peninsular India. The factors responsible for degradation of mangroves are exploitation due to demand for wood and wood products; conversion of mangroves for agricultural and human habitation purposes, exploitation of fisheries, issues of encroachment and tourism. In addition to these, browsing and trampling by wildlife like deer, which are abundant in the Middle Andaman and livestock, which are often seen in areas close to human inhabitation (Rajiv Kumar, 2000).Threats in Gujarat
The Gujarat mangroves are called "open scrub mangroves" and are considered as the "most degraded one" (Blasco, l975).
The mangroves serve as the source of firewood for the local inhabitants and for those from adjoining areas. The mangroves form the principal source of fodder for cattle and camel especially in the Gulf of Kachchh and in the Great Rann. In the Gulf of Khambhat, mangroves are heavily exploited and reduced to open scrub forest.
Construction of dams across rivers like Rukmawati, Khari, Phot and Bhukhi and several other rivers have changed flow patterns of water and increased salinity and siltation. Several mining, cement and salt pan industries, etc., which are developing fast along the mangrove forests, have increased siltation, salinity and pollution in the coastal waters. Another serious threat to the mangroves of Gujarat is oil pollution that is likely to increase due to increased terminal pipeline passages and refineries (Thivakaran, l998).
Threats in Maharastra and Goa
The Bombay coast earlier had luxuriant mangrove vegetation till l670, but since then, large scale reclamation has destroyed the mangrove forests. The mangrove lands are privately owned in almost all parts of Maharashtra. The people have raised the level of mangrove land after clearing the vegetation; inflow of high tide water is stopped and preceded with farming or construction of buildings. This is being done under the Kar Land Development Programme (Bhosale and Mulik, l991). In some areas of Maharashtra, roads are being constructed right in the mangrove areas (Bhosale and Mulik, l991). Pollution has decreased the extent of mangroves on the banks, especially on the Thane creek of Maharashtra (Kadam, l992). The domestic sewage and industrial effluents damage mangroves in many places (Bhosale and Mulik, l991). The Mahim Creek is worst of the polluted creeks on the west coast, especially with arsenic (Rao et al., l991).
Threats in Karnataka
Pollution, tree felling and encroachment for agricultural or aquacultural operations are disturbing mangroves on the Karnataka coast.
Threats in Kerala
Kerala once had over 7,000 hectares of mangroves fringing its unique estuarine systems. It has now become reduced to a few discrete stands, confined to some small pockets of the Kerala backwaters (Ramachandran and Mohanan, l987). The removal of mangroves for agriculture, firewoods, constructions of houses and bunds etc., has drastically altered the ecology of the swamps (Scott, l989).
The local people are not aware of the value of mangroves, and they do think that the mangrove waters are responsible for breeding of mosquitoes. This has resulted in clearance of mangroves for agriculture in many areas, which has led to the formation of acid sulphate soil. This ultimately reduces the agriculture production of rice and coconut. To cite a specific example, in Thanneermukkam, a barrage has been constructed to prevent the seawater intrusion into the Vembanad estuary for paddy cultivation on reclaimed lands. This has resulted in reduced salinity of the estuarine water and in over-dominance of freshwater, throughout the year, resulting in stagnation of water bodies. This situation has reduced the fishery resources, declined the mangroves and encouraged profuse growth of freshwater weeds such as Eichhornia, Salvinia etc. The death and decay of the weeds and settlement in the bottom has made the Vembanad Lake shallow and is dying (Untawale Personal Communication). Also local people misuse the backwaters and this activity damages the fringing mangroves.
Remedial Measures
Remedial measures for mangrove conservation and management are given here-under:
·
Allow the local communities to cultivate the fast growing mangrove species like Avicennia in degraded areas.·
Provide alternative sources of timber (like Casuarina)·
Implement silviculture strategies like practising the crop rotation once in 15 years in alternate strips (60m wide at an angle of 45° to the waterways), and regeneration naturally by using seeds of nearby mangrove trees.·
Ban entry of cattle during monsoon.·
Provide alternative source of fodder.·
Encourage the people to cultivate fodder species through inter-cropping with Casuarina.·
Implement dairy development scheme for the local communities.·
Develop bio-fencing using toxic mangrove species like Excoecaria agallocha.·
Prevent mechanised craft operations in shallow waters of mangroves.·
Allow the fishing nets with >20mm mesh size that prevents the catch of juvenile fishes.·
Ban fishing activities during the critical stage of fish breeding (premonsoon and summer) thereby allowing development of juvenile fishes.·
Create awareness of mangroves about the conservation of mangroves.·
Involve the local people particularly womenfolk in planning and implementation of management action plans.·
Seize fire-arms from license holders for preventing poaching of wildlife from mangroves.·
Restore and recover abandoned shrimp ponds, with mangrove planting.·
Develop environmentally sound aquaculture integrated with mangrove silviculture and fisheries for benefit of local communities.·
Prevent the water flow reduction in rivers that feed mangrove habitats.·
Ban any waterway barrier that affects the mangroves drastically.·
Flushing the dry hypersaline soil with tidal waters through the construction of artificial creeks.·
Drain the stagnant saltwater in the mangrove habitats before summer.·
Implement massive planting programmes to strengthen the river banks.·
Plant mangroves on the mudflats that are formed newly by siltation.·
Identify the cyclone-prone areas and strengthen with mangrove planting.Conclusion
Our pioneering investigations show that mangroves can be sources of valuable products like black tea, mosquitocides, gallotannins, microbial fertilisers, antiviral drugs, and UV-screen compounds (Ravi and Kathiresan, l990; Kathiresan and Pandian l991, l993; Premanathan et al., l992; Ravikumar, 1995; Kathiresan, l995; Kathiresan et al., l995; Moorthy and Kathiresan, l997; Kathiresan, 2000). Mangroves can be developed as ‘cash crops’ and as sources of high value commercial products and fishery resources and as sites for a burgeoning ecotourism industry. Their unique features may also make them ideal sites for experimental studies of biodiversity and ecosystem function (Kathiresan and Bingham, 2001). All this will require that the resource is understood, carefully managed, and protected. Involvement of local communities in conservation and education in ‘wise’ use of our precious mangrove resources will ensure that these unique ecosystems survive and flourish.
Acknowledgements
The author is thankful to the Director and all authorities of Annamalai University for providing necessary help.
References
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The Western Australian Mangrove
This web page has been created with a view to improving the communication between mangrove researchers around the world. The aim is to provide information on techniques and other information relating to mangrove research, and hopefully avoid the need to ‘re-invent the wheel’.
Website: http://wwwscience.murdoch.edu.au/centres/others/mangrove/
International Society for Mangrove Ecosystems
This society has a mandate to promote research and surveys and to associate with other scientists and organisations with the purpose of promoting the conservation, rational management, and sustainable utilisation of mangroves; to serve as an international data-bank on mangrove ecosystems.
Website: http://www.mangrove.or.jp/
FAUNAL RESOURCES IN MANGROVE ECOSYSTE
MJ.R.B. Alfred and Ramakrishna
Zoological Survey of India, KolkataIntroduction
Mangroves represent a characteristic littoral forest ecosystem, dominated by some specially adapted salt
tolerant plant community that grows at land-sea interphase, border sheltered seacoasts and estuaries of tropical and subtropical regions. Mangroves are also usually referred to as community of plants and animals in the tidal swamp forest, which exchange matter and energy with adjacent terrestrial and marine ecosystems. Their distribution, association and zonation from deepwater to upland communities are influenced by climate (temperature and rainfall), salinity and tidal range, substrate, underlying geology and wave energy. Mangrove requires areas with sufficient protection from strong winds and wind generated waves, as wave action prevents seedling establishment. As a consequence, the mangrove communities tend to be located in sheltered coastal areas, surrounding highly indented estuaries, embayment and offshore islands protected by reefs and shoals.Of the several ecosystems, mangroves are least understood, though it is a valuable resource in tropics, being used traditionally and directly as timber, firewood, building material and mine supports, commercial fishing, charcoal, tannin production, food in the form of crabs, prawns, honey, molluscs, and indirectly as an area of recreation, cultural significance, wildlife, education and aesthetic values. The importance of mangrove can be well understood by the fact that the leaves of the mangrove contain large amount of tough, comparatively indigestible cellulose, lignin and wax, unsuitable for terrestrial herbivore. One of the major processes occurring in the mangrove ecosystem is the formation of detritus by micro-organisms such as Methanobacterium, Methanosprillum, Methanococcus (anaerobic microbes) and nitrogen fixing bacteria such as Azotobacter, Desulfovibrio as well as the meiofauna on cellulose, lignin, resin, carotenoids of the leaf and transforms into proteins and carbohydrate enriched particles ready for digestion by the faunal groups.
