368
11.4 Discussions
The above results are discussed in the following ways;
11.4.1 Causes of Mangrove Degradation
Several causes of mangrove degradations have been identified by the present study
for the region of Sundarban under tropical hot and humid climate.
1. Human uses of mangroves: Historical land reclamations and permanent settlement started in the Sundarban since 1810 when the areas of mangroves (about
20,000 km
2
) were distributed in three administrative districts (Buckerganj,
Khulna and 24-Parganas) of undivided Bengal at the coastal zone of Ganga delta.
The entire forest belt was separated into several islands by intricate networks of
tidal creeks, and active distributary channels of the Ganga delta supported by
seasonal discharges of fresh waters with frequent river flood, and seaward transport of sediments. At present, mangroves are thriving only in areas of 4962 km
2
land surface occupied by the West Bengal portion of Sundarban (North and
South 24-Parganas districts) in India, and the remaining areas are distributed in
the deltaic islands of Bangladesh Sundarban (Buckerganj and Khulna districts).
The poverty stricken people use non-timber forest resources in the buffer
areas of mangrove forest to support their livelihood. Various tourism infrastructures have been emerging within the forest belt in the expanse of mangroves.
Mangroves are also lost from many places due to the dispersal of wastes nearby
the harbors and market places adjacent of tidal creeks. As population pressure is
increasing day by day at the northern and southwestern administrative blocks
fringed by existing mangrove forests, the human uses of mangroves also may be
rapidly increased in the buffer areas.
2. Fishery development: Construction of various aquaculture ponds within the
forest belt, clay mining from the tidal flat for building the mud built walls to
protect the fish ponds, emerging number of dry fish processing platforms, as well
as the development of temporary colonies of fishermen along the interface of
back shore mangroves and sandy shores have severely reduced the areas of mangrove forests in the Sundarban. Hence the release of untreated waters from the
fish farm ponds into the tidal flats and construction of harbors, jetties, sluice
gates and bridges like engineering structures also have disturbed the growth and
survival of mangroves in the pristine environment of Sundarban. The rate of
encroachment of fishery development in the forest and the forest fringe areas has
been rapidly increased in the previous decades (1990s and 2000 onward).
3. Hypersalinity: Supra-tidal flats of islands and shore fringed areas of the
Sundarban are affected by infrequent tidal inundation due to configuration
changes on the island surface with uneven distribution of sediments in the sedimentary depositional environment. Such immersion of certain portions of the
A.K. Paul et al.
11.4 Discussions
The above results are discussed in the following ways;
11.4.1 Causes of Mangrove Degradation
Several causes of mangrove degradations have been identified by the present study
for the region of Sundarban under tropical hot and humid climate.
1. Human uses of mangroves: Historical land reclamations and permanent settlement started in the Sundarban since 1810 when the areas of mangroves (about
20,000 km
2
) were distributed in three administrative districts (Buckerganj,
Khulna and 24-Parganas) of undivided Bengal at the coastal zone of Ganga delta.
The entire forest belt was separated into several islands by intricate networks of
tidal creeks, and active distributary channels of the Ganga delta supported by
seasonal discharges of fresh waters with frequent river flood, and seaward transport of sediments. At present, mangroves are thriving only in areas of 4962 km
2
land surface occupied by the West Bengal portion of Sundarban (North and
South 24-Parganas districts) in India, and the remaining areas are distributed in
the deltaic islands of Bangladesh Sundarban (Buckerganj and Khulna districts).
The poverty stricken people use non-timber forest resources in the buffer
areas of mangrove forest to support their livelihood. Various tourism infrastructures have been emerging within the forest belt in the expanse of mangroves.
Mangroves are also lost from many places due to the dispersal of wastes nearby
the harbors and market places adjacent of tidal creeks. As population pressure is
increasing day by day at the northern and southwestern administrative blocks
fringed by existing mangrove forests, the human uses of mangroves also may be
rapidly increased in the buffer areas.
2. Fishery development: Construction of various aquaculture ponds within the
forest belt, clay mining from the tidal flat for building the mud built walls to
protect the fish ponds, emerging number of dry fish processing platforms, as well
as the development of temporary colonies of fishermen along the interface of
back shore mangroves and sandy shores have severely reduced the areas of mangrove forests in the Sundarban. Hence the release of untreated waters from the
fish farm ponds into the tidal flats and construction of harbors, jetties, sluice
gates and bridges like engineering structures also have disturbed the growth and
survival of mangroves in the pristine environment of Sundarban. The rate of
encroachment of fishery development in the forest and the forest fringe areas has
been rapidly increased in the previous decades (1990s and 2000 onward).
3. Hypersalinity: Supra-tidal flats of islands and shore fringed areas of the
Sundarban are affected by infrequent tidal inundation due to configuration
changes on the island surface with uneven distribution of sediments in the sedimentary depositional environment. Such immersion of certain portions of the
A.K. Paul et al.