distribution of mangroves along the red sea coast of the arabian...
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Open access e-Journal Earth Science India, Vol. 3 (III), July, 2010, pp. 154-162 http://www.earthscienceindia.info/; eISSN: 0974 – 8350
Distribution of Mangroves along the Red Sea Coast of the
Arabian Peninsula: Part 2. The Southern Coast of Western Saudi Arabia
M. Asif Khan, Arun Kumar*and Abdul Muqtadir Center for Petroleum and Minerals, Research Institute
King Fahd University of Petroleum and Minerals
Dhahran 31261, Saudi Arabia *Email:[email protected]
Abstract
Historical Landsat Enhanced Thematic Mapper (ETM) data of the years
1999, 2000 and 2001 were used to numerically illustrate the distribution of mangroves along the southern Saudi Arabian Red Sea coast from Al-Lith (Latitude
20o 08' 22'', and Longitude 40o 16' 17.23'') in the north to the Saudi Arabia -Yemen border (Latitude16o 41' 16'', and Longitude 42o 46' 27.18'') in the south. A
similar study covering the northern part of the Saudi Arabian Red Sea coast from
Sharm Zubair in the north to Al-Lith in the south has already been published as
first part of this ongoing study. The distribution of mangroves in both northern and southern Red Sea coast of Saudi Arabia is patchy and they do not occur as a
continuous forest and are generally restricted to the low energy quieter environments. Mangroves occupy similar environments in both regions and are
under similar stresses caused by various anthropogenic activities and camel
grazing. However, mangrove growth in south is relatively denser in comparison to
north due mainly to the tropical climate, more wadis, higher rainfall and nutrients
and less saline waters.
Introduction Saifullah (1994) presents an overview of various mangrove studies along the Red
Sea coast of Saudi Arabia and concluded that information on the subject is inadequate.
Early publications merely reported on mangrove occurrences (Vessey-Fitzgerald, 1955, 1957; Migahid, 1978) and their brief ecological studies (Zahran et al., 1983; Frey et al.
1984). However, detailed ecological studies of mangrove ecosystem along the Saudi
Arabian Red Sea coast were published by Mandura et al. (1987, 1988) Khafaji et al.
(1988, 1991) and Saifullah et al. (1989). However, there are no published accounts of
geographical distribution, numerical data about area covered and environments of
mangrove habitats along the Saudi Arabian Red Sea coast.
Present study provides numerical information about area covered by mangroves
at several sites and the environments in which they grow along the Red Sea coast of the
Arabian Peninsula. Historical Landsat Enhanced Thematic Mapper (ETM) data of the
years 1999, 2000 and 2001 was used in this study. First part of this study covered
twenty locations covering a length of 930 km of the northern Red Sea coast of Saudi
Arabia from Sharm Zubair in the north to Al-Lith in the south (Kumar et al. 2009, Fig. 1&2). We extend that work to the southern Red Sea coast of Saudi Arabia (Fig.1)
covering a length of 500 km and it forms second part on this ongoing study. This paper
reports similar study on fifteen more sites (Fig.2; sites 21 through 35) and two more
locations on offshore islands (sites 36 and 37). Detailed introductory remarks and
information about Red Sea is given in Kumar et al. (2010).
Distribution of Mangroves along the Red Sea Coast of the Arabian Peninsula: Part 2: Asif Khan et al.
155
Fig. 1: Study area along the southern Red Sea coast of Saudi Arabia.
Fig. 2: Locations of 17 study sites along the southern Red Sea coast of Saudi Arabia
Red Sea Coastline of the Arabian Peninsula
Red Sea coastline of the Arabian Peninsula is dry without much vegetation except
for few species of halophytes and mangroves. Geomorphologically coastal regions vary
from rugged coast due mainly to marine terraces to coastal sabkhas, alluvial plains and
wadis of up to thirty km width occasionally having small hills of Neogene sediments (Fig.
3). There are a large number of dry river beds, alluvial fans and estuaries locally known
as wadis that dot all along this long coastline. The mountains to the east and the coastal
Open access e-Journal Earth Science India, Vol. 3 (III), July, 2010, pp. 154-162 http://www.earthscienceindia.info/; eISSN: 0974 – 8350
plains have large number fluvial channels that transport water and sediment during rains
either into the lagoons or in the open sea (Morley, 1975). Due to Quaternary sea-level
changes diverse types coastal environments have developed that range from open shelf
basins to fringing, barrier or patch reefs to various littoral environments like lagoons
(Jado and Zölt, 1984). A large number of coral reef islands of various sizes and shapes
are present some near shore and others far offshore in the Red Sea, the most notable
being the Farasan Islands which are located around forty km away from the coastline. Several lagoons and bays both small and large meander through this long coastline and
at times become saline lakes because they get disconnected from the sea due either to
local tectonics or Quaternary sea-level changes.
