06-bioresourcesstatu.. - M. S. Swaminathan Research Foundation

-- 2olf1
1981
1961
1941
1921
1901
Docadal Growth Rate
lo_ •....... j
•10 0 .",wlh""e 10 20 30
Figure. 4: Decadal Growth Rate for
Orissa and Kendrapara .
Of the six important panchayats, the highest
growth is observed in Rangani, that has more of
agricultural area (see map). Satbhaya shows the
least increase in population.
Figure 4 shows that is the 1941-1961,there was a
greater increase in population in the district.
IV. Biodiversity and
Conservation Values
I. Flora
This sanctuary harbours one of India's largest
mangrove forest in terms of number of species and
levels of variation in ecological conditions.
Primary productivity of the mangrove trees, by
harnessing solar energy and production of
biomass, increases the secondary and tertiary
productivity of the area. It is estimated that
mangrove detritus production of a ton per hectare
has a potential fish yield of 800-1000 kgi'hll/year
(Lal 1990) Decline in offshore shrimp catch and
populations of mangrove mud crabs has been
attributed to destruction of mangroves in
Indonesia (UNESCO, 1987). Thus these plant
formations not only form a base for secondary
production within themselves but also increase the
productivity of neighbouring water bodies.
The earliest description of the vegetation of this
region is provided by Haines (1921-25) followed by
taxonomical and ecological studies by Banerjee
(1985), Banerjee and Rao (1990),
Choudhury,(1984,1987,1989,1990). The description
presented here is adapted from Patnaik and
Choudhury (1989) and Kanvinde and Das (1995).
The vegetation can be classified into mangal and
salt brush formations. The highlights of the
vegetation being the occurrence of three species
each of Avicennia, Sonneratia, Rhizophora,
Xylocarpus and Heritiera in sanctuary. A list of
mangrove species and associates
Annexure 1.
is presented in
Manga! formations
Bhitarkanika
The mangrove elements are mostly concentrated
along the network of creeks and channels. It
extends from the sheltered bays to the elevated
banks of the upper riparian zone, where the
composition of the mangrove community is
different due to the presence of non-mangals and
transitory mangals. The mangals are classified
into three categories .
Eumangals: These are typical mangrove taxa,
which survive water logging due to the periodic
submersion through tidal action and are adapted
for. high variations in salinity and poor soil
aeration. The eumangals are generally evergreen
and show a high degree of xerophytism through
morphological and reproductive adaptations.
Almost pure formations of Porteresia coarctata -
a dominant grass element - are gregarious along
the banks which are submerged during the tide.
181
Semimangals: The elements of this category
exhibit various adaptations characteristic of
halophytes. In many cases they are, however
devoid of pneumatophores and vivipary. These
taxa grow very close to the river banks and creeks
Transitional Mangals: The plants of this category
have features of halophytes, but are well adapted
to more terrestrial habitats. The majority of them
are deciduous while some are evergreen. These
are found in areas where tidal action is limited or
absent and the salinity is low.
Saltbrush formations
The sandy vegetation is found along the littoral
tract of Satbhaya and Gahirmatha. This
vegetation is mostly composed of shrubby and
herbaceous elements. The characteristic elements
of this terrain are Spinifex littoralis, Cyperus
arenarius, Hydrophylax maritima, Ipomea pescaprae,
Launea sarmentosa, Gisekia
pharmacoidess, Suadea maritima, S.monoecia,
and Vetivera zizanoides.
ii. Thuna (This section on Fauna Is contributed
by Dr Sudhakar Kar, Research officer, Wildlife
Wing, Forest Department, Gov!. of Orissa)
The animals that are associated with the
mangroves, cover a wide range of invertebrate and
vertebrate groups (Kenneally, 1982, Kar, 1981,
Dash and Kar, 1990; Kar and Satapathy; 1996 and
Kanvinde 1997) (Annexure - 2)