A b s t r a c t - TERI School of Advanced Studies · A b s t r a c t West Bengal is a ......
Transcript of A b s t r a c t - TERI School of Advanced Studies · A b s t r a c t West Bengal is a ......
EX-SITU REHABILITATION OF MANGROVE SPECIES
SAKTI SANKAR DEY
CONSERVATOR OF FORESTS,SOUTH,WEST BENGAL
A b s t r a c t
West Bengal is a state which has a long stretch of coastal line towards its south and south
west.Except sundarban, mangrove vegetation is not so much prevalent in south-western part
bordering Odisha.Mangrove is required to be generated in areas along the sea shore of Bay of
Bengal to protect the coastal people out of cyclone and tsunami.Bay of Bengal is also receding
towards south and south east leaving a vast tract as coastal mud flat.Due to salinity,most of the
areas remains vegetation less.What history says and which is authenticated from Bengali literature
that mangrove plants were existing along the coastal line bordering south western parts of West
Bengal.While rehabilitating mangrove in these areas, it is found that at first stage gregarious
monocoteledonus grass locally known as Dhani grass (Porteresia coarctata) comes out as green
carpet which made a hindrance for raising plantation.As an experiment mangrove species were
taken from silviculturally selected seed trees from Dakshin 24 Pargana District of West Bengal which
is a part of Sundarban delta.Some of them were regenerated in the nursery and some others were
planted directly in the planting site.Out of 15 species planted only 5 species namely
Kankra,Garan,Sada byne,Kala byne and Harguja species showed promising results.Other species
though survived in some plots but their existence is not so much to make a conclusion.Plantatons
were undertaken since 2002.Growth data were recorded.For present study data taken in 2012 have
been taken into consideration for each year’s plantation and comaparative study has been done to
reach a conclusion.
Keywords: Mangrove rehabilitation,Coastal Mud Flat.
Introduction
Mangrove species are available in the entire sundarban delta of West Bengal and which
extends upto Bangladesh.Though they are found sporadically in other areas along the coastal line
out of sundarban delta still their presence is not so much significant from the point of view of area of
coverage.From the famous novel of Rishi Bankim Chandra Chattopadhyayd’s Kapalkundala, evidence
is available that mangrove were there along the seashore of south western part of West Bengal.But
due to receding Bay of Bengal the mangrove species have been destroyed with time and at present
there is no trace of mangrove.Habitation has been made,township has been created.A vast tract of
land is found barren with presence of sea crustacians.These land is known as coastal mud flat.The
soil is mostly saline.Porosity is nearly zero.Nutrient status is very poor.The habitation located at
nearby treeless coastal line is very much vulnerable to natural calamities like cyclone and tsunami.It
is very much needed to raise vegetative cover on these un-arable land to save people living along
the coastal line.These vast tract of resumed land could be used to increase the green coverage of the
state.West Bengal is a state which has second maximum population density within the
country.There is a very little scope to increase green cover in lands used for agriculture.
Mangroves that are grown in saline soil is of various types according to their adaptability to
salinity and inundation.Some species loves to grow in areas having less salinity with less
inundation.Some are very much prone to salinity and inundation.Some species have their
requirement of sweet water flow near their root zone.Some species never withstand a little trace of
saline water.
Utmost care has been taken to collect seeds from the silviculturally selected mother
trees.Sometimes viviparous germinated seeds were collected with care depending on the
phenotypical superiority.After that collection in the field culling were done in the rearing zone as
well as in nursery site to reach near qualitative superiority.Though the present experiment is site
specific but the result can be used in other coastal areas of West Bengal as well as in India having the
similarity of edaphic and climatic conditions.
Objectives
i) To evolve a proper method of Afforestation pattern for a long stretch of intertidal coastal
muddy flat through a Pilot Plantation.
ii) Creation of Coastal shelter Belt with a mixture of mangrove species. The species composition
will be as per the requirement of the area and soil type.
iii) Assisting in the colonization of locally available mangrove viviparous seedlings by taking
necessary measures.
iv) To standarise the species which are hardy enough to withstand all probable hazards of
survivability.
v) Preventing biotic interference by fencing and helping local floor species to grow freely.
vi) Regular soil analysis to monitor the change in salinity and other properties.
vii) To know the performance of mangrove species which are hardy enough to grow against
Dhani grass infestation.
viii) Experimental plantations were raised in different locations like Mankariput,Biramput and
Dakshin Kadua to cover a long stretch of diversified land.
ix) To recover a long stretch of coastal mud flat land under vegetation against becoming a
grazing ground.
x) To facilitate shelter for the local fisherman community against cyclone and flooding
devastation.
xi) To protect the nearby crop field against brine inundation.
xii) To increase the per unit area production.
xiii) To utilize a vast fallow coastal mud flat and to protect the valuable land against further
encroachment.
xiv) To protect coastline against erosion.
xv) To increase green cover for the state.
xvi) To change the soil characteristics with the help of mangrove root system.
xvii) To stabilize the huge land mass against shifting.