Fig. 3: A generalized geomorphological cross-section of the Red Sea coast of
Saudi Arabia showing various environments and plant communities
(modified after Saifullah, 1994).
Climatically this long coast line covers both tropical and subtropical zones.
Monsoons originating in the Indian Ocean cause rain fall in southwestern Saudi Arabia
and the area around Al Lith approximately form the northern limit of influence of
monsoon in this region. The yearly average rainfall along the foot hills is 100 mm and approximately 300 mm on mountains 1000 m above sea level (Jado and Zölt (1984).
Thus rainfall and groundwater enrichment increases significantly from north to south.
This demarcation is very interesting and impacts environmental variables and mangrove
growth (Table- 1). Surface temperatures in the Red Sea increases southward in response
to latitude but salinity of surface water increases northwards indicating intrusion of low
salinity water of Gulf of Aden into the Red Sea (Edwards, 1987). The tidal amplitude
along the Red Sea coast is very low, which is ~50 cm in the northern and southern coast
that gradually decreases towards the center, close to zero near Jeddah (Edwards, 1987).
Materials and Methods
The study area is located along the southern Red Sea coast of Saudi Arabia from
Al-Lith in the north to Saudi Arabia – Yemen border in the south between Latitudes 20o
08' 22'' and 16o 41' 6'' (Fig. 1 & 2). Historical Landsat Enhanced Thematic Mapper (ETM)
data of the years 1999, 2000 and 2001 were used (Table-2). The ETM data has seven
spectral bands (Table-3). The spatial resolution of ETM data is 28.5 meters. Research
methodology and details about image processing techniques used in this paper is given
in Kumar et al. (2010).
Distribution of Mangroves along the Red Sea Coast of the Arabian Peninsula: Part 2: Asif Khan et al.
157
Table-1: Environmental differences between mangroves of northern and southern
regions of the Red Sea coast of Saudi Arabia (after Saifullah, 1994).
North South
1. Sub-tropical and tropical
2. Rocky substrate
3. Fewer Wadis
4. Less rainfall
5. Low nutrients
6. More saline
7. One species of mangroves
8. Poor growth of mangroves
9. Dwarf forest
10. Flowering and fruiting
October-April
11. Litter fall 2.16 gm m day
12. Bostrychia tenella absent 13. Mudskippers absent
Tropical only
Muddy substrate
Many Wadis
More rainfall
High nutrients
Less saline
Two species of mangroves
Dense growth of mangroves
Fringe forest
Flowering and fruiting
March-August
3gm m day
Present
Present
Table-2: Satellite image data used in the study.
Location Sensor
Image
Acquisition Date
site-21 ETM 03-06-2000
site-22 ETM 03-06-2000
site-23 ETM 28-04-2001
site-24 ETM 28-04-2001
site-25 ETM 28-04-2001
site-26 ETM 28-04-2001
site-27 ETM 28-04-2001
site28 ETM 28-04-2001
site-29 ETM 13-08-1999
site-30 ETM 05-04-2001
site-31 ETM 05-04-2001
site-32 ETM 05-04-2001
site-33 ETM 05-04-2001
site-34 ETM 05-04-2001
site-35 ETM 09-09-2000
site-36 ETM 05-04-2001
site-37 ETM 05-04-2001
Table-3: Landsat spectral bands.
Landsat 7
(ETM+
sensor)
Wavelength
(micrometers)
Band 1 0.45 - 0.515
Band 2 0.525 - 0.605
Band 3 0.63 - 0.69
Band 4 0.75 - 0.90
Band 5 1.55 - 1.75
Band 6 10.40 - 12.5
Band 7 2.09 - 2.35
Open access e-Journal Earth Science India, Vol. 3 (III), July, 2010, pp. 154-162 http://www.earthscienceindia.info/; eISSN: 0974 – 8350
Fig. 4: Satellite image of mangroves
shown in green color at site 21.
Fig. 5: Satellite image of mangroves
shown in green color at site 22.
Fig. 6: Satellite image of mangroves
shown in green color at site 23.
Fig. 7: Satellite image of mangroves
shown in green color at site 24.
Fig. 8: Satellite image of mangroves
shown in green color at site 25.
Fig. 9: Satellite image of mangroves
shown in green color at site 26.
Distribution of Mangroves along the Red Sea Coast of the Arabian Peninsula: Part 2: Asif Khan et al.
