360
dominated by island mangrove colonies are seriously damaged due to the magnitude of geomorphic changes resulted by the landfall of Phylin cyclone in 2013
(Paul et al. 2014).
Mangroves prevail in the fragile environment of the Andaman Islands (Samanta
and Panda 2012) dominated by carbonate sediment depositional platforms maintain
their species richness. According to their studies, the true mangrove species are
mostly found to grow in the intertidal zones along the tidal creeks of Andaman
Islands. Currently, the mangroves of carbonate platforms are damaged in many
places due to the magnitude of tsunami waves in Andaman in 2004 (Paul 2005). The
Sundarban mangroves however, have been suffering from rapid destruction and
degradation (Ghosh and Naskar 2012) by direct and indirect interference of human
systems with the mangrove ecosystem of the largest delta. The views of some workers (Acharya and Mohapatra 2012) represent the observable causes of degradation
of Bhitarkanika mangroves in Odisha state of India. The tropical deltas mangroves
of the region are significantly affected by anthropogenic threats (overuse and conversion). In one of the study made by Majumdar et al. (2012) it is noted that the
holophytic grasses of the younger eastern island platform of the Hugli downstream
section are luxuriant in growth in comparison to the swampy mangrove forests of
the island (Nayachara Island). However, the higher platform with mangrove vegetation covers has reached a self maintaining stage in equilibrium with the present
geomorphic processes, loss of tidal drainage, present tidal range with mature channel creeks and inundation frequency.
The coastal wetland loss can be assessed in the regions of Sundarban if the mangrove degradation checklist is prepared by exhaustive survey work on spatiotemporal basis. Environmental protection and conservation of mangrove wetlands depend
on consideration of degradation checklist with estimated sequential factors.
11.2 Materials and Methods
The study was conducted in the southwestern part of the Sundarban coast (Henry’s
Island, Fredrick Island, Patibania Island, Freserganj and Bakkhali) with special
emphasis on the forested and reclaimed areas of Namkhana Abad in between river
Muriganga and river Saptamukhi (Fig. 11.1).
During the field survey, hypersaline tracts and over wash sand fan lobes, as well
as the exposed consolidated mud banks (with presence of mangrove tree stumps)
were identified for various measurements and monitoring changes of shoreline
characters. Soil pits were constructed in the hypersaline tracts and on the surfaces of
over wash fan lobes with the help of forest department for sediment sampling, for
finding the productive swamp mud layers and underlying peat swamp, and also for
minor measurements and photographic documentations. Total station survey was
conducted in some selected areas of the shores in which mangrove dieback was also
evident. Contour plan with erosion-deposition sites were prepared to find out the
coastal morphometric behavior of the low lying shores formerly dominated by
A.K. Paul et al.
dominated by island mangrove colonies are seriously damaged due to the magnitude of geomorphic changes resulted by the landfall of Phylin cyclone in 2013
(Paul et al. 2014).
Mangroves prevail in the fragile environment of the Andaman Islands (Samanta
and Panda 2012) dominated by carbonate sediment depositional platforms maintain
their species richness. According to their studies, the true mangrove species are
mostly found to grow in the intertidal zones along the tidal creeks of Andaman
Islands. Currently, the mangroves of carbonate platforms are damaged in many
places due to the magnitude of tsunami waves in Andaman in 2004 (Paul 2005). The
Sundarban mangroves however, have been suffering from rapid destruction and
degradation (Ghosh and Naskar 2012) by direct and indirect interference of human
systems with the mangrove ecosystem of the largest delta. The views of some workers (Acharya and Mohapatra 2012) represent the observable causes of degradation
of Bhitarkanika mangroves in Odisha state of India. The tropical deltas mangroves
of the region are significantly affected by anthropogenic threats (overuse and conversion). In one of the study made by Majumdar et al. (2012) it is noted that the
holophytic grasses of the younger eastern island platform of the Hugli downstream
section are luxuriant in growth in comparison to the swampy mangrove forests of
the island (Nayachara Island). However, the higher platform with mangrove vegetation covers has reached a self maintaining stage in equilibrium with the present
geomorphic processes, loss of tidal drainage, present tidal range with mature channel creeks and inundation frequency.
The coastal wetland loss can be assessed in the regions of Sundarban if the mangrove degradation checklist is prepared by exhaustive survey work on spatiotemporal basis. Environmental protection and conservation of mangrove wetlands depend
on consideration of degradation checklist with estimated sequential factors.
11.2 Materials and Methods
The study was conducted in the southwestern part of the Sundarban coast (Henry’s
Island, Fredrick Island, Patibania Island, Freserganj and Bakkhali) with special
emphasis on the forested and reclaimed areas of Namkhana Abad in between river
Muriganga and river Saptamukhi (Fig. 11.1).
During the field survey, hypersaline tracts and over wash sand fan lobes, as well
as the exposed consolidated mud banks (with presence of mangrove tree stumps)
were identified for various measurements and monitoring changes of shoreline
characters. Soil pits were constructed in the hypersaline tracts and on the surfaces of
over wash fan lobes with the help of forest department for sediment sampling, for
finding the productive swamp mud layers and underlying peat swamp, and also for
minor measurements and photographic documentations. Total station survey was
conducted in some selected areas of the shores in which mangrove dieback was also
evident. Contour plan with erosion-deposition sites were prepared to find out the
coastal morphometric behavior of the low lying shores formerly dominated by
A.K. Paul et al.