Farasan Islands

Climate

There are no weather stations located in any part of the archipelago. The climatic data is, therefore, collected from Jizan meteorological station. Similar to the climate of Tihama region in the mainland, all islands are also generally dry with unpredictable rain. The data recorded from 1985 to 1998 shows that the highest average precipitation was reported in December and the highest average temperature was in the months of June and August.

Flora and Vegetation

The flora comprises about 200 species of flowering plants in 49 families. Occasional rains, condensation of dews or underground water sources are the main influential factors for the growth of annual vegetation in these islands. The highest concentration of the vegetation is seen in the sheltered wadis with fine silty-clay. The southeastern area of Farasan Al-Kabir, where the land is rugged, contains the highest number of plant species whereas the northwestern unbroken plateau and the western facing shoreline are devoid of plants except for a few annual species. Among the higher plants, a considerable number of them are halophytes or semi-halophytes and the growth of these plants is influenced by the salinity of the soil and the proximity to the seashore. Vegetation along the shoreline of Farasan and Sajid islands, particularly along the inlets and bays is dominated by Avicennia marina whereas in Zifaf and Dumsuq islands another mangrove, Rhizophora mucronata, also show its presence along with Avicennia marina.

The overall vegetation of Farasan Islands is interesting in two aspects: (a) because of its similarity to the distribution of natural plant communities and (b) its similarity to the  floral elements of the Tihama Region of the southwestern region of mainland; Saudi Arabia. The plant communities at the south eastern part of the island, where the density of the vegetation is noticeably high, are dominated by small trees and shrubs such as Acacia ehrenbergiana, Commiphora gileadensis and Salvadora persica. Occasionally trees like Hyphaene thebaica and shrubs such as Cadaba glandulosa, Grewia tenax,  Indigofera oblongifolia  and climbers such as Cissus quadrangularis, Pentatropis nivalis are also present in varying densities. Annuals in this area are, mainly, represented by Zygophyllum simplex, Polycarpaea spicata, Euphorbia granulata and others. At the edges of the ravines where the substrata are somewhat exposed due to erosion, isolated subshrubs such as Aerva javanica, Capparis sinaica and Ochradenus baccatus were present along with a considerable number of annuals.

Overall four sets of distribution patterns can be found in the islands, ranging from a very narrow restricted distributions, such as rare, scattered to dominant or abundant. Apparently, the populations of Acacia ehrenbergiana and Zygophyllum simplex are the most dominant species in the interior regions of the southern parts of Farasan Al-Khubra and other main islands while the populations of Limonium axillare, Halopeplis perfoliata, Zygophyllum coccineum and Suaeda monoica dominate along the coastal and subcoastal regions. The occurrence of grasses are also significant throughout the area. These are mostly represented by Sporobolus helvolus, Dichanthium foveolatum, Panicum turgidum, Hyparrhenia hirta, and Tricholaena teneriffae.  In open plains where the plants mainly concentrate in and around small depressions and under the shelters of boulders, the representative ephemerals are Zygophyllum simplex, Eragrostis ciliaris, Amaranthus viridus and others. The sheltered habitats of the inlets and bays, particularly in Farasan Al-Khubra, are calm and allow the free flow of sea-water during high tide. These areas are conducive for the growth and survival of Mangrove species. However, an association of the 2 mangrove species, Avicennia marina and Rhizophora mucronata known to occur was not encountered at the inlets along the south eastern coastal regions of Farasan Al-Khubra. It is probably due to large scale urbanization and the construction of a new port in the vicinity of mangrove habitats.

Sasid (Sajid or Saqid) Island, the second largest Island in the Archipelago is also an open flat reef with shallow wadis. Vegetation of this island is dominated by halophytic communities such as Limonium axillare, Suaeda monoica and occasional trees such as Hyphaene thebaica. Abandoned agriculture lands are a common sight on this island especially near old dwellings. The commonest species at these locations in order of abundance are: Acacia ehrenbergiana, Commiphora giladensis, Indigofera oblongifolia, Grewia tenax, Capparis sinaica, Indigofera spinosa, Aerva javanica, Blepharis ciliaris and Dichanthium foveolatum.

Topography of other islands are more or less similar to the two major islands. Broad wadis between the elevated ridges are characteristic of the Zifaf Island. Mangrove populations in this island, represented by both Avicennia marina and Rhizophora mucronata, are dense and rich and not impacted by external influences. Vegetation of the coastal sandy areas, is represented by Limonium axillare and Aeluropus lagopoides; and along the gentle slopes and ridges, the vegetation is dominated by occasional clumps of Commiphora gileadensis, Cocculus pendulus, Aerva javanica and Indigofera oblongifolia. The vegetation of Dawshak and Dumsuq islands are also more or less similar to other smaller islands except for the presence of species such as Commiphora erythraea in the latter island. These two islands are devoid of any inlets favorable for the growth of mangroves, although the presence of mangroves was reported in some works. The terrain of some of the smaller islands (Ra’s Rasib (Mandar), Abu-Tuk) along the northern sides of Sasid Island is, to a certain extent, barren and sparsely vegetated. However, on the northern side of the Ra’s Rasib island, dense communities comprising Limonium axillare, Suaeda vermiculata and Suaeda monoica were recorded.