Article scientifique
Sécheresse 2006 ; 17 (1-2) : 179-94
The rangelands of the Arabian Peninsula
Shaukat A. Chaudhary1
Henry Noël Le Houérou2
Copyright © 2017 John Libbey Eurotext. Téléchargé par un robot venant de 88.99.165.207 le 15/06/2017.
1
82 Coronation Road,
Baulkam Hills,
NSW 2153
Australia
<[email protected]>
<[email protected]>
2
327, rue A.L. De Jussieu,
34090 Montpellier
<[email protected]>
Abstract
The Arabian peninsula covers an area of some 3 million km2, to a large part desertic
traversed by nomadic pastoralists, now settled or on their way to settling. Elevation
varies from sea level to nearly 3,800 m asl in North Yemen. In spite of the overall
aridity and high temperatures, climates are contrasted as a function of elevation and
continentality. The flora includes over 3,400 species of vascular plants, and the
vegetation offers many types as a function of climate and substrate. Primary
production averages an order of magnitude of 80 kg DM/ha/yr largely depending
on annual plants. Stocking rates vary greatly from less than 10 to over 40
sheep-equivalents per km2. The stocking rate is ca 43 million sheep-equivalent and
the human stock ratio is 0.8 SE/person. Some 170,000 km2 of game reserves, of
regional and national parks, have been established since the 1970s, especially in
Saudi Arabia, where native species have been successfully reintroduced and the
environment restored.
Key words: Arabia, desert, animal husbandry, wildlife, rangelands, parklands.
Résumé
Les parcours de la péninsule Arabique
La péninsule Arabique occupe quelque 3 millions de km2, en grande partie désertiques, parcourus par des éleveurs nomades sédentarisés ou en cours de sédentarisation. L’altitude varie du niveau de la mer à près de 3 800 m au Nord Yémen. En dépit
de l’aridité générale et des températures élevées, les conditions climatiques sont
néanmoins très contrastées en fonction de l’altitude et de la continentalité. La flore
compte plus de 3 400 espèces de plantes vasculaires. La végétation est assez variée
en fonction du climat et du substrat. La productivité primaire est de l’ordre de
80 kg MS/ha/an, en grande partie basée sur les plantes annuelles. La charge
animale varie de moins de 10 à plus de 40 ovins-équivalents par km2. Un vaste
programme de réserves de faune, de parcs régionaux et nationaux, a été mis en
oeuvre, depuis les années 1970. Elles couvrent actuellement quelque 170 000 km2,
particulièrement en Arabie saoudite. De nombreuses espèces animales autochtones
y ont été réintroduites. Les conditions de milieu et la végétation y sont restaurées.
L’élevage a évolué vers un type d’élevage hors-sol avec une alimentation artificielle
fondée sur les grains et aliments concentrés achetés sur le marché mondial. Le total du
bétail est de 43 millions d’équivalents-ovins et le rapport bétail/population humaine
de 0.8 mouton-équivalent par habitant.
Mots clés : Arabie, désert, élevage, faune sauvage, parcours, parcs.
Sécheresse vol. 17, n° 1-2, janvier-juin 2006
179
180
East
ARABIAN SHIELD
FAULTED & DISSECTED
MOUNTAINS
ARABIAN SEDIMENTARY SHELF
INTERIOR HOMOCLINE
INTERIOR PLATFORM
TERTIARY & QUATERNARY
LAVA FLOWS
WASIA CATCHMENT
ASIR
DAMMAM CATCHMENT
TIHAMA
RED SEA
GULF
PRECAMBRIAN BASEMENT COMPLEX
Figure 1. Geological structure of the Arabian peninsula, W-E cross-section approximately on the
20° N. [1].
France in the South, the two connected by
a rather crescent shaped body of deep
sand and high sand dunes known as the
Dahna or Ad Dahna. Stable sand in a
desert is a blessing for the vegetation. Any
precipitation received on the sand moves
vertically downwards and is conserved
there. This moisture is available to the
vegetation, albeit adapted plant species,
through a vapour-pump mechanism [3],
which draws up the water vapours through
diffusion to the upper sand layers during
daytime and the vapours condensing at
night as internal dew available to the plant
roots for normal growth of adapted
species. Also, the very high diurnal variation in temperature on sand surface allows
for heavy dew formation on clear nights
even under relatively low relative humidity
conditions.
Table 2 and figures 2-4 show the usually
broadly recognized divisions of areas
into different ranges of aridity with reference to average annual precipitation
alone. Based upon this classification,
the vast Sand Sea, the Empty Quarter of
Southern Arabia fall into the desert wasteland category. However, the actual
situation is that this is an area with a
relatively high vegetation cover, which
in the Eastern Empty Quarter straddles
Saudi Arabia, parts of the United Arab
Emirates, Oman, and Yemen. Also, the
deep sands of the Great Nafud, the
20
Mean Temperature
30°
22
24
26
26
24
24
28
26
22
The Arabian Peninsula is a large region
covering an area of more than 3 million km2 between the latitudes approx
12o-34o35’ N and 34o-60oE. The topography varies from sea level in the coastal
plains to over 3,000m (with Jabal Nabi
Shuayb in Yemen being the highest peak
at 3,766m). In general, the Arabian Peninsula is characterized by cloudless days
with low relative humidity, the summer
temperatures reaching up to 50°C while
the night temperature minima may be
much lower, particularly in the interior
highlands, showing large diurnal range.
The winter minimum temperatures often
fall below freezing point resulting in frosty
conditions in the interior, particularly in the
northern and central regions and at high
altitudes ((figures 1 and 2; table 1). Some
of the peaks, mostly in the North, may
receive a thin snow cover in the winter in
some weeks. Because of the tectonic
movements of the earth plates the sea
bottom rose up about 18 million years
ago, a movement which also resulted in
the folding and faulting and eastward
tilting of the rock strata. The net result is
visible in the present physical features of
the Arabian Peninsula (figure 1).
The Arabian Peninsula lies in the northern
geographical belt of great deserts. The
soils in most parts of the Arabian Peninsula
are young and have not had much pedogenic development due to dearth of moisture and continual renewal of the surface
by erosion or deposition. Likewise, windblown soluble salts, gypsum and calcium
carbonate, are still being added to the
soils faster than they are removed in many
parts. However, in scattered, small and
large areas with relatively better moisture
regimes and protected from severe erosion
and deposition processes, soils do have
genetic horizons and could therefore be
considered as come of age. Also, in many
parts of the Peninsula, particularly in the
East and the Eastern Empty Quarter and
locally at other places many closed basins,
the Sabkhas, are present in the small to
very large Sabkha systems receiving
runoff from adjacent areas or from higher
ground far in the West or South, without
any drainage outlets. These areas have
high water tables and the soils are highly
saline. Sometimes, the surface of these
soils may have thick puffs or crusts of salts.
The subsoil water here may be salty (with
sodium chloride) or with high concentration of other salts as in the South Eastern
Empty Quarter.
About 30% of the Arabian Peninsula is
covered with sand in the form of Sand
Seas, the Great Nafud in the North and
the vast Empty Quarter about the size of
West
20
Copyright © 2017 John Libbey Eurotext. Téléchargé par un robot venant de 88.99.165.207 le 15/06/2017.
Geographic setting
20°
24
22
20
26
?
18
?
40°
50°
60°
Figure 2. Map of mean annual temperature in °C [2].
Sécheresse vol. 17, n° 1-2, janvier-juin 2006
Table I. Climatic parameters in the Arabian Peninsula - 10 parameters, 43 stations [2].
Copyright © 2017 John Libbey Eurotext. Téléchargé par un robot venant de 88.99.165.207 le 15/06/2017.
Station
Abha
Abu Dabi
Ahsa
Arar
Baha
Bahrain
Bisha
Buraimi
Dhahran
Dubai
Fahud
Gassim
Gizan
Guriat
Hail
Ja’aluni
Jeddah
jouf
Khamis
Mushait
Khasab
Madinah
Majis
Makkah
Marmul
Masirah
Najran
Qairoon Hariti
Qaysumah
Rafah
Ras al
Khaymah
Riyadh
Saiq
Salalah
Seeb
Sharjah
Sharurah
Sur
Tabuk
Taif
Thumrait
Turaif
Wejh
Yenbo
Altitude
(m)
WMO
no.
