166
decaying litter fall and root growth and by trapping sediment from the ambient
water. The process of building peat helps mangroves keep up with sea level rise.
For example, in western Jamaica, mangrove communities were able to sustain
themselves because their rate of sedimentation exceeded the rate of the midHolocene sea level rise (ca. 3.8 mm/year) (Hendry and Digerfeldt 1989).
Mangroves can expand their range despite sea level rise if the rate of sediment
accretion is sufficient to keep up with sea level rise and if migration is not blocked
by local conditions, such as infrastructure (e.g., roads, agricultural fields, dikes,
urbanization, seawalls, and shipping channels) and topography (e.g., steep
slopes). A study in the Adelaide river area of the Northern Territory in Australia
showed that the landward zone of mangroves doubled in size in the last twenty
years (Jones 2002). Thus, inland wetland migration can offset the losses of
coastal wetlands in areas that have low-lying coastal uplands (Houghton et al.
2001). In Moreton Bay of Australia about 3807 ha of mangroves were lost due to
a combination of natural causes and mangrove clearing over a 24 – year period
Table 6.4 Top 10 most impacted countries with a 1 m sea level rise (percentage impact in
parenthesis)
Rank Land area
Population
GDP
Urban areas
Agricultural
land
Wetlands
1
The
Bahamas
(11.57)
Vietnam
(10.79)
Vietnam
(10.21)
Vietnam
(10.74)
A.R.Egypt
(13.09)
Vietnam
(28.67)
2
Vietnam
(5.17)
A.R. Egypt
(9.28)
Mauritania
(9.35)
Guyana
(10.02)
Vietnam
(7.14)
Jamaica
(28.16)
3
Qatar (2.70) Mauritania
(7.95)
A.R. Egypt
(6.44)
French
Guiana (Fr)
(7.76)
Suriname
(5.60)
Belize
(27.76)
4
Belize (1.90) Suriname
(7.00)
Suriname
(6.35)
Mauritania
(7.50)
The Bahamas
(4.49)
Qatar
(21.75)
5
Puerto Rico
(1.64)
Guyana
(6.30)
Benin (5.64) A.R. Egypt
(5.52)
Argentina
(3.19)
The
Bahamas
(17.75)
6
Cuba (1.59) French
Guiana (Fr)
(5.42)
The Bahamas
(4.74)
Libya (5.39) Jamaica
(2.82)
Libya
(15.83)
7
Taiwan,
China (1.59)
Tunisia (4.89) Guyana
(4.64)
United Arab
Emirates
(4.80)
Mexico
(1.60)
Uruguay
(15.14)
8
The Gambia
(1.33)
United Arab
Emirates
(4.59)
French
Guiana (Fr)
(3.02)
Tunisia (4.50) Myanmar
(1.48)
Mexico
(14.85)
9
Jamaica
(1.27)
The Bahamas
(4.56)
Tunisia
(2.93)
Suriname
(4.20)
Guyana
(1.16)
Benin
(13.78)
10
Bangladesh
(1.12)
Benin (3.93) Ecuador
(2.66)
The Bahamas
(3.99)
Taiwan,
China (1.05)
Taiwan,
China
(11.70)
Source: Dasgupta et al. (2009)
6 Mangroves: A Potential Vegetation Against Sea Level Rise
decaying litter fall and root growth and by trapping sediment from the ambient
water. The process of building peat helps mangroves keep up with sea level rise.
For example, in western Jamaica, mangrove communities were able to sustain
themselves because their rate of sedimentation exceeded the rate of the midHolocene sea level rise (ca. 3.8 mm/year) (Hendry and Digerfeldt 1989).
Mangroves can expand their range despite sea level rise if the rate of sediment
accretion is sufficient to keep up with sea level rise and if migration is not blocked
by local conditions, such as infrastructure (e.g., roads, agricultural fields, dikes,
urbanization, seawalls, and shipping channels) and topography (e.g., steep
slopes). A study in the Adelaide river area of the Northern Territory in Australia
showed that the landward zone of mangroves doubled in size in the last twenty
years (Jones 2002). Thus, inland wetland migration can offset the losses of
coastal wetlands in areas that have low-lying coastal uplands (Houghton et al.
2001). In Moreton Bay of Australia about 3807 ha of mangroves were lost due to
a combination of natural causes and mangrove clearing over a 24 – year period
Table 6.4 Top 10 most impacted countries with a 1 m sea level rise (percentage impact in
parenthesis)
Rank Land area
Population
GDP
Urban areas
Agricultural
land
Wetlands
1
The
Bahamas
(11.57)
Vietnam
(10.79)
Vietnam
(10.21)
Vietnam
(10.74)
A.R.Egypt
(13.09)
Vietnam
(28.67)
2
Vietnam
(5.17)
A.R. Egypt
(9.28)
Mauritania
(9.35)
Guyana
(10.02)
Vietnam
(7.14)
Jamaica
(28.16)
3
Qatar (2.70) Mauritania
(7.95)
A.R. Egypt
(6.44)
French
Guiana (Fr)
(7.76)
Suriname
(5.60)
Belize
(27.76)
4
Belize (1.90) Suriname
(7.00)
Suriname
(6.35)
Mauritania
(7.50)
The Bahamas
(4.49)
Qatar
(21.75)
5
Puerto Rico
(1.64)
Guyana
(6.30)
Benin (5.64) A.R. Egypt
(5.52)
Argentina
(3.19)
The
Bahamas
(17.75)
6
Cuba (1.59) French
Guiana (Fr)
(5.42)
The Bahamas
(4.74)
Libya (5.39) Jamaica
(2.82)
Libya
(15.83)
7
Taiwan,
China (1.59)
Tunisia (4.89) Guyana
(4.64)
United Arab
Emirates
(4.80)
Mexico
(1.60)
Uruguay
(15.14)
8
The Gambia
(1.33)
United Arab
Emirates
(4.59)
French
Guiana (Fr)
(3.02)
Tunisia (4.50) Myanmar
(1.48)
Mexico
(14.85)
9
Jamaica
(1.27)
The Bahamas
(4.56)
Tunisia
(2.93)
Suriname
(4.20)
Guyana
(1.16)
Benin
(13.78)
10
Bangladesh
(1.12)
Benin (3.93) Ecuador
(2.66)
The Bahamas
(3.99)
Taiwan,
China (1.05)
Taiwan,
China
(11.70)
Source: Dasgupta et al. (2009)
6 Mangroves: A Potential Vegetation Against Sea Level Rise