Vegetation & Biogeography of The Sand Seas Of Arabia

David Watts, Abdulatif H. Al-Nafie, Watts

• Publisher: Routledge
• Year: 2014
• Print ISBN:
  9780710306197
• eBook ISBN:
  9781317847847
• Topic: Social Sciences
• Subtopic: Anthropology
• Index: Social Sciences

First published in 2005. Although most of the wealth of Saudi Arabia's flora lies in the wetter and hilly south-west of the country, the sand seas are covered by a relatively diverse range of plant species, with several distinctive plant communities. This is the first book to consider and analyse, both quantitatively and qualitatively, the patterns, nature, and communities of the vegetation of the sand seas, using new techniques. The result is a sound, complete and readable analysis of the vegetation of the sand seas, and one which will be of particular use to biogeographers, ecologists, environmental scientists, planners, conservationists, and those interested in the preservation of Saudi Arabia's natural heritage.

CHAPTER 1

PRELUDE

Saudi Arabia extends over an area of 2,200,518 km², or about 68.5% of the Arabian peninsula. This huge mass of land makes it the tenth largest country of the world in terms of area, covering about 1.47% of the earth's land surface, and about 5% of the Asian continent. It is nearly half the size of Europe. Saudi Arabia extends over 16 degrees of latitude, from 32 15 at the Jordanian frontier in the north to 16 30 at the border of Yemen; and between 34 E and 56 E longitude (Fig. 1.1).

Within this area, sand seas, which may be defined as extensive areas of now largely-stable sand, cover about one third of the interior, constituting one of its most prominent physical features. From north to south, they are named 1) The Great Nafud; 2) Ad Dahna; 3) a group of sand dune bodies that extend along the western side of the Tuwayq escarpment; and 4) Ar Rub' Al Khali (the Empty Quarter), including Nafud Al Jafurah. Of these Ar Rub'Al Khali is by far the largest, extending over 640,000 km², or an area 2.62 times the size of the United Kingdom, and just a little larger than France. The Great Nafud, or An Nafud, is the second largest body of sand, covering about 62,884 km . These two sand bodies are connected by the Ad Dahna sand belts, which extend approximately 1,425 kms from southeast of An Nafud to the northern areas of Ar Rub'Al Khali. These sand seas, and others that are interspersed within the interior part of the Arabian peninsula, have within them a complex variety of dune forms, including traverse, longitudinal, star and red sand mountains, some of which reach heights of 300m above the general land surface.

The Arabian peninsula, and the sand seas within it, have been largely overlooked and neglected by both biogeographers and plant geographers, though it is a very significant region for both. Its importance is the consequence of its location at the meeting point of three continents and two major plant geographic regions. Yet Saudi Arabia in particular has all too frequently been regarded by both non-professionals and many scientists as a ‘lifeless’ environment, even though Miller & Nyberg (1991) have recently reported 2030 plant species as being present in the country.

This inherent contradiction appears to have been derived in part at least from the great classic desert travel narratives of the nineteenth century and the first half of the twentieth century, some of which described the sand seas as being inhospitable to all forms of life and completely vegetationless. A clear example may be taken from Palgrave's (1871) description of An Nafud, which he passed through during his travels in central and eastern Asia in the summer of 1862:

‘Much had we heard of (this) from Bedouins and countrymen, so that we had made up our minds to something very terrible and impracticable. But the reality, especially in these dog-days, proved worse than aught heard or imagined. We were now traversing an immense ocean of loose reddish sand, unlimited to the eye, and heaped up in enormous ridges running parallel to each other from north to south, undulation after undulation, each swell two or three hundred feet in average height, with slant sides and rounded crests furrowed in every direction by the capricious gales of the desert. In the depths between, the traveller finds himself as it were imprisoned in a suffocating sand pit, hemmed in by burning walls on every side; whilst at other times, while labouring up the slope, he overlooks what seems a vast sea of fire, swelling under a heavy monsoon wind, and ruffled by a cross-blast into little red-hot waves. Neither shelter nor rest for eye or limb amid torrents of light and heat poured from above on an answering glare reflected below.’