In India, the mangroves are distributed in east and west coasts as well as Andaman and Nicobar group of Islands. The extent of distribution of this group is as given below: The total area occupied by mangroves in the
country as estimated by Forest Survey of India (FSI) during 1999 is 4,871 km2 which forms 0.15 per cent of the total geographic area, in comparison to Indian Remote Sensing data (IRS) (Nayak, 1993) data of 4474 km2 and 6740 km2 of the Ministry of Environment and Forests, Govt. of India (MoEF) (1987). The total area under mangrove vegetation is always a subject of discussion, however, the mangrove vegetation is found in the states of Gujarat (Gulf of Katchh), Maharashtra (Achra and Ratnagiri), Goa, Karnataka (Coondapur), Kerala (Vembanad), Tamil Nadu (Pitchavaram, Point Calimere), Andhra Pradesh (Coringa, Godavari delta, Krishna estuary), Orissa (Bhitarkanika, Mahanadi delta), West Bengal (Sunderban) and Union territory of Andaman & Nicobar Islands (Northern Andaman and Nicobar Islands). The National Committee on Mangroves and Coral reefs of the Ministry of Environment and Forests, Government of India, has identified all the mangrove areas of the country for conservation and management.
Faunal Composition
The faunal components in a mangrove ecosystem comprising of terrestrial, estuarine or marine groups, are adapted for stressful situation of widely fluctuating environmental parameters. The faunal groups are generally confined to hard substrate offered by mangrove vegetation and comprising of sessile (porifers, cnidarians), wandering species (king crabs), muddy substrate with burrowing forms (in-fauna consisting of polychaetes, brachyuran crabs, wood boring animals, mud burrowing bivalves and gobid fishes) and forms errant on substratum (epi-fauna exemplified by oysters, barnacles).
Table 1.
Distribution of mangroves in different states of India
S.no. State/UT Mangrove cover (km2)
MoEF IRS FSI (1987) (1993) (1999) 1. Andaman and Nicobar Islands 1,190 770 966 2. Andhra Pradesh 200 480 397 3. Goa 200 5 5 4. Gujarat 260 1,166 1,031 5. Karnataka 60 19 3 6. Maharashtra 330 138 108 7. Orissa 150 187 215 8. Tamil Nadu 150 90 21 9. West Bengal 4,200 1,619 2,125 Total 6,740 4,474 4,871
Report by Gopal and Krishnamurthy (1993) includes invertebrates of more than 229 species of crustaceans, 212 species of molluscs, 50 species of nematodes, 150 species of planktonic and benthic organisms and 500 species from the Indian mangroves. Recent analysis among vertebrates, by the scientists of Zoological Survey of India includes mammals represented by 36 species, 177 species of birds, 22 species of reptiles and 300 species of fishes. A high degree of species diversity can also be well understood from the case study on the Sunderban mangrove by Das and Nandi (1997) with 1434 species distributed in supralittoral (486 species), intertidal (499 species), and estuarine (449 species). Species richness in mangrove inhabiting fauna of West Bengal, Tamil Nadu and Andaman & Nicobar Islands are well studied while that of west coast are fragmentary. In terms of species richness, Sunderban Mangroves of West Bengal ranks first with 1434 species representing 20 phyla followed by 914 species of Andaman & Nicobar Islands and 801 of Tamil Nadu. Recent analysis on the faunal distribution including the mangroves of Kerala, which was hitherto under represented, is given Table 2.
Faunal Distribution Pattern
Faunal associations are usually associated with tidal expanse, tidal amplitude in respect of shore animals, while in case of mangrove associated fauna, the distribution is also related horizontally from the landward mangroves towards the sea as well as vertically from the tree canopy to the lower parts of the plants (Table 3).
The majority of mangrove fauna is composed of invertebrates, arachnids and insects besides, fouling communities on mangrove roots consisting of members belonging to porifera, coelenterata, bryozoa, polychaeta, mollusca and arthropoda on the roots.
Wood Boring Molluscs are the dominant as mobile epibenthos with the main species being Littorina, Nerita, Cerithedia, Neritina, Telescopium, Pythia, Stenothyara, Haminea, Assiminia, Onchidium.The first publication on the wood boring molluscs of mangroves of India, causing extensive damage dates
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Table 2.
Faunal distribution in the mangrove area of India
Taxa Number of Species
East Coast West Coast Island WB Ori Andhra Tn Guj Maha Goa Kar Ker A&N Invertebrata Porifera 1 - 3 - - - 1 - - - Cnidaria 33 3 8 - - - 2 1 1 - Ctenophora 2 - 1 - - - - - 1 Platyhelminthes 41 - 16 - - - - - - - Nemertinea 2 - - - - - - - - Rotifera 4 - 14 23 - 16 6 4 18 - Nematoda 68 - 2 40 - - - - - - Acanthocephala 3 - - - - - - - - - Sipuncula 2 - - - - - - - - 2 Molusca 142 54 63 53 24 53 42 28 29 100 Annelida 78 36 27 26 - 8 4 6 7 8 Crustacea 240 55 75 76 28 37 55 32 25 100+ Insecta 201 - 19 113 - - 16 22 67 311 Echinodermata 20 - 3 - - 3 3 1 2 7 Chordata Pisces 176 48 79 217 65 32 42 17 122 253 Amphibia 8 5 4 3 - - - - 1 3 Reptilia 58 46 12 7 - 3 3 4 13 7 Aves 163 174 63 178 147 121 56 38 196 53 Mammalia 40 31 13 12 - 1 1 - 13 8 Meiofauna - 11 - 40 - - - - - 53 Microfauna 104 2 - - - - - - - - Others 12 - - - - - 14 8 24 2 Total 1,434 465 402 801 240 284 245 161 518 915 Note: represents values need to be updated
Table 3.
Faunal associations with principal habitats of mangroves
Principal habitat Key faunal species Tree canopy Bats, birds, insects, mites and spiders Higher part Littorina scabra, Lamprid beetles, Lower part & roots Littorina scabra, Onchidium, Sesarma, Mud flats Terebralia palustris, Cerithedia alata, fiddler crabs (Uca spp.) Coralline/rocky flat Cerithium corallinum, Planaxus sulcatus, Grapsus strigosus, Thalamita spp. Coast mud of mangrove edge Polychaetes, Bivalves (Batissa and Gelonia spp.) Seaward mangroves Sessile fauna (Modiolus striatulus,Isognomon ephippium,
oysters, barnacles, and serpulid wormsDead trees and stumps Marine wood borers, sessile fauna Edge of streams and rivulets Scylla serrata, Periopthalmus spp., Boleopthalmus boddarti, Cerubrus rhyncopus Creeks and bays Shrimps, prawns and fishes back to 1954 by Roonwal, reporting the occurrence of teredinid borer Bactranophorus thoracites as a ‘pest’ in Sunderban mangroves. Since then the species diversity and damage caused by several species are recorded from various parts of the country by Rajgopal (1970), Subba Rao (1983), Santhakumaran (1986), Dev Roy & Das (1985), and others. Among the ten species of Teredinids, six species viz., Teredo fercifera, Nausitora hedleyi, Bankia bipennata, Banka rochi, Nototeredo edax and Uperotus rehderi are reported from Andaman, four
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species viz. Bactranophorous thoracites, Dicyathifer manni, Lyrodus pedicellatus and Nausitora dunlopei have been recorded both from Andaman and Nicobar Islands. Besides above, several bivalves such as Isognomon ephippium and Modiolus striatulus cover thickly the underground roots and stems of mangroves.
Amphibian diversity is comparatively low and limited to freshwater species intruding to the area occasionally the coastal environment, amphibious species such as Rana cyanophlictis, R. tigerina, R. hexadactyla, R. limnocharis, Rhacophorus maculates and Microhyla ornata inhabit the mangroves of Sunderbans (Mandal & Nandi, 1989).
Reptiles that inhabit the mangroves include crocodile, snakes and lizards. Salt water crocodile Crocodilus porosus is found in almost all such large islands of Andaman and the Nicobars, occasionally in Sunderbans which support mangrove swamps. Andaman water monitor lizard (Varanus salvator andamanensis) is common during the breeding season of the crocodiles, as the lizard is fond of lifting crocodile eggs. Dog faced water snake Cerberus rhynchops is frequently seen, showing that reptiles penetrate deep into mangroves. Furthermore, many lizards, of the genus Goniocephalus subcristatus, Calotes versicolor, Mabuya carinata, M. dissimilis, were seen throughout the mangroves. Turtles and terrapins are represented by Batagar baska, Lepidochelys olivacea, Trionyx gangeticus, Trionix hurum, Lissemys punctata. Of these, Lepidochelys olivacea is found to be distributed in all the mangrove areas of the country.
Birds use mangroves as the roosting and feeding sites. It is common to see the Grey herons (Ardeola cinera), Night herons ( Nycticorax nycticorax), Egrets ( Egretta intermedia and Egretta garzetta) in Sundarban mangroves, besides above as many as 16 species belonging to the family Ardeidae has been recorded. Among kingfishers, as many as 6 species are recorded from the Sunderbans, 8 species from Andaman & Nicobar Islands, usually represented by Alcedo atthis, Halcyon smirnensis, H. pileata, H. chloris, H. coromanda, Ceryle rudis, Pelargopsis amauropera, P. capensis. This is mainly related to the unique adaptations noticed in the intertidal ecosystem, by the fishes, especially the mudskippers belonging to Gobidae.
Fishes diversity has been very high in mangroves. It has also been postulated that mangroves are nursery grounds for many commercially important fish species and positive correlations have been drawn between fish population abundance and mangroves.