Materials and Methods
i) Seed collection
Seeds were collected from the mother trees selected at Dakshin 24 Pargana District of
West Bengal comes under Sundarban delta.Seeds were collected from the good quality
mother trees at Jharkhali and Gadkhali area.The mother trees were marked first
observing the good bole,tapper,branching and vegetative foliage.They are short listed
again and the numbers were taken to a reasonable limit.
ii) Some mangrove species are having viviparous germination.The germinated seedlings were
collected when they have fallen down to the ground.Sorting and culling is done instantly
at the place of collection to reach to superiority.
iii) Seedbed preparation
Seeds are sown directly in the polypots for germination.Size of the polypots were 6” x 6”
made of recycled polythene.Germinated seedlings were reared for 3 months in the
nursery.Nursery was created at the planting site to reduce the transportation shock and
for acclimatisation.Only Farm Yard Manure (FYM) was used for nutrient supplement.No
chemical fertilizers were used in nursery.
iv) Germination and growth characteristics
After seed sowing,the watering was done twice a day and weeding and hoeing was done
as and when required.The observations of seed germination were recorded till the
germination completed.
v) Planting was done in the month of August-September depending upon the tidal rise.Planting
was done at a distance of 2m x 2m.The method of planting was dig and plant method.A
hole is made by using crowbar at the dimension of 12”deep and 4” circumference.Depth
may vary as per the root length of the seedlings. The seedlings are placed in the hole
and pressed around the collar by feet.
vi) Different blocks are made for different species.Blocks were selected for a particular species
as per randomised numbers.
vii) The growth data is collected in the month of February and March of 2012 and tabulated
accordingly for each species separately. The data are analysed for performance study.
Result and Discussion
Table – 1 Growth study of seedlings raised at Mankaraiput during 2001-2002.
Mouza : Mankaraiput
Area : 1ha
Year of plantation : 2002
Name of Sps
Plot -1 Plot-2 Plot-3
Girth
in cm
Height
in m
Girth
in cm
Height
in m
Girth
in cm
Height
in m
Pandanus
fascicularis 9.2 2.95
Heritiera
fomes 1.3 1.95
Excoecaria
agallocha 12.0 1.55 15 2.70
Ceriops tagal 10 1.62 10.0 1.64 10 1.63
Avicennia
officinalis 12.0 1.23 11 0.89
Acanthus
illcifolius 15.8 2.85 17.5 2.86 18.0 2.84
Avicennia
marina 0.34 1.87 0.33 1.86 0.11 1.86
Bruguiera
gymnorhiza 0.50 2.12 0.6 2.13 0.7 2.11
Seedling measurement were taken during March,2012.
Table – 2 Growth study of seedlings raised at Mankaraiput during 2002-2003.
Mouza : Mankaraiput
Area : 1.6 ha
Year of plantation : 2003
Name of Sps Plot -1 Plot-2
Girth in cm Height in m Girth in cm Height in m
Bruguiera
gymnorhiza 14 1.14 22 2.85
Excoecaria
agallocha 21 1.97 21 3.96
Ceriops tagal 13 1.22 19 1.69
Avicennia
officinalis 06 0.82 15 2.12
Avicennia alba 11 1.28 11 1.17
Acanthus
illcifolius 10.5 2.12 9.9 2.12
Avicennia
marina 27.0 1.40 0.29 1.5
Seedling measurement were taken during March,2012.
Table – 3 Growth study of seedlings raised at Mankaraiput during 2003-2004.
Mouza : Mankaraiput
Area : 1.2ha
Year of plantation : 2004
Name of Sps Plot -1 Plot-2 Plot-3
Girth in cm Height in m Girth in cm Height in m Girth in cm Height in m
Pongamia
glabra 32 4.25 13 1.90
Heritiera
fomes 5 0.51
Excoecaria
agallocha 14 1.00
Ceriops tagal 14 1.68
Avicennia
marina 18 1.07
Avicennia
officinalis 10 0.75
Acanthus
illcifolius 9.8 1.95 9.7 1.94 9.6 1.96
Seedling measurement were taken during March,2012.