Such descriptions, taken during the extremely hot summer months, helped to establish a stereotypical view of the sand seas, and discouraged individuals from making even short visits to their margins, let alone penetrating deep into them to conduct more detailed investigations. But at other times of the year, it is clear that visitors to the sand seas did not experience such extreme conditions. Thus Lady Anne Blunt (1968), who also visited An Nafud, but during the winter season (January, 1879), provided a much more favourable view, and a visual image which is very similar to the impression of this particular sand sea as it appears today, for the person who has never seen sand seas of such magnitude:

‘At half past three o'clock, we saw a red streak on the horizon before us, which rose and gathered as we approached it, stretching out east and west in an unbroken line. It might at first have been taken for an effect of mirage, but on coming nearer we found it broken into billows, and but for its red colour not unlike a stormy sea seen from the shore, for it rose up, as the sea seems to rise, when the waves are high, above the level of the land. Somebody called out ‘the Nafud’, and though for a while we were incredulous, we were soon convinced. What surprised us was its colour, that of rhubarb and magnesia, nothing at all like the sand we had hitherto seen, and nothing at all like what we had expected. Yet the Nafud it was, the great red desert of central Arabia. In a few minutes we had cantered up to it, and our mares were standing with their feet in its first waves.

January 13 - We have been all day in the Nafud, which is interesting beyond our hopes, and charming into the bargain. It is, moreover, quite unlike the description I remember to have read of it by Mr Palgrave, which affects one as a nightmare of impossible horror. It is true he passed it in summer, and we are now in mid-winter, but the physical features can not much be changed by the change of seasons, and I cannot understand how he overlooked its main characteristics. The thing that strikes one first about the Nafud is its colour. It is not white like the sand-dunes we passed yesterday, nor yellow as the sand in parts of the Egyptian desert, but a really bright red, almost crimson in the morning when it is wet with the dew. The sand is rather coarse, but absolutely pure, without admixture of any foreign substance, pebble, grit or earth, and exactly the same in tint and texture everywhere. It is, however, a great mistake to suppose it barren. The Nafud, on the contrary, is better wooded and richer in pasture than any part of the desert we have passed since leaving Damascus. It is tufted all over with Ghada (Haloxylon persicum) bushes, and bushes of another kind called Yarta (Arta -Calligonum comosum), which at this time of the year when there are no leaves, is exactly like a thick, matted vine … Wilfred says that the Nafud has solved for him at last the mystery of horse breeding in Central Arabia. In the hard desert there is nothing a horse can eat, but here there is plenty. The Nafud accounts for everything. Instead of being the terrible place it has been described by the few travellers who have seen it, it is in reality the home of the Bedouins during the greater part of the year.’

The relative richness of the flora of the sand-seas for grazing, especially in northern Saudi Arabia, has also been commented on by several other travellers. Y. Al-Hamawe (1178–1228 A.D.) described Ad Dahna in his geographical dictionary, Mu'agam al Buldan, as being ‘one of the best and richest pasture grounds in the world, sufficient in good years for all Arab nomads’ (Al-Hamawe, 1955). G.A. Wallin (Professor of Arabic in the University of Helsingfors, Finland) visited in 1845, and described the vegetation of An Nafud as being ‘one of the richest pasture-grounds in Arabia, but for want of wells and sources, it can only be visited by the nomads during the spring, when the rain gathers in ponds and pools’ (Wallin, 1848). Somewhat later, J.A. Philips (1882) summarised the descriptions of his contemporary travellers of the vegetation of An Nafud as follows: ‘Although the Nafud has been described as a totally barren waste, recent travellers state that it is everywhere, excepting on the highest summits of the sand hills, thickly sprinkled with brushwood, garda trees, and tufts of grass, the ‘fulijes’ being especially well clothed with vegetation.’

