Hail |
Topography The Hail (Hayil) region of Saudi Arabia, located between 250 35` and 290 00` N longitudes and 390 01` and 440 45` E latitudes, is an exposed complex of Precambrian igneous and metamorphic rocks. It is part of the vast phanerozoic formations that overlap the northern and eastern edge of the Arabian Shield. The Hail region covers an area of 118,322 sq. km (= 445,684 sq. miles). It is named after the large Wadi Hail (formerly called Al-Odair valley) in the Shammar Mountain region and is bordered in the north by Al-Jauf and Northern Frontier Emirates, to the west by Tabuk and Medina Al-Munawarra regions, to the south by Qassim Province and to the east by Central and Eastern Provinces. The study area is characterized by several landscape units, such as isolated mountains, peneplains, escarpments, wadis and sand-seas. The Hail valley extends to the north-east through a narrow corridor linking the city with the Shamrah Mountain.
The Shammar Mountains form a major feature of Hail region. It has of two mountain ranges namely Aja, made up of granite and Salma composed of basalt. The entire region is about 1000 m high and the height of the mountains varies from 100-600 m. Jabal Aja situated between Hail town and the An Nafud desert is the largest mountain in the study area. The principal part of Hail is composed of Nafud desert, covering about 64,000 sq. km and composed of reddish sand. It lies at an elevation of 900 m from sea level. The sands are stained red because of the iron oxide coating on the sand grains. The desert is believed to be the product of Quaternary episodes of increased Aeolian activity and composed of 60-120 m high barchanoid and transverse dunes. Major parts of the desert is formed of sand dunes. However, interdunal depressions can also be observed with relatively thin sand cover. An-Nafud, the second largest desert in the Arabian Peninsula. It is connected to the largest Arabian Desert in the south, the Rub’a al Khali (the Empty Quarter), by Ad-Dahna belt, a narrow curved sand body separating the central Najd from Eastern Arabia. Hail Region js relatively an excellent area for pasturage. Over the years, due to intense grazing and unsustainable use of the region's resources, the area has changed into a less productive one with a few shrubs and trees (mainly Acacias) in wadis and foothills. However, the region's mountains housed a number of endemic and rare species, some of which are not present in any other part of Saudi Arabia.
Climate The weather system of Hail Region is generally arid to extra arid. It is influenced by two main pressures, namely Siberian high in winter and tropical low in summer. It is also influenced by Saudi Arabia’s unique topography with mountains bordering on the west and the Najd Plateau on south and east. The sun-rays, as in other parts of Saudi Arabia, are intense and seldom diffused by clouds. Summer temperatures typically rise as high as 50 0C during day time with diurnal variation of about 25 0C. Winter temperatures hover around freezing at night especially at higher altitudes although the ground occasionally freezes and daytime temperatures nearly always reach 25 0C in the sun. The wind in the Hail emirate comes from the north or northwest and is a great evaporative force causing immense physical damage. At certain times of the year, especially during spring, the wind builds up 4-5 days severe dust storms known as ‘Shamals’ in which air is full of grit (sand + silt), often rise to hundreds of meters. The rainfall is erratic. The main source of precipitation in the region is from the winter cyclones originating from the Mediterranean Sea and eastern Atlantic Ocean. Although most of the precipitation of this region is from winter storms, summer storms from the south western region also have an insgnificant share in some years. Snow fall and hail storms are also not uncommon during the winter months.
Vegetation Vegetation of the mountains is influenced by the floras of Mediterranean countries, while that of the An Nafud sand seas, open plains and wadis are related to the floras of Saharo Arabian and Irano-Turranean phytogeographical regions. Though the vegetation of various landscape units are clearly distinguished in most places, the borders between units in certain areas (such as in the north-east and south-east of the study area) are difficult to demarcate because of overlapping. Rhus tripartita is one of the major components of the vegetation of the mountains followed by Ficus palmata. Other important perennials include Cymbapogon commutatus, Periploca aphylla, Gomphocarpus sinaicus, Pergularia tomentosa, Blepharis ciliaris and Trichodesma spp.. The east facing mountainous sides are somewhat steep and generally devoid of any significant diversity. Nevertheless, species such as Rhus tripartita, Aerva javanica, Cenchrus ciliaris, Ephedra foliata and Astragalus spinosa forms into small communities in shades and crevices. The shaded areas of the mountains on the north western parts, on the other hand, have a rich floristic composition. Although the vegetation is spread over the shaded areas, majority of plants can be seen along ravines and ditches where sand and silt accumulate during rainy season. Representative plants in these areas include: Noaea mucronata, Heliathemum kahiricum, Gymnocarpos decandrum, Ballota undulata, Silene schweinfurthia, Paracaryum rugulosum, etc.