Rain
(mm)
Max
temp
(°C)
Min
temp
(°C)
Temp
range
(°C)
Mean
temp
(°C)
ACF of
rain
ACF of
temp
CV of
rain
CV of
temp
Mean
fog days
2093
16
178
549
1652
2
1162
299
17
8
170
647
7
504
1002
154
4
669
2056
14112
41217
40420
40357
41055
41150
41084
41244
40416
41194
41262
40405
41141
40360
40394
41024
40361
41114
253
80
108
66
150
86
97
104
91
116
24
145
129
53
116
39
47
63
215
34.1
47.6
49.4
47.0
38.6
45.7
42.8
50.8
49.5
47.3
50.7
47.0
45.3
47.7
43.5
49.0
49.0
46.0
36.0
0.0
5.4
-2.3
-5.6
0.0
7.0
-0.8
2.5
2.6
7.4
5.6
-4.0
11.8
-8.0
-9.4
6.5
9.8
-7.0
-0.8
16.0
15.9
17.5
16.5
13.6
9.0
18.9
18.2
15.2
13.2
19.4
17.7
11.6
19.9
17.6
19.3
13.8
16.6
15.3
18.6
27.1
26.5
21.8
22.7
26.5.
24.8
27.9
26.5
27.2
28.8
24.2
30.6
19.8
21.5
26.6
28.4
21.5
20.0
0.22
-0.02
0.01
0.21
0.16
0.09
0.36
0.08
0.19
0.03
0.04
0.17
-0.05
0.11
0.07
0.00
0.17
0.18
0.20
0.88
0.91
0.89
0.89
0.85
0.90
0.84
0.79
0.89
0.91
0.69
0.89
0.87
0.87
0.90
0.85
0.86
0.89
0.84
0.42
0.79
0.80
0.46
0.32
0.70
0.56
1.23
0.61
0.60
1.21
0.39
0.61
0.49
0.47
1.39
0.96
0.36
0.31
0.03
0.00
0.02
0.03
0.03
0.02
0.03
0.06
0.02
0.00
0.05
0.03
0.01
0.03
0.03
0.03
0.02
0.02
0.04
13.7
3
636
4
240
269
19
1212
878
358
444
31
41420
40430
41246
41030
41304
41288
41128
40373
40362
41184
198
78
125
96
41
51
50
236
133
100
131
49.0
47.5
50.0
49.8
49.0
45.2
42.0
38.3
50.3
48.5
48.2
8.4
3.0
5.7
10.0
5.4
12.3
-0.5
4.2
-4.0
-5.8
4.4
9.6
15.1
12.6
16.0
17.3
10.4
17.0
10.6
17.1
18.8
16.9
28.2
27.9
26.1
30.8
27.7
26.6
27.7
21.6
25.0
23.0
27.4
0.20
0.16
0.12
0.24
0.01
0.0.1
0.25
0.26
0.06
0.23
0.14
0.89
0.89
0.90
0.87
0.72
0.87
0.85
0.77
0.90
0.89
0.91
0.64
0.53
0.70
0.68
1.82
1.20
0.70
0.58
0.36
0.42
0.61
0.02
0.02
0.02
0.02
0.07
0.01
0.02
0.01
0.02
0.03
0.00
0.3*
0.2
5.4*
0.0
3.7*
0.5
10.3
7.2
-
614
1755
20
40437
41254
41316
126
350
85
47.4
36.3
44.7
-4.4
-3.6
10.8
18.5
12.6
11.0
24.8
18.1
26.4
0.13
0.12
0.48
0.88
0.89
0.81
0.63
0.33
0.37
0.02
0.03
0.01
15
35
725
14
768
1453
467
852
24
10
41256
41196
41136
41268
40375
41036
41314
40356
40400
40439
86
115
36
92
46
204
47
82
26
30
49.2
49.2
45.3
48.9
44.4
39.5
46.0
44.4
44.1
49.4
10.0
2.5
0.8
10.6
-3.7
-1.2
1.6
-8.0
5.1
6.5
11.0
16.8
18.4
12.7
16.8
14.7
16.8
17.3
11.4
15.2
28.7
26.8
27.5
29.3
22.0
22.9
27.1
18.7
24.9
27.6
0.09
0.00
0.13
0.01
0.05
0.10
-0.04
0.10
0.06
0.29
0.88
0.91
0.85
0.88
0.88
0.87
0.29
0.88
0.85
0.86
0.78
0.66
0.66
0.69
0.56
0.42
1.50
0.43
0.74
1.07
0.01
0.00
0.03
0.02
0.03
0.03
0.7
0.03
0.02
0.02
5.1
3.4*
0.8*
(16.2*)
2.0*
0.1
0.0*
0.5
*12.1
0.1*
12.5
6.7
12.1
10.5
8.4
4.0
07
21.1
7.8
1.4
6.0
6.6
54.0
4.8
5.1
22
WMO no: World Meteorological Organization number; ACF: autocorrection of coefficients; CV: coefficients of variation; *: fog
observations available for 1987-1995 only.
Western Empty Quarter, the Dhana and
the Wahiba Sands support perennial
vegetation available to livestock and
wildlife as forage and shelter even
during the summer.
Sécheresse vol. 17, n° 1-2, janvier-juin 2006
The low rainfall in Arabia combined with
mostly anormal soils has resulted in the
presence of very specialized kinds of
plants and plant communities in most parts
of the Peninsula. The seaward facing
mountains and submontane areas are
under the influence of seasonal monsoons
for a short period or are bathed in
cloud/fog in the upper elevations and possess relatively better moisture regimes. The
181
Table II. Approximate surface area of arid rangelands (with average precipitation ranges) in the
Arabian Peninsula (in 1,000 km2) [4].
Country
Total Area
18
2,150
22
84
212
527
3,513
Kuwait
Saudi Arabia
Qatar
UAE
Oman
Yemen
Total
interior of the Peninsula has the harshest
environment. The terrestrial habitats vary
from the mangrove forests to coastal and
intermountain Acacia woodlands to
Junperus-Erica fog forests to tall shrub,
deep sand plant communities, park-like,
dew-dependent shrub communities completely devoid of annual plants, to barren,
highly saline Sabkhas. These habitats support or supported varied biodiversity, the
flora and fauna being very rich to very
poor at places, common to very uncommon and specialized at places. Of all the
resources of this region, vegetation alone
is the renewable resource of Arabia. Agriculture being extremely limited and erratic
in the past, the very life of most of the
inhabitants was directly or indirectly
Desert
Wasteland
50 > P mm
-700
--107
70
877
dependent upon the vegetation and in
most cases the very basis of survival of
man through his livestock. The deserts
have a low productivity and low carrying
capacity [6, 7]. On the other hand, the
wealth and status of a pastoralist is determined on the basis of the number of his
livestock. The result has been a historic
overgrazing of the rangelands. In the past
however overgrazing was rather benign.
Herd sizes were periodically cut down by
droughts. For example, it is recorded that
in the drought year of 1950 in Saudi
Arabia, in the Al Hasa and Qateef area,
85% of the sheep, 98.5% of the camels
and 86% of cattle died [8]. Comparable
losses (75% of small stock) were reported
from the arid zone of Tunisia during the
Mean Rainfall
30°
50
0
0
10
15
0
10
50
Copyright © 2017 John Libbey Eurotext. Téléchargé par un robot venant de 88.99.165.207 le 15/06/2017.
Non Arid Non
Arid
Desert
Desert
P > 400 mm 400 > P > 100 mm 100 > P > 50 mm
-18
-10
200
1,240
--22
--84
2
12
91
40
160
257
52
390
1,674
0
15 200
100
50
0
20
20°
250
50
3-year droughts of 1946-1947-1948 [9].
The drought affected the vegetation too,
but the time it took for the livestock herds to
build up again, gave enough respite for
the vegetation to regenerate. A similar
situation still exists in some other parts of
the desert world, such as for example in
1999 in the Cholistan desert of Pakistan
where herds of livestock suffered heavy
mortality as result of the periodic drought!
The good fortune of Arabia after the economic boom from oil wealth sadly proved to
be unfortunate for the rangelands. As
early as 1972, Kingery had estimated that
two thirds of the natural vegetation of
Saudi Arabia had been destroyed by overgrazing and tree felling for fuel [10].