Table – 4 Growth study of seedlings raised at Mankaraiput during 2004-2005.
Mouza : Mankaraiput
Area : 0.25ha
Year of plantation : 2004
Name of Sps Plot -1 Plot-2 Plot-3
Girth in cm Height in m Girth in cm Height in m Girth in cm Height in m
Heritiera
fomes 12 1.98
Excoecaria
agallocha 42 7.50 15 1.38 18 3.25
Bambosa tulda 16 6.21
Xylocarpus
granatum 09 1.45
Acanthus
illcifolius 9.8 1.96 9.7 1.94 9.6 1.95
Seedling measurement were taken during March,2012.
Table – 5 Growth study of seedlings raised at Mankaraiput during 2002-2003.
Mouza : Dakhin Kadua
Area : 2.6 ha
Year of plantation : 2003
Name of Sps
Plot -1 Plot-2 Plot-3 Plot-4 Plot-5
Girth in
cm
Height in
m
Girth in
cm
Height in
m
Girth in
cm
Height
in m
Girth
in cm
Height
in m
Girth
in cm
Height
in m
Casuarina
equisetifolia 55.0 33.50 45.0 46.21 42.5 26.25 56.0 42.23
Acacia
auriculiformis 56.00 35.00
Borassus
flabelifer 9.45
Acacia
nilotica 21.0 5.20 22.0 4.56
Pongamia
glabra 40.27 14.56 18.47 3.195 25.0 6.29
Bambosa
tulda 13.0 19.00
Acanthus
illcifolius 10.2 2.85 10.1 2.84 10.3 2.86 10.2 2.85 10.2 2.85
Avicennia
marina 28 1.45 27 1.44 29 1.46 29 1.45 27 1.45
Bruguiera
gymnorhiza 18 1.99 17 20 19 1.98 19 1.99 17 1.98
Seedling measurement were taken during March,2012.
Table – 6 Growth study of seedlings raised at Dakhin Kadua during 2003-2004.
Mouza : Dakhin Kadua
Area : 4 ha
Year of plantation : 2004
Name of
Sps
Plot -1 Plot-2 Plot-3 Plot-4 Plot-5 Plot-6 Plot-7 Plot-8
Girth in cm
Height in m
Girth in cm
Height in m
Girth in cm
Height in m
Girth in cm
Height in m
Girth in cm
Height in m
Girth in cm
Height in m
Girth in cm
Height in m
Girth in cm
Height in m
Bruguiera gymnorhiza
21.0 1.56 25.0 3.24 37.0 2.57 25.0 2.19 22.0 2.93 19.0 2.60 20.0 2.54
Ceriops
tagal 18.0 1.12 14.0 1.38 20.0 2.60
Avicennia alba
Avicennia
officinalis 13.0 0.95 10.0 0.99 15.0 1.87 35.0 3.25 26.0 265 17.0 2.09 15.0 2.50 30.0 3.32
Avicennia maina
10.0 0.99 10.0 0.95 30.0 1.85 6.0 5.30 29.0 3.18
Sonneratia
caseolaris 76.0 6.30
Acanthus illcifolius
9.7 1.95 9.8 1.94 9.6 1.96 9.6 1.95 9.8 1.94 9.7 1.96 10.0 1.80 9.7 1.95
Aegiceras
carniculatum 11.0 1.56
Rhizophora apiculata
12.0 1.14 22.0 3.10
Seedling measurement were taken during March,2012.
Table – 7 Growth study of seedlings raised at Dakhin Kadua during 2004-2005.
Mouza : Dakhin Kadua
Area : 0.5 ha
Year of plantation : 2005
Name of Sps Plot -1 Plot-2
Girth in cm Height in m Girth in cm Height in m Bruguiera
gymnorhiza 12.0 1.92
Heritiera
fomes
Aegiceras
carniculatum 8.0 0.85
Acanthus illcifolius
10.0 2.32 7.0 1.12
Avicennia
marina 14.0 2.20 16.0 2.93
Avicennia officinalis
15.0 1.87
Ceriops tagal 14 1.14 10 1.16
Seedling measurement were taken during March,2012.
Table – 8 Growth study of seedlings raised at Biramput during 2004-2005.