Mammals present in the mangroves include monkeys (Macaca fascicularis umbrosa in Andaman, Macaca mulatta in Sunderbans), flying foxes (Pteropus melanotus, Pteopus giganteus and Cynopterus sphinx). Several casual visitors of bats are also on record such as Megaderma lyra, Rhinopoma hardwickii, Hiopposideros lankadiva, Pipistrellus mimus, Scotophilus kuhli), and wild pigs frequenting the mangroves (Sus scrofa andamanensis, Sus scrofa nicobarica.).
Brachyuran crabs occupy a major part of the intertidal zone of mangrove ecosystem. As many as 35 species of crabs which have been recorded from Andaman and Nicobar Islands belong to the family Portunidae, Grapsidae, Ocypodidae, Mictyridae, Xanthidae and Gerarcinidae and the common genera are Uca, Ocypode, Dotilla, Macropthalamus, Grapsus, Metopograpsus, Sesarma, Metaseserma, Metaplax, Portunus, Thalamita, Scylla, Charybdis, Mictyris, Epixanthus, Pilumnus, Baptozius and Cardisoma. In contrast to Andaman and Nicobar group of Islands, the diversity of crabs in Sundarbans is comparatively higher with nearly 52 species, of which 13 are pelagic and 39 are benthic belonging to 11 families and 26 genera. Mangrove crab diversity is very high with an estimated 275 species from six families of brachyurans (true crabs) associated with the mangrove ecosystems of the world. A comparison to the distribution of crabs of the world, with two major mangroves of the country (Andaman and Nicobar, and Sunderbans ) is given below in Table 4.
Faunal components that are distributed towards landward side of the mangroves are large crabs belonging to Cardiosoma carnifex, medium crabs such as Sesarma (Chiromantes) bidens, Sesarma longipes; small crabs such as Uca lactel, Uca (Deltuca) dusumieri, Uca ( Thalassuca) vocans; Molluscs such as Cerithedia allata, Cerithedia quadrata etc. Animals that are distributed in the mid-forest mangroves are large crabs belonging to Scylla serrata, Thalamita crenata, Epixanthus frontalis, Euricarinus grandidieiri. And
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Table 4.
Global status of crab species versus crabs of major mangroves of India
Family No. of species World Andaman & Nicobar and Sunderbans Per cent Geocarcinidae 4 1 25.0 Grapsidae 166 26 15.7 Mictyridae 1 1 100.0 Ocypodidae 87 19 21.8 Portunidae 5 3 60.0 Xanthidae 12 3 25.0 species belonging to smaller crabs (Sesarma, Uca, Macropthalamus), molluscs (Terebralia, Cerethidia, Crossastrea, Isognomon, Perenia), the gobid fishes (Glossogobius giuris, Gobiopterus chuno, Apocryptes bato, Brachygobius nanus, Boleopthalmus boddarti, Periopthalmus vulgaris, P. koelreuteri, Ophiocara aporos, Oxyurichthys dasi and Quisquilius eugenius) and several species of insects. Faunal components that are distributed towards the seaward side of the mangroves are several species of crabs belonging to Sesarma, Epixanthus, Ocypode, Scylla, Thalamita, Macropthalamus, Dotilla, Uca; molluscs such as Terebralia, Cerethedia, Saccostrea, etc. A commonality has been found in the distribution of crabs and mollucs in the mid forest as well as towards the seaward distribution, as many of them occupy both the niches and the demarcation is incomplete.
Mangrove crabs have been shown to be ecologically significant in many ways, as they keep much of the energy within the forest by burying and consuming leaf-litter. The faeces may form the basis of a coprophagous food chain contributing to mangrove secondary production, such as food for juvenile fish inhabiting the adjacent waterways, indicating crabs help near shore fisheries. Crabs themselves are food for threatened species such as the crab plover. Their burrows alter the topography and sediment grain size of the mangrove and help to aerate the sediment. It has been found that removing crabs from an area caused significant increases in sulfides and ammonium concentrations, which in turn affects the productivity and reproductive output of the vegetation. Their findings support the hypothesis that mangrove crabs are a keystone species.
Values: The coastal environment with its resource system is interlinked with the human activities in both land and marine environments as in Figure 1.
The coastal zone may encompass a wide variety of diverse habitats and ecosystems such as estuaries, lagoons, mangroves, coral reefs, and sea grass beds, etc. These ecosystems have inbuilt features often known as "functions" in context to coastal resource system. These functions may be in the form of primary and secondary productivity to sustain a large percentage of the flora and fauna and also forms the linkage with the marine, terrestrial as well as the mangrove vegetation in the coastal environment. In mangrove communities, much of the primary production is exported to the other coastal communities that are related to function and energy flows in the coastal ecosystem. Microbial action is most important to transform the hard cellulose to more usable forms of organic compounds of proteins, simple sugars and fatty acids. In conditions where the mangroves are present when low wave energy and depositional condition persists, high amount of peat formation will occur, which in turn helps in primary productivity and subsequent deposition of plant organic matter. The value of the goods and services from the mangrove vegetation (modified in relation to Indian context from Hamilton and Snedaker 1984,) that are often neglected/left out in understanding such ecosystem as given in the Table below, should be taken into account to generate value of each ecosystem.
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The policy and management actions to be involved in addressing the coastal developmental activities are therefore to be based on the sound knowledge of natural processes and the functions of the mangrove ecosystem that are operating at that given time and place (Table 6). Further, the changes involved for e.g., construction of barrages, dams in the upper stretches of the river have caused substantial damage to the river flow. Thus altering the environmental condition, causing widespread damage to the nursery ground for juvenile fishes, affecting the fish catch composition, also need to be looked into for the policy management.
In terms of economic value (Brown, 1997), mangrove eco-system stands unique as shown in the flow diagram (Fig 2). In terms of goods and ecological services, mangrove ecosystem cannot be directly evaluated through market mechanism (after Costanza et.al., 1997 and Moberg and Folke, 1999), but involvement of community participation will certainly enhance the ecosystem value at the same time, it is sustainable in its approach.
Community Utilisation of Animal Resources
The increasing interest of government on tribal people living in Andaman and Nicobar Islands and an upsurge in respect for knowledge held by these tribals, demonstrates a fundamental change in attitude towards these tribes and their skills and talents. The tribes in the Andaman and Nicobar are major users of the mangroves, where there is an
Table 5. Valuation of goods and services from mangroves
Location of ‘goods’ and ‘services’ On-site Off-site Marketed Usually included in an economic analysis (e.g., charcoal. woodchips, tannin, timber, mangrove crabs) May be included (e.g., fish or shellfish caught in the adjacent waters)
Non Marketed Seldom included (e.g., medicinal uses of mangrove, domestic fuel wood, food in times of famine, nursery area for juvenile fish, feeding ground for estuarine fish, aesthetic and wildlife) Usually ignored (e.g., nutrient flows to nutrient flows to estuaries, buffer to storm damage)
Table 6.
Natural processes and functions of the mangrovesabundance of animal and plant resources. There are three potential types of plant use in tribal society, viz., food, medicines and other purposes including tools and weapons (Fig. 3).
Ecosystem function Corresponding goods and services Habitat for resident and transient population
Refusia (nursery and habitats of rich floral, faunal
and microbial taxa)Portion of gross primary production extractable as
foodFood production (sea weeds, finfish, shell fish,
and sea food products)Portion of gross primary production extractable as
raw material
Raw materials (poles, charcoal, wood chips,
domestic fuel, wood for house construction,
material for medicines and curioTropic-dynamic regulations of populations
Biological control (feeding places within and
between ecosystems)Capacity, damping and integrity of ecosystem in
response to environmental fluctuationsDisturbance regulation (shoreline protection,
sediment retention, buffer for storm)Recovery of mobile nutrients and removal or
breaking down excess prxenic nutrient compoundsWaste treatment (waste assimilation and nitrogen
fixation)Providing opportunities for recreational values Recreation (tourism, recreation, viewing and
studying wildlife)Recent exploration by the scientists of Zoological Survey of India (2002) in the tribal dominated area of Andaman and Nicobar has yielded positive result on their dependency of the faunal resources. The main
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vertebrate components of the mangrove fauna are the fishes and birds, which are mostly transitory. Besides spearing fish, tribals made use of various types of fish traps, located near mangroves. The mangrove monitor (Varanus indicus) the estuarine crocodile (Crocodylus porosus), are consumed by these tribals occasionally. The crustaceans and molluscs are the main two invertebrate groups, which are exploited by tribals as a food source in Andamans. The mud crab, Scylla seratta, is an important food source. Prawns and shrimp are other components of the crustacean fauna of the mangroves but usually occur in small numbers. Records of exploitation of Telescopium telescopium and Terebra palustris, Nerita nerita, Pugilina cochlidium, Saccostrea and Crossastrea as food are also available. In respect of usage of animal resources, there appears to be a similarity with the aboriginals of Australia,
whether this is accidental or due to the similarity in distribution pattern of faunal elements is a matter of discussion.
Conclusion
One of the prime objectives of the conservation and sustainable utilisation of biological resource approach is to identify the structure and function including the biodiversity and productivity, values and uses, stake-holders and target species, hazards and risk assessments, indicators and strategies and many more for the effective implementation of management strategies for the species in particular and ecosystem at large.