Because of the affluence of the individuals
and of some government policy decisions
to subsidize the Bedouins, the natural
checks on the livestock sizes and duration
of the stay of the herds in the rangelands
disappeared. Subsidies were introduced
in an effort to have self-sufficiency in meat
production based upon desert rangeland
for an increasing meat-hungry population
(tables 3 and 4) without the realization
that the only way to be self-sufficient in
meat would be through livestock farming just like poultry-farming in a desert
region!
For example, in Saudi Arabia, at the beginning the subsidies were based on the number of animals in the individual herd. Later,
Saudi Arabia instituted subsidized barley
as livestock feed to keep the animals off the
rangelands. Sadly that too has been
misused there and elsewhere in the Arabian Peninsula. Instead, the herds both
commercial and individually owned stay on
the rangelands longer and in larger numbers using energy from the subsidized barley to destroy the rangelands! In the developed world the rangelands belong to
someone or individuals who take care of
the rangelands own the grazing rights. It is
only in the developing countries that the
rangelands do not belong to anyone and,
apparently, every one has a license to destroy the rangelands through his livestock or
by uprooting range shrubs for use as fuel
and cut down trees for making charcoal or
use as timber or fence posts or pull down
trees so that the animals can graze upon the
canopy which otherwise would have been
out of reach of the animals!
100
?
20 150
25 0
0
300
400
40°
Figure 3. Map of mean annual rainfall in mm [2].
182
150
Bioclimatology
and phytogeography
?
50°
60°
The northern portion of the Peninsula is a
part of the Mediterranean world with
winter rains and summer drought.The
southern part, in turn, belongs to the tropiSécheresse vol. 17, n° 1-2, janvier-juin 2006
ADEN (300 m)
[42-50]
28,3˚ 46
BAHREIN (4 m)
[10]
HAIL (970 m)
21,2˚99
13,8
7,8
22,8
16,1
HENDSCHAM (30 m) 26,7˚ 126
[9]
JEDDAH (6 m)
[10-5]
27,2˚
79
KUWEIT
[7]
MUSCAT (5 m)
[45]
24,4˚ 122
28,9˚ 66
22,8
15,6
SANA'A (2360 m)
[1-2]
RIYAD (585 m)
PERIM (60 m)
[19]
28,1˚ 96
19,2
9,4
9,4
-2,8
KAMARAN ISLAND (8 m) 30,0˚ 74
[8-6]
23,3
18,9
19,4
12,8
15,6
8,3
Copyright © 2017 John Libbey Eurotext. Téléchargé par un robot venant de 88.99.165.207 le 15/06/2017.
25,8˚ 94
17,5˚ 390
SHARJU (5 m)
[8]
24,7˚ 81
7,6
-7,2
25,6˚ 104
12,1
2,8
Figure 4. Ombrothermal diagrams according to the Bagnouls & Gaussen model (P=2t) [5].
Each mark in the graphs corresponds to 20 mm of mean monthly rainfall or 10°C of mean monthly temperature.
cal world with summer rain and winter
drought.
The separation between these two major
bioclimatic and phytogeographic entities
is a line joining Jeddah to Muscat [5, 13,
14]. Figure 5 shows this major separation line and figure 4 provides a number
of ombrothermal graphs showing the distribution of dry and rainy seasons throughout the Peninsula. As one can see from
those, the situation is complex within the
above-mentioned framework.
In the dry interior, most of the plant species
recorded belong to the Mediterranean kingdom [12, 14-18], while the south and
southwest part of the Peninsula (Asir, Tihamas, Yemen, S Oman) belong to the InterTropical Region. Yet Mediterranean
genera number some 500 in the dry
Yemen highlands [15].
Table III. Population, area, density, GDP/inh in the Arabian Peninsula [11].
States
Bahrain
Kuwait
Oman
Qatar
Saudi Arabia
Un. Ar.Emir.
Yemen
Total
Population (2003)
103
709
2,396
2,599
624
23,520
4,041
19,173
53,062
GDP: Gross Domestic Product.
Sécheresse vol. 17, n° 1-2, janvier-juin 2006
Area (2003)
103 . km2
0.69
4.65
212.50
11.00
2,150.00
83.60
528.00
3,059
Density (2003)
inh/km2
1,028.0
515.3
12.2
56.7
10.9
48.3
36.3
17.3
GDP/inh. (2004)
$/inh/yr
10,880
19,280
7,875
13,020
9,460
16,270
530,00
7,358
The Flora
The vascular flora of the Arabian Peninsula amounts to some 3,420 species, the
rate of endemism is 17.4% (same order of
magnitude as the Sahara which is
2.8 times larger). Circa 52% of the overall
species are shared with the Sahara [17,
18]. But the arid land flora represents only
a fraction (circa a third) of this overall
richness (box 1).
The statistics on national floras is shown in
table 5. The arid land flora of the Peninsula is most probably in the 1,0001,500 spp bracket (29-44%). A large
proportion of the flora is bound to the
southwest semiarid and subhumid
mountains of Hedjaz, Assir, Yemen, and
South Oman (Dhofar) [21, 22, 25-28].
Native vegetation in the rangelands
There has been intense overgrazing
amounting to destruction of the vegetation
in Arabia [1, 8, 10, 15, 25, 29-31].
183
Table IV. Changes in human population in the Arabian Peninsula, 1900-2000, in millions [12].
Copyright © 2017 John Libbey Eurotext. Téléchargé par un robot venant de 88.99.165.207 le 15/06/2017.
Kuwait
Saudi
Arabia
Qatar
United Arab
Republic
Oman
Yemen
Total
1900
1950
1960
1970
1980
1990
2000
0.2
1.7
0.3
3.2
0.5
4.0
0.7
6.2
1.4
9.4
2.1
14.1
3.2
21.2
0.1
0.2
0.1
0.3
0.2
0.4
0.2
0.6
0.3
1.0
0.4
1.6
0.5
2.7
0.4
2.5
0.1
3.0
5.3
0.2
5.5
9.6
0.3
6.0
11.4
0.7
6.5
14.9
1.0
7.9
21.0
1.5
10.5
30.2
2.3
14.0
43.9
2.2
11.0
38.6
Lebanon [32], the complete elimination of
Juniperus procera subsp. polycarpos
forests and Acacia origena woodlands in
the highlands of Yemen, elimination of
Juniperus procera from the Erkwat mountains of the Sudan, and recently, continuing
devastation and death of vast tracts of
Juniperus procera forests in Saudi Arabia
highlands and a worrisome situation
concerning the juniper forests and stands
in Djibouti, Oman, and in Baluchistan
(Pakistan), as well as of the Acacia woodlands in all of the Arabian Peninsula
[33-35]. Destruction of rangelands and
Under normal moderate use of desertic
rangeland, the vegetation can support
mixed herds of camels, sheep and goats.
Persistent increased pressure on vegetation begins to affect the composition of the
stands species-wise and its structure till a
stage is reached where a rangeland may
not support sheep. Then camels and goats
constitute the main herds. These are the
hardiest of livestock, particularly the goats
which have devastated in the past whole
plant communities, changing the whole
ecosystem. Stunning examples of these are
the secondary destructions of forests in
30°
Increase
1900-2000
3.0
19.5
45°
60°
45°
45°
Temperate
other vegetation cause a concurrent
domino effect on the wildlife. The direct or
indirect elimination of large carnivorous
fauna by man, e.g. of the leopard, the wolf
and hyena now allows the livestock and
their owners to destroy the vegetation
without any fear to the owner or risk to the
livestock! Vast areas right up to the Syrian
Desert in the North, which, at one time,
could support the Asian lion, the leopard,
the cheetah and the wolf have been degraded to unrecognizable, depauperate plant
communities. Best stands of vegetation in
the interior of Arabia used to be in the
runnels, broad wadis and other areas
receiving runoff or on the gentle mountain
slope in the southeast. There were relatively very rich stands of communities or community complexes of Haloxylon salicornicum (Rimth) or Rhanterium epapposum
(Arfaj) in such areas in the interior. The
same areas now support dense stands of
green vegetation. But these stands are
mostly comprised of unpalatable shrubs or
herbs, the increasers, like Rhazya stricta
(Harmal), Pulicaria undulata (Githgath),
Astragalus spinosus (Qiddad) or other
shrubs like Euphorbia balsamifera. In
Oman and the United Arab Emirates, the
non-palatable Pulicaria edmondsonii or
Astragalus fasciculatus or other shrubs like
Euphorbia larica cover such good habitats. Stands of these increasers signify
potentially very productive rangeland
habitats but with the original plant communities devastated or from which allpalatable species have been almost totally
eliminated. In other devastated ranges, the
deep to thin sand cover originally present
has been blown away leaving vast barren
tracts of fine, mostly clayey soils strewn
with gravel at places as in the Dibdibba
plains in the northeast of Saudi Arabia
and parts of Kuwait.