Mouza : Biramput
Area : 2.6 ha
Year of plantation : 2005
Name of
Sps
Plot -1 Plot-2 Plot-3 Plot-4 Plot-5 Plot-6 Plot-7
Girt
h in
cm
Heig
ht in
m
Girth
in cm
Heig
ht in
m
Girt
h in
cm
Heig
ht in
m
Girth
in cm
Heigh
t in m
Girth
in cm
Heigh
t in m
Girt
h in
cm
Heigh
t in m
Girt
h in
cm
Heigh
t in m
Phoenix paludosa
18 2.07
Heritiera fomes
24 4.48 11 1.96 25 5.80 10 2.14
Excoecaria agallocha
28 4.55 20 2.98 30 5.12
Ceriops tagal
Avicennia alba
18 1.92 22 4.10 25 4.23
Xylocarpus granatum
35 5.96 28 4.84
Name of Sps
Plot-8 Plot -9 Plot-10 Plot-11 Plot-12 Plot-13 Plot-14
Gir
th
in cm
Heigh
t in m
Gi
rth
in cm
Heigh
t in m
Girt
h in
cm
Heigh
t in m
Girt
h in
cm
Heigh
t in m
Girt
h in
cm
Heigh
t in m
Girt
h in
cm
Heigh
t in m
Girt
h in
cm
Heigh
t in m
Bruguiera
gymnorhiza 1.064 0.591 0.594 0.437 0.523 0.577 0.562
Acanthus illcifolius
0.52
Excoecaria
agallocha
Ceriops tagal 14 1.15 10 1.14 12 1.16 11 1.15 13 1.15 12 1.15 12 1.15 Avicennia officinalis
0.29 0.261 0.422 0.337
Avicennia alba 0.29 0.491 0.449 0.433
Seedling measurement were taken during March,2012.
Table – 9 Growth study of seedlings raised at Dakhin Kadua during 2008-2009.
Mouza : Dakhin Kadua
Area : 2 ha
Year of plantation : 2009
Name of Sps
Plot -1 Plot-2 Plot-3 Plot-4
Gir
th
in cm
Heigh
t in m
Gir
th
in cm
Heigh
t in m
Girt
h in
cm
Heigh
t in m
Girt
h in
cm
Heigh
t in m
Bruguiera
gymnorhiza 5.0 0.59 6.0 0.45 10.0 0.65 12.0 0.72
Acanthus illcifolius
7.2 0.95 7.0 0.94 7.4 0.96 7.2 0.95
Ceriops tagal 0.9 0.98 0.8 0.97 1.0 0.99 0.9 0.98 Sada Payne Avicennia officinalis
5.0 0.50 5.0 0.45 10.0 0.72 10.0 0.60
Avicenia marina 5.0 0.35 5.0 0.52 6.0 0.55 6.0 0.52
Seedling measurement were taken during March,2012.
Table – 10 Growth study of seedlings raised at Dakhin Kadua during 2009-2010.
Mouza : Dakhin Kadua
Area : 5 ha
Year of plantation : 2010
Name of Sps
Plot -1 Plot-2 Plot-3 Plot-4 Plot-5 Plot-6
Girt
h in
cm
Height
in m
Girt
h in
cm
Height
in m
Girth in
cm
Heigh
t in m
Girth
in cm
Heigh
t in m
Girth
in cm
Height
in m
Girth
in cm
Height
in m
Bruguiera gymnorhiza
12.0 0.62 11.0 0.68 13.0 0.75 15.0 0.75 12.0 0.64 10.0 0.80
Ceriops tagal 9.5 0.30 9.5 0.29 9.6 0.28 9.4 0.29 9.5 0.29 9.5 0.29
Avicennia officinalis 7.0 0.49 13.0 0.62 10.0 0.41 3.0 0.52
Avicennia alba
Avicenia marina 10.0 0.70 12.0 0.62 11.0 0.58 15.0 63.0 10.0 0.78
Acanthus illcifolius 5.4 0.76 5.2 0.75 5.6 0.77 12.0 62.0 15.0 0.95
Name of Sps
Plot -7 Plot-8 Plot-9 Plot-10
Girt
h in
cm
Height
in m
Girt
h in
cm
Height
in m
Girth in
cm
Heigh
t in m
Girth in
cm
Height
in m
Bruguiera
gymnorhiza 12.0 0.65 11.0 0.81 9.0 0.72 10.0 0.98
Ceriops tagal
Avicennia officinalis 7.0 0.75 3.0 0.40
Avicennia alba 9.5 0.3 9.6 0.28 9.5 0.28
Avicenia marina 9.0 0.65
Acanthus illcifolius 4.0 0.48
Seedling measurement were taken during March,2012.
Table – 11 Growth study of seedlings raised at Dakhin Kadua during 2010-2011.
