Journal of Global Biosciences ISSN 2320-1355 Volume 5, Number 1, 2016, pp. 3591-3603 Website: www.mutagens.co.in E-mail: [email protected] [email protected] Research Paper LIFE- FORM AND GEOGRAPHICAL DISTRIBUTION OF IN ALONG ALTITUDINAL GRADIENT IN SOUTH- WEST SAUDI ARABIA

A.A. Salman

Botany Department, Faculty of Science, Port Said University, Port Said, Egypt Now, Biology Department, Faculty of Science, Jazan University, Saudi Arabia .

Abstract A study was conducted to identify species, diversity, life form and relevant species to Red sea climate. Study sites were positioned along a transect from the Red Sea coast and extending eastward to Baysh town, then northward along Abha–Jizan road to El’ Darb town, extending eastward through the mountains to Abha City and northward from Abha to El Sodah town and its surrounding area. Jazan region located in the southwestern part of Saudi Arabia (lat. 16 ° 54' N & long. 42 ° 33' E). The vegetation analysis of along an altitudinal gradient in south-west Saudi Arabia has disclosed some generalities in vegetation characters and species diversity. The complex interaction of different environmental factors in relation to altitude leads to variation of habitat types and different plant communities and vegetation belts. Vegetation along the altitudinal gradient showed three zones. At low altitude (0–500 m a.s.l.), the Tihamah coastal marshes, plains and foothills have discrete plant communities on dis- continuous substrates and habitat types. At high altitude (up to 2500 m), the Asir highlands have discrete communities determined by topographic form (slopes, ridges and crests). The intermediate altitudes (500 –2500 m) have continuous plant communities. Vegetation in the intermediate altitudinal belt attains the highest species richness and diversity with relatively high evenness. Analysis data involved two steps: classification (using TWINSPAN) and ordination ( using CANOCO).The studied area is under the influence of two floristic regions: The Sudano- Zambesian (especially Afroriental and South Arabian Domain) and Irano- Turanian region, with extension to Mediterranean (mainly Eastern Medi- terranean) and Saharo-Sindian region ( Middle and Western). The results of this study confirm that the study area is a subtropical desert and belongs floristically to the Sudanian territory and also that therophytes are the most frequent life-form in this region. Key words: Life- form; geographical distribution; altitudinal gradient; Saudi Arabia.

INTRODUCTION The southwestern region of Saudi Arabia is unique in regard to its nature, landform, climate and water availability [1]. Several ecological studies have been done in some of the phytogeographical regions of Saudi Arabia [2], [3], [4], [5], [6], [7], [8], [9], [10], [11]). Most of Journal of Global Biosciences Vol. 5(1), 2016 pp. 3591-3603 ISSN 2320-1355 these studies were based on qualitative field observations and interpretation of the authors. The Sarawat and Asir highlands constitute a major part of south-western Saudi Arabia, and have a temperate climate at elevations above 2000 m a.s.l. On the other hand, the Tihamah coastal plains located to the west of the mountain chain at elevations ranging between 0 to c. 500 m are characterized by arid environments. The transition between these two ecologically distinct areas has a complicated topography with different exposures, slopes, valleys, and sharp and flat peaks. These variations in elevation and topography have resulted in distinctive vegetational zones along the altitudinal gradient from sea level to the highest peak c. 3000 m. [12]discussed vegetation, species diversity and floristic relations in south- western Saudi Arabia and demonstrated remarkable change with altitude. [13], [11]. The study area divided vegetation into six parts according to geographical zones and types of tree species [14]. Plant species and individuals can be grouped into different life-form classes based on structural and functional similarities [15]. A plant life form is usually understood as a growth form that displays an obvious relationship to key environmental factors [15]. For example, mean annual temperature or annual rainfall and altitudinal gradient [16]can be viewed as strategies for obtaining resources [17]Iranian west and west-south forests, Iranian central flat forest and south forest of Iran (Khalig-Omani sub region). Iranian south forests (Khalig-Omani sub region) belong to vegetation zone of Sahara-Sindianan. This zone has subtropical climate and temperate winter. Annual rainfall is 150 to 300 mm and most is in winter [18]. The soil of the most areas in the zone is limy [14]. Investigated area is lo- cated at khonj forests with dominant species, Zizphus spina Christi that is considered as indicator of Khalig-Omani sub region [19]. According to results from [20], the study of plant life-forms is important for the following reasons: plant life-forms provide the basic structural components of vegetation stands and are the most obvious levels of subdivision for describing and explaining vegetation structure. Plant species and individuals can be grouped into different life-form classes based on structural and functional similarities [15]. A plant life form is usually un- The south-western territory of the Arabian peninsula is interesting from a floristic and phytogeographic point of view because of its relation to the neighboring regions of Africa and Asia [21], [22] ; [23] ; [24] ; [25] ; [26] ; [27] ; [28], [29], and [11]. However, the rugged topography and inaccessibility of the mountainous escarpment of this region have resulted in a paucity of studies on plant ecology and no complete survey of the flora. Previous studies on vegetation of Asir are fragmentary and rely on qualitative description of the vegetation [2]; [29]; [30]; [31]; [32]. While the vascular flora of Saudi Arabia is now becoming better known, its vegetation has been very little studied. In our previous publication [33], [11],the distribution of plant communities on the Tihamah coastal plains in relation to soil properties was discussed. The aim of this paper is to examine the spatial pattern of floristic composition at species and to clarify the correlation between plant distribution and altitude factors in south –western , Saudi Arabia. The present study focuses on the altitudinal zonation, community types and species diversity of the vegetation starting from sea level of the Tihamah plains to an elevation of c. 3000 m a.s.l. on the western slopes of the Asir highlands