The saline coastal rangelands
30°
30°
Mediterranean
Tropical
15°
15°
30°
45°
60°
Figure 5. Limits between temperate, Mediterranean and tropical bioclimates and biochores
[14, 15].
184
The western and southwestern seacoast
and the Red Sea islands have dense
patches of mangrove mostly consisting of
Avicennia marina [36-41]. At places
Rhizophora mucronata is present mixed
with Avicennia marina. The two constitute
a major source of feed for native populations of gazelles in the Red Sear islands.
Also, these are lopped as fodder for
camels. Other components of vegetation
on the Red Sea islands used as browse or
shelter by goats and the native gazelles
are occasional groves and thickets of Salvadora persica, Capparis decidua, Acacia ehrenbergiana, Suaeda monoica,
Suaeda fruticosa (=Suaeda vermiculata),
Cadaba rotundifolia, Commiphora myrrha, C. erythraea , and Ziziphus spinachristi in abandoned fields and some other
halophytes like Limonium axillare, LimoSécheresse vol. 17, n° 1-2, janvier-juin 2006
Box 1
Floristic richness
Copyright © 2017 John Libbey Eurotext. Téléchargé par un robot venant de 88.99.165.207 le 15/06/2017.
– the Saq, 370,000 km2: 66 families, 235 genera, 378 spp, spp/gen.=1.61 [16];
– N. Saudi Arabia, 1,4 million km2 : 43 families, 235 genera, 300 spp,
spp./gen.=1.66 [19];
– SE Saudi Arabia, 605,000 km2: 66 families, 312 genera, 565 spp,
spp/gen.=1.81 [20];
– North Oman: 125 families, 639 genera, 1 200 spp, spp/gen.=1.9 [21-23];
– United Arab Emirates: 91 families, 296 genera, 620 spp, spp/gen.= 2.1 [24].
nium cylindrifolium, etc. The prominent
sedge and grass components are Cyperus
conglomerates, Aleuropus lagopoides,
Hyparrhenia hirta, Panicum turgidum,
Dichanthium foviolatun, Sporobolus helvolus, Tricholaena teneriffae and Urochondra setulosa.
The western coast near the sea supports
saline plants common to the Red Sea
islands. The areas a little away from the
sea with a sand cover, depending upon
the depth of the sand and the water table
below it have various saline plant communities constituting the rangelands for
camels. Highly saline areas with high
water table usually carry Suaeda-Tamarix
community. Suaeda monoica, Suaeda fruticosa and scrubby Tamarix plants form
important range communities for camels.
Coastal dunes have dense clumps of Aleuropus lagopoides and Panicum turgidum.
Similar areas lower down the Tihamas in
Yemen have Aleuropus lagopoides, Aleuropus massauensis, and Odyssea mucronata thickets.
The mangroves along the east coast are
patchy. These lack Rhizophora mucronata
and consist of Avicennia marina alone.
Most of the mangrove areas have been
badly degraded through human activity.
At one time probably these provided significant forage for camels. Because of the
general eastward incline of the Peninsula
most of the ancient river systems drained
eastwards. Because of this tilt the eastern
region historically had important oasis
areas and the water table was generally
high. Springs and artesian well water has
been available in the region. As a result,
luxuriant patches of salt-tolerant shrubs
and shrubby trees and date palms have
been present at suitable locations. The
Qateef and Al Hasa oasis areas in Saudi
Arabia also had significant agricultural
activity besides date production and livestock in the past. Most of the better moisture regime areas have thick stands of
Tamarix shrubs and trees mixed with selfsown date palms. Vast coastal areas with
a relatively high water table and moderate
to thick sand cover support shrubby salttolerant vegetation consisting of Seidlitzia
rosmarinus, Suaeda fruticosa, Suaeda
maritima, Zygophyllum spp. often accompanied by Cyperus macrorrhizus and
some other Cyperus spp. and sedges.. At
places where the sand is relatively deep,
often Calligonum comosum bushes are
found. These are very important rangelands. As in other areas too, these have
been subjected to extreme grazing!
Some of the major camel ranges are found
on sub-irrigated sandy areas where the
wadis reach and end up in the sea in the
west or the Empty Quarter in the East. Such
areas have almost impenetrable thickets of
Salvadora persica mixed with Tamarix
(nilotica?) in the southern Tihamas. These
impenetrable thickets have narrow gullies
carved around patches of the vegetation
through grazing by camels. At places, this
vegetation covers probably over hundreds
of square kilometers. This vegetation
extends onto the alluvial plains between
wadis where, because of cultivation by
man and other disturbances, this kind of
vegetation has been reduced to isolated,
but still impenetrable, thickets. Towards the
Empty Quarter near Najran for example,
a vast area of Calligonum comosum and
Tamarix nilotica formed a similar impenetrable community but this has completely
disappeared with the conversion of that
area into agricultural land. Northern
Tihamas/coastal areas have the usual
halophytes like Suaeda monoica, and
Suaeda fruticosa with shrubby Tamarix
plants in coastal areas. The mangroves at
some places here too have Rhizophora
mucronata stands at places mixed with
Avicennia marina.
Acacia woodlands
The Tihamas, the coastal plains in the
West, having a tropical lowland climate,
are the major Acacia woodlands in Saudi
Arabia and Yemen while extensive woodland patches are also found in localized
plain areas in the southern and southeastern regions [30, 31, 42-45]. Mostly, the
major species is the Acacia tortilis ssp.
tortilis, the ssp. raddiana is restricted to the
northern parts of the Tihamas and the
interior. The second layer of the woodlands is formed by Acacia ehrenbergiana
and Leptadenia pyrotechnica. The woodlands extend into the intermountain valleys
and plains and onto the lower slopes of
the adjoining mountains. The floor of
the woodlands has a host of perennial, tall
and low shrubs, grasses, and annual and
perennial herbs. These woodlands should
Table V. Overall floristic vascular species richness of the Arabian Peninsula [14].
Country
Kuwait
N. Oman
Qatar
East S. Arabia
Un. Ar. Emir.
Gulf States
N. S. Arabia
Saudi Arabia
Yemen
Dhofar
Socotra
Arab.Penins.
Sécheresse vol. 17, n° 1-2, janvier-juin 2006
Families
Genera
Species
Spp / Gen
55
118
42
78
91
101
100
120
140
83
91
141
198
397
223
306
296
400
350
837
880
401
273
1,105
374
506
334
565
620
700
900
2,320
2,200
750
850
3,420
1.9
1.3
1.5
1.8
2.1
2.0
2.6
2.7
2.7
1.9
3.1
3.1
Endemics
Nr
%
27
3.9
50
5.5
398
5.8
137
6.2
60
8.0
270
32.0
595
10.1
Areal Richness
Spp. 10 -4 km2
208
145
152
9.3
74
9.2
6.4
9.1
46.0
60.0
2,125
17.4
185
Copyright © 2017 John Libbey Eurotext. Téléchargé par un robot venant de 88.99.165.207 le 15/06/2017.
have been and still are the major rangelands for camels and goats and mixed
herds of goats and sheep. One can visualize these woodlands full of gazelles and
other wild life in ancient times. But now, of
the wildlife, only gazelles are to be seen in
some protected areas out of the reach of
mechanized transport. The woodlands
have been under extreme grazing pressure. Combined with woodcutting and
charcoal making, these woodlands have
suffered a lot. The vegetation within easy
reach of the livestock has been overgrazed. There is absolutely no regeneration as
the seedlings that come up stand no
chance against the onslaught of the livestock. The shepherds have now resorted to
pulling down the trees with the use of ropes
or cables tied to their pickup trucks. This
way the livestock can reach what otherwise had been out of their reach, but the
trees mostly get uprooted and die. Most of
the trees are old, and in some stands the
pods are often infested with insects destroying even the seed! The palatable
shrubs and herbs have suffered severe
overgrazing and are often reduced to
small, dense, individual clumps.