159
Fig. 10: Satellite image of mangroves
shown in green color at site 27.
Fig. 11: Satellite image of mangroves
shown in green color at site 28.
Fig. 12: Satellite image of mangroves
shown in green color at site 29.
Fig. 13: Satellite image of mangroves
shown in green color at site 30.
Fig. 14: Satellite image of mangroves
shown in green color at site 31.
Fig. 15: Satellite image of mangroves
shown in green color at site 32.
Open access e-Journal Earth Science India, Vol. 3 (III), July, 2010, pp. 154-162 http://www.earthscienceindia.info/; eISSN: 0974 – 8350
Fig. 16: Satellite image of mangroves
shown in green color at site 33.
Fig. 17: Satellite image of mangroves
shown in green color at site 34.
Fig. 18: Satellite image of mangroves
shown in green color at site 35.
Fig. 19: Satellite image of mangroves
shown in green color at site 36.
Fig. 20: Satellite image of mangroves shown
in green color at site 37.
Distribution of Mangroves along the Red Sea Coast of the Arabian Peninsula: Part 2: Asif Khan et al.
161
Results and Discussion
Fig. 4 through 20 show images of geographical distribution as well as areas of
mangroves at sites 21 through 37 respectively (Table-4). Like distribution in the
northern coast mangroves along the southern coast also occur in small patches and the
areas covered by them vary considerably. They do not occur as a continuous forest and
mostly their distribution is restricted to the quieter environments, for example, bays,
lagoons, narrow channels, and inland face of offshore islands. However, not all
mangroves occupy quieter environments they also inhabit higher energy intertidal
environments and seaward face of the near shore islands. The environmental and
anthropogenic stress is evident here also as was observed in the northern coast.
Saifullah (1994) lists several environmental differences in the mangroves of the
northern and the southern Saudi Arabian Red Sea coast (Table-1). We observe denser
growth of mangroves along the southern coast in comparison to the northern coast and
thus support the observation of Saifullah (1994). This dense growth in south is due
mainly to the tropical climate, more wadis, higher rainfall and nutrients and less saline
waters along the Red Sea coast. The small size, scattered and sparse distribution of
individual trees in the north is due to narrow tidal zone, oligotrophic waters and high
salinity of waters along the Red Sea coast (Saifullah, 1994). The mangrove species
Avicennia marina occurs all along the Saudi Arabian coast and on the islands, but
Rhizophora mucronata occurs only in the Farasan Islands (Mandura et al., 1987). The
third and final part of this study will include a similar study along the Red Sea coast of
Yemen.
Table- 4: Area of mangrove forests (hectares) at the seventeen locations along with
their latitude and environmental setting.
Site Latitude Deg. Min.
Sec.
(range)
Mangrove area in
hectares
Environment
21 20 08 22 to
19 58 40
92.8 Bay, intertidal environment
22 19 49 22 to 19 33 56
211.3 Lagoons, near shore islands
23 19 35 32 to
19 14 25
398.3 Lagoons, near shore
islands
24 18 53 43 to
18 32 35
103.8 Bay, intertidal environment
25 18 33 16 to
18 21 08
130.1 Bays and brackish water
coastal lakes
26 18 21 19 to
18 09 44
250.8 Lagoons, Bays, near shore
islands
27 18 12 30 to
18 03 18
207.4 Lagoons, Islands and
intertidal environments
28 18 04 06 to
17 54 55
284.8 Lagoons, Bays, Islands and
intertidal environments
29 17 52 47 to
17 43 02
45.1 Bay, intertidal environment
30 17 37 49 to
17 29 43
46.0 Lagoon, Bay, intertidal
environment
31 17 31 34 to
17 23 28
44.6 Lagoons and Bays
32 17 24 32 to 17 16 26
129.0 Bays
Open access e-Journal Earth Science India, Vol. 3 (III), July, 2010, pp. 154-162 http://www.earthscienceindia.info/; eISSN: 0974 – 8350
33 17 12 57 to
16 56 59
519.2 Lagoon, Bay, intertidal
environment
34 16 53 08 to
16 37 08
186.1 Lagoon, Bay, intertidal
environment
35 16 30 47 to
16 21 37
90.2 Bay, intertidal environment
36 16 52 56 to
16 37 51
181.1 Lagoons, Nearshore islands
37 16 49 43 to
16 41 16
35.3 Nearshore islands
Acknowledgements: We thank King Fahd University of Petroleum and Minerals (KFUPM),
Dhahran, Saudi Arabia for permission to publish this paper.
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