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 ... Introduction Mangrove species are available in the entire sundarban ... out of sundarban

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.


Mouza : Mankaraiput

Area : 1.6 ha


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



Mouza : Mankaraiput

Area : 1.2ha


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



Mouza : Mankaraiput

Area : 0.25ha


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



Mouza : Dakhin Kadua

Area : 2.6 ha


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


Table – 6 Growth study of seedlings raised at Dakhin Kadua during 2003-2004.


Area : 4 ha


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




Area : 0.5 ha


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


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


Table – 8 Growth study of seedlings raised at Biramput during 2004-2005.

Mouza : Biramput

Area : 2.6 ha


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


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




Area : 2 ha


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


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




Area : 5 ha


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


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




Area : 2.0 ha


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


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


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


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 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,


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).

Documents

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 ... Introduction Mangrove species are available in the entire sundarban ... out of sundarban