MATERIALS AND METHODS Study area The study region located in the southwestern part of Saudi Arabia (lat. 16 ° 54' N & long. 42 ° 33' E). The research area is on start from coastal plains of Jazan region at the sea surface level to Abha (up to 2000 m. above sea level). The current study was performed south-western, Saudi Arabia Fig. 1 a .The transect area was nearly more than 300 k.m. The study period was for one year (March 2012 to March 2013). The altitude in this region varies from 0 m. to 3000 m. above sea level Study sites were positioned along a transect from the Red Sea coast and extending eastward to Baysh town, then northward along Abha–Jizan road to El’ Darb town, extending eastward through the mountains to Abha City and northward from Abha to El Sodah town and its surrounding area (Fig. 1b). Six altitudinal belts were recognized: 0–1, 1– 100, 100–500, 500–2000, 2000 –2500, and > 2500 m a.s.l. Altitudes were determined from http://mutagens.co.in 3592 Journal of Global Biosciences Vol. 5(1), 201 6 pp. 3591-3603 ISSN 2320-1355 altimeter readings adjusted for regular daily fluctuations of temperature and pressure in the area. The environmental setting of the study area is reported in [30], [33], [29]and [11]. General ly, the climate varies from dry and hot in the Tihamah plains to wet and cold and often foggy at high altitudes. The coastal belt is very hot and dry all year round with mean annual temperature 30·2°C and mean annual rainfall of 26·7 mm. Most rainfall is e xpected during winter and spring. Above 2000 m elevation, the mean annual temperature drops to 16·8°C and the average annual rainfall increases to 655·2 mm

(a)

(b) Fig.(1):- showing (a) Saudi Arabia (b) showing location of the study area A total of forty-three stands in 15 sampling sites (Fig. 1b) were located to cover the altitudinal gradient along the transect. The sampling quadrates (10 × 10 m2) were placed about 300 m away from the motorable road to eliminate any disturbance which may have bee n caused to the vegetation. Sampling sites were selected, representing the most common habitats and herbaceous communities in the data as described by [34], [35], [12], and [36]. Soil samples measured and described by [34], [12], [36]and [11]. Sampling sit es in the mountainous escarpment were all selected towards the west or south -west exposure(Fig.2), while in Tihamah plains, because of the gentle elevation gradient, the sampling sites were nearly level. During March 2012 to March 2013, for every sampling site, a floristic list and count were taken from 10 quadrates from which the mean relative density and relative frequency of the perennial species were calculated as the fraction of sample quadrates containing the species. Plant canopy cover as percentage of ground surface was determined by the line intercept method [15]. Five line intercept transects, randomly placed within every quadrate, oriented east–west, were studied. The sum of the relative density, relative frequency and relative cover gave the impo rtance value [37] for different species as following: Density = (number of individuals/area sampled) Relative density = (density for a species)/ (total density for all species) × 100 Frequency = (number of sampled quadrates in which species occurs)/ (t otal number of

http://mutagens.co.in 3593 Journal of Global Biosciences Vol. 5(1), 201 6 pp. 3591-3603 ISSN 2320-1355 quadrates sampled) Relative frequency = (frequency value for a species)/ (total of frequency values for all species) × 100 Cover = (total of intercept lengths for a species)/ (total transect length) × 100 Relative cover = (total of intercept lengths for a species)/ (total of intercept lengths for all species) × 100 Importance value = relative density + relative frequency + relative cover

Classification and ordination of the stands were carried out by multivariate analysis (cf. [33], and [11] . The TWINSPAN [38] technique was applied for classification using the importance value of the species. The DECORANA technique [39] was applied to demonstrate two - dimensional ordination of the plots. Species diversity and evenness [37] were determined in the different altitudinal belts. The Shannon - Wiener index (H') was calculated from the following formula:

Where s = number of species, and pi = proportion of individual also per species in the community made up of s species with known proportion ions p1, p2, p3, ps. The Shannon - evenness index (E1 = H'/ln s) was applied to quantify the evenness component of diversity. Floristic identification is according to [40], [41], [42], [43] and [44], [45], [46]. A detailed list of the recorded species in this s tudy is found in [29] . The phytogeographical treatment of the species’ floristic elements followed [29]. Species identification followed [47],[29].and [11].

A D

B E

http://mutagens.co.in 3594 Journal of Global Biosciences Vol. 5(1), 201 6 pp. 3591-3603 ISSN 2320-1355

C

Fig.2:(A,B,C,D and E) showing the different altitudinal belts and the sampling

RESULTS species and life-forms spectrum Life- form and geographical distribution of plants in along altitudinal gradient in south - west Saudi Arabia the study area by TWINSPAN were recognized into Six vegetational groups(Fig. 3), from the 43 stands sampled along the altitudinal gradient. Each group represents a vegetation zone. Plant species distribut ion overlap in the transitional zones at the differe nt altitudinal belts as shown in Table 1 and in the DCA ordination (Fig.4). The six vegetation zones and their altitudinal ranges are reviewed below. Group A Only Avicennia marina (Forssk.) Vierh. and Aeluropus lagopoides (L.). Trin. ex Thw. are present in the narrow coastal marshes of the Baysh area. Avicennia marina occupies the intertidal mangrove habitats, while A. lagopoides is found in the littoral salt marshes.