Productivity in mangroves is very high and has a direct impact on the health and functions of the marine ecosystem. The primary production is exported to other coastal communities that are related to function
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and energy flow in the coastal system. Aquatic, semi-aquatic and terrestrial communities adapted at stress conditions generally represent mangrove fauna. The abundance and diversity of fauna in the mangrove ecosystem is very high and are distributed in three conspicuous zones viz., 1. Proximal zone 2. Middle zones and 3. Distal zone. Crustaceans are one of the most important pervasive invertebrate groups found in the marine environment and mangrove community is no exception. Being living resources, mangroves are self-maintaining and renewable. This brief listing further substantiates the importance of the mangrove ecosystem towards maintaining global biodiversity and their further role in foreshore protection, reducing erosion by cyclones and impact of storm surge.
Acknowledgement
The authors wish to express their sincere thanks to Dr. A.K. Das and Dr. Radhakrishnan for their help during the compilation.
Reference
Alfred, J.R.B.; Das, A.K.; Sanyal, A.K. 2002. Ecosystems of India. Kolkata, Zoological Survey of India.
Brown, E. Barbara.1997. Integrated Management: South Asia, Report submitted to Department for International Development of the United Kingdom.
Costanza et.al. 1997. The value of the world’s ecosystem services and natural capital. Nature, 387: 253-260
Das, A.K.; Devroy, M.K.1989. A general account of the mangrove fauna of Andaman and Nicobar Islands. Kolkata, Zoological Survey of India. 173p.
Forest Survey of India, Dehradun. 1999. State of forest report. Dehradun, The author.
Hamilton, L.S.; Snedaker, S.C. 1984. Restoration and establishment. In: Handbook for mangrove management. IUCN. pp. 102-108.
India. Ministry of Environment and Forests. 1987. Mangrove in India: Status report. New Delhi, The author. pp.52-55.
Macnae, W. 1968. A general account of the fauna and flora of mangrove swamps and forests in the Indo-Pacific region. Advances in Marine Biology, 6: 73-270
Michie, M. 1993. The use of mangroves by Aborigines in northern Australia. Channel Island Field Study Centre occasional paper, No. 5.
Moberg, E.; Folke, C.1999. Ecological goods and services of coral reef ecosystems Ecological Economics, 29: 215 - 233
Mondal, A.K.; Nandi, N.C. 1989. Fauna of Sundarban mangrove ecosystem, West Bengal, India. Kolkata, Zoological Survey of India.
Nayak, S.T. 1993. Remote sensing applications in the management of wetland ecosystem with special emphasis on management of mangrove ecosystem and coastal protection. 21p.
Roonwal, M.L. 1954. Batranophorus thoracites (Gould) as a pest of living trees in Sunderbans, Bengal (Mollusca: Teredinidae). Current Science, 23: 301.
Global Mangrove Database and Information System (GLOMIS)
This is a project of the International Society for Mangrove Ecosystems (ISME) with financial support from the International Tropical Timber Organization (ITTO) and of the Government of Okinawa (Japan). GLOMIS is based at Okinawa and coordinates four Regional Centres located in Brazil, Fiji, Ghana and Malaysia.
Website: http://www.glomis.com
BIODIVERSITY CONSERVATION IN INDIAN SUNDERBAN AT LANDSCAPE LEVEL: PRESENT STATUS AND STRATEGIES
Atanu Kumar Raha
Sunderban Biosphere Reserve, West BengalSunderbans
Suderban, the largest delta in the world, consists of 10,200 sq km of mangrove forest, spread over India (4,200 sq km of reserved forest) and Bangladesh (6,000 sq km approx of reserved forest) and is also the largest mangrove forest in the world. Another 5,400 sq km of non-forest, inhabited region in India, along the north and north-western fringe of mangrove forest, is also known as Sunderban region in India. Hence, the total area of Sunderban region in India is 9, 600 sq km. which constitutes the Sunderban Biosphere Reserve.Indian Sunderban is bound on the west by river Muriganga and on the east by rivers Harinbhahga and Raimangal. Other major rivers flowing through this eco-system are Saptamukhi, Thakuran, Matla and Goasaba. River Matla divides Sunderban Reserved Forest into Sunderban Tiger Reserve (on the east) and reserved forest of South 24 Parganas forest division.
Uniqueness of Sunderban Forest
Sunderban Biosphere Reserve was constituted by Government of India (GoI) in 1989. It was done to establish a formal mechanism for coordinating and integrating diverse activities of conservation, research and training for creating a better situation of harmony between man and environment. It received the recognition of UNESCO, under its Man and Biosphere (MAB) programme, in November 2001. Sundarban Biosphere Reserve has also been included as the second biosphere reserve from India, other than Nilgiri Biosphere Reserve, in the global network of biosphere reserves in November 2001.
Sunderban National Park, forming the core area of Sunderban Tiger Reserve, received recognition as World Heritage Site, by UNESCO in 1987. Sunderban Reserved Forest has been nominated by GoI for recognition as Ramsar Site (a wetland of international importance). Sunderban Tiger Reserve was constituted by GoI under Project Tiger scheme, in 1973. Sunderban is the only mangrove forest in the world, which is the home of tiger. Sunderban Tiger Reserve has the highest population of tiger in the world.
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Importance of Sunderban Ecosystem
Sunderban has extremely rich diversity of aquatic and terrestrial flora and fauna. Sunderban’s highly productive ecosystem acts as a natural fish nursery. Sunderban mangrove reduces the fury of cyclonic storm and prevents erosion due to tidal action. Finally, millions of people depend on Sunderban ecosystem for their livelihood and sustenance through fishing, collection of honey and fuelwood/timber.
Area and Extent
Administrative boundary of the Sunderban is spread over two districts i.e. North 24-Parganas and South 24-Parganas, covering 19 blocks (Table 1).
Table 1.
Administrative boundary of the Sunderban
District Block South 24 Parganas
Sagar, Namkhana, Kakdwip, Patharpratima, Kultali, Mathurapur-I and II, Jaynagar-I and II, Canning-I and II, Basanti, Gosaba North 24 Parganas Hingalganj, Hasnabad, Haroa, Sandeskhali – I and II, Minakhan Topography and Soil
Geologically, the Sundarbans delta is the largest prograding delta on the globe. The region is covered solely by quaternary sediments carried and deposited by the rivers Ganges, Matla and Bidyadhari. The present depositions of detritus have formed since last 6,000 years of stable phase. In the recent past, the Bengal basin suffered some neotectonic movements. Between 12th and 16th century, there was an easterly tilt of Bengal basin, which resulted in shift of Ganges towards east, and river Padma became active. During this period, the Matla and Bidyadhari river systems formed innumerable network of creeks between Ganga and Padma. During the 16th century, the Ganges flow shifted almost totally eastwards into river Padma, and the Matla and Bidyadhari river system got completely cut off from sweet water source and is presently fed by the back water of sea. The main estuaries from west to east in Indian Sundarbans are Hooghly, Saptamukhi, Thakuran, Bidya, Bidyadhari, Gosaba Kalindi and Raimongal. The average tidal amplitude in these estuaries ranges from 3.5 to 5.0 m.
Climate and Rainfall
Although the region is situated south of the tropic of Cancer, the temperature is equable due to its proximity to the sea. Average annual maximum temperature is around 350 C. The summer extends from middle of March to middle June and the winter from December to February. The monsoon usually sets in around middle of June and lasts up to middle of September. Rough weather lasts from 15th March to 15th September and the fair weather prevails between mid-September to mid-March. Average annual rainfall is 1,920 mm. Average humidity is about 82 per cent and is more or less uniform throughout the year.
Administrative Structure
Director, Sunderban Biosphere Reserve and Chief Conservator of Forests (South) is the Head of Sunderban Biosphere Reserve. The entire region is distributed between Sunderban Tiger Reserve, under the Field Director, and 24 Parganas South forest division, and South 24 Parganas forest division under DFOs.
Sunderban Reserved Forest
The extent of mangrove reserved forest in Indian Sundarban is around 4,260 sq km, which is under jurisdiction of Chief Conservator of Forests (South) and Director, Sunderban Biosphere Reserve, and is administratively divided into Sundarban Tiger Reserve (area 2,600 sq km) and South 24 Parganas forest division (area 1,660 sq km). Out of this total recorded forest area, 55 per cent is under land vegetation cover and the remaining 45 per cent is under water body/ inter-tidal zone. Field Director and Conservator of Forests is in charge of Sunderban Tiger Reserve and a Divisional Forest Officer is in-charge of South 24 Parganas forest division. Joint Director, Sunderban Biosphere Reserve and Consevator of Forests/South Circle is the direct controlling officer of DFO, South 24 Parganas division.
Nearly 40 per cent of the reserved forest area has been brought under protected area (PA) network,
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which is as follows:
Sundarban National Park (1330 sq km);
Sajnekhali Wildlife Sanctuary (362 sq km);
Lothian Wildlife Sanctuary (38 sq km); and
Haliday Wildlife Sanctuary (6 sq km).Sunderban Tiger Reserve
Sunderban Tiger Reserve was created by a Govt. order dated 23rd December 1973, under the ‘Project Tiger’ scheme of MoEF, GoI. It is part of the Sunderban Biosphere Reserve and has a total reserved forest area of 2,585 sq km. Within the Reserve, 1,330 sq km has been notified as Sunderban National Park which also forms the core area of the reserve. The remaining area of the reserve forms the buffer zone and Sajnekhali Wildlife Sanctuary is part of this zone. Sunderban National Park had been declared as a World Heritage Site by UNESCO in 1987.
