الفهرس | Only 14 pages are availabe for public view |
Abstract Ecological studies were carried out on seagrass communities in Wadi El Gemal National Park in the southern of Egyptian Red Sea coast. A total of 26 meadows of seagrass were marked, mapped and seagrass diversity and abundance were investigated. Eleven species of seagrasses were recorded; four species were new records to the whole Red Sea, the Egyptian waters of the Red Sea and WGNP. Halodule pinifolia (Miki) den Hartog is newly recorded to the whole Red Sea (Red Sea proper, Gulf of Suez and Gulf of Aqaba), while Enhalus acoroides (L.f.) Royle, represents a new record to the Egyptian waters of the Red Sea and Halophila decipiens Ostenfeld and Cymodocea serrulata (R.Brown) Ascherson were recorded for the first time in the area of WGNP. The meadows areas ranged between 0.024 ha and 498.2 ha with total area estimated 1783.08 ha. The seagrass coverage ranged between (82.5% ± 8.7) and (17.5% ± 8.0) in different sites. However, the higher overall mean coverage was recorded at sheltered sites than exposed ones. The total coverage of seagrass found to be higher at shallower and deeper waters, rather than the middle depths of 5-20m. Halphila stipulacea was the most dominant species in both 26 studied sites and the 5 studied depths (0-25m). 8 sites were selected to study the seasonal variations through 6 seasons between fall 2006 to winter 2008. The annual mean for both shoot & rhizome biomass/m? at different sampling sites has shown that Thalassodendron ciliatum (Hamata) had the highest biomass, while Halophila decipiens (Ras Bughdadi A) had the lowest value. 12 species of associated macroalgae were recorded at different studied sites. Seagrasses and algae showed obvious seasonal changes with nearly uni-modal seasonal pattern. A total of 45 macro-invertebrate species were recorded. Faunal composition showed regional differences. Most of the species were recorded at Hamata site. Species similarity between different sites appeared to be low. The algal epiphyte biomass was greatest during spring 2007 at Qulaan site which was dominaned with Thalassia hemprichii. While the lowest biomass recorded during winter 2007 at Ras Bughdadi C site which was dominated by Cymodocea serrulata. |