Group B Vegetation types in this group occur over 1 –100 m a.s.l. and to the west of Baysh town. Sand form ation habitat types constitute the major landform in this elevational range. The defining plant species of the salt-affected sandy flats near the coastal marshes are Aeluropus lagopoides, Cyperus conglomeratus Rottb. and Fagonia bruguieri DC . Common speci es on the sandy plains are Acacia tortilis (Forssk.) Hayne subsp. raddiana (Savi) Brenan and subsp. tortilis, Dipterygium glaucum Decne., Leptadenia pyrotechnica (Forssk.) Decne. and Tephrosia purpurea subsp. apollinea ( Delile) H. Hosni & El Karemy. The c oastal and inland sand dunes and hills are occupied by Cadaba rotundifolia Forssk., Cissus quadrangularis L., Panicum turgidum Forssk. and Lasiurus scindicus Henrard Group C This group occurs from c. 100 to 500 m a.s.l. in an area extending from the west o f Baysh to Al’Darb town. A characteristic feature of the habitat types in this altitudinal belt are wadis and water runnels. The landscape is characterized by gentle gradients. The plains are covered by coarse sand and stone fragments and are known as grav el desert. These plains are interrupted by depressions that receive runoff water, and windblown and waterborne fine materials. Several vegetation types were recognized in the various habitats of this altitudinal belt. The wadis and water runnels are occupi ed by plant communities defined by Acacia tortilis subsp. raddiana and subsp. tortilis , A. ehrenbergiana Hayne, Hyphaene thebaica (L.) Mart., Calotropis procera Aiton, Jatropha pelargoniifolia Courbon, Triumfetta rhomboidea Jacq. and Ziziphus spina-christi (L.) Desf. On the gravel plains, the important species are Acacia tortilis subsp. tortilis , A. asak (Forssk.) Willd., Indigofera spinosa Forssk., Caralluma penicillata ( Defl.) N. E. Br., Lasiurus scindicus and Leptadenia pyrotechnica . The depressions

http://mutagens.co.in 3595 Journal of Global Biosciences Vol. 5(1), 2016 pp. 3591-3603 ISSN 2320-1355 harbour denser vegetation than the surrounding gravel habitats. The important species vary among the different depressions depending on the water regime and soil characteristics. Among the common species here are Acacia sp., Dipterygium glaucum, Fagonia schweinfurthia Hadidi, Heliotropium arbainense Fresen., Leptadenia heterophylla Decne, Tephrosia purpurea , Farsetia longisiliqua Decne. and Panicum turgidum . Group D Vegetation types in this group occur from 50 to c. 2000 m a.s.l. The landscape here is mountainous. The bedrock is exposed on most slopes and fine soil material is confined to pockets and crevices or among outcrops. Flat and protected sites are covered with mixtur es of rock fragments, varying in size, and loose gravel forms the soil substrate. The distribut ion of vegetation types seems to be influenced by the topographic variation. Plant communities on the rocky slopes are defined by Acacia tortilis subsp. raddiana , A. asak, A. etbaica Schweinf . subsp. etbaica, Barleria acanthoides Vahl, Cocculus pendulus (J. R. & G. Forst.) Diels, Dobera glabra (Forssk.) Juss. ex Poir., Hyparrhenia hirta (L.) Stapf, Pupalia lappacea (L.) Juss. and Triumfetta rhomboidea , where plants root in rock crevices. The common species among the rocky outcrops are Abutilon fruticosum Guill . & Perr., Acacia tortilis subsp. tortilis, Boerhavia diffusa L., Dactyloctenium scindicum Boiss., Lindenbergia sinaica ( Decn e.) Benth. and Forsskaolea tenacissima L. In the protected sites with loose gravel soils common plants are Anisotes trisulcus , Capparis spinosa L., Commicarpus helenae (Roem. & Schult.) Meikle, Euphorbia triaculeata Forssk., Fagonia schweinfurthia , Ficus cordata Thunb. subsp. salicifolia (Vahl) C. C. Berg, Reseda sphenocleoides Defl. and Ziziphus spina-christi . Group E This altitudinal belt (c. 2000 –2500 m a.s.l.) lies within the Asir and Sarawat highlands which forms a major part of the south-western region. On dry sites, plant communities are defined by Hyparrhenia hirta, Pennisetum setaceum (Forssk.) Chiov., Onopordon ambiguum Fresen., Lycium shawii Roem. & Schult., Echinops spinosus L., Acacia etbaica and A. asak. In sites where the soil is more developed among outcrops, shrubb y vegetation prevails with Commicarpus helenae , C. plumbagineus (Cav.) Standl., Dodonoea viscosa (L.) Jacq., Lavandula citriodora A. G. Miller, Ochradenus baccatus Delile and Rumex nervosus Vahl. Plant communities with A. Rich., Acacia negrill Forssk., Lavandula dentata L., arabicus Steud. and Astragalus atropilosulus subsp. abyssinicus ( Hochst.) J. B. Gillett are established on the slopes and protected crests. Species which tend to constitute the vegetation on moist substrates are Ficus palmata Forssk., F. cordata subsp. salicifolia , Lavandula dentata L., L. citriodroa , Osteospermum vaillantii ( Decne.) T. Norl., Solanum incanum L., S. sepicula Dun. and Withania somnifera (L.) Dun. Group F Vegetation in this group is distribut ed around and above 2500 m a.s.l. The boulder- strewn wet slopes, ridges and crests are densely covered by Juniperus procera , which may form pure stands usually festooned with the lichen . The shrubb y Clutia myricoides Jaub. & Spach, Euryops arabicus , Lavandula dentata , Conyza incana Willd. and Asparagus africanus Lam. may form an open understory. On dry slopes are mixed communities of Juniperus procera, Acacia negrii Forssk., Dodonaea viscosa and Rumex nervosus . The common species in sites with more soil among outcrops are Alkanna orientalis (L.) Boiss., Anthemis tigrensis J. Gay ex A. Rich, Nepeta deflersiana Schweinf. ex Hedge, Psiadia arabica Jaub. & Spach, Rosa abyssinica R. Br. and Salix subserrata Willd. On the dry exposed rocky slopes that are subject to severe wind erosion, cushion-plant communities predominate commonly with Argyrolobium confertum Polhill, Cichorium bottae Defl. and Minuartia filifolia (Forssk.) Schweinf. ex Mattf. The associated species here are Clutia myricoides , Euryops arabicus and Telephium sphaerospermum Boiss.

