Mangrove fauna is generally represented by acquatic, semi-acquatic and terrestrial communities adapted at stress conditions. As many as 8 species of mammals, 53 species of birds, 7 species of Reptiles 3 species of Amphibian, 253 species of fish, 13 species of polychaetes, 410 species of Arthropods and 53 species of Meiofauna are reported from the mangroves of Andaman & Nicobar Islands.
In general, the following three conspicuous zones are identified.
1. Proximal Zone
This zone is towards
water front, subject to regular tidal effect where intensity of soil
accumulation and inundation is a continuous process.
The mangrove species in this zone
are specially adapted with stilt roots, prop roots for stability
and anchorage. Main species
with these features are Rhizophora apiculata and Rhizophora
mucronata. On rocky
and coral reef substrata, Avicennia,
are also found. Both
Avicennia and Sonneratia produce pneumatophores.
Above the Rhizophora/ Avicennia line luxuriant group of
gymnorrhiza B. Cylindrica,
Lumnitzera racemosa, L.
littoralis, Ceriops tagal and Aeguiceras corniculatum occur.
Soil formation in the Core Zone is congenial for mangrove growth
wherein the trees attain a height of 10-15 metres in compact blocks.
Ceriops and Bruguiera develop a strong hold fast in
the form of knee roots or bent roots as a special adoption for
supporting the erect bole.
Towards island area mangroves like Excoecaris agallocha,
trees like Heritiera littoralis
and xylocarnus spp. In association of Phoenix paludosa,
Nypa fruticans, Acanthus ilicifolius and
ferns like Acrostichum aureum occur, the latter occurring
precariously in thick patches. Both Heritiera and Xylocarpus
produce buttresses and help in containing soil in their cavities.
Generally the salinity is on lower side in this Zone occurring towards
hill sides where run off of fresh water is for a prolonged period. The
duration of tidal submersion is low in this Zone compared to water front
Being living resources,
mangroves are self maintaining and renewable. For example as a coastal
protection barrier, Mangroves maintain themselves at no cost and in the
vent of tropical storm, the damages sustained will be self repaired
without cost. Similarly both the direct and indirect harvests of
products from mangroves are renewable yet, the mangroves resource is
renewable only if the ecological processes governing the systm are
The leaf fall from the mangrove
trees also contributes substantially to formation of detritus which
supports coastal fisheries.
Mangroves constitute a unique
habitat for wild animals and birds. They provide nesting breeding places
Mangroves provide breeding
grounds for fish and other marine animals.
Mangrove serve as potential
recreation site for fishing, boating, bird watching, sight seeing and
photography. This has special significance for the Andaman & Nicobar
Islands having tourism potential.
Mangroves provide vast scope for
scientific and socio-economic studies.
Extraction of mangrove fuel and land development including
agriculture has contributed to extensive damage of mangroves in some
areas. Although damage to mangrove ecosystem from insecticides
and pesticides used in agriculture and their run off, deliberate
and operational discharges from ships, oil spills due to accidents and
industrial outflows are not reported in the island, but these have
caused extensive damage to mangroves ecosystem in other areas. Mangroves
are traditionally used for aquaculture. There is tremendous demand for
mangrove fish in international market. The prospectus of potentially
quick economic games have caused a rapid rate of clearing of mangroves
for development of brackish waterfish products. Excessive exploitation
of mangroves could result
in lower litter production and consequently could effect productivity of
CONSERVATION AND MANAGEMENT OF MANGROVES IN A & N ISLANDS
Chengappa, in 1951 had estimated that
Bruguiera species constitute about 26 to 30% of
mangrove area of South and Middle Andaman Division. He
prescribed clear felling and selection- felling of Bruguiera
trees along with other natural mangrove trees. Although no systematic
working of mangroves was followed in the subsequent years a small area
was worked in North and South Andaman under selection system by removal
of marked trees under the shelter wood system by removal of marked trees
under the selection wood system, in which 40 well formed Rhizophora and
Bruguiera poles per hectare were left out as standards uniformly spaced.
Precautionary measures were also taken to leave protection belt of 20
metres width along the main creek on either side and 10 metres width
along the smaller creek on either side to guard against sea erosion.
Brush wood barriers across the creeks the were also left to hold the
seeds of Mangrove species from washing away along with the tides.
In the past the mangrove forests were worked for extraction of fuel wood around Port Blair to meet the domestic requirement of the people. The Andaman Timber Industry and Chatham Power House were also using mangrove fuel wood for running their boilers. However, the mangrove fuel wood extraction and sale of mangrove has been totally stopped in the islands.
The limited extraction
in the past of mangroves for fuel wood and poles from Government forest
has not caused any damage to the Mangroves. But in the revenue areas, the destruction of mangroves is
conspicuous and at places the area has been reclaimed for agriculture as
well for settlement. The extent and
condition of the crop and the threat under which such mangrove
area lie presently is required to be assessed.
MANAGEMENT ACTION PLAN DEVELOPED BY THE DEPARTMENT OF ENVIRONMENT &
FORESTS INCLUDES :
demarcation of mangrove area including mapping of degraded mangroves
areas using remote sensing as well as ground survey.
Regular patrolling in creeks to check possible destruction of
existing mangroves and protecting rare species of mangroves found in
Ecological restoration of degraded mangroves by raising nurseries
and replenishing degraded mangrove areas through artificial
4. Publicity and awareness campaign through film shows, organizing seminars, nature camps, distributing publicity materials etc.
Text based on : ‘Mangroves of
Andaman and Nicobar Islands’ by J.C.Dagar, A.D.Mongia and
Photograph : Courtesy
Rajiv Kumar, IFS.