Floral Diversity of Sundarban Mangroves
According to Champion and Seth classification, the Sundarban forest falls under the sub group 4B tidal swamp forest, with sub-divisions namely, Mangrove type 4B/TS1, 4B/TS2, Salt water type mixed forests 4B/TS3, Brackish type 4B/TS4 and Palm type 4B/E1.
In general, the northern boundary and new depositions are characterised by baen (Avicennia marina, A. alba, A. officinalis) flanked by foreshore grassland of Oryza coarctata (Dhani grass). Baen is gradually replaced by genwa (Excoecaria agallocha) and then goran (Ceriops spp.). The southern and eastern associates include garjan (Rhizophera spp.), kankra (Bruguiera spp.), and few patches of sundari (Heritiera fomes). Pure hental (Phoenix spp.) forest exists in relatively high land and compact soil. Dhundul (Xylocarpus granatum), passur (Xylocarpus mekongensis) and nipa (Golpata) palm swamps are extremely limited in existent. The flora includes 26 true mangrove species, 29 mangrove associates, and 29 back mangrove species of 40 families and 60 genera.
Mangrove and Aquatic Fauna
History of Faunal Changes Over the Last Two Centuries According to Hunter’s statistical account of Sundarban written in 1878, ‘tigers, leopards, rhinoceros, wild buffaloes, wild hogs, wild cats, barasinga, spotted deer, hog deer, barking deer, and monkeys are the principal varieties of wild animals found in Sundarbans’. However, over the last 100 years or so, due to habitat degradation and ecological changes, the faunal compositions in Indian Sundarbans have undergone sea change. Some of these animals in Sundarbans which became extinct during the last two centuries are Javan rhino, wild buffalo, swamp deer and barking deer.
Present Status of Faunal Resources
Sundarban mangrove forest is the single largest home of the Bengal tiger. Sunderban is also the only mangrove forest in the world having the tiger as its indigenous population. As per December 2001 census, the tiger population in Indian Sunderban is around 271, out of which Sundarban Tiger Reserve has 245 tigers and South 24-Parganas forest division has 26 tigers. There are 15 species of mammals, 8 species of birds and 17 species of reptiles, which are included in the Schedules I and II of Wildlife (Protection) Act, 1972. Total number of species, included in Appendix I of CITES Regulation, are 14.
Sundarbans also harbours a good number of rare and globally threatened animals including estuarine crocodile (Crocodilus porosus), fishing cat (Felis viverrina Bennett), common otter, water monitor lizard (Varanus salvator), Gangetic dolphin (Platinista gangetica), snubfin dolphin (Orcella brevirostris), river terrapin (Batagur baska), marine turtles like olive ridley (Lepidochelys olivacea), green sea turtle (Chelonia mydas), hawksbill turtle (Eritmochelys imbricata), etc. Six species of shark and ray, which are found here, are included in Schedule I of Wildlife (Protection) Act. These indicate that Sundarban Reserved Forest is a natural biodiversity hot spot.
The flagship species of Sunderban is the Bengal tiger (Panthera tigris). Among other mammals, ground fauna comprises of wild boars, spotted deer, porcupines and rhesus macaque. Among the reptiles, the king cobra, the common cobra, common krait, russells viper comprise the community of venomous reptiles, while the python, chequered kil-back, dhaman, green whip snake and several other species constitute the non-venomous snakes. The tidal creeks harbour Homalopsid snakes adapted to living in water, the common being
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the Cereberus rhynchops. The sea-facing beach of the reserved forest forms the nesting ground for olive ridley turtles (Lepidochelys olivacea). The water monitors along with wild pigs, terns and sea gulls are the greatest predators of their eggs and hatchlings. The endangered river terrapin (Batagur baska) also uses the beaches as their nesting ground.
The birds are in plenty including a large number of migrants from the higher latitudes that visit the area in winter. It consists of herons, egrets, cormorants, storks, green pigeons, sand pipers, large and small spoonbills, darters, seagulls, teal, partridges and a great variety of wild geese and ducks. Migratory species include goliath heron, etc.
The cetaceans include snubfin (Irrawady) and Gangetic dolphin and the former is more frequently sighted in the estuarine region. The black finless porpoise (Necmeris porosus) is also found in the rivers near the estuary. The marshes and tidal rivers offer asylum to the estuarine crocodile, one of the most endangered and the largest of crocodiles. A wide variety and assortment of fish, molluscs, crabs and prawns inhabit the estuaries.
The amphibious mud-skipper fish such as Peripthalmus and Boleopthalmus arouse considerable interest. Also found are at least 15 species of shark and rays like whale shark, tiger shark, hammer headed shark, saw fish, guitar fish, etc. Among the crustaceans, commonly found are the one armed fiddler crab (Uca spp) and the two species of trilobite (Tache-pleursgygus and Carcinoscropius rotundicauda). The latter is also known as the horse shoe crab, which are living fossils and are protected owing to its medicinal value.
Insects abound in the forests amongst which the honey bee (Apis dorsata) is a source of considerable income for the poor fringe people.
Faunal diversity in mangroves is as follows:
Total no. of species are 1,586 which includes 481 vertebrate species, 1 hemichordate species, 1,104 invertebrate species, and 106 protozoan species. Total species included in Sch. I of WLP Act are 24 that has 15 mammals, 8 birds and 17 reptiles. Total species included in Appendix I of CITES Regulation are 14.The People: Demographic and Socio-Economic Profile
Growth of population
During post-independence period, this region witnessed sudden influx of population mainly due to migration. The displaced persons forcibly occupied lands, cleared forests for habitation and several colonies sprung up in this manner. This has exerted negative impact on the economy of fringe population.
As compared to the state average of 25.6 per cent, nearly 36.5 per cent of the population belongs to SC/ST. Nearly 95 per cent of the population primarily depend on agriculture, which is mostly rain-fed monocropping, and about 50 per cent of agriculturists are landless labourers. During agricultural lean season, people resort to fishing and collection of prawn seeds, even risking their lives to man-eating tigers and crocodiles. During April - May, some people also enter the reserved forests with permits, for collection of honey which is entirely purchased back by forest department.
Backwardness of the region and near-total dependence of the people on the natural resources of mangrove ecosystem can be attributed to the following factors:
Uncontrolled population (1.2 to 3.9 m in 50 years) growth with low income level, lack of large scale industries and related employment opportunities, poor or absence of irrigation facility leading to rain-fed, monocropped agriculture, loss of productivity of potential cultivable land due to large scale expansion of aquaculture/ prawn farming, lack of organised transport and communication facility, absence of electricity supply in most of the islands, raising of river bed due to construction of embankments, leading to occasional flooding whenever there is a breach, lack of medical facility, public health care and proper sanitary facilities and occasional furies of cyclonic storm.
Out of 4,500 sq.km of inhabited areas, there are only 42 km of railway line and about 300 km. of metalled road network. The only means of communication between the islands is the waterways which is not at all well-organised and people have to depend on the private mechanised boats which are
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sometimes a serious life-risks. There is acute shortage of pucca/ well-maintained jetties. Due to obvious reason of inaccessibility, much of the inhabited areas are yet to avail of the conventional electricity supply. Of late, there has been some perceptible breakthrough in the field of solar power supply to a few locations.
Cultural Uniqueness
Sundarban represents a society that is primarily agricultural. The people live in villages are adjoining forests which is the home of Bengal Tiger. For survival, these people have to fight with the nature day in and day out. The hardships of daily existence have given rise to fraternal feelings and non-communal traditions. Members of both Hindu and Muslim communities worship the same gods and goddesses, gazis and pirs. The two most famous among them are Dakshin Ray and Banabibi. Dakshin Ray is worshiped as the god of tiger and all those who enter the forests for subsistence, worship Dakshin Ray irrespective of their caste, creed and religion. Banabibi, on the other hand, is considered as the protector of the inhabitants of the forests. She is popular both amongst Hindus and Muslims.
The Problems and Issues to be Addressed
The threats to the mangrove eco-system are arising partly, due to biotic pressure from the surrounding environment and, partly due to human induced or natural changes in the upper catchment. These can be outlined as below:
·
Reduced flow of sweet water into Sunderban mangrove system·
Extension of non-forestry land use into mangrove forest·
Straying of tiger into villages along the western boundary of Sundarban·
Demand for small timber and fuel wood for local consumption·
Poaching of tiger, spotted deer, wild boar, marine turtles, horse shoe crab, etc·
Uncontrolled collection of prawn seedlings·
Uncontrolled fishing in the water of reserve forests·
Critical maintenance need for 3,500 km long earthen embankments, around inhabited islands, to prevent
river water entering the islands during high tide·
Continuous trampling of river/creek banks by fishermen and prawn seed collectors·
Chemical pollution through marine paints and hydrocarbons·
Long international border along the eastern boundary of Indian Sunderban·
Organizational and infrastructure deficienciesCurrent Management Scenario
Objectives of Management
The Sundarbans Biosphere Reserve is being so managed as to fulfil the three complimentary functions of a biosphere reserve namely
(1) Restoration of the unique mangrove ecosystem of Sundarbans and conservation of its biodiversity.
(2) Development of sustainable economic, social activities of the population living in the biosphere reserve.
(3) Facilitating research, monitoring, education and training to perpetuate the achievements made.