The Acacia woodlands consist of several
plant communities or sub-communities, the
variation occurring depending upon the
kind of soil, the depth of the soil and the
moisture regimes. Other trees coming in at
various habitats are Commiphora spp.,
Euphorbia cuneata trees, succulent
Euphorbia spp., etc. The narrow wadis
and streams here favour the presence of
Acacia abyssinica, a tree acacia,
Hyphaene thebaica, the Doum palm. Acacia hamulosa and Acacia oerfota are the
increaser species here.
The Acacia woodlands extending on to
the lower western slopes are more open or
denser, again depending upon elevation
and aspect of the slope while also the
composition of Acacia and of other tree
species too changes. At lower elevation
the small tree Acacia asak and or Acacia
senegal and Acacia mellifera thickets
become more common. At an elevation of
around 1,400m above sea level the northand west-facing slopes characteristically
support Acacia etbaica as small trees. The
vegetation here tends to be much denser
than on slopes with other aspects. Also,
these are the slopes, which have mostly
been used by man in the past to transform
into terraces for agriculture. At about
1,600m above sea level the Acacia
etbaica community merges into the Juniperus procera community with Teclea nobilis,
Maesa lanceolata, Tarchonanthus camphoratus, Nuxia oppositifolia, and Olea
europaea ssp africana as the main tree
components.
186
In the coastal Acacia woodlands in the
West, the western lower slope and in the
highland ranges two characteristic components of the communities are Salsola
spinescens and Indogifera spinosa as low
shrubs, Lyceum shawii as a tall shrub, and
Maerua crassifolia as a small tree. These
four species suffer the major brunt of overgrazing. The two low shrubs, Salsola spinescens and Indigofera spinosa, are often
grazed to almost their root level and very
often are not visible in the landscape any
more.
High altitude Acacia woodlands
The high altitude Acacia origena (also
formerly called A. negrii by some
authors), normally is a component of Juniperus community. But at places where Juniperus procera has been taken out, Acacia
origena is thriving in Saudi Arabia
because of the ‘armour’ of long, thick
spines that its lower branches develop
following browsing by livestock. This
species forms probably a transition phase
for junipers to regenerate under its protection and is present only as isolated stands
of woodland. Vast areas of Acacia origena woodland in Yemen have disappeared and occasionally one sees severely
lopped stumps, the branches having been
lopped away as fodder for goats. Sometimes also seen are woodland stands of
Acacia gerradii at similar elevations [23,
27, 29, 33, 34, 44, 46].
It is interesting to notice that usually Acacia
gerradii stands or individual trees are distributed along the old caravan routes from
the mountains into the interior going northeast or southeast. Is it simply because the
old routes usually run next to seasonal or
perennial streams and the seed of this
species got distributed along those tracks
or that these are the areas that met the
higher water requirement of this Acacia
and the caravan routes followed the
available water and shade? A similar
situation is to be seen in the distribution of
Prosopis cineraria in the Wahiba Sands of
Oman and the United Arab Emirates
sector of the Eastern Empty Quarter where
this tree follows the traditional caravan
tracks between the high sand dunes,
which probably were wadi beds at one
time, and the same question comes to
mind there too!
Juniperus woodlands and forests
The west-facing higher elevations in the
western mountains at an elevation of
about 1,600m above sea level and above
support rather open woodlands to dense
juniper forests [3, 13, 23, 27, 29, 30,
33-35, 46-48]. In the northern region, the
northern Sarawat mountains, at about and
north of the latitude 20o 20/ N, the Medi-
terranean juniper, Juniperis phoenicea is
found now in isolated patches on isolated
peaks. This is often accompanied by
Amygdalus korschinskii at lower levels.
Near Taif, we have an overlap of J. phoenicea and J. procera. Apparently, the latter is less tolerant of aridity.
Juniperus procera is found in the southern
Sarawat or the Asir: at one time its distribution extended into the highlands of Yemen
from where it has now disappeared. A
third juniper species, Juniperus excelsa ssp. polycarpos, is found on Jabal
Akhdar in Oman at elevations of 1,3502,300m mixed with other small trees and
shrubs. At 2,300m and above it forms
open evergreen woodland.
Intact trees in all the three Juniperus
species have more or less pyramidal
shapes with their lower branches spreading at, or just above, ground level. In
addition to any precipitation received in
the regions of their distribution, these trees
are dependent, may be probably more so,
upon the moisture that they can comb out
of the clouds/fog received there. It is a
well-known fact that about a square meter
of mesh can comb out about 4.5 litres of
moisture from clouds/fog per 24 hours.
Also, it is a fact that goats love juniper
leaves and branches and the shepherd lop
down branches of junipers to feed their
goats. As a result of the goat browsing and
of the cutting down of branching, the trees
lose most of their moisture-harvesting
canopy. The goats eat up the seedlings.
The ‘nurse’ vegetation on the ground that
protects seedlings is also destroyed
through overgrazing or trampling. Most of
the trees present apparently are ancient in
age. The dieback of upper branches is
normal during years of drought. But now
the junipers at lower elevations over hundreds of square kilometers of forests have
died in Saudi Arabia while other tree
species like Maesa lanceolata in the same
stands have survived. The junipers at
higher elevations in Saudi Arabia form
forests or dense woodlands alone or in a
community together with Erica arborea,
another tree species adapted for combing
moisture out of the clouds/fog coming in
from the Red Sea in the West. These forests
and woodlands are in dire need of protection. Without protection these will suffer the
same fate that junipers have suffered in
Yemen in the past. One wonders if some
body has thought of re-afforestation in the
highlands of Yemen!
The Highlands
The Asir Plateau and other highlands at or
above 2,000m elevation support or at one
time supported Juniperus procera communities [3, 5, 13, 23, 29, 47-49]. Near Taif
at a latitude of about 20o 20/ N, at places
Sécheresse vol. 17, n° 1-2, janvier-juin 2006
Copyright © 2017 John Libbey Eurotext. Téléchargé par un robot venant de 88.99.165.207 le 15/06/2017.
both Juniperus phoenicea and J. procera
are found. Below 2,000m elevation, Juniperus procera is found in sheltered valleys.
Olea europaea ssp. africana is a characteristic component of the vegetation. Acacia etbaica and Acacia asak are equally
common. Acacia tortilis and at just a few
places Acacia albida are present as tall
and/or large trees. The vegetation in
general is open woodland. The stands thin
out on exposed east- and south-facing
slopes from where often the tree and tall
shrub components are missing or have
been taken out. Such areas have Acacia
ehrenbergiana, Lyceum shawii, Salsola
spinescens and Indigofera spinosa as the
main shrub components. In places like
Sahel Rokba (near Taif) for example in
Saudi Arabia the vegetation has been so
degraded that distances needed for grazing by the goats are such that their hooves
are often worn out and tender, the animals
then preferring to graze on their front
knees! In areas to the south in southern
Asir and neighbouring Yemen territory,
large stands of the non-palatable Euphorbia balsamifera cover the degraded
slopes often accompanied by the poisonous Euphorbia schimperi. Because of
probably a little better moisture regime
and small-rock cover here, the grasses
Chrysopogon plumulosus and Hyparrhenia hirta are more noticeable. The tree and
tall shrub components accompanied by
Dodonea viscosa thin out on lower slopes
but continue in narrow wadis down the
slope.
