Plant Communities
Vegetation of Saudi Arabia is generally divided into five broad categories. 1. Vegetation of the coastal plains and Sabkhas 2. Deserts and scarcely vegetated areas 3. Dwarf shrublands 4. Woodlands and xeromorphic shrublands of high altitude areas and 5. Wadi Communities.
Coastal zones and sabkhas
a. Coastal zones and sabkha vegetation and very open drought-deciduous thorn woodlands of the coastal plains and lower foothills.
Saudi Arabia has an extensive coastline in the western (Red Sea) and eastern sides (Arabian Gulf). Mangroves, halophytes, open xeromorphic and drought-deciduous thorn woodlands dominate the coastal zones of Arabian Gulf and Red Sea. Mats of algal plants are dominant in shallow coral reefs where the substrate is hard while sea grasses are dominant in shallow, sandy substrates. Sea grass flora of Saudi Arabia is somewhat diverse. Out of 11 species recorded from Arabian Peninsula, 7-8 species are reported from Red Sea coast and Arabian Gulf. Coastal zone is characterized by low sand dunes and saline marshes. Vegetation is generally scattered and poor in such terrains, often seen with extensive monospecific stands such as Halocnemum strobilaceum, Halopeplis perfoliata, Limonium axillare, Nitraria retusa, Odyssea mucronata, Suaeda monoica, S. vermiculata, Zygophyllum coccinium, Z. simplex etc.
Mangrove stands, represented by Avicennia marina and Rhizophora mucronata, occupy in the protected bays and estuaries of Saudi coast. Among the two, the former is the most commonest, distributed along the Red Sea coast and the Arabian Gulf while the latter is known from the southern Tihama coast and Farasan Archipelago. Depending on the soil texture whether it is saline, silt, sand or alkaline, several populations and plant associations have been found in the southwestern and northwestern coastal lands (Tihama).
Coastal and sabkha vegetation and open drought deciduous thorn woodlands (1 and 13), Deserts and sparsely vegetated areas (8, 9 & 11), Dwarf shrublands and related communities (10 & 12, Montane woodlands and xeromorphic shrublands (2, 3, 4, 5, 6 & 7), Wadi Communities (14)
(Courtesy: Frey and KÜrschner, 1989, Ghazanfar and Fisher, 1998, Chaudhary and Juwayed, 1999)
2.Deserts and sparsely vegetated areas.
a.Open xeromorphic dwarf-shrublands of rock and gravel deserts.
Dominant species: Acacia tortilis, Haloxylon salicornicum, Astragalus spinosus, Gymnocarpos decandrum, Achillea fragrantissima, Halothamnus bottae, Tephrosia apollinea, Salvadora persica, Cadaba farinosa, Leptadenia pyrotechnica,
b. Deep sands
Dominant species: Calligonum comosum, Haloxylon persicum, Calligonum crinitum ssp. arabicum, Dipterygium glaucum, Tribulus macropterus var. arabicus, Artemisia monosperma, Centropodia forsskalii, Stipagrostis drarii, Scrophularia hypercifolia, Eremobium aegyptiacum, Cyperus conglomeratus, Cutandia memphitica, Plantago boissieri
c. Scarcely vegetated sand dunes and sand covered gavel plains.
Dominant species: Acacia spp. and Calligonum comosum.
3. Dwarf shrublands
a. Very open Xeromorphic dwarf shrublands
Dominant species: Calligonum comosum, Haloxylon salicornicum
b. Open xeromorphic dwarf shrublands
Dominant species: Haloxylon salicornicum, Rhanterium epapposum, Acacia gerrardii, Acacia ehrenbergiana, Ziziphus nummularia, Lycium shawii.
4. Montane woodlands
a. Drought deciduous thorn woodlands and shrublands (Acacia–Commiphorawoodlands between 500-1000 m asl)
Dominant species of northern parts of southern Hijaz Mountains (Jeddah-Taif): Acacia asak, A. ehrenbergiana, A. hamulosa, A. etbaica, Commiphora kataf, C. myrrha, Delonix elata, Euphorbia cuneata, Maytenus senegalensis
Dominant species of the middle parts of southern Hijaz Mountains (Asir): Acacia ehrenbergiana, A. hamulosa, A. mellifera, Cadaba farinosa, Dobera glabra, Maerua crassifolia, Euphorbia fractiflexa, Indigofera spinosa, Panicum turgidum, Chrysopogon plumulosus, Blepharis ciliaris,
Dominant species of the southern parts of southern Hijaz Mountains (adjoining mountains near Yemen border) Acacia ehrenbergiana, A. mellifera, A. tortilis, Adenium obesum, Aloe officinalis, Combretum molle, Delonix elata, Dobera glabra, Hyphaene thebaica, Maerua crassifolia
b. Drought deciduous thorn woodlands (Acaciawoodlands along the western and eastern upper slopes between 1000-1500 m asl)
Dominant species: Acacia asak, A. etbaica, A. origena, Adenium obesum, Anisotes trisulcus, Barleria bispinosa, Cadia purpurea, Grewia spp.
c. Semi evergreen Sclerophyllous woodlands and sclerophyllous scrub (between 1500-1800)
Dominant species: (Barbeya oleoides-Olea europaea community of the Taif Mountains) Acacia etbaica, Dodonaea viscosa, Olea europaea
Dominant species: (Barbeya oleoides-Olea europaea community of Asir Mountains) Buddleja polystachya, Carrisa edulis, Celtis africana, Nuxia congesta, Maesa lanceolata, Tarchonanthus camphorates
d. Evergreen Needle-leaved Woodlands. (Vegetation of highest part of the northern and southern Hijaz Mountains)
Dominant species of northern mountains: Juniperus phoenicea, Artemisia seiberi, Astracantha echinatus ssp. arabicus, Tanacetum santolinioides, Launaea spinosa, Colutea istria, Eringium glomeratum, Prunus korshinskyi, Asperagus aphyllus, Astragalus sparsus
Dominant species of Taif Mountains: Juniperus procera, Euryops arabicus, Psiadia punctulata, Rhus retinorrhea
Dominant species of Jabal Soodah: Acacia gerrardii, A. seyal, Erica arborea, Juniperus procera, Lavandula dentata, Rumex nervosus, Rosa abyssinica, Otostegia fruticosa, Psiadia punctulata, Dodonaea angustifolia, Centaurothamnus maximus, Hypericum revolutum, Clutia myricoides, Myrsine africana, Pentas lanceolata, Carissa edulis .
Dominant species of the mountains of Jizan Province: Juniperus procera, Acacia gerrardii, Euryops arabicus, Dodonaea angustifolia, Hypericum revolutum, Cordia abyssinica, Nuxia congesta, Rosa abyssinica
e. Mixed formations of drought deciduous shrublands, xeromorphic succulent shrublands and open xeromorphic grasslands & very open xeromorphic semi-desert shrublands.(East facing and north facing slopes)
Dominant species: Vegetation of these areas are mainly dominated by succulent plants such as Euphorbia spp., Dracaena, Klenia and Aloe along with Acacia gerrardii, A. oerfota and A. etbaica.
5. Wadi communities
Several plant communities have been identified along the banks and wadi bottom, especially along the wadis of Najd and Tihama areas. Main wadis in Saudi Arabia are Wadi Rimah, Wadi Fatima, Wadi Hanifa, Wadi Dawasir, Wadi As Sabha, Wadi Nissah and Wadi Al-Batin
a. Dominant species of the Central region:Acacia gerrardii, A. raddiana, A. ehrenbergiana, A. tortilis, Rhazya stricta, Lycium shawii, Pennisetum divisum,Lasiurus scindicus, Ochradenus baccatus, etc.
b. Dominant species of Tihama region:Acacia ehrenbergiana, Ziziphus spina-christi, Salvadora persica, Leptadenia pyrotechnica, Tamarix nilotica, Hyphaene thebaica, Abutilon pannosum, Panicum turgidum, Desmostachya bipinnata, Dobera glabra, etc.