Strategies for Management
I. Constitution of management unit
The total area of this biosphere reserve has been divided into the following inter-related zones:
(1) The core zone is a compact block of reserved forest covering approximately 1,700 sq. km lying in the eastern portion of Sundarban adjoining Bangladesh border and is bound by Matla river in the west and butts into Bay of Bengal. This is a fully conserved area and it contains the Sundarban National Park and is devoted to conservation of bio-diversity, including primitive area which has remained as a central island within the reserve forests free from any external disturbances since a long time ensured through legislation. Nature in pristine glory exists there.
(2) Buffer zone comprises majority of mangrove areas including reserved forests areas adjoining area surrounding the above core zone and includes portion of the buffer zone of tiger reserve, Sajnakhali Wild Life Sanctuary and compact reserved forest blocks laying between Matla and Thakuran under 24-Parganas forest division.
(3) Transition zone
·
Covers the balance of the biosphere reserve area, which contains mangrove areas mostly in non-forest areas and reclaimed areas with agriculture.
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·
Area of co-operation– variety of agriculture activities, stakeholders agree to work together to manage and sustainably develop area’s resources for benefit of people.·
Area of great economic and social significance for regional development.II. Goals and activities
A. Protection of mangrove ecosystem
Intensification of surveillance: The northern and western fringes of Indian Sunderban are heavily populated and lack of agricultural production and job opportunities haunt the remote villages. The result is the intense biotic pressure on the forest from the fishermen, wood collectors, honey collectors, and poachers of tiger and deer. The organized timber and wildlife mafia exploit the poverty of the villagers. Therefore, the immediate need for conservation of the mangrove eco-system is to strengthen the organizational infrastructure of the forest department. Since in the estuarine forest, the only means of communication is watercrafts, a few watercrafts, including speed boats, have been supplied to facilitate faster movement of the patrolling staff posted in remote camps. Establishment of land-based camps and check posts is to ensure round the clock vigil on the transit routes of illegal forest produces. Radio telephone sets are also supplied to bring all the offices and camps under a unified RT network. Improved firearms like 0.315 rifles supplied to field staff as replacement of conventional and out-dated DBBL guns. Mobile and satellite phones are provided to the senior officers, up to the rank of DFOs, to facilitate communication and organizing raids against the wildlife mafia in the city.
B. Habitat improvement
Afforestation/Soil Conservation
1. Afforestation with mangrove species.: There are large strips of newly created mudflats and char lands as well as nearly 3, 500 km of embankments, which have been afforested with the following objectives, stabilisation of the mudflats, restoration of mangrove eco-system, stabilisation of the embankments and conservation of the threatened and denuded species.
2. Afforestation with fast-growing and indigenous spp.: The slopes and base of the embankments, away from the tidal action, have been planted with indigenous and quick growing species to meet the local demand of fuel/fodder and small timber.
3. Land development and improvement of soil-moisture: Some of the islands within the mangrove forest do not experience regular inundation by tidal action, due to turtle-back shape at the centre of the islands. This results into increase in salinity and formation of saline blanks which do not support any vegetation. It is proposed to dig canals across some of these areas, on experimental basis, to facilitate tidal flooding and increased moisture in such barren areas. Artificial and natural introduction of mangrove seeds may improve the vegetal cover.
4. Distribution of seedlings for planting on private lands.
Habitat development activities:
(1) Development of water holes to supply sweet water to the wild animals.
(2) Opening up canopy through construction of observation lines. Such measures also help the growth of herbivores.
C. Reduction of Man-Animal conflict
Straying of tigers from the reserved forests into the habitations along the northern and western fringes of Sunderban forest occasionally result into death of cattle/human beings as well as tiger. Illegal entry of fishermen into core areas as well as entry of honey-collectors into the forest also leads to killing of a number of people by the tigers. An ex-gratia relief of Rs 30,000.00 is paid for human casualty.
In order to prevent straying of tiger into villages, nylon net as well as goran chita fencing are being erected along the forest-village interface. Tranquilisation and capture of the straying animal and their subsequent release into the forest, is also frequently resorted to. Making the fringe villagers aware of the need for conservation of tiger through the FPC/EDCs has been extremely effective. Training of the staff in use of tranquilizer gun, use of capture cage/net, quick officials’ response at the time of straying and generating support of the villagers are part of capacity building initiatives to tackle tiger straying. These efforts, coupled with ecodevelopment activities are paying dividend. Between 1994-95 and 2001-02, there had been 25 recorded cases of tiger straying,
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leading to death of 10 tigers whereas during 2002-03 to 2003-04, there had been 16 cases of tiger straying with only one tiger getting killed. This is definitely an example of people-forester partnership towards conservation, the process being initiated more than half-a-decade back.
D. Tiger census
The technique of estimating tigers by using pugmarks was developed by S.R. Chowdhury in Orissa. The practice has been since adopted al over India for counting the tigers. In Sunderban, the technique has been slightly modified and instead of taking pugmark on tiger tracer, fresh left hind leg pugmarks are obtained by taking plaster of Paris cast. Each cast is duly indexed. The cast is subsequently translated on the graph paper by using pugmark tracer. Thereafter, several distinguishable morphological features of tiger pugmarks are obtained and analysed, based on field knowledge as well as by computer software, to arrive at the estimated tiger population. Tiger census is held in Sunderban every 2 years and the latest census has been conducted in January 2004. The uniqueness of 2004 census is that Bangladesh officials also could be involved in organising their first ever total census in Bangladesh Sunderbans from February 26 to March 3, 2004. Six officials of Bangladesh Sunderban had been trained up in India who participated in the Indian census exercise and subsequently, trained their own people for organising census in Bangladesh Sunderban. This is an example of cooperation between two neighbouring countries to preserve a single eco-system with the active support of UNDPs of two countries.
Years of census Population STR 24 Pgs (S) Total 1999 254 30 284 2001 245 26 271 2004 249 25 274
E. Eco-development and JFM support activitiesNo governmental efforts to conserve and create assets/ resources can be successful and sustainable unless the people concerned actively participate in planning and management of the resources. Participatory or Joint Mangrove Management (JMM) is thus the basis of sustainable conservation of mangrove eco-system. On the basis of the experiences of peoples’ participation in forest management in south-western Bengal, West Bengal forest department have issued orders facilitating the formation of Forest Protection Committees (FPC) around the reserved/ protected forests, and Eco-Development Committees (EDC) around the national park and sanctuaries of Sunderban region also. Till now, 34 FPCs and 14 EDCs have been registered and functioning in Sunderban reserved forest.
Members of the FPCs and EDCs participate in protection of the forests against exploitation. However, since large population in the fringe villages are intensively dependent on the resources of the mangrove eco-system, closure of the resource against exploitation will lead to further unemployment and starvation of the people below poverty line. Such actions are bound to alienate the people and will go against the concept of conservation. Therefore, our effort is to create ‘alternate livelihood options’ for these target groups and dilute the biotic pressure on the ecologically fragile mangrove ecosystem. Whatever development funds are made available for the forest fringe villages, will be utilised for creating resources through the process of micro-level planning and participatory implementation.
Socio-economic and natural resource survey of the region shows that sweet water for irrigation and drinking purpose is a scarce commodity. Due to shortage of sweet water, agriculture in the region is highly under-developed and productivity is very low. Mere provision of fresh, sweet water can bring revolution in the agricultural practices and generate tremendous employment and resources. Since the region is blessed with moderately high rainfall, well-distributed, conservation of the rainwater through impounding in canals and ponds should receive the topmost priorities in the resource generation sector. Availability of irrigation water during dry months can convert the mono-cropped areas into multiple cropping. Construction of irrigation canals and ponds constitute important component of eco-development activities.
The sweet water ponds and canals can also be simultaneously used for fresh water aqua-culture to generate additional income for the beneficiaries selected from the landless families and marginal farmers.
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Vocational training and training and other input in cottage industries, apiculture, mushroom cultivation, floriculture, etc can help to make the forest-dependent people more self-sufficient. Efforts will also be made to encourage the poorer section of the people form self-help groups to avail of bank loans to start their own ventures/trades.
The FPC/EDC members will be encouraged to create community fund, through their contributions from the benefits derived out of JFM support services, which will help sustain the development activities in the villages even after the withdrawal of the project fund.
Confidence building activities
Building up of trust between the foresters and forest fringe dwellers form the key to success of JFM/ JMM. Activities like construction of village brick paths greatly facilitate communication and help better marketing of agricultural and other produces. Similarly, construction of pucca jetties, installation of solar lights, janata insurance coverage of the FPC/EDC members and organising regular medical camps in remote locations, where medical help is not readily available, help in creation of goodwill and makes the people more responsive towards protection of the mangrove eco-system.
Like the forests in other parts of the state, government resolutions have also been issued for adoption of Joint Forest Management in Sunderban reserved forests of India. The resolutions provide guidelines for formation of Forest Protection Committees and Eco-Development Committees and implementation of development activities within and outside the forest areas. Various JFM support activities and eco-development activities can be categorised as follows:
(A) Community development projects
Construction of irrigation canals for rain-water harvesting, construction of sweet water ponds for irrigation as well as fresh water pisciculture, construction of village brick paths to improve communication, construction of jetties, digging of tube-wells for drinking water supply, supply of solar lights, organising regular medical camps in remote areas and construction of embanks for protection of villages.
