Effects of Salinity Intrusion in Mangrove Wetlands...
Transcript of Effects of Salinity Intrusion in Mangrove Wetlands...
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:[email protected]
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
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500
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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
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5
10
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25
30
Jan
Feb Mar Apr May Jun Ju
lAug Sep Oct
Nov Dec
Time
wat
er S
alin
ity E
Cw
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m
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2002
2003
Salinity Increase at 5 Places
Water Salinity in the Sundarbans in 2003
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10
20
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1 2 3 4 5 6 7 8 9 10 11 12
Time
Salin
ity d
enci
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MunchiganjMirgangKoramjalRupsha riverKasiabad
3rd Order Polynomial Salinity Model at NilKamol-HironPoint
Nilkamal - Hiron Point
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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