The foothills and the central plains
The foothills and the central plains have
what can be called as very thin stands of
Acacia tortilis, Acacia ehrenbergiana,
Maerua crassifolia with scattered Acacia
hamulosa, and Lyceum shawii tall shrubs
[3, 8, 10, 16, 19, 20, 23, 27, 29-31, 42,
45, 50-55]. All of these are badly grazed
except that the more prickly Acacia hamulosa survives much better. Acacia tortilis
becomes smaller in size. Most conspicuous change in the rangeland is the presence of Haloxylon salicornicum as the
main component of the vegetation. The
range in general comprises of AcaciaHaloxylon salicornicum community. Salsola spinescens and Indigofera spinosa
are still found nearer the foothills mostly
disappearing from the vegetation away
from the foothills. Maerua crassifolia is
present as small trees. Acacia ehrenbergiana, Acacia hamulosa, and Lycium
shawii form the tall shrub layer. This vegetation continues well into the Western Empty
Quarter on areas lacking deep sand
cover. The community is also composed of
a horde of annual and perennial herbs
and low shrubs following the autumn/
Sécheresse vol. 17, n° 1-2, janvier-juin 2006
winter rains. A valuable range covering a
huge area that has suffered and is still
suffering severe overgrazing by camels,
goats and sheep. Additionally, the
Bedouins pull up plants of Haloxylon salicornicum from the roots and use these as
fuel. Maerua crassifolia too has been grazed to the situation where it is seen as
occasional, half dead trees. Acacia hamulosa in certain areas is present as an
increaser because of its being more prickly. This community was probably the most
widespread in the Arabian Peninsula!
Haloxylon salicornicum is the major component of the perennial vegetation fabric
of the interior desert. At places it is grazed
down to its very base making it difficult
even to recognize it. Acacia-Haloxylon
ranges often show clumps of Panicum turgidum, Pennisetum divisum, and Lasiurus
scindicus. Distribution of these three grasses is widespread. Panicum turgidum particularly is found as different ecotypes/
phenotypes in the western, central and
eastern Arabia as a result of varying salinity levels or grazing pressures. When the
tree component is missing or has been
removed, these areas may be referred to
as ‘grasslands’.
Haloxylon salicornicum is/was present as
a (primary?) community by itself as
Haloxylon salicornicum steppe in mostly
alluvial plains often with a thin or deeper
sand cover or with a gravel cover in areas
with wind-eroded surface. This community,
however, has been completely eradicated
by man and his livestock in some areas, as
for example, in the Dibdibba plains in the
northeastern Saudi Arabia and parts of
Kuwait. There, it could be recognized by
long-dead root-stumps with some occasionally showing one or two small shoots.
At places because of some subtle change
in the soil, probably the thickness of sand
cover or better drainage of certain areas,
Haloxylon salicornicum is replaced by
Rhanterium epapposum to form an
Acacia-Rhanterium community or alone
forming the Rhanterium steppe as also
reported by Vesey-Fitzgerald [31, 40,
41]: interestingly, somehow he missed to
mention Haloxylon salicornicum in his
papers! Like Haloxylon salicornicum,
Rhanterium epapposum too suffers very
badly from overgrazing by livestock.
Under extreme overgrazing, this shrub too
is grazed down to the roots. Such sustained overgrazing of habitats changes the
appearance and composition of the rangelands. In the central and southern interior
of the peninsula, the best rangelands have
undergone such changes and the vegetation there consists of dense stands of nonpalatable increasers like Rhazya stricta,
Zilla spinosa, Astragalus spinosus, Pulica-
ria undulata, Harwoodia dicksonii, etc. as
already indicated earlier.
Some of the wadis coming down from the
western mountains become seasonal
streams or torrents that end up in the sand
banks of the Eastern Empty Quarter.
Areas, which are flooded by the backed
up floodwater often, are highly saline and
are the saline Suaeda monoica, Suaeda
fruticosa rangelands for camels. Suaeda
monoica sometimes attains arborescent
size with thick trunk. Unfortunately, such
areas have been subject to intense grazing and destructive human activities and
may not survive for too long! The borders
of these areas where water stands and
which are less saline usually have the
ubiquitous fringe or clumps of Calotropis
procera! Calotropis seeds carried by wind
get established wherever some water has
accumulated. These are not palatable. If
given to hungry livestock when nothing
else is available, according to one
Bedouin shepherd, the livestock can tolerate this forced feeding for a maximum of
three days and even then they get the runs
(diarrhoea).
Northern rangelands
The northern rangelands can be categorized as Salsola steppe lacking any tree
component except the deep sand patches
(which have the Nafud kind of vegetation
to be described below) [2, 3, 8, 10, 16,
19, 29-31, 42, 43, 45, 50, 51, 55-59]. In
general, the soil is loamy covered with
flinty limestone shards. The Salsola species
present here are Salsola cyclophylla, S. tetrandra, and Salsola villosa (previously
known as S. chaudharyi or S. mandavillei) accompanied by Halothamnus iraqensis, Haloxylon salicornicum, Traganum
nudatum and Cornulaca setifera in various
combinations forming a number of plant
communities depending on subtle variations in the soil. Salsola villosa is the most
prevalent species in the vast and very
productive northern rangelands. At one
time, reportedly, it formed such dense
stands that it was difficult to ride through
these on horseback. As with other rangelands, overgrazing has resulted in severe
degradation of these rangelands. However, studies at the Animal and Rangeland
Development Research Center in Al Jouf
[56, 57] have shown that a complete
protection of a rangeland there for 3 to
4 years can bring the range back to a
healthy stage provided some of the major
range components were still present! This
rangeland is primarily sheep and camel
range.
187
Copyright © 2017 John Libbey Eurotext. Téléchargé par un robot venant de 88.99.165.207 le 15/06/2017.
The Great Nafud
and the Nafud kind of vegetation
The Great Nafud is a vast area of sand
dunes, hollows and deep sand-sheets in
Northern Arabia. It is an area of valuable
pasturage for wildlife and livestock though
at present in a badly degraded state [1, 3,
8, 10, 13, 16, 23, 27, 29, 30, 42, 45,
50, 53, 55, 60]. Original vegetation
consisted of tree-like Haloxylon persicum,
the Ghada tree forming isolated dense
thickets. Other characteristic perennial
components of the vegetation are Calligonum comosum (Arta’a), Artemisia monosperma (Aadhar), Scrophularia hypericifolia (Alqa’a) and Stipagrostis drarii (Nussi),
Centropodia fragilis (Hajain), Convolvulus
bushiricus (Rukhami), Cyperus macrorrhizus (Andhab), Moltkiopsis ciliata
(Halm), and Monsonia heliotropioides
(Qarna).
Following the winter rains the surface of
the sand (except in the moving sand areas)
is covered with a dense cover of annual
and perennial herbs (box 2).
Patches of Haloxylon salicornicum or
Rhanterium epapposum are found in the
interdune areas in the Dahna and peripheral regions of the Great Nafud in the north
as well as in the northern sand-sheet areas
where these two are present as components of remnants of a degraded Calli-
gonum comosum-Scrophularia hypericifolia community. The Dahna and the sands
of the Western Empty Quarter carry the
Nafud kind of vegetation.
The Empty Quarter
The Empty Quarter [29-31, 62-65] is, as
the name suggests, a little-known zone; it is
an area of over 640,000 km2 (20% of the
surface area of the Peninsula); it can be
divided into at least two distinct regions,
the Western Empty Quarter which has an
Acacia-Maerua-Haloxylon salicornicum
communityonitseasternfringesasacontinuation of the foothills and the Central Plains
vegetation with Acacia hamulosa as an
increaser. This gradually merges into the
Nafud kind of vegetation as the thickness
of the sand increases towards the middle.
This is the area that receives some winter
rains.
The Eastern Empty Quarter is more like a
vast Sabkha with sand dunes and “sand
mountains” up to about 300m tall and
thick layers of sand-sheets covering most
of the area. The major part of this Sand
Sea carries three plant communities. Primarily, because the rainfall here is erratic if
any in some years, the sand surface totally
lacks any annual vegetation component.
The sand surface is bare between the
park-like distribution of just a few peren-
nial shrubs: Calligonum arabicum (=Calligonum crinitum ssp. arabicum), Tribulus
arabicus, Cornulaca arabica and the
sedge Cyperus eremicus on the sand
dunes and sand mountains. Lower reaches
of the dunes and the sand-sheets additionally carry the perennial Limeum arabicum.