(B) Individual beneficiaries oriented schemes
Apiary and mushroom cultivation, diggery, goat rearing, duckery and poultry, vocational training for cottage industries like boutique printing, etc., development of self help groups and training and input for vocations/ professions like tailoring, cycle repairing, etc.
F. Eco-tourism
Sunderban is a nature’s school for the eco-tourists. Though Bengal tiger is the flag- ship species of this unique mangrove forest, yet it offers many other wonders of the nature to the visitors. Seeing a Bengal tiger in this 4,200 sq km of dense mangroves, where visitors have only access to water-ways, has a chance of one in thousands. Thanks to the shyness and cautious attitude of this magnificent animal, it has survived the bullets and trap nets of poachers in this most difficult terrain, over the ages. However, the more curious spotted deer out on the mud flat for grazing during low tide, the lazy estuarine crocodiles basking in the winter sun, the water monitor lizards moving like the fabled dragons and the avifauna like kingfisher, adjutant stork or white-bellied eagles are common sights for the nature lovers.
The nature’s magic of high tide-low tide, the mangrove species like rhizophores having stilt roots, or Pneumatophores having breathing roots, or Phoenix (Golpata) providing perfect camouflage for the tigers, teach the tourists about Nature’s determination to survive and sustain. The pre-historic mud-skipper or many species of crabs, fish and oysters/mollusks can make the visitors enthralled. And a glorious sun rise at Kalash, or enchanting sunset in the Sunderban forest can be a ‘Joy for ever’.
Eco-Tourism Destinations and Access
The entry point to Sunderban Tiger Reserve is either Sonakhali via Canning, or Bagna via Dhamakhali. For visiting south 24 Parganas forest division, on the western part of river Matla, the entry points are Namkhana, Raidighi or Jharkhali via Canning/Basanti. Entry Permits are available at Canning, Sonakhali and Bagna for Sundarban Tiger Reserve and at Canning, Namkhana and Raidighi for western part of Sunderban forest.
The eco-tourism centres are located at Sajnekhali, Dobanki, Netidhopani and Burir Dabri in Sundarban
Forestry Bulletin-39
Tiger Reserve, and at Bonie camp (Sundarikati), Bhagabatpore Crocodile Project, Lothian island sanctuary and Kalash beach. There are two nature interpretation centres located at Sajnekhali and Bhagabatpore, and one eco-museum at Sudarikati. The canopy walk at Dobanki, the mangrove trail at Burirdabri and the tallest watch tower at Bonie camp are added attractions for the eco-tourists.
Research and Monitoring
The current and proposed research plan for sunderban:
·
Development of biosphere resource information centre·
Study of tiger ecology and behaviour using GPS radio collar·
Study on changes in soil and water quality parameters·
Ecological studies on mangrove vegetations·
Re-introduction of captive-bred estuarine crocodiles and Olive Ridley Turtle·
Development of software for tiger pugmark analysis for census·
Mangrove vegetation mapping on real-time basis using RS/GIS·
Status survey of avifauna of Sunderban Biosphere Reserve·
Pilot survey of dolphins and estuarine crocodiles·
Socio economic study on dependence of fringe people on Sunderban forest·
Crab fattening /oysters culture program for alternate livelihood·
Studies on fin-fish and shell-fish production in mangrove ecosystemGIS development in Sunderban Biosphere Reserve
Sunderban reserved forest is a vast and remote land mass, criss-crossed with hundreds of rivers, creeks and tidal channels. The civilisation and human habitation comes to a halt along the northern and north-western fringe of the mangrove forest. These natural boundaries are also the end of the roads, and further entry into the tiger land is only with water crafts.
The difficulties can be well appreciated if we look into the past system of mangrove resource monitoring and survey. The working plan of 24 Parganas forest division, spread over the undivided Bengal, was first written by Mr Curtis between 1924 and 1929. According to this first most-elaborately written working plan, Mr Curtis had incurred an expenditure of Rs 2,12,000.00 at that point of time for carrying out the detailed survey to demarcate forest block and Compartment boundaries, and preparation of forest stock maps depicting the status, extent, quality of forest vegetation and species composition, etc. We can imagine the amount of money, labour and will that was involved in such conventional survey during those days. The tremendous job, carried out almost 75 years ago, is all the more apparent because of the fact that the same performance could not be repeated later till date.
The GIS Cell in W.B. forest department was first opened during 1999-2000 and forest department carried out the triennial assessment of state’s forest cover, as in 2000, using its in-house facilities and expertise. Subsequently, a full fledged GIS Cell has also been opened in the Office of Director, Sunderban Biosphere Reserve. The GIS Cell has one licence each of ARC/INFO, ARCVIEW 8.1 and TNT Mips GIS Software, and ERDAS and EASIPACE Image Processing Software. Satellite Data (Scene) for the Districts of 24 Parganas (S) and (N), Nadia and Murshidabad have been procured from NRSA, Hyderabad for the period 1981, 1986, 1989, 1994, 1997, 1999, 2001 and 2003. High resolution IKONOS satellite data have also been procured during 2003 and IRS P-6 data procured for March 2004, for more critical analysis of the mangrove forest. Time-series analysis of the mangrove vegetation and hydrological features have been carried out with the data available for more than two decades.
Managing the Trans-boundary
Ecosystem of Sunderbans1. UNDP project on Indian Sunderban
A. UN Foundation (Ted Turner Foundation) had sanctioned a fund of US $ 100,0000 for the preparatory Phase Project on ‘Conservation of Biodiversity in Sunderban through a Two-Country Approach’. UNDP, India and UNDP, Bangladesh had jointly taken up the project, as early as in 2000-01 and had approached India and Bangladesh for
Forestry Bulletin-40
appointment of two national project coordinators, one for each country, for drawing up of the Joint Project Document for Indian and Bangladesh Sunderban.
B. A joint project inception workshop was organized by UNDP, Bangladesh at Dhaka on 1st and 2nd December, 2001 which was attended, inter alia by NPC, India and FD/STR.
C. A joint field visit to Bangladesh was organised from 11 Feb to 15 Febuary, 2002 which was attended by an eight member Indian delegation.
D. A joint field visit to Indian Sunderban was organised from 12 to 18 March, 2003. Bangladesh delegation included two representatives of UNDP, Bangladesh, representatives of UNESCO, Delhi, one CF of B.F.D., Dy Secy, Forest, GOB and NPC/Bangladesh.
E. A National level workshop was organised at Kolkata ( Rotary Sadan ), jointly with Nature Environment and Wildlife Society, a Kolkata-based NGO, on 20th April which was inaugurated by Chief Minister of W. Bengal. The attending Bangladesh delegation included NPC/Bangladesh, two representatives of each of UNDP, Bangladesh and India and one C.F. of Bangladesh forest Department.
F. A number of meetings of the multi-disciplinary core committee, formed for the preparatory phase project, was held in Kolkata for the purpose of consultation and input for the project preparation.
G. A joint consultative meeting was held at Dhaka on 12 May, 2002 which was attended by an Indian delegation.
H. The project document, jointly written, was submitted to UNDP in July 2002. However, due to unforeseen circumstances, UNF retreated from their assurance of US $ 3 million for funding the main project.
Subsequently, the issue was taken up with UNDP, India who had agreed to fund part of the project, involving India country specific components, from UNDP, India’s Country Programme. Accordingly, the project document was re-cast and was submitted to GOI for formal sanction and signing of agreement with UNDP. The project document on ‘development of sustainable livelihood for conservation of biodiversity in Sunderban’ was finally approved by GOI and UNDP, New Delhi in September 2003. The total approved project cost is US $ 500,0000. The flow of fund under the project has started from March 2004 and will continue till March 2006.
2. Joint Tiger Census in Indian & Bangladesh Sunderban
MoEF, Govt. of India and Department of Economic Affairs had approved implementation of a preparatory phase project on ‘Conservation of Biodiversity in Indian Sunderbans through two-country approach’ with fund support from United Nations Foundation (UNF) routed through UNDP–India and UNDP–Bangladesh. Under the same project, Director, Sunderban Biosphere Reserve was appointed as National Project Coordinator (NPC) for India. NPC of the two countries prepared a joint project document on and the same was submitted to UNDP/India and UNDP/Bangladesh for seeking further fund support for implementation of the project.
In course of preparation of the project document, officials of the two countries involved in the process of consultation had identified a few aspects of collaboration which included ‘joint tiger census’, collaborative research on changes in flora and fauna, prevention of cross-border poaching, etc.
Due to non-availability of fund support from UN Foundation in implementation of the Joint Project, UNDP-India and UNDP-Bangladesh decided to collaborate in the field of ‘joint tiger census’ with balance UNF fund available from the preparatory phase project.
Six officials of Bangladesh forest department, had visited India from 11 to 21 January, 2004. These officials were trained at Sajnekhali and were attached to the census teams in Sunderbans under the supervision of field Director, Sunderban Tiger Reserve. Two Senior officials of UNDP, Dhaka had also visited Kolkata in connection with the census.
During discussion with the officials of Bangladesh forest department and UNDP, it was agreed that Bangladesh forest department will organise a similar tiger census in whole of Bangladesh Sunderbans from 26 February to 3nd March, 2004.