During the first decade of the twentieth century, J. Lorimer rated the desert vegetation of the Nafud very positively: ‘There is abundant desert vegetation and, but for the absence of watering places, the Nafud would be permanently inhabited. The grazing is excellent, and when the winter rains have made a sojourn possible the surrounding Bedouins repair to the Nafud with their flocks and herds. North of ‘Alam-an-Nafud’ (the middle of the Nafud) the principal plant is the Ghada (Haloxylon persicum) which yields good firewood and charcoal; south of that point it is the Arta (Calligonum comosum) which when leafless resembles a thickly matted vine. The commonest plant however is Ader (Artemesia monosperma) with stiff green leaves and brownish-yellow flowers: there are also Nasi (Stipagrostis plumosa), a good kind of camel grass, and Hamrah (Sakhbar -Cymbopogon commutatus), a blue, prickly plant that is excellent forage for horses’ (Lorimer, 1970).

In the winter of 1909, A. Musil (Professor of Oriental Studies at Charles University, Prague) travelled through the northern parts of the Arabian peninsula. Although the motive of his journey was historical, he collected some plant species from the northern part of the Arabian peninsula which he visited, and gave some accounts of the vegetation: ‘the elliptical hollows surrounded by the dunes are called ka'ar. Each of these hollows is deepest at the western end of the ellipse, where it forms a huge funnel-like pit, that is called farse. Between the hollows, or ka'ar, are larger or smaller low sandy flats called nawazi. In these, as in the hollows, raza (Ghada - Haloxylon persicum), arta (Calligonum comosum), sobot (Sabat - Stipagrostis drarii), kasba (Qasba - Centropodia forsskalii or fragilis), ader (Ather - Artemisia monosperma), tubejz (Khubbayz-Malva parviflora) and tarba (Turbah - Silene villosa) grow, and in spots even arfeg (A'rfaj - Rhanterium epapposum), alka (A'lqa - Scrophularia hypericifolia) and hamat (Molthiopsis ciliata), of which camels are especially fond’ (Musil, 1927). From this trip, he also noted the striking coloration of many of the plants, which give An Nafud much of its distinctiveness: ‘the dry plants of the Nafud are of various colours: dry hamat is like silver, nasi (Stipagrostis plumosa) and sobot yellow like straw, arta is ashy, ader dark green and almost black, raza brightly white, with its new young sprouts yellow with a greenish tinge’. In winter 1915, Musil carried out a further expedition to north Nadj and the southern fringes of An Nafud. He noted that ‘tree-like raza plants cover the whole of the An Nafud desert’, and that ‘fresh grasses were springing up all around us, and the perennials arta, hamat and ader were fresh. Old withered ader is called slejg. The Nafud is all overgrown with perennials and annuals, very few tracts being completely bare’ (Musil, 1928).

Between Musil's two trips, Captain G. E. Leachman of the Royal Sussex Regiment made a journey in spring 1911 to north and east Arabia. He described An Nafud as having ‘a great attraction for the Bedouins, especially in the spring months, when it provides grazing far superior to any other district, and even in summer it provides dry grass for the camels. This year, owing to exceptional rains, the Nafud was covered with grass and weeds growing to a height of at least a foot, while many forms of flowers, such as dandelions and daisies, gave it a bright appearance. A bush known as arfui (A'rafja- Rhanterium epapposum), much appreciated by camels, is very common, and also a tree called ‘sider’, a species of Acacia, growing to a height of six feet or more and considered the best wood for fuel in Arabia’ (Leachman, 1911).

D. Carruthers, a naturalist, in his quest for the orxy explained why the Nafud was a suitable habitat for this species: ‘Once on the dunes, I realised the secret of the oryx's chosen haunt. Here was food in plenty, besides a safe retreat. There was a tall, yellow grass like hay (Stipagrostis drarii) (in fact the Bedouin cut and store it) and a heavy growth of tamarisk. There was the ghada, which grew into great spreading bushes above the sand, and extended its roots an incredible distance below it in search of moisture. Where the sand had been blown away, and the roots were left exposed, they straggled for fifteen yards or more over the surface. The Nafud was evidently neither rainless nor without vegetation, and therefore was not a moving sand mass, except in a minor degree. That the great dunes and their corresponding hollows were stationary was proved by the vegetation upon them, and also by the fact that recognised camping grounds and ancient wells have existed in certain localities for ages. The Nafud is considered by the nomads to be a veritable paradise during the spring months, when the pastures are full of nourishment’ (Carruthers, 1935).