The smaller interdune sabkhas and the
edges of the larger sabkhas support only
Zygophyllum mandavillei. When Chaudhary surveyed the Eastern Empty Quarter
in the spring of 1991 [63], the year of
exceptional rains in the Empty Quarter, the
Eastern Empty Quarter was probably the
best vegetated area in Saudi Arabia next
to the Asir. Calligonum, the taller shrubs
along with the other shrubs showed a
regular park-like distribution. Because of
the rains in that year, the sand surface was
covered by a multitude of seedlings of
Cyperus eremicus. This vegetation, apparently, consisted of 3-7 discrete age
groups.
The sabkhas there had a thick, rather puffy
salt crust up to about 10cms in thickness.
The water table in these sabkhas was at a
depth of about 11/2m and the water did
not taste of sodium chloride. Where such
sabkhas were covered with a thick sand
layer, pure stands of Seidlitzia rosmarinus
were found. An aerial reconnaissance of
the Seidlitzia stand near Khaur Hamdan (a
Box 2
The vegetation cover of the Nafud
The following is a list of the various herbs found in the Nafud. Ephemerals or tachytherophytes are underlined; these are short-lived
desert annuals whose life-cycle may be closed in a few days or weeks. These species are collectively called Ashab in the Peninsula or
Aacheb in the Sahara and Ghizzu in North Sudan) [61].
Aaronsohnia factrovoskyi, Aizoon canariensis, Allium atroviolaceum, A. sindjarensis, Anastatica hierichuntica, Anisosciadium
lanatum, Anthemis deserti, Aristida adscensionis, Arnebia decumbens, A. linearifolia, Asphodelus refractus, A. viscidulus, Astragalus
asterias, A. bombycinus, A. corrugatus, A. hauarensis, A. schimperi, A. sieberi, A. tribuloides, Atractylis cancellata, A. carduus.
Bassia eriophora, Brachypodium distachyon, Brassica tournefortii, Bromus danthoniae, B. fasciculatus, B. madritensis, B. tectorum.
Cakile arabica, Calendula arvensis, C. tripterocarpa, Cenchrus ciliaris, Centaurea ammocyanus, C. pseudosinaica, Centropodia
fragilis, Chrozophora tinctoria, Colchicum ritchii, Convolvulus bushiricus, C. oxyphyllus, C. pilosellifolius, Cutandia memphitica,
Cynodon dactylon, Cyperus macrorrhizus. Dipcadi erythraeum, Diplotaxis acris. Echium arabicum, Emex spinosus, Enneapogon
desvauxii, Eremobium aegyptiacum, Eremopogon confusum, Erodium neuradiifolium, E. deserti, Euphorbia granulata. Fagonia
bruguieri, F. glutinosa, F. indica, Farsetia aegptia, F. burtoniae, Filago desertorum, Fumaria parviflora. Gypsophila capillaris,
G. viscosa. Haplophyllum tuberculatum, Heliotropium crispum, H. digynum, Herniaria hirsuta, Hippocrepis bicontorta, H. unisiliqua,
Hordeum murinum, Horwoodia dicksoniae, Hyoscyamus pusillus, Hypecoum pendulum. Ifloga spicata, Kickxia aegyptiaca,
Koelpinia linearis. Lasiurus scindicus, Launaea angustifolia, L. capitata, L. mucronata, Leptaleum filifolium, Leysera leyseroides, Linaria
haelava, Lotononis platycarpa. Malcolmia africana, M. grandiflora, Mathiola arabica, M. grandipetala, Matricaria aurea,
Medicago arabica, M. laciniata, M. orbicularis, Mesembryanthemum forsskalii, Monsonia heliotropioides, M. nivea, Morettia
parviflora. Neurada procumbens, Notoceros bicorne. Onobrychus ptolemaica. Panicum turgidum, Parapholis incurva, Paronychia
arabica, Pennisetum divisum, Picris cyanocarpa, Plantago afra, P. amplexicaulis, P. boissieri, P. ciliata, P. cylindrica, P. ovata, P.
psammophila, Polycarpaea repens, P. robbairea, Pteranthus dichotomus, Pulicaria arabica, P. undulata, P. guestii. Reichardia
tingitana, Reseda alba, Roemeria hybrida, Rostraria pumila, Rumex pictus, R. vesicarius. Savignya parviflora, Scabiosa olivieri,
Schimpera arabica, Schismus arabicus, S. barbatus, Sclerocepahalus arabicus, Scorzonera musilii, Senecio glaucus, Silene arabica,
S. villosa, Stipa capensis, Stipagrostis drarii, S. obtusa, S. plumosa, Spergula fallax, Spergularia marina, Suaeda fruticosa (=S.
vermiculata). Tribulus pentandrus, T. macropteris, T. terrestris, Trigonella anguina, T. hamosa, T. stellata, Tripleurospermum
auriculatum. Zilla spinosa, Zygophyllum simplex.
188
Sécheresse vol. 17, n° 1-2, janvier-juin 2006
Rangeland production, stocking
rates and carrying capacity
Heady estimated the carrying capacity of
Saudi Arabia’s rangelands to ca. 5.0 hectares per sheep-equivalent that is
20 sheep or 1 camel/km2 in 1963 [42,
50]. Many of the recommendations made
in Heady’s founding report have been
carried through during the past 40 years.
These, as well as the studies carried out in
the other countries of the peninsula, now
permit, thanks to the surveys and research
done during this period, to have a global
Sécheresse vol. 17, n° 1-2, janvier-juin 2006
Box 3
Results of the survey of the rangelands of the Saq
This very detailed study, involving 24 scientists and technicians, found out an estimated
carrying capacity (CC) of 13.2 hectares per ovine unit (OU) (40 kg dry sheep), i.e.,
7.57 OU/km2 or 303 kg Lwt/km2.
These varied from:
– Excellent rangelands: CC>38 OU/km2 or 1 OU>2.6 hectares;
– Good rangelands: 38>CC>24 OU/km2 or 2.6>OU>4.2 hectares;
– Fair rangelands: 24>CC>16.5 OU/km2 or 4.2>OU>6.1 hectares;
– Poor rangelands: 16.2>CC>10 OU/km2 or 6.1>OU>10.0 hectares;
– Very poor rangelands: 10>CC 10.0 hectares>OU.
Overall: 7.6 OU/km2 or 13.2 ha/OU, meaning rangelands in poor condition, on the
average.
evaluation of the present situation which
seems to be close to reality. A good example of the above is the survey of the rangelands (box 3) of the Saq (370,000 km2)
conducted by Boudet et al. (figure 6,
[16]), [66].
Other studies, less detailed or on less
extensive areas were consistent with these
conclusions [10, 31, 48, 49, 54, 55].
Productivity of annual plants was plotted
against their canopy cover; it was found to
fit the following overall equation
(figure 6):
Y = −70.38 + 19.64 lognX
Where Y = canopy cover % ;
X = production in Kg DM/ha
Or, in decimal log:
Y = -70.38 + 45.22log10·X·[16].
The study found that the carrying capacity,
as measured by range primary production
figures in DM/ha/yr, roughly was commensurate, at the time of the study, with the
stocking rates estimated from statistics and
from actual animal counts in the field.
Rangeland restoration
and rehabilitation
Rangeland restoration
Rangeland restoration occurred in the
large protected areas indicated above.
Many other smaller scale trials have
shown throughout Northern Africa and
South West Asia that productivity in exclosures is 2 to 4 times higher than in the
nearby freely grazed ranges [12, 18, 31,
56, 57, 62, 67-73]. This is a fact
witnessed in all arid lands of the world,
and the Arabian Peninsula is no exception
ANNUAL PLANTS
y
Canopy cover %
Copyright © 2017 John Libbey Eurotext. Téléchargé par un robot venant de 88.99.165.207 le 15/06/2017.
vast lake of brackish water) showed that
the stands continued southwards for hundreds of kilometers extending into Oman
southwards. It was then presumed that
probably it was a very large interdune
sabkha system that was covered with a
rather deep layer of sand! Some other
areas with decapitated sand dunes in the
southern part towards the Oman border
had richer vegetation consisting of Tamarix pycnocarpa, Seidlitzia rosmarinus,
and Zygophyllum mandavillei. Khaur
Hamdaan, the brackish water lake had
thick stands of Phragmites australis and
Tamarix nilotica.
