Document Details
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Document Type |
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Thesis |
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Document Title |
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GEOGRAPHICAL DISTRIBUTION AND SOME ECOLOGICAL REMARKS ON MANGROVE STANDS BETWEEN RAS-AL-TURFA AND BAB-AL-MANDAB USING REMOTE SENSING التوزيع الجغرافي وبعض الخصائص البيئية لبيئات المانجروف الواقعة بين رأس الطرفة وباب المندب بإستخدام الاستشعار عن بعد |
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Subject |
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Faculty of Marine Sciences |
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Document Language |
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Arabic |
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Abstract |
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Mangroves, where are important components of the world’s coastal ecosystems, are threatened by the expansion of human settlements, the boom in commercial aquaculture, the impact of tidal waves and storm surges, due to global warming. Such threats are leading to the increasing demand for mapping mangroves and their sustainable management. Detailed mangrove maps for the purpose of measuring the extent of the decline of mangrove ecosystems. Detailed mangrove maps at the community level are, however, not easy to produce, mainly because mangrove forests are very difficult to access. Without doubt, remote sensing is a serious alternative to traditional field-based methods for mangrove mapping, as it allows information to be gathered from the forbidding environment of mangrove forests, which otherwise, logistically and practically speaking would be extremely difficult to survey. Remote sensing applications for mangrove mapping at the fundamental level are already well established but, surprisingly, a number of advanced remote sensing applications have remained unexplored for the purpose of mangrove mapping at a finer level.
The objective of this study was to use Landsat Thematic Mapper (TM) and the Enhanced Thematic Mapper Plus (ETM+) Satellite images information to determine the geographical distribution of mangrove stands in the southeastern coastal belt of the Red Sea in 1987 and 2002 time periods. The Red Sea coast extending between Ras-Al-Turfa in the north and Bab-Al-Mandab in the south was studied and found to have very extensive growth of mangroves.
Mangroves belonged to only one species Avicennia marina Vierh in all places, except for Farasan Archipelago and Kamaran Island where another species Rhizophora mucronata was also reported. GIS analysis of Satellite images data reveals that the total mangrove forests cover is approximately, 2442 and 2141 hectares in 1987 and 2002, respectively. The largest continuous mangrove stands are found in several localities.
The mangrove stands of Al-Midaya, Khor Abu Saba and North Yemen’s Red Sea coast were the largest and the most dense of them all. The data shows that the area of mangrove forest decreased by 301 hectares in 15 years. In addition the decline in Ras-Qarn, North Al-Hodiada and Khor Farasan was 97 hectares along Saudi Arabian coast and 204 hectares along Yemen coast. The total decline in the mangrove cover was apparently high and is 12.3% in 15 years. Among all localities Ras-Qarn, North Al-Hodiada and Khor-Farasan showed greater decrease in density.
The degradation of Southern Red Sea mangroves may be attributed to escalating pressure of urban development, human activities and settlements.
Biotic communities occurred in distinct zones on shores of Ras-Al-Turfa and Khor-Al gandal. Environmental parameters including soil characteristics also depicted the typical nature of mangrove ecosystems.
The coastal topography of the study area showed that the coastline as wide as a 50 km in breadth in low-lying Jazan and Yemen coast. The entire plain consists of terraced alluvial deposits traversed by numerous drainage channels of many wadis originating in the mountains and discharging near the sea shore. These wadis collect water from the mountains during occasional rains and flash floods and bring it to the plain and sea shore along with the alluvium and sediments carried during their course through drainage channels.
In addition these images display the wadis that have been drawn along the study area that includes the main and branch wadis that penetrate the southern area of the Red Sea coast starting from wadi Baysh north of Jazan city and down to wadi Mowza south of Al-Mukha near Bab-Al-Mandab. The study area between Ras-Al-Turfa, North Jazan and The North of Yemen’s Red Sea coast was delimited from the seashore by a special land form called Sabkha. This is a tidal flat, not more than 5 km wide, which is inundated with sea water only a few times a year during exceptionally high tides. |
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Supervisor |
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Prof. Dr. Abdullah S. Mandura |
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Thesis Type |
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Master Thesis |
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Publishing Year |
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1430 AH
2009 AD |
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Co-Supervisor |
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Dr. Rashad A. Bantan |
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Added Date |
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Wednesday, December 30, 2009 |
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Researchers
| فؤاد أمين حسن | Hasan, Fuad A | Researcher | Master | |
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