Northern Tihama

Location of Northern Tihama, extending from Jeddah in south to Haql vilage in north

Northern Tihama, a narrow strip of undulated coastal zone situated between Red Sea on its western side and a chain of mountains (Hijaz) on its entire eastern side. It is a 1080 km long sandy and silt area extending from Jeddah in the south to Haql town in the north. The strip is more or less at sea level in the south or slightly elevated towards east as a result of the silt coming from the Hijaz Mountains. The plains along the eastern side of the coastal zone is wide in the southern parts (between Jeddah and Yanbu) and narrow in the northern sector, north of Yanbu. Tihama is virtually absent near Haql area where its sea shore merges with the foothills of escarpments. Shore line is somewhat undulate margined with some creeks penetrating into the land. Rainfall is erratic along the coast, occurring mainly between October and February. Less than 20 mm rainfall is recorded in the Jeddah and Yanbu stations. Maximum average temperature ranges between 25 and 33 0C and humidity ranges between 50-75%. Unlike the southern Tihama region, the mangrove population is not dense and continuous in the entire coastal marshy land except in some of the creeks near Thuwal, Yanbu and in some islands off Al-Wajh where dense stands of healthy Avicennia marina could be seen. The northern limit of the distribution of Avicennia marina along the Red Coast in Saudi Arbia appears to be near Sharm Zubeir, off the coast between Al-Sourah and Sharmaa. Rhizophora mucronata, the only other mangrove reported along Red Sea coast is also found in a few locations north of Jeddah (Umm Ruma Island, Dugm Sabq, Gama’an Island, Shibara Island, etc). However, its main populations are found in Al Wajh Bank, an Archipelago comprised of about 50 islands located south west of Al Wajh. 

Unlike the southern Red Sea Islands, northern Red Sea Islands (Al Wajh Bank) are devoid of any dense vegetation. Majority of these islands are sandy while others are rocky with small hillocks of 5m high or less. Vegetation is almost nil in most of the islands except in a few where salt bushes such as Arthrocnemum macrostachyum, Halocnemum strobilaceum, Zygophyllum spp. etc dominate in patches. 

The plains of Northern Tihama are composed of stones and sand with differing soil depths. Vegetation between Jeddah and Yanbu is more or less similar to the that of the plains of southern Tihama. The most dominant among them is the widely spaced Acacia tortilis-Maerua crassifolia association. However, M. crassifolia is in a highly degraded state, mostly seen as heavily grazed and cushion-formed. Other Capparaceae species dominant in the sand dunes and stony plains of southern Tihama, such as Dipterygium glaucum, Cadaba glandulosa are less frequent north of Jeddah. Similarly Commiphora spp., dominant in the foothills of southern Tihama, is almost nil in the northern Tihama. Most of the areas during summer are dry and barren. Dominant species of the plains and foot hills are the scattered A. tortilis intermixed with A. ehrenbergiana.  Abutilon pannosum, Lycium shawii,  Ochradenus baccatus, etc. dominate in shallow silt depressions and Leptadenia pyrtotechnica and Rhazya stricta dominate in sandy hummocks. Common grasses in these areas are Panicum turgidum, Pennisetum divisum and occasionally Lasiurus scindicus and Aristida spp. Coastal areas are mainly dominated by salt bushes composed of chenopods and Zygophyllum spp. Limonium axillare, Arthrocnemum macrostachyum, Halopeplis perfoliata and Zygophyllum coccineum are the most dominant along the northern sabkhas. In general, L. axillare grow in low lying areas or in localized depressions while Z. coccineum dominate in areas covered by coral rocks or coral sands. The areas north of Jeddah the coastal zone is covered by white coral sand supporting dense stands of Suaeda monoica and Anabasis setifera. On the eastern side where the soil is less saline, the vegetation is dominated by Acacia ehrenbergiana, Anastatica heirochuntica, Senna italica and Hyparrhenia hirta.

Sabkhas of the coastal areas of Thuwal are densely vegetated with salt bushes. It supports Zygophyllum coccineum and Aeluropus lagopoides along with Desmostachya bipinnata, Indigofera oblongifolia and Astragalus spinosa in some locations. Sands overlain the crusty salt substratum support a number of annuals such as Sonchus oleraceus, Launaea mucronata, etc.

Trees are generally few in the entire Tihama area. Among the large trees, Acacia raddiana, A. johnwoodii, Capparis decidua, Maerua crassifolia and Hyphaene thebaica,  are prominent. Further north, the coastal zones near Rabigh and south of Yanbu are devoid of any appreciable level of vegetation due to the development of industries and corniches or occasionally with secondary vegetation dominated by Aeluropus lagopoides, Cressa cretica, Halopeplis perfoliata and Zygophyllum coccineum. At places where they form into dense stands sand accumulates at the base of these shrublets and provide habitats for other mesophytes such as  Fagonia indica,  Glinus lotoidesLotus corniculatus, Picris cyanocarpa, etc. Ruderals and the common invasive species, Prosopis juliflora also dominate around new settlements and along road sides.

Coastal lines of Yanbu are with several creeks, most of which provide shelters for the growth of Avicennia marina. Sea in this area is very shallow. Cymodocea rotundata, the wide leaved sea grass occurs in such waters. 

The coastal zone is bounded on the east by salty flats or small dunes of coral sand. In some places north of Yanbu industrial city, coastal areas are often enclosed by coral rock and drained sand gullies. Saline coasts are dominated by Arthrocnemum macrostachyum, Tamarix aucheriana, Suaeda vermiculata, Sporobolus spicatus, while the sandy soil towards the interiors are dominated by Acacia ehrenbergiana and A. tortilis associated with Taverniaria spartea. During spring, most of the herbaceous flora of the plains and foothills near Wajh and Umlaj are mostly  seen along the drainage channels, alluvial plains and other silt filled depressions. Ravines are dominated by Gymnocarpos decander, Ochradenus baccatus, Zilla spinosa and Aerva javanica. Another striking species in the area is the Retama raetam, usually found in plains close to foothills.

Coastal areas of Duba is dominated by Aeluropus lagopoides, Juncus rigidus and Nitraria retusa. In some places it is seen in close associations with Haloxylon salicornicum, Seidletzia rosmarinus, Suaeda monoica or Zygophyllum coccineum. Open plains, not far away from the coastal zone, the branched palm tree, Hyphaene thebaica is seen intermixed with Acacia ehrenbergiana.  

The extreme northern side near Haql, Tihama is narrow with a rocky terrain. In some places the escarpment is seen very close to the sea shore. Haloxylon salicornicum dominate in these areas along with Acacia tortilis, Fagonia mollis, Capparis decidua and Stipagrostis plumosa. Small water channels and runnels originate along the slopes and reach the sea. During rainy season, silt accumulates in small ditches along the slopes and provide habitats for a diverse herbaceous flora comprised of Aizoon canariense, Arnebia hispidissima, Bassia muricata, Blepharis ciliaris, Caylusea hexagyna, Cucumis prophetarum, Diplotaxis harra, Fagonia bruguieri, Launaea capitata, Trigonella hamosa, Zilla spinosa and Zygophyllum simplex (Tetraena simplex).

 

Maerua crassifolia
Vachellia tortilis
Arthrocnemum macrostachyum

Flora of Northern Tihama

Acanthaceae

Blepharis ciliaris

Justicia flava

Aizoaceae

Aizoon canariense

Mesembryanthemum nodiflorum

Amaranthaceae

Aerva javanica

Amaranthus graecizans

Amaranthus hybridus

Amaranthus viridis

Anabasis setifera

Arthrocnemum macrostachyum

Atriplex farinosa

Bassia muricata

Bienertia cycloptera

Chenopodium glaucum

Chenopodium murale

Digera muricata

Halocnemum strobilaceum

Halopeplis perfoliata

Haloxylon salicornicum

Salsola imbricata

Salsola lachnantha

Salsola spinescens

Salsola volkensii

Seidlitzia rosmarinus

Suaeda aegyptiaca

Suaeda monoica

Suaeda vermiculata

Amaryllidaceae

Pancratium maximum

Apiaceae

Anisosciadium lanatum

Deverra triradiata

Apocynaceae

Calotropis procera

Cynanchum acutum

Leptadenia pyrotechnica

Odontanthera radians

Pergularia daemia

Pergularia tomentosa

Rhazya stricta

Aracaceae

Hyphaene thebaica

Phoenix dactylifera

Asparagaceae

Asparagus falcatus

Asphodelaceae

Asphodelus fistulosus

Asteraceae

Asteriscus hierochunticus

Atractylis mernephthae

Centaurea pseudosinaica

Centaurea schimperi

Centaurea scoparia

Cotula sp.

Echinops erinaceus

Echinops erinaceus

Echinops polyceras

Echinops viscosus

Ifloga spicata

Iphiona scabra

Launaea capitata

Launaea intybacea

Launaea massauensis

Launaea mucronata

Launaea procumbens

Picris babylonica

Picris cynocarpa

Pluchea ovalis

Pulicaria guestii

Pulicaria jaubertii

Pulicaria undulata

Reichardia tingitana

Senecio flavus

Sonchus oleraceus

Boraginaceae

Arnebia hispidissima

Echium horridum

Gastrocotyle hispida

Heliotropium aegyptiacum

Heliotropium arbainense

Heliotropium bacciferum

Heliotropium curassavicum

Heliotropium europeam

Heliotropium rariflorum

Trichodesma africanum

Brassicaceae

Anastatica hierochuntica

Anastatitica heirochuntica

Diplotaxis acris

Diplotaxis harra

Diplotaxis harra

Eremobium aegyptiacum

Eremobium aegyptiacum s. lineare

Eremobium lineare

Erucaria hispanica

Farsetia aegyptia

Farsetia longisiliqua

Farsetia longisiliqua

Farsetia stylosa

Farsetia stylosa

Morettia parviflora

Morettia parviflora

Notoceras bicorne

Sisymbrium erysimoides

Zilla spinosa

Capparaceae

Cadaba farinosa

Cadaba glandulosa

Cadaba oblongifolia

Capparis decidua

Capparis sinaica

Cleome amblyocarpa

Cleome brachycarpa

Cleome glaucescens

Cleome noeana

Cleome viscosa

Dipterygium glaucum

Maerua crassifolia

Caryophyllaceae

Gymnocarpos decandrum

Gypsophila capillaris

Paronychia arabica

Polycarpaea repens

Polycarpaea robbairea

Pteranthus dichotomus

Sclerocephalus arabicus

Silene linearis

Spergula fallax

Convolvulaceae

Convolvulus fatmensis

Convolvulus glomeratus

Convolvulus hystrix

Convolvulus pilosellifolius

Cressa cretica

Cuscuta campestris

Cuscuta planiflora

Seddera latifolia

Cucurbitaceae

Citrullus colocynthis

Cucumis prophetarum

Cymodoceaceae

Cymodocea rotundata

Cyperaceae

Cyperus conglomeratus

Ephedraceae

Ephedra foliata

Ephedra aphylla

Euphorbiaceae

Andrachne telephioides

Chrozophora oblongifolia

Chrozophora tinctoria

Euphorbia cuneata

Euphorbia granulata

Euphorbia retusa

Gentianaceae

Centaurium spicatum

Geraniaceae

Erodium deserti

Erodium laciniatum

Erodium touchyanum

Monsonia nivea

Juncaceae

Juncus rigidus

Lamiaceae

Lavandula coronopifolia

Lavandula pubescens

Otostegia fruticosa

Salvia aegyptiaca

Salvia deserti

Salvia deserti

Teucrium leucocladum

Teucrium polium

Leguminosae

Acacia ehrenbergiana

Acacia gerrardii

Acacia hamulosa

Acacia johnwoodii

Acacia oerfota

Acacia origena

Acacia raddiana

Acacia tortilis

Astragalus fatmensis

Astragalus schimperi

Astragalus vogelii v. fatmensis

Crotalaria aegyptiaca

Indigofera coerulea

Indigofera oblongifolia

Indigofera spinosa

Lotus corniculatus

Prosopis juliflora

Psoralea plicata 

Retama raetam

Senna alexandrina

Senna italica

Taverniaria spartea

Tephrosia nubica

Trigonella hamosa

Trigonella stellata

Loranthaceae

Plicosepalus curviflorus

Malvaceae

Abutilon pannosum

Abutilon pannosum

Abutilon sp.

Hibiscus micranthus

Malva parviflora

Malva verticillata

Subfamily-Grewioideae

Corchorus depressus

Corchorus olitorius

Grewia mollis

Grewia tembensis

Grewia tenax

Menispermaceae

Cocculus pendulus

Molluginaceae

Glinus lotoides

Gisekia pharnaceoides

Neuradaceae

Neurada procumbens

Nitrariaceae

Nitraria retusa

Nyctaginaceae

Boerhavia diffusa

Orobanchaceae

Cistanche phylepaea

Plantaginaceae

Kickxia pseudoscoparia

Plantaginaceae

Plantago amplexicaulis

Plantago ciliata

Plantago ovata

Plumbaginaceae

Limonium axillare

Poaceae

Aeluropus lagopoides

Aristida adscensionis

Cenchrus ciliaris

Centropodia forsskalei

Cymbopogon schoenanthus

Cynodon dactylon

Desmostachya bipinnata

Dichanthium annulatum

Enneapogon desvauxii

Eragrostis barrelieri

Hyparrhenia hirta

Lasiurus scindicus

Panicum turgidum

Paspalidium desertorum

Pennisetum divisum

Poa annua

Schismus barbatus

Sporobolus spicatus

Stipa capensis

Stipagrostis ciliata

Stipagrostis plumosa

Polygonaceae

Calligonum comosum

Rumex vesicarius

Resedaceae

Caylusea hexagyna

Ochradenus baccatus

Oligomeris linifolia

Reseda decursiva

Reseda sphenocleoides

Rhamnaceae

Ziziphus spina-christi

Rhizophoraceae

Rhizophora mucronata

Salvadoraceae

Salvadora persica

Scrophulariaceae

Kickxia aegyptiaca

Solanaceae

Datura innoxia

Lycium shawii

Solanum glabratum v. sepicula

Solanum incanum

Solanum sepicula

Tamaricaceae

Tamarix aucheriana

Tamarix nilotica

Urticaceae

Forsskaolea tenacissima

Verbenaceae

Avicennia marina

Xanthorrhoeaceae

Asphodelus fistulosus

Zygophyllaceae

Fagonia bruguieri

Fagonia glutinosa

Fagonia indica

Fagonia mollis

Fagonia schweinfurthii

Fagonia tristis

Seetzenia lanata

Tribulus pentandrus

Tribulus terrestris

Zygophyllum album

Zygophyllum coccineum

Zygophyllum fabago

Zygophyllum hamiense var. qatarense

Zygophyllum simplex

A  view of the Northern Tihama. Haql, near Jordan border