It is widely believed that in the middle
Miocene (ca. 20 million years ago) to
Pliocene (ca. 13 million years ago),
the Empty Quarter area had a subtropical
climate with abundant supply of fresh
water. It is also thought that in the
Pleistocene the climate changed to alternating very long periods of aridity and rains
[64, 65]. As a result, at least two generations of fresh water lakes (between
21,000-17,000 years ago and 9,0006,000 years ago) in the form of old pluvial
lakebeds are found. Such lakebeds with
gypsic or calcic crusts are found in the
form of terraces higher above the saline
sabkha levels. These pluvial old lakebeds
with a thin layer of sand support a community of Halothamnus bottae alone or in
combination with Salsola cyclophylla.
At certain places there were level sabkha
areas with extremely high concentration of
sodium chloride, which at places was
encrusted as thin layers. Such areas were
sterile. At places these had pure stands of
Heliotropium bacciferum or of Aeluropus
lagopoides. At certain other places in
small patches with some sort of the erratic
rain water flow through them some components of the Nafud kind of vegetation
consisting of Monsonia nivea, Neurada
procumbens and Polycarpaea repens
could be seen: the major perennial components of the Nafud vegetation, i.e. Calligonum comosum, Artemisia monosperma
and Stipagrostis drarii are totally missing.
75
Loamy
Pebbly
Sandy
{
{ Substrate
{
50
Y=-
l og x
• 45,22
70,38
40
30
20
10
5
1
2 10
50
100
150
200
250
300
550
570
Productivity (kg of dry matter/ha)
x
Figure 6. Relationship between canopy cover and DM biomass in desert ephemerals in Saudi
Arabia [16].
189
Table VI. Livestock numbers and density in the Arabian Peninsula 2003 [4].
State
Cattle
Camels
Sheep
Goats
Asses
Bahrain
Kuwait
Oman
Qatar
Saudi Arabia
Un. Ar. Emir.
Yemen
Total
Conv. Factor
TLUa
13
20
315
15
340
110
1,400
2,213
0.70
1,549
1
20
125
51
260
250
264
971
1.20
1,165
17
850
355
200
8,250
560
6,500
16,732
0.20
3,346
16
130
1,000
180
2,700
1,450
7,250
12,726
0.18
2,291
7
28
100
500
635
0.50
318
Density
TLU / km2
ha / OU
24.1
0.82
9.6
2.08
2.9
6.90
11.5
1.74
1.0
20.00
9.2
2.17
7.4
2.70
2.8
7.14
Total TLU = 8,669* = 43,345 sheep-equivalents: ca. 0.82 sheep-equivalent per person;
Copyright © 2017 John Libbey Eurotext. Téléchargé par un robot venant de 88.99.165.207 le 15/06/2017.
a
Tropical Livestock Unit: 1 head of dry, mature cattle-equivalent, weighing 250 kg, kept at maintenance condition.
[56, 57]. The regeneration process may
however be fastened by a few other
actions such as planting fodder shrubs,
soil-water works to increase percolation
and reduce erosion, practicing deferred
rotational grazing. The time-honored hima
system was already established some thirteen centuries ago in the Arabian Peninsula [59]. This may have been the first
attempt at rational range management in
history. It consisted of setting aside from
the grazing grounds for one or several
seasons a portion of the range in order to
let it regenerate. This was carried out
through consensus among rightful users
and enforced through the villages’ counsels of elders. This innovative system is
cited in the Quran, which indicates it had
been operating for a while in Hijaz and
Asir at the time of the Hegira.
Another very efficient tool for the regeneration of rangelands is curbing subsidies to
feed supplementation. This administrative
measure is actually a strong incentive to
desertization. As animals are fed most,
and sometimes all, their nutritional needs
by concentrate feed, mainly barley grain,
bought on the world market and sold for a
symbolic price to the stockmen, via state
agencies, this is clearly an incentive to
herders to keep as many animals as they
physically can handle, regardless of the
consequences on the environment. This
fact has been denounced time and again
by range scientists in many countries of
North Africa and South West Asia over the
past 30 years, sometimes with success but
often to no avail [67-72].
Prospects for range rehabilitation
The basic range material is still present in
the plant communities but has become rare
because of more than half a century of
severe over-stocking. There are for ins-
190
tance some 300 spp of grasses in the
Peninsula (280 in Saudi Arabia alone)
[16, 19-21, 24, 26, 47, 72-79]. They
include some 100 perennials among
which 55-60 species may be considered
as good, productive forage grasses amenable to cultivation.
There are also a number of forage shrubs,
some of which have proved usable in
reserve plantations such as Atriplex halimus [56, 57]. Finally, there is the possibility of swapping the current cultivated fodder species, Rhodes Grass (Chloris
gayana), and Alfalfa (Medicago sativa)
with species that are much more waterefficient producing 2-4 kg of DM/m3 of
water vs 0.5-1 [72-74]. Finally there is the
possibility of growing forage species from
currently available but unused brackish
aquifers, such as Atriplex spp, Sporobolus spp. and others.
Livestock numbers densities
and their evolution
1990s. Apparently, this number declined
later as the number of dairy cattle
increased over the years displacing
camels as the main source of milk! Sheep
numbers appear to have peaked in the late
1990s. The number of goats is the highest
in the late 1990s-early 2000s as for the
camels! A reduction in barley price subsidy might explain the decrease in the
number of sheep, and possibly for some
decrease in the number of camels. Is the
cause of decline in the number of goats
due to a dwindling of the area of woodlands, forests and shrub cover in Saudi
Arabia? Or is the official data really a true
reflection of the number of livestock?
The density of livestock shown in tables 6
and 7 shows a density 40% higher than
the carrying capacity estimated by Heady
in 1963 [42, 50], for Saudi Arabia,
which represents 70% of the surface area
of the Peninsula (table 1).
Wildlife protection
and rehabilitation
Indications of the livestock populations
and densities are given in tables 6 and 7.
From the data in table 7, it appears that
the number of camels peaked in the
Range protection began in Saudi Arabia
with the creation of the National CommissionforWildlifeConservationandDevelop-
Table VII. Abridged livestock numbers in Saudi Arabia, 1982-2003 [80].
Year
Camels
Sheep
Goats
Cattle
1999-2003
1994-1998
1989-1993
1984-1988
1982-1983
253,694
410,385
412,098
385,398
339,240
7,346,088
7,559,139
6,723,196
6,780,654
6,393,380
2,293,534
4,222,929
3,730,089
3,188,044
2,618,75
299,848
261,915
207,900
250,855
231,663
Sécheresse vol. 17, n° 1-2, janvier-juin 2006
Copyright © 2017 John Libbey Eurotext. Téléchargé par un robot venant de 88.99.165.207 le 15/06/2017.
ment in 1978 (NCWCD) [81-85]. According to the NCWCD, there was some
170,000 km2 of land (8.1% of the area of
the kingdom) under some status of protected areas. Conservation is thus in the process of becoming a reality as large areas
of desert have been put in exclosures for the
rehabilitation of wildlife. According to the
NCWCD there were 22 large protected
areas in Saudi Arabia, in 2000. These
have various status: protection from grazing
by livestock (17,000 km2 in 18 areas),
regulated hunting 50,000 km2. The first
areas were closed in 1978. The various
categories recognized are:
– Special Natural Reserve (SNR) prime
sites of biological excellence. Only scientific research and low impact recreation
are permitted. They are administered by
the NCWCD;
– Natural Reserves (NR) are small areas of
high natural excellence administered by
the NCWCD;
– Biological Reserves (BR) are small areas
of biological importance, isolated stations,
breeding sites for key species, administered by local authorities, fully protected
from human disturbance, along with the
hima concept. The hima or grazing reserve
concept is briefly analysed in the range
management and rehabilitation section;
– Resource Use Reserves (RUR). These are
relatively large areas in each of which the
emphasis is resource management rather
than conservation, administered by local
authorities with the assistance of the
NCWCD.
Each of these sites had particular objectives of conservation for one or several species of plants or wildlife (box 4). Four sites
had an area between 10,000 and
21,000 km2 and 7 areas between
1,000 and 8,000 km2.
Just to give an idea of the efficiency of the
program, the reserve of Mahazat as-Sayd
(2,241 km2 fenced), the mean annual
rainfall 1991-1998 was 138mm (50240), the mean annual temperature was
ca. 24°C (6-42), the elevation is 1,000m.
The reserve was established in 1988 and
a founