Effects of Salinity Intrusion in Mangrove Wetlands Ecosystems in

the Sundarbans: An Alternative Approach for Sustainable Management

ByShafi Noor Islam and Albrecht GnauckDept. of Ecosystems and Environmental InformaticsBrandenburg University of Technology at Cottbus

P.O. Box - 101344, D-03013 Cottbus, GermanyPhone: +49-355-692831, Fax: +49-355-692743

e-mail:shafinoor@yahoo.com

W3M International Conference Organised by Warsaw Agricultural University

Wierzba, Poland22-28th September ,2005

The Sundarbans Mangrove Wetlands Site Location in the Ganges Catchment Area

The Sundarbans Mangrove Forest covers 6017 sq.km : 62% lies in Bangladesh and rest of 38% in India. Latitude :21°31´N and 22°30´N. Longitude: 89°18´E and 90°18´E. Elevation: 0.9-2.1

m.

C H I N A

Scale 1 inch = 500 Km Sundarbans

BANGLADESH

Dhaka

KathmunduDelhiThimpu

China

Ganges

Brahmaputra

Calcutta

Farakka Barrage

TIBET

I N D I A

M Y A N M A R

Yamuna

Ganges

NEPAL

GonookBHUTAN

NGanges

An Overview• Wetlands constitute a part of Humans natural heritage. Wetlands have played a significant role in development of human society. The natural productivity of wetlands is an invaluable component of the environment, which is hotspot of biodiversity and the world‘s most productivie ecosystems. • Mangrove wetlands is one of the productive ecosystems and provides ideal habitats for a variety of plants and animals.• The Sundarbans reserve forest is one of the most important and largest contiguous mangrove forests in the world and has been significantly threatened from a number of directions for many years.• It is a Natural World Heritage site (1400 km²) declared by UNESCO in 1997 and also Ramsar site Wetlands(601,700 ha 1992) basis of wetlands types:F, G, I , M and considered of the critiria 1c,2a,2b,2c,3b,4b, the largest living wetlands in the world.

Goemorphological and Wetlnads Importance

• Wetlands consists of a large number of fluvial and tidal landscapes, features created by three mighty rivers GBM. Annually 2.3 billion tons of sediment are transported by the major rivers of Bangladesh and having a profound effect on the floodplains and the coastal region.

• The Environment and Ecosystems of the coastal region is characterised by the unique geophysical phenomena, such as sea surges and waves, upland discharge and sedimentation, erosion and accretion, and storms and cyclones.

Unique Aspect

Nypa fruticanHeritiera fomes

Panthera tigris tigrisAxis axis

Heritiera fomes

Vegetation Pattern in the Sundarbans

Vegetation Composition

21%

29%1%2%5%

15%

14%

9% 1%1%2%

Sundari Sundari-GewaSundari-Passur Sundari-Passur-KawraGewa Gewa-SundariGoran-Gewa Gewa -GoranKeora OtherGoran

Notabaki Khal

M alancha- M andarbaria

Arpongasia Deboki

N ilkam al - H ironpoint

Passur - Passakhali

Betm ar G ang -Kathka

Sibsa -Nalianala

Heritiera fomes-21%

H. fomes-Excoecaria agallocha-29%

Excoecaria agallocha -5%

E.agallocha-h. fomes -15%

Cerops decandra- E.agallocha-14%

E. agallocha- C.decandra-9 %

Sonneratia apetala-1%

Tourism in the Sundarbans World Heritage Site

Annually 120,000 Tourists Visited the Sundarbans World Heritage Site

Socio-Economic Aspect

Socio-Economic Aspect

• Provides livelihood and employment to

wood cutters, fishermen, collector of

honey, wax, shell, shrimp fry , timber traders and other

workers.• 3.5 million people

directly dependent and 6 million people are

indirectly dependent on the Sundarbans

resources

Deltaic Rivers System in the Sundarbans

N

Bay of Bengal

Forest intersected by an elaborate network of rivers, channels and creeks, water area of 175,600 ha . Passur,Sibsa and Raimangol.