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MoEF, Govt. of Bangladesh had agreed to the proposal of UNDP-Dhaka regarding holding the tiger census in Bangladesh Sunderbans in the last week of February, 2004. MOEF, Govt. of Bangladesh, had also agreed to invite Indian officials to attend the tiger census in Bangladesh Sunderbans in February / March, 2004.
As a follow up of the above Project, an Indian delegation, comprising six officials, had visited Bangladesh from 25 February to 4 March, 2004.
During discussions on 25 February 2004, Secretary, MoEF, Govt. of Bangladesh requested Principal Secretary, Forest to continue the bilateral cooperation in the field of conservation of Royal Bengal Tiger and Sunderban biodiversity as a whole. He appreciated the role of Indian officials in organising the joint tiger census with Bangladesh. Both the Indian and Bangladesh officials agreed that periodic meetings of Indian and Bangladesh forest officials, working in India/Bangladesh Sunderban, will help develop a coordinated effort by India and Bangladesh in curbing illegal poaching, indiscriminate prawn seed collection, arresting negative changes in mangrove vegetation composition like reversing the trend of extinction of Sundari species and monitoring the status of tiger population on both sides of the border.
The actual census in Bangladesh Sunderbans took place from 26 february to 3 March 2004. There were 32 census parties, each comprising 8 members including forest officials and one each from local school/collage/NGO and Bangladesh NCC. The enthusiasm of the participating Forest officials at the field level was overwhelming. These field level officials had already been trained up by 6 senior officers of Bangladesh forest department who had earlier visited Indian Sunderban and participated in the tiger census held from 14 to 20 January 2004 by the West Bengal forest department. Till 3st March 2004, more than 1, 200 pugmarks were collected which are being analysed subsequently for arriving at the estimated tiger population figure. The process is expected to take a few more months before final figures can be arrived at.
The debriefing session was held at Dhaka on 29 February, 2004, at which Secretary, MoEF and MIC, E&F, Govt. of Bangladesh also participated. It was felt that Forest & Environment Minister of Bangladesh may also visit Indian Sunderban, sometimes in July/August 2004, in order to participate in the joint declaration of the Census result.
References
Chowdhary, A.B. and Chowdhary, Amalesh. 1994. Mangroves of Sunderbans. V. 1. India. IUCN.
Forest change detection studies and wetland mapping through IRS satellite data. 1994. Kharagpur, RRSSC.
National Workshop on Forestry Planning through I.T., Kolkata, April 2000. Proceedings. The author.
Raha, A.K 2002. Monitoring changes in Sunderban mangroves using RS/GIS In: Asian onference on GIS, Bangkok, 2002. The author.
Review Meeting of Biosphere Reserves in India and their Management, New Delhi, September 2000. 2002. Proceedings. New Delhi, Ministry of Environment of Forests.
Socio-economic survey in the fringe villages of Sunderban Reserved Forest. 2002 onsultancy study by Shukla Sen under UNDP Project.
Status Report on conservation and management of biodiversity of Indian Sunderbans. 2002. Consultancy study by IISWBM, Kolkata under UNDP Project.
West Bengal. Forest Department. 2000. Management plan of Sunderban Tiger Reserve for 2000-01 to 2009-10. The author.
West Bengal. Forest Department. Sunderban Biosphere Reserve. Comprehensive anagement action plan on Sunderban Biosphere Reserve. The author.
West Bengal. Forest Department. Sunderban Biosphere Reserve. 2004. Indian Sunderban: An overview. The author.
West Bengal. Forest Department. Working plan of South 24 Parganas forest for 1997-98 to 2006. Calcutta, West Bengal. Forest Department.
SUSTAINABLE UTILISATION OF MANGROVE ECOSYSTEM FOR LOCAL COMMUNITY DEVELOPMENT
Rajiv Kumar
Extension Division, Forest Research Institute, Dehradun –248 006
Introduction
Mangrove ecosystem is one of the most productive coastal ecosystems of the world, which has played a crucial role in development of local communities since time immemorial. There are many mangrove species, which are useful to the rural people in meeting their day-to-day requirements of fuelwood, fodder, timber, poles and tannin (Table-1). However, mangroves in India were over-exploited and destroyed on large scale prior to 1980. Main activities, which resulted in destruction of mangroves were unscientific wood extraction andconversion of mangrove areas for agriculture, horticulture, aquaculture and human settlement. India has lost 40 per cent of the mangrove areas of what existed a century ago (Krishnamurthy, Choudhary and Untawale, 1987). The National Remote Sensing Agency (NRSA) recorded a decline of 7000 ha of mangroves in India within a six-year period from 1975 to 1981. This unsustainable utilization of mangroves posed a serious threat to their conservation and consequently adverse effect on the development of local communities. Realising gravity of the problem, Government of India in 1986 banned felling of mangroves and launched a centrally sponsored scheme for conservation and development of mangrove ecosystem. Mangrove ecosystem offers numerous wood and non-wood forest products (NWFP) for the local communities. Mangroves also provide various services to the coastal community, which are crucial for their prosperity and provide a healthy environment around them.
Utilisation of Wood Products
At present there is total ban on felling of mangroves in India. Therefore, we will be traditional and potential utilisation of wood products offered by the mangrove ecosystem will be discussed with special reference to the state of Goa and Andaman and Nicobar Islands, where author worked for 9-10 years.
Fuelwood
Mangrove wood was preferred as fuelwood because of its high calorific value. Calorific value of various species normally ranges between 4700 to
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Table 1.
Useful mangroves for rural communities
Fuelwood Fodder Timber and poles Tannin Rhizophora mucronata Avicennia marina Avicennia officinalis Rhizophora mucronata Rhizophora apiculata Bruguiera parviflora Avicennia marina Rhizophora apiculata Avicennia officinalis
Rhizophora apiculata
Sonneratia alba
Bruguiera
gymnorrhizaAvicennia marina Acrostichum aureum Sonneratia caseolaris B. parviflora Avicennia alba Ceriops tagal B. cylindrica Sonneratia alba Ceriops tagal Sonneratia caseolaris Kandelia candel Bruguiera gymnorrhiza
Bruguiera
gymnorrhizaCeriops tagal S. alba, Xylocarpus granatum X. mekongensis X. moluccensis. Table 2.
Properties of mangrove woodsSource: Untawale (1998)
Name of species
Calorific
value (cal/kg)
Weight (kg/cu.ft.)
Hard-ness
Specific gravity
Ash (%)
Rhizophora mucronata 4,888 23 Very Hard 0.81 0.9 Bruguiera gymnorrhiza 4,700 28 Hard - 1.1 Ceriops tagal 5,150 25-30 Hard - 1.1 C. roxburghiana 5,347 21-25 Hard - - Heritiera minor
5,028
(sap wood)26-30
Very Hard
0.84
1.9
5,261
(Heartwood)26-30
Very Hard
Sonneratia apetala
4,901
(sap wood)18
Moderate
0.60
2.2
Lumnitzera racemosa 5,137
(sap wood)24-26
Hard
-
0.6
5,424
(Heartwood)Excoecaria agallocha 4,767 - Soft - 3.18 Aegiceras corniculatum Very Low 18 Moderate - 0.9 5300 cal/kg (Table-2). The coastal communities in India used most of the mangrove species as fuelwood. Along the mangrove bearing coastal areas in Goa, there are 62 villages with a total population of over 2.00 lakhs. Mature stands under suitable condition may yield over 270 m3/ha within 30 years, equivalent to MAI of 9-10 m3/ha (FAO, 1994). In Andaman and Nicobar Islands (A& N Islands), local people preferred mangrove species belonging to the genus Rhizophora, Ceriops, Sonneratia, Avicennia and Bruguiera for firewood. Fishermen in the islands used Avicennia marina wood for fish smoking as it burns with little smoke. In A& N Islands, between a four-year period from 1981-82 to 1884-85, 14, 000 to 26,000 m3 mangrove wood was extracted per year (Table-3). In addition to meeting people’s demand, a large portion of mangrove wood was being utilised for commercial purposes prior to 1987. One powerhouse at Port Blair and three major plywood industries namely M/S Kit ply, M/S Jayshree Timber Products and M/S Andaman Timber Industries were using mangrove fuel for their boilers. Even government’s steam vessels were using mangrove fuel for generating steam.
Fodder
Avicennia marina, Bruguiera parviflora, Rhizophora apiculata and Acrostichum aureum were used in Andaman Islands as fodder for cows, buffaloes and goats.
Timber
Generally, mangrove woods are not very important as timber. Rhizophora, Bruguiera, Sonneratia species are not used as timber as they split and warp when dried. Most of the mangrove wood have high density, which makes it difficult to work. However, Avicennia species which have relatively lesser density were used as timber for construction of houses and carpentry items in the Andaman Islands.
Charcoal
Wood density largely determines yield of charcoal from wood,
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Table 3.
Extraction of mangrove wood and charcoal in Andaman and Nicobar Islands
Forest Divisions
By Government Agencies (m3)
By Private Agencies
payment of royalty (m3)Total extraction of mangrove wood (m3)
Extraction of Charcoal (Tonnes)
1981-82
North Andaman
0 472 472 0.96 Middle Andaman
157 4,405 4,562 7.56 Baratang Division
130 207 337 3.92 South Andaman
0 20,586 20,586 0 Nicobar Division