Although very useful in terms of their description of the appearance of the Arabian sand seas and of some of the species which occur on them, it must be admitted that there are some deficiencies in these accounts in respect of their usefulness for an analysis of their vegetation. Indeed, a review of the vegetation was not the prime reason for any of these journeys. Further, the information provided by these travellers about the vegetation is scattered throughout their narratives, and requires a great effort to be traced and compiled. Also, those species which are listed are identified by their Arabian names, which is not particularly useful for non-Arabic speakers. However, Musil (1927, 1928) provided many Latin equivalents, as well as giving very brief characterisations of the Arabian botanical terms that appear in these works.

In summary, one may say that most of the information which these reports provide is inadequate for scientific analysis except in limited areas, such as those especially close to sand dune fringes along the desert tracks: interior parts of the and seas were not accessible, and so were not described. With the exception of Musil's descriptions, most travellers also limited their observations to the large perennial species that are useful for firewood, or species which are useful for forage. Some reports are conflicting: this is no doubt due to the season of the visit, summer or winter, or to the different tracks that people followed. There is also the problem that since most visitors to the sand seas during the 19th century had of necessity to travel in disguise due to local hostilities (see Mrs Blunt, 1968); circumstances were unfavourable for detailed geographical observation. Those who travelled during summer time, such as Palgrave, further must have journeyed most of the time at night, and so did not have the opportunity to see much of the desert vegetation and its features.

The modern, scientific literature of the sand seas of Saudi Arabia is also quite scarce, and is summarised below.

In his capacity as locust officer, D. Vesey-Fitzgerald produced several papers of an introductory nature on the vegetation of Saudi Arabia. One (1957) is especially concerned with the vegetation of the central and eastern parts of the Arabian peninsula, mostly north of the tropics, which covers a large part of the northern sand seas. Broadly speaking, he suggested that the vegetation of the sand seas was characterised by a few perennial species and a wealth of annuals, this being based on observations from five different locations in the Great Nafud (An Nafud) and Ad Dahna. The dominant perennial vegetation species of the deep sand which he described were Calligonum comosum, Artemesia monosperma, Monsonia nivea and Scrophularia hypericifolia. Haloxylon as a common genus is not mentioned. Additionally, a variety of patchy annual mesophytic herbs and grasses grew on the sand during the winter season, especially in sheltered hollows and depressions, as well as along the sand dune footings and margins, where some moisture is available.

In a further report on locust habitats in the Arabian Peninsula, G. Popov and W. Zeller (1963) categorised the central and eastern parts of the peninsula as being sub-desert vegetation, as follows: ‘Sub-desert vegetation develops in the areas receiving less than about 100 mm of rainfall, over most of the Arabian peninsula, notably on the plains and the sands of the Nejd (Najd) and the Hassa (Al Hassa) and the drier hills of Hijaz (Al Hijaz). In central and eastern Arabia, much of the sub-desert vegetation is halophytic, especially on the plains, where such gen...

Table of contents

• Cover
• Half Title
• Title Page
• Copyright Page
• Foreword and Acknowledgements
• Dedication
• Table of Contents
• 1. Prelude
• 2. The Environment
• 3. Palaeoenvironments, Vegetation History, the Development of the Sand Seas and Biogeographic Affinities
• 4. Flora of the Sand Seas
• 5. Plant Communities of the Sand Seas
• 6. Human Uses of the Sand Seas and their Vegetation
• 7. Conclusions
• Plates
• Figures
• Tables
• Index of Plant Names
• References