At lower altitudes the terrain is composed of large boulders and gravels. Vegetation in this part is dominated by Ochradenus baccatus, Zoegea purpurea, Aerva javanica, Pennisetum setaceum, Astragalus spinosus, Teucrium polium, Lycium shawii, Fagonia indica, etc., whereas in the foothills Haloxylon salicornicum is dominant among the shrublet category, associated with Zilla spinosa, Rhanterium epapposum and Astragalus sieberi.
The wadi system in the Hail Region, in general, is part of the Wadi Rimah drainage. Acacia gerrardii is the major component dominating in these wadis, along with occasional shrubs such as Lycium shawii, Ochradenus baccatus, Rhazya stricta, Convolvulus oxyphyllus, Zilla spinosa, Senna italica, Pulicaria undulata and Rhanterium epappsoum. In general four vegetation groups are present in the region. They are annual vegetation cover, Haloxylon persicum-Artemisia monosperma-Stipagrostis drarii community, Calligonum comosum-Artemisia monosperma-Scrophularia hypercifolia community and ecotone communities. The ecotone community is further divided into Haloxylon-Calligonum-Pituranthos triradiatus-Scrophularia community and Rhanterium-Calligonum-Pituranthos-Scrophularia community. These communities have remarkable representation in sand dunes such as lower dune and upper dune or middle dune areas. However, Calligonum-Artemisia-Scrophularia community is the most widely spread plant groups in the entire Nafud area.
Majority of species in the Hail region are annuals. The representation of trees is insignificant, represented by only 1%. Members of Composite dominate the flora (Asteraceae-71 species) followed by Gramineae (Poaceae –37 species), Cruciferae (Brassicaceae – 36 species), Caryophyllaceae (24 species) and Leguminosae (Fabaceae - 21 species). 24 families are monotypic. The largest genus in the flora is Plantago (Plantaginaceae) with 10 species, followed by Astragalus (Leguminosae) with 9 species. Flora of Hail Region (Species present in Jabal Aja are marked with an Asterisk (*) |
ACANTHACEAE
*Aizoon hispanicum L. AMARANTHACEAE *Aerva javanica (Burm.f.) Juss. ex Schultes Agathophora alopecuroides (Del.) Fenzl *Amaranthus graecizans L. *Amaranthus viridis L. Atriplex dimorphostegia Kar. & Kir. Bassia muricata (L.) Asch. *Beta vulgaris ssp. maritima (L.) Arcang. *Chenopodium murale L. Halocnemum strobilaceum (Pallas) M. Bieb. Halothamnus iraqensis Botsch. Haloxylon persicum Bunge ex Boiss. *Haloxylon salicornicum (Moq.) Bunge *Noaea mucronata (Forssk.) Asch. & Schweinf. Salsola cyclophylla Baker *Salsola imbricata Forssk. Salsola tetrandra Forssk. Suaeda aegyptiaca (Hasselq,) Zoh. Suaeda vermiculata Forssk.
AMARYLLIDACEAE
*Allium stamineum Boiss.
APIACEAE / UMBELLIFERAE Anisosciadium isosciadium Bornm. *Anisosciadium lanatum Boiss. Deverra triradiata ssp. triradiata (Hochst.) Aschers
*Ducrosia anethifolia (DC.) Boiss. *Scandix pecten-veneris L. *Torilis leptophylla (L.) Reichb. f.
(including subfamily- Asclepiadoideae) Gomphocarpus sinaicus Boiss. Pergularia daemia (Forssk.) Chiov. Pergularia tomentosa L. Periploca aphylla Decne Rhazya stricta Decne
ASPARAGACEAE *Leopoldia tenuiflora
BORAGINACEAE Alkanna orientalis (L.) Boiss.
Anchusa milleri Willd.
*Asperugo procumbens L.
*Lappula sinaica (DC.) Aschers. *Paracaryum rugulosum (DC.) Boiss.