http://mutagens.co.in 3596 Journal of Global Biosciences Vol. 5(1), 2016 pp. 3591-3603 ISSN 2320-1355

Figure 3. Dendrogram of 43 stands representing the study area. Six distinct vegetational groups are produced from the TWINSPAN technique along the differe nt altitudinal belts. A = sea level ( ± 1 m); B = 1–100 m; C = 100–500 m; D = 500–2000 m; E = 2000 –2500 m; F = > 2500 m.a.s.l

Figure 4. Ordination of stands separates the six vegetational groups A, B, C, D, E and F. The first and second axes are derived from the Detrended Correspond ence Analysis ( DCA). Group A was deleted to scatter the other groups.

http://mutagens.co.in 3597 Journal of Global Biosciences Vol. 5(1), 2016 pp. 3591-3603 ISSN 2320-1355

Table 1. Average importance values (IV) (out of 300) of the perennial species in the six vegetational groups resulting from the TWINSPAN technique. Repetition of some species in more than one vegetational group indicates the overlap of species distribution in the transitional zones at different altitudinal belts. Species are arranged in every group in descending order according to the importance value. Species IV Species IV Species IV Species IV Species IV Species IV

Group A* Group B Group C Group D Group E Group F

Avicennia 214 Cadaba 140 Acacia tortilis subsp. 34· Anisotes trisulcus 24 Rumex nervoss 27· Juniperus procera 96·7 marina ·1 rotundifolia ·2 tortilis 7 ·3 5 Aeluropus 85·9 Panicum 34·7 Acacia tortilis subsp. 25· Acacia asak 19 Acacia elbaica 18· Cichorium bottae 32·7 lagopoides turgidum raddiana 7 ·3 1 Cissus 28·9 Dipterygium glaucum 20· Seddera latifolia 17 Hyparrhenia hirta 13· Clutia myricoides 18·8 quadrangularis 5 ·5 2 Cyperus 25·3 Caralluma penicillata 19· Boerhavia diffusa 15 Dodonaea viscosa 12· Minuartia fillifolia 15·9 conglomeratus 7 ·0 8 Acacia tortilis Hyphaene thebaica 17· Abutilon 13 Astragalus Dodonaea viscosa 14·4 4 fruiticosum ·7 absyssinicus subsp. tortilis 23·2 Indigofera spinosa 17· Pupalia lappacea 11 subsp. 12· Euryops arabicus 13·5 4 ·0 atropilosulus 5 Lasiurus 15·6 Panicum turgidum 9·5 Indigofera spinosa 10 Nepeta defiersiana 10· Lavandula dentata 10·9 scindicus ·6 4 Dipterygium 11·1 Leptadenia 9·2 Withania 10 Echinops spinosus 9· Argyrolobium 10·4 glaucum heterophylla somnifera ·5 2 arabicum Leptadenia 9·2 Lasiurus scindicus 8·3 Dobera glabra 9·3 Acacia asak 7· Rumex nervosus 9·8 pyrotechnica 4 Tephrosia Tephrosia purpurea Acacia etbaica 8·7 Acacia negril 7· Conyza incana 9·6 purpurea 2 subsp. 3·6 subsp. apollinea 7·6 Triumfetta 8·2 Lavandula 6· Asparagus africanus 9·3 apolinea rhomboidea citriodora 4 Acacia tortilis Triumfetta rhomboidea 7·6 Lindenbergia 8·1 Solanum incanum 6· Themeda triandra 7·6 sinaica 3 subsp. 3·6 Jatropha pelargoniifolia 6·5 Cocculus pendulus 7·6 Commicarpus 6· Alkanna orientalis 5·5 raddiana helenae 2 Aeluropus 3·2 Leptadenia 6·2 Acacia tortilis Ficus palmata 6· Psiada araboca 5·2 lagopoides pyrotechnica 1 Fagonia bruguieri 3·0 Calotropis procera 5·9 subsp. raddiana 7·5 Lavandula 6· Nepeta defiersiana 4·3 pubescens 1 Ziziphus spina-christi 5·5 Hyparrhenia hirta 7·2 Ficus cordata Rosa abyssinica Fagonia schweinfurthia 4·8 Barteria 6·7 subsp. salicifolia 6· subsp. salicifolia 3·5 acanthoides 0 Aerva javanica 4·8 Heliotropoium Commicarpus Acacia negrii 3·4 Acacia etbaica 4·3 longiflorum 5·4 plumbagineus 5· Salix subserrata 3·2 6 Farsetia longisiliqua 4·1 Ficus cordata Lavandula dentata 4· Telephium 3·0 8 sphaerospermum Acacia asak 3·6 subsp. salicifolia 5·2 Onopordon 4· Anthemis tigrensis < 3 ambiguum 4 Cadaba rotundifolia 3·5 Commicarpus 5·1 Pennisetum 4· Argyrolobium < 3 helenae setaceum 3 confertum Capparis spinosa 3·1 Reseda 4·8 Ochradenus 4· sphenocleoides baccatus 2 Acacia ehrenbergiana 3·0 Capparis spinosa 4·5 Withania somnifera 4· 2 Heliotropium 3·0 Acacia tortilis Osteospermum 4· arbainense vaillantii 1 Acacia hamulosa 3·0 subsp. tortilis 3·9 Clutia myricoides 3· 9 Cissus rotundifolius 3·6 Lycium shawii 3· 6 Fagonia 3·6 Solanum sepicula 3· schweinfurthia 6 Dactyloctenium 3·4 Onopordon 3· scindicum heteracanthum 0 Forsskaolea 3·0 Juniperus procera 3· tenacissima 0 Euphorbia 3·0 Rosa abyssinica 3· triaculeata 0 Ziziphus spina- 3·6 Euryops arabicus < christi 3 *Altitudinal ranges: A = 0–1 m; B = 1–100 m; C = 100–500 m; D = 500–2000 m; E = 2000– 2500 m; F = > 2500