Mouza : Dakhin Kadua
Area : 2.0 ha
Year of plantation : 2011
Name of
Sps
Plot -1 Plot-2 Plot-3 Plot-4 Plot-5
Girt
h in
cm
Heig
ht in
m
Girth
in cm
Heig
ht in
m
Girt
h in
cm
Heig
ht in
m
Girth
in cm
Heigh
t in m
Girth
in cm
Heigh
t in m
Ceriops tagal 0.3 0.12
Avicennia officinalis
0.6 0.5 0.4 0.35 0.4 0.28 0.5 0.25 0.5 0.32
Avicennia marina
0.5 0.35
Xylocarpus granatum
Bruguiera gymnorhiza
0.6 0.5 0.6 0.60 0.6 0.5 0.7 0.50 0.8 0.70
Aegiceras carniculatum
0.3 2.1 0.4 0.16 0.3 0.21 0.4 0.17
Acanthus illcifolius
0.35 0.57 0.34 0.56 0.36 0.58 0.35 0.57 0.35 0.57
Ceriops tagal 0.08 0.64 0.07 0.63 0.09 0.65 0.08 0.64 0.08 0.64
Seedling measurement were taken during March,2012.
Table – 12 Growth study of seedlings raised at Dakhin Kadua during 2011-12.
Seedling measurement were taken during March,2012 at collar region.
Seedling Av Height (m)
2011-12
Acanthus illcifolius 0.36
Avicennia marina 0.32
Avicennia officinalis 0.40
Bruguiera gymnorhiza 0.50
Ceriops tagal 0.58
Table – 13 Average height of species in m.
Chart-1
Year
Average height of species in m
Acanthus
illcifolius
Avicennia
marina
Avicennia
officinalis
Bruguiera
gymnorhiza
Ceriops
tagal
2002 2.85 1.87 1.66 2.12 1.64
2003 2.12 1.45 1.47 1.99 1.45
2004 1.95 1.07 0.75 1.95 1.68
2005 1.72 2.56 1.87 1.92 1.15
2009 0.95 0.48 0.56 0.6 0.98
2010 0.76 0.66 0.53 0.74 0.76
2011 0.57 0.35 0.34 0.56 0.64
2012 0.36 0.32 0.4 0.5 0.58
Table – 14 Average girth of species in m.
Year
Average girth of species in m
Acanthus
illcifolius
Avicennia
marina
Avicennia
officinalis
Bruguiera
gymnorhiza
Ceriops
tagal
2002 17.4 0.36 0.135 0.20 0.10
2003 10.2 0.28 0.105 0.18 0.16
2004 0.97 0.18 0.1 0.14
2005 0.85 0.15 0.15 0.12 0.12
2009 0.72 0.05 0.07 0.08 0.09
2010 0.54 0.11 0.07 0.11 0.08
2011 0.35 0.005 0.004 0.033 0.08
2012 0 0 0 0 0
Chart-2
Conclusion
It is found from the above chart-1 that Bruguiera gymnorhiza attained the highest height
than all other 4 species.
From chart -2 it is evident that Acanthus illcifolius attained the highest average girth than
four others.
Among 15 species namely Pandanus fascicularis, Excoecaria agallocha, Heritiera fomes,
Ceriops tagal, Avicennia officinalis, Bruguiera gymnorhiza, Excoecaria agallocha, Ceriops
tagal, Avicennia alba,Sonneratia caseolaris,Aegiceras carniculatum,Rhizophora
apiculata,Acanthus illcifolius, Avicinia marina planted only five namely Acanthus illcifolius,
Avicennia marina, Avicennia officinalis, Bruguiera gymnorhiza, Ceriops tagal are found
promising.
Within these five promising species Acanthus illcifolius was found best suitable for that
area.Sequentially then comes Avicenia marina, Bruguiera gymnorhiza, Ceriops tagal,
Avicennia officinalis
All the above five species survived and performed well in the places at Dakhin
Kadua,Mankaraiput and Biramput are resistant to Dhani grass growth.Inspite of gregarious
growth of Dhani grass (Porteresia coarctata) in the planting site the growth and developmant of
Acanthus illcifolius, Avicennia marina, Avicennia officinalis, Bruguiera gymnorhiza, Ceriops
tagal did not hampered.
References:
1. Annual Research Report,2012-13 of Silviculture (South) Division,Midnapur,West
Bengal,India.
2. WRM’s bulletin No.151,Feb,2010.
3. Information Brochure of Institute of Ocean Management,Kodal Building,Anna
University,Chennai-600025.
4. Giri et al ; Status and distributin of mangrove forests of the world using earth observation
satellite data.Global Ecological Biogeography,20,154-159 (2011).