Cyclone and Storm Surge - Iczmpwb.org

2.23
2.4.10. Flora and fauna
The Natural Forest Resources consists of the mangrove forests which constitute a major resource in
terms of the area, density and diversity of mangrove species they contain. In this Division the forest
area consists of many low flat island called locally as "Char Land' and mud banks separated by a
network of anastomotic channels and rivers, the courses of which are very much prone to frequent
alteration. There is a dynamic state of erosion in some areas and creation of new mud banks and
char land in others.
The vegetative colonisation of newly formed land follows the pattern of natural succession. At first,
pioneer species establish on the site. In the case of mangroves, the seeds of these species are
dispersed by water, floating in on the high tides and lodging in the soft mud as the tide recedes.
Species of Avicennia, Rhizophora, and Sonneratia are the typical mangrove pioneers. These
pioneers are adapted to the diurnal inundation by the tides, and in fact, depend upon it. As they grow
they induce further sedimentation by reducing the velocity of water flowing past and trapping silt. As
the sedimentation build up and the duration and frequency of inundation reduces, other species like
Bruguieria, Xylocarpus, Exoecaria etc, are established. Like other natural forest succession, the
pioneers are comparatively faster growing but shorter living than species coming later ion the
sucession.
Where the accretion of the sediment reaches a level where the tidal inundation is rare, the vigor and
regenerative capacity of the mangrove species fade away. These types of land tend to become
dominated by a low thicket palm like Phoenix paludosa. Besides the frequency and duration of tidal
inundation, salinity level plays a major role in influencing the occurrence of mangrove species. As a
result of change in salinity profile the occurrence of species like Sundari (Heritiera fomes) has
become less since it is sensitive to change in salinity level.
With the progress of reclamation in the Sundarbans and increase in human population, the wild life is
faced with gradual extinction. The most noted species are Royal Tiger, Cheetal (Spooted dear) and
the Crocodiles. In Sundarbans tigers very often carry away wood-cutters, honey collectors and others
from the forest area. They are great swimmers and there are instances that they carry away men
from boats anchored in mid stream. The crocodiles in Sundarbans known as Estuarine Crocodiles
(Crocodilus Porosus) are also man eater.