species richness and diversity Vegetation zones along the altitudinal gradient showed interesting differences in species richness (Fig. 5(a). The lowest richness value, an average of 1·67 ± 0·36 species, was recorded in the coastal marshes of vegetation zone A. An increase in richness (average 9·76 ± 2·83) was recorded in the adjacent sand formation vegetation zone B. The richness in the next vegetation zone C increased to 23·92 ± 5·25. The highest species richness of 39·83 ± 6·41 was recorded in vegetation zone D at the altitudinal range from c. 500 to 2000 m a.s.l. This was followed by a decrease in richness at subsequent higher altitudes where

http://mutagens.co.in 3598 Journal of Global Biosciences Vol. 5(1), 2016 pp. 3591-3603 ISSN 2320-1355 values of 27·78 ± 3·56 and 14·11 ± 2·84 were recorded in vegetation zones E and F, respectively. The Shannon diversity index ( H') at the community level in the six vegetation zones is also shown in (Fig. 4(a)) on which H' is high over most of the altitudinal range. The highest values of 3·5 ± 0·81, 3·8 ± 0·63 and 3·9 ± 0·86 were recorded in vegetation zones C, D and E, respectively. The H' values decrease d to 1·8 ± 0·35 in vegetation zone B (1–100 m a.s.l.) and 2·6 ± 0·61 in the altitudinal belt above 2500 m a.s.l. supporting the vegetation zone F. The lowest H' value of 0·6 ± 0·13 was recorded at the lowest altitudinal belt of the vegetation zone A, i.e. coastal marshes. Values of evenness are shown in (Fig. 5(b)) where vegetation zone B (1–100 m) has attained the lowest value of 0·65 ± 0·15, i.e. the least equally abund ant the species and the least equal distribution within the plant communities. The four vegetation zones A, C, D and E have attained relatively high and similar evenness values of 0·86 ± 0·20, 0·83 ± 0.15, 0·87 ± 0·20 and 0·84 ± 0·20, respectively. The vegetation zone F (above 2500 m a.s.l.) demonstrated an intermediate evenness value of 0·72 ± 0·10.

Figure 5. (a) Species richness ( □) and Shannon index (O) and (b) evenness of the six vegetational groups. See legend of Fig. 2 for explanation of groups. Values are means ± S. D. ( N = 3).

Relation between the altitudes Factors and species distribution Results in Table 2 indicate that 31·8% of the studied taxa are uniregional, being native to the Sudano-Zambesian region; of these 5·9% are endemic taxa native to south- western Arabia, and 4·6% are confined to high altitudes (over 2000 m a.s.l.). About 9·1% of the species are of very limited geographical distribut ion, only known from higher altitudes of south-western Arabia and Ethiopia (South Arabian Domain), sometimes penetrating the Jebel Elba massif of Egypt and Sudan (subendemics). Only 4·1% are distribut ed all over the Sudano-Zambesian and 12·6% are confined to the east Sudano-Zambesian (Afroriental and South Arabian Domain). About 67·9% of the recorded species are biregional and pluriregional, extending their distribut ion all over the Sudano-Zambesian, Irano- Turanian, Saharo-Sindian and Mediterranean. The biregional Sudano-Zambesian and Irano- Turanian constitute the highest value (17·4%), while cosmopolitan taxa constitute the lowest value (8·3%). The pluriregional Sudano-Zambesian, Irano- Turanian and Saharo-Sindian constitute 8·1% ofthe total numb er. The same result applies to the biregional East Sudano- Zambesian (Afroriental & South Arabian Domain) and east Mediterra nean (8·5%). It should be noticed that both the endemic and subendemic taxa are confined to higher altitudes over 2000 m a.s.l., while the biregional and These variations may be attributed to the climatic differe nces, substrate discontinuities and mountainous escarpment along the altitude. Alti Phytogeographical region tud Uniregio no.1 Bi- and pluriregiona

http://mutagens.co.in 3599 Journal of Global Biosciences Vol. 5(1), 2016 pp. 3591-3603 ISSN 2320-1355

e Sud.- Sud.- (m (Sud East Sud.- Zamb. Zamb. a.s.l. ano- East Sud.- Zamb. +Ira.- +Ira.- ) Zamb Suda Suda Zamb.+ +Irano Tur.+S Tur.+S Cos esian no- no- East - aharo- ah.- mop Ot Ende parti Zamb Zamb Mediter Turani Sindia Sind.+ Paleo olita her mics ally esian esian ranean an n Medit. tropic n s

1– 500 0·5 1·8 8·7 0·5 3·6 7·8 4·0 6·4 8·5 1·8 2·2 500 – 200 0 0.9 0·5 1·9 2·3 0·9 4·6 1·4 2·0 0·9 0 1·8 >20 00 4.6 6·9 2·1 1·3 4·0 5·0 2·7 5·0 1·8 0·5 3·0 Tot al 6 9·2 12·7 4·1 8·5 17·4 8·1 13·4 11·2 2·3 7·0

DISCUSSION

Life- form and geographical distribution of plants in along altitudinal gradient in south- west Saudi Arabia. demonstrate remarkable change with altitude. The Tihamah plains (about 0– 500 m a.s.l.) includes differe nt habitat types, i.e. coastal marshes, sand formations, gravel plains, depressions, dry wadis and water runnels. These habitat types support discrete plant communities (cf. [33]and [11]. Again, on the Asir highlands (above 2500 m) discontinuous plant communities exist on discrete habitat types. This appears to represent slope and exposure effects at the high elevation. In contrast, the transitional range between 500–2500 m is characterized by continuity in vegetation change from one altitudinal belt to the next, with broad transitional areas and overlap between low and high altitude vegetation. Similar results and observations were described by [25] in Sudan, [2]in Saudi Arabia, [29] in Egypt, [48] in Ethiopia, [30] inSaudi Arabia , [49] in Oman ,and [50], [11].The results show variations in species richness, diversity and evenness among the differe nt altitudinal belts. These variations may be attributed to the climatic differences, substrate discontinuities and mountainous escarpment along the altitude dinal gradient. Most studies on diversity– altitude relationships in other regions [51], [52]., [53]. ; [48]; [54].; [55] ; [49]demonstrated different trends and correlations with altitude. In south-west Saudi Arabia, the plant species diversity attained the highest values at the intermediate elevations, decreasing in the highlands and the low altitudinal belts. The study area is mainly influenced by the Sudano-Zambezian region which is bound ed at the north by the desert and semi-desert of the Saharo-Sindian region while in the south it extends to the desert and semi-desert of the Karroo- Namib region [29] ; the extension of Sudano- Zambezian region into western and southern Arabia has been suggested by [56], and [57]. According to [29], the Saharo-Sindian region extends from the Atlantic coasts of Morocco and Mauritania eastwards to Sinai and extratropical Arabia, south Iraq, Iran, Baluchistan, desert of Sind and the Punjab. The extent of this floristic element in western and southern Arabia has not yet been satisfactorily determined [29] recognized five subregions ( Domains) within the Sudano Zambez- ian region; of these the Afroriental Domain includes

http://mutagens.co.in 3600 Journal of Global Biosciences Vol. 5(1), 2016 pp. 3591-3603 ISSN 2320-1355 lowland Ethiopia, Somalia, and Kenya, and south Arabian Domain which is an extension of the Sudano-Zambesian including parts of Saudi Arabia, Yemen and southern Arabia bordering the coasts of the Red Sea and the Gulf of Aden. At both species, population and community levels, it is difficult to determine which altitudinal properties are most important. Future work should attempt to define environmental constraints on the species distribution recorded here. ACKNOWLEDGMENT The authors are grateful to the helpful comments and suggestions of anonymous reviewers and editors.This work was carried out while Salman, A. A. is working as a teaching staff as assistant teacher in Biology department, Faculty of science, Jazan University, Saudi Arabia. I wish to express my deepest gratitude to Mr. M. A. Nabih an assistant lecture in Faculty of Science, Biology department, Jazan University, Saudi Arabia, field work assistant.

REFERENCES [1]. Abulfatih, H. A. Wild plants of Abha and its surroundings Proceeding of the Saudi Biol. Soc. 1981; 5: 143-159. [2]. Vesey-Fitzgerald, D.F. (1955). Vegetation of the Red Sea coast south of Jedda, Saudi Arabia. Journal of Ecology , 43 : 477–489. [3]. Khodair, A. Ecological studies in Riyadla district. M.Sc. Thesis, Ain Shams University, Egypt. 1963. [4]. Popov, G. & Ziller, W. Ecological Survey Report on the 1962 survey in the Arabian Peninsula, U.N. Special Fund, Desert Locust Project Programme Report (FAO(U'NSF/DC/ES6). 1963; 94 pp. [5]. Batanouny, K. G. Vegetation along the Jeddah-Meccaroad: patteren and process as affected by human impact. J. of Arid Environ. 1979; 2: 21- 30. [6]. EI-Sharkawi, H.M., Fayed, A.A. & Salama F.M. Vegetation of inland desert wadis in Egypt. II. Wadi E1-Matuli and Wadi E1-Qarn. Feddes Reportorium, 1982; 93: 125-133. [7]. Zahran, M. A. Vegetation types of Saudi Arabia. Fac. of Meteoro. And Arid Environ. King Abdul-Aziz Univ. press. Jeddah. 1982; pp. 61. [8]. Batanouny, H. H. & Baeshin, N. A. Plant communities along Medina- Badr road across the Hedjaz mountains,Saudi Arabia. Vegetation. 1983; 53: 33-43 [9]. Younes, H. A., Zahran, M. A. & E1-Qurashy, E.M. Vegetation-Soil relationship of a sea- inlandward transect, Red Sea Coast, Saudi Arabia. J. of Arid Environ. 1983; 6: 349- 356 [10]. Baierle, H. V., El-Sheikh, A. M. & Frey, W. Vegetation and Flora im mittleren Saudi Arabien (AI-Taif-Riyad), Beih. Tubinger Atlas Vorder Orient, Reihe A (Naturwissenschaften), 22: Wiesbaden. 1985. [11]. Salman.A.A.,2015.Correlation between plant distribution and edaphic factors in coastal plains of Jazan region, Saudi Arabia.Journal of Applied Biology & Biotechnology Vol. 3 (03), pp. 042-049. [12]. Hegazy, A.K., El-Demerdash, M.A., and Hosni, H.A. Vegetation, species diversity and floristic relations along an altitudinal gradient in south-west Saudi Arabia. Journal of Arid Environments. 1998; 38: 3- 13 [13] Salman, A. A and Zaghloul,. Usage of Herbal Remedies for the Management of Vaginal Infection among Women in Jazan Area at Saudi Arabia. The Egyption Socity For Enviromental Science. CATRINA), 2012; 7 (1):87-96. [14]. Marvi Mohadger MR. 2005. Silviculture. Tehran: Tehran University Press, p.387. [15]. Mueller- Dombois, D. & Ellenberg, H. (1974). Aims and Methods of Vegetation Analysis. New York: John Wiley & Sons. 547 pp. [16]. Mera G, Hagen MA, Orellana JA. 1999. Aerophyte, a new life form in Raunkiaer’s classification? Journal of Vegetation Science, 10 (1): 65–68. [17].Crosswhite F, Crosswhite C. 1984. A classification of life forms of the Sonoran desert with emphasis on seed plants and their survival strategies. Deser Plants, 5: 131–161 [18]. Mossadegh A. 2005. Silviculture. Tehran: Tehran University Press, p. 481

http://mutagens.co.in 3601 Journal of Global Biosciences Vol. 5(1), 2016 pp. 3591-3603 ISSN 2320-1355

[19].Assareh MH. 2008. Biological characteristics of Christian Thorn Trees in\mIran and description of other Ziziphus species . Iran: Research Institute of Forests and Rangelands, p. 571. [20].Box EU. 1981. Macroclimate and plant forms: an introduction to predictive modeling in phytogeographical. Junk Publ. La Haya, Tasks for Vegetation Science, 1: 1−258 [21].Kassas, M. (1955). The mist oasis of Erkwit, Sudan. Journal of Ecology, 44: 180–194. [22].Kassas, M. (1957). On the ecology of the Red sea coastal land. Journal of Ecology, 45: 187–203. [23].Kassas, M. & Zahran, M.A. (1965). Studies on the ecology of the Red sea coastal land. II — The district from El-Galala El-Qibliya to Hurghada. Bulletin de la Socie´te´ de Ge´ographie d’Egypte, 38: 155–193. [24].Kassas, M. & Girgis, W.A. (1970). Plant life in the Nubian desert east of the Nile, Egypt. Bulletin de l ‘Institute d’ Egypt, 20: 47–71. [25].Mandaville, J.P. (1973). A contribution to the flora of Asir, southwestern Arabia. Field Research Publications, 4: 1–13. [26].Wickens, G.E. (1976). The Flora of Jebel Marra (Sudan Republic) and its Geographical Affinities.Kew Bulletin Additional Series V. London: HM SO. 199 pp. [27].Boulos, L. (1985). A contribution to the flora of the Asir mountains, Saudi Arabia. Arab Gulf Journal of Scientific Research, 3: 67–94. [28].Migahid, A.M. (1988). Flora of Saudi Arabia (3rd Edition). Riyad: King Saud University Press. 3 vols, 683 pp [29].Hosni, H.A. & Hegazy, A.K. (1996). Contribution to the flora of Asir, Saudi Arabia. Candollea,51: 169–202 [30].Brooks, W.H. & Mandil, K.S.D. (1983). Vegetation dynamics in the Asir woodlands of southwestern Saudi Arabia. Journal of Arid Environments, 6: 357–362. [31].Abulfatih, H.A. & Emara, H.A. (1988). Altitudinal distribution of the hemiparasitic Loranthaceae in southwestern Saudi Arabia. Biotropica, 20: 81–83. [32]Abulfatih, H.A., Emara, H.A. & Hashish, A.E. (1989). The influence of grazing on vegetation and soil of Asir highlands in south western Saudi Arabia. Arab Gulf Journal of Scientific Research, 7: 69–78. [33]E1-Demerdash,M.A., A. K. Hegazyt and A. M. Zilay. Vegetation-soil relationships in Tihamah coastal plains of Jazan region, Saudi Arabia.Journal of Arid Environments. 1995; 30:161- 174. [34]. El-Demerdash, M., A. Hegazy and A. Zilay, 1994. Distribution of the plant communities in Tihamah coastal plains of Jazan region, Saudi Arabia. Vegetation, 112: 141-151. [35].Moustafa, A. and J. Klopatek, 1995. Vegetation and Landforms of the St. Katherine area, Southern Sinai, Egypt. Journal of arid Environments, 30: 385-395. [36].Salman, A. A. Ecological studies on vegetation of wadi systems on South Sinai, Egypt, Ph.D. Thesis, Botany Department, Fac. of Sci., Ismailia, Suez Canal University, Egypt, 2004; pp: 188. [37].Ludwig, J.A. & Reynolds, J.F. (1988). Statistical Ecology: a primer on methods and computing. New York: John Wiley & Sons. 337 pp. [38]. Hill, M.O. TWINSPAN–A FORTRAN Programme for Arranging Multivariate Data in an Ordered Two-way Table by Classification of Individuals and Attributes. Cornell University, Ithaca, N.Y., 1979; pp: 90. [39].ter Braak, C.J.F. (1987). CANOCO — A FORTRAN program for canonical community ordination by [partial] [detrended] [canonical] correspondence analysis, principal components analysis and redundancy analysis ( ver. 2.1) . Wageningen: T NO Institute of Applied Computer Science. [40].Tackholm, V. Students Flora of Egypt. 2 "d ed., Cairo Univ. Press. 1974; pp. 888. [41]. Migahid, A. M. Flora of Saudi Arabia. 3nd ed. Vol. 1 and 2, King Saud Univ. Press. 1989. [42].Batanouny, K. G. Ecology and Flora of Qatar. Centre for Sci. and Applied Res. Univ. of Qatar, Alden press, Ltd. Oxford. 1981; pp 239

http://mutagens.co.in 3602 Journal of Global Biosciences Vol. 5(1), 2016 pp. 3591-3603 ISSN 2320-1355

[43].AI-Hubaishi, A. & Hohenstein, K. M. An Introduction to the Vegetation of Yemen. Ecological Basis, Floristic Composition and Human Influence. Deutsche Gesellschaftftlr Technische Zusammenarbeit (GTZ) GmbH. 1984; pp 209. [44].Mandaville, J. P. Flora of Eastern Saudi Arabia. Kegan Paul International Ltd. London and New York, 1990; pp 482 [45].Boulos,L. Flora of Egypt: volume four (Alismataceae- Orchidaceae). Al-Hadara publishing, Cairo, Egypt, 2005; pp:617 [46]. Boulos,L. Flora of Egypt: (Chacklist revised annotated Ed.). Al- Hadara publishing, Cairo, Egypt, 2009; pp:410 [47].Boulos, L. (1995). Flora of Egypt Checklist . Cairo: Al Hadara Pub lishing. 287 pp. [48].Beals, E.W. (1969). Vegetational change along altitudinal gradients. Science , 165 : 981– 985. [49].Ghazanfar, S.A. (1991). Vegetation structure and phytogeography of Jabal Shams, an arid mountain in Oman. Journal of Biogeography , 28 : 299–309. [50].Salman.A.A., Zaghloul M.S. and Moustafa A,A, Conservation and Productivity of Two Threatened Species Nepeta septemcrenata and O riganum syriacum subsp. Sinaicum in Saint Catherine Protectorate, South Sinai, Egypt.. Assiut Univ. J. of Botany 2010 , 39(1), P- P.81-99. [51].Whittaker, R. H. (1965). Dominance and diversity in land plant communities. Science , 147 : 250–260. [52].Whittaker, R. H. (1970). Communities and Ecosystems . New York: McMillan. 385 pp. [53].Whittaker, R. H. (1977). Evolution of species diversity in land communities. Evolutionary Biology , 10 : 1–67 [54].Moral, R. del (1972). Diversity patterns in forest vegetation of the Wenatchee mountains, Washington. Torrey Botanical Club Bulletin , 99 : 57–64. [55].Hamilton, A.C. & Perro tt, R.A. (1981). A study of altitudinal zonation in the montane forest belt of Mt. Elgon, Kenya/Uganda. Vegetatio , 54 : 107–125. [56]. White, F. & Le´ onard, J. (1991). Phytogeographical links between Africa and south- west Asia. Flora et Vegetatio Mundi , 9: 229–246. [57].Salman.A.A,, Moustafa., A.A., Zaghloul., M.S and Raafat.,H. . Age structure of Ficus benghalensis L.: a Threatened Introduced Population in Ismailia, Egypt. Life Science Journal 2014;11(11):90-97

http://mutagens.co.in 3603