There are 4 estuaries and width of these estuaries are extended about 10 km.

i.Bangra estuary

ii.Kunga estuary

iii.Malancha

iv.Raimangol

Bangra

Kunga

Raimangal

Fresh Water Discharge of Ganges River

Ganges Discharge at Hardinge in Dry Season

0

500

1000

1500

2000

2500

3000

3500

4000

1962 1970 1973 1975 1980 1991 1998 2000 2002Time

Wat

er M

³ /S

Ganges Water Discharge at Hardinge Bridge in Dry Season

y = -138565Ln(x) + 1E+06R2 = 0.8835

y = -0.0097x4 + 77.301x3 - 230027x2 + 3E+08x - 2E+11R2 = 0.9859

0

500

1000

1500

2000

2500

3000

3500

4000

1960 1965 1970 1975 1980 1985 1990 1995 2000 2005Time

Reihe1

Logarithmisch (Reihe1)

Polynomisch (Reihe1)

Shortage of Sweet Water Flow and Impact on the Mangrove Ecosystem

Reduction in soil moisture

Lowering of groundwater levels

Less water is available for agriculture

Reduced of

ground- surface water quality

Reduced crops, increased shrimp cultivation

Reduced flow in the Ganges

Reduced flow in the distributaries of

the Ganges

Increased water salinity

Surface water is too saline for use in irrigation

Health risk from salinity of drinking water

Disturbance of fish habitat

Reduced water depth restricts navigation

Problems for water using in industries

Problems for salinity sensitive plants , Heritiera fomes top dying etc

Water Salinity

Water salinity in Passur River , Mongla Port

0

5

10

15

20

25

30

Jan

Feb Mar Apr May Jun Ju

lAug Sep Oct

Nov Dec

Time

wat

er S

alin

ity E

Cw

ds/

m

1998

1999

2000

2001

2002

2003

Salinity Increase at 5 Places

Water Salinity in the Sundarbans in 2003

0

10

20

30

40

50

60

1 2 3 4 5 6 7 8 9 10 11 12

Time

Salin

ity d

enci

ty E

Cw

ds/

m

MunchiganjMirgangKoramjalRupsha riverKasiabad

3rd Order Polynomial Salinity Model at NilKamol-HironPoint

Nilkamal - Hiron Point

0

5

10

15

20

25

30

1-Jul 1-Aug 1-Sep 2-Oct 2-Nov 3-Dec 3-Jan 3-Feb 6-Mar 6-Apr 7-May 7-Jun

Time

Sal

inity

in p

pt

1992-1993 1994-19951997-1998 1998-19992000-2001 2001-20022002-2003 Polynomisch (2001-2002)Polynomisch (1998-1999) Polynomisch (2002-2003)Polynomisch (1994-1995) Polynomisch (1997-1998)

Data source: IWM 2003

Yearly Salinity Model

Minimum Salinity Isohaline

Effects of Salinity

Mangrove Forest Destroying and Attracting for Shrimp Cultivation

Shrimp Cultivation and Changing of Landscapes

Shrimp Farming Extension Due to Salinity Intrusion in Sundarbans

Threatened Mangrove Wetlands Ecosystems

Topdying of Sundari(Heritiera fomes) Plants

• Heritiera fomes forest type is decreasing rapidly. At tpday‘s rate the forest will disappear within next 47 years.

• Moderately affected 255 Sq.km Severely affected 199 sq.km are severely affected.

• Forest divides into -Excoecaria agallocha, -Heritiera fomes - Sonneratia apetalaWorking Cycle

Loss of Biodiversity • 20 mangrove species are available out of 70 species• Large part 45% mangroves are disappeared• High salinity has brough about a biodiversity loss• Topdying process• Reduction of fish habitat• 12 species of plants and animals already vanishedExtinct animals: Javan rhinoceros, Single horned rhinoceros, Water buffalo, Swamp deer, Mugger Crocodile, Gaur and Hog Deer

The Sundarbans Mangrove Wetlands Management

• The present Sundarbans Management Plan it is forest wood harvesting plan only, so a integrated multidisciplinary plan is needed

• The national wetlands policy which has been drafted by MoEF, Until now it is not implemented. The main features of this policy are as follows; - Maintenance of Biodiversity - Maintenance of Ecosystems Functions - Promostion of Economical Development

• Principles for Sustainable Resource Utilisation

Alternative Approach for Management

• Ganges water diversion and sharing is not just a geo-techno-political issue it is also a humanitarian problem• The dominant floral and fauna species are affected by topdying and some unknown disease which is recognised as key management concern in the Sundarbans wetlands• Reduce substantial use of mangrove resources and establish eco-tourism considering 350 meters buffer zone for tourists and the shrimp fry collectors in the heritage site• Interaction is needed between states where it is a common concern for wise use of Ganges water resources• The community as a whole may participate in and all classes of benefits from biodiversity conservation and management• An integrated planning and management tool based on GIS and a wetlands simulation Model and water quality indicators should be developed

Conclusions

• During the last 100 years the Sundarbans has lost over 12 species of plants and animals. Therefore the Community as Whole may participate in process of management , preservation and improvement.

• Initiatives are needed to develop strategies for adequate management plan based on monitoring of flora and fauna and water quality with co-operation and appreciation of local people and international community.

• To protect the mangrove wetlands ecosystems and endangered plant and animal species and their habitats high water salinity have to be reduced by increasing sweet water input.

Thank YouFor Your Attention