*Trichodesma africanum
var.
africanum (L.) R.Br. BRASSICACEAE /CRUCIFERAE *Alyssum homalocarpum (Fischer & Meyer) Boiss. Anastatica hierochuntica L. Arabidopsis erisymoides Hedge & Kit Tan *Brassica tournefortii Guan. Cakile arabica Velen. & Bornm. *Capsella bursa-pastoris (L.) Medikus *Carrichtera annua (L.) DC. *Clypeola aspera (Guauer) Turril *Clypeola jonthlaspi L. *Diplotaxis acris (Forssk.) Boiss. Diplotaxis erucoides (L.) DC. Eremobium aegyptiacum ssp. lineare (Del.) Boiss. *Eruca sativa Miller *Farsetia aegyptia Turra Farsetia burtoniae Oliver. Farsetia stylosa R.Br. *Hirschfeldia incana (L.) Lagr. Horwoodia dicksoniae Turril *Isatis lusitanica L. Lepidium aucheri Boiss. *Lepidium draba L. *Malcolmia africana (L.) R.Br. Maresia pygmaea (Del.) O. Schulz Matthiola arabica Boiss. *Matthiola longipetala (Vent.) DC. Morettia canescens Boiss. *Morettia parviflora Boiss. Moricandia sinaica (Boiss.) Boiss. *Neotorularia torulosa (Desf.) Hedge & Leonard Notoceras bicorne (Aiton f.) Amo Raphanus sativus L. *Savignya parviflora (Del.) Webb Schimpera arabica Hochst. & Steudel *Sisymbrium irio L. *Sisymbrium orientale L. *Zilla spinosa (L.) Prantl.
*Wahlerbergia campanuloides (Del.) Vatke.
CAPPARACEAE
*Cleome amblyocarpa Barr. & Murb.
*Cleome rupicola
Vicary
CAPRIFOLIACEAE
CARYOPHYLLACEAE
Dianthus cyri Fisch & C.A. Mey.
*Minuartia meyeri (Boiss.) Bornm.
*Silene apetala
Willd. *Silene schweinfurthii Rohrb.
*Silene villosa
Forssk. CISTACEAE *Helianthemum aegyptiacum (L.) Mill. *Helianthemum kahiricum Del.
*Helianthemum ledifolium (L.) Mill. COLCHICACEAE
*Colchicum ritchii R.Br. COMPOSITAE /ASTERACEAE *Aaronsohnia factorovskyi Warb. & Eig.
Acantholepis orientalis
Less.
Anthemus edumea Eig.
*Calendula arvensis L.
*Carduus pycnocephalus var. pycnocephalus L.
*Flaveria trinervia (Spreng.) Mohr
*Hedypnois rhagadioloides (L.) F.W. Schmidt
*Lasiopogon muscoides (Desf.)
DC.
*Matricaria aurea (Loefl.) Sch.- Bip.
*Pallaenis heirochuntica (Michon)
Greater *Pulicaria undulata (L.) C.A. May
*Pulicaria vulgaris Gaertn.
Scorzonera syriaca Boiss. & Bl.
*Sonchus oleraceus L. *Zoegea purpurea Fresen.
CONVOLVULACEAE *Convolvulus arvensis L.
*Convolvulus oxyphyllus
ssp.
oxycladus Rech. f. *Sedum hispanicum L. *Umbilicus horizontalis (Guss.) DC.
CUCURBITACEAE *Citrullus colocynthis (L.) Schrader *Cucumis prophetarum var. prophetarum L.
CYNOMORIACEAE
CYPERACEAE Cyperus macrorrhizus Nees
*Scirpoides holoschoenus (L.) Sojak
*Pterocephalus brevis
Coult.
*Scabiosa palaestina L.
EUPHORBIACEAE *Andrachne telephioides L.
*Chrozophora tinctoria (L.) Raf. *Euphorbia chamaepeplus Boiss. & Gail. *Euphorbia granulata var. granulata Forssk. Euphorbia helioscopia L.
*Euphorbia hirta L.
*Phyllanthus maderaspatensis L. |
FRANKENIACEAE
Frankenia revoluta
Forssk.
GENTIANACEAE
GERANIACEAF
*Erodium cicutarium (L,) L'Her
Erodium oxyrhynchum var.
oxyrhynchum M. Bieb. *Geranium rotundifolium L.
Monsonia nivea (Decne.) Decne. ex Webb. IRIDACEAE
*Moraea sisyrinchium
JUNCACEAE
LAMIACEAE / LABIATAE
*Lavandula coronopifolia Poir.
*Mentha longifolia ssp. schimperi
(Briq.) Briq.
LEGUMINOSAE .
*Astragalus atropilosus (Hochst.) Bunge
*Astragalus spinosus (Forssk.) Muschl.
*Trigonella hamosa L.
*Gagea reticulata (Pall.) J.A. & J. H.
Schultes
MALVACEAE
MORACEAE
NEURADACEAE
NITRARIACEAE
NYCTAGINACEAE *Boerhavia repens L.
Commicarpus arabicus Meikle OROBANCHACEAE *Cistanche phelypaea (L.) Cout. *Orobanche cernua var. cernua Loefl.
PAPAVERACEAE
*Papaver decaisnei Hochst. & Steudel.
*Papaver dubium var.
laevigatum (M. Bieb.) Kadereit
PLANTAGINACEAE *Antirrhinum orontium L. Kickxia acerbiana (Boiss.) Tackh. & Boulos *Kickxia aegyptiaca (L.) Nab. *Kickxia pseudoscoparia V.W. Smith *Linaria haelava (Forssk.) Del. *Plantago afra L. Plantago amplexicaulis Cav. *Plantago boissieri Hausskn. & Bornm. *Plantago ciliata Desf. *Plantago coronopus L. Plantago cylindrica Forssk. *Plantago ovata Forssk. Plantago psammophila Agnew & Chalabi-Ka'bi *Veronica anagallis-aquatica ssp. anagallis-aquatica L.
*Limonium lobatum (L.f.) Chaz.
POACEAE /GRAMINEAE
Avena sterilis ssp. sterilis L. *Bromus danthoniae Trin. Bromus fasciculatus Presl. *Bromus sericeus Drobov. *Cenchrus ciliaris L. Cenchrus pennisetiformis Hochst. & Stedudel ex Steudel Centropodia forsskaolii (Vahl) Cope Centropodia fragilis (Guinet & Sauvage) Cope Cutandia memphitica (Sprengel) K. Richter *Cymbopogon commutatus (Steudel) Stapf. *Cynodon dactylon (L.) Pers. Enneapogon desvauxii P. Beauv. *Enneapogon persicus Boiss. *Eragrostis barrelieri Dav. Eragrostis minor Host *Hordeum murinum ssp. glaucum L. *Hordeum spontaneum K. Koch *Hyparrhenia hirta (L.) Stapf *Lamarckia aurea Moench *Oropetium capense Stapf *Oryzopsis holciformis (M. Bieb.) Hack. Pennisetum orientale L.C. Rich *Pennisetum setaceum (Forssk.) Chiov. *Phalaris minor Retz. *Polypogon monspeliensis (L.) Desf. *Rostraria cristata (L.) Tzvelev *Rostraria pumila (Desf.) Tzvelev *Schismus barbatus (L.) Thell. Sorghum halepense (L.) Pers. *Stipa capensis Thunb. Stipagrostis drarii (Tackh. de Wint. Stipagrostis hirtigluma (Steudel. ex Trin.) & Rupr.) de Wint. *Stipagrostis obtusa (Del.) Nees
*Tetrapogon villosus Desf.
*Vulpia sp.
POLYGALACEAE
Polygala schwartziana Paiva
POLYGONACEAE *Emex spinosa (L.) Campd.
*Polygonum argyrocoleum
Steudel ex Kunze *Portulaca oleracea L.
PRIMULACEAE
PTERIDOPHYTES
ACROSTICHACEAE Acrostichum aureum L.
ADIANTACEAE *Adiantum capillus-veneris L. *Cheilanthes coriacea Decne.
*Cheilanthes villea
RESEDACEAE
*Oligomeris linifolia (Vahl) J.F. Macbr. *Ziziphus nummularia (Burm.f.) Wight & Arn.
Ziziphus spina-Christi
var. spina-Christi (L.) Willd. RUTACEAE
Haplophyllum tuberculatum (Forssk.) A. Juss. SANTALACEAE *Thesium humile Vahl
SCROPHULARIACEAE Scrophularia deserti Del. Veronica anagallis-aquatica ssp. anagallis-aquatica L.
*Solanum villosum Mill.
TAMARICACEAE
XANTHORRHOEACEAE Asphodelus refractus Boiss.
Asphodelus viscidulus Boiss.
ZYGOPHYLLACEAE *Fagonia indica Burm f. Fagonia olivieri DC. *Seetzenia lanata (Willd.) Bullock.
Tetraena simplex Zygophyllum propinquum ssp. migahidii (Hadidi) J. Thomas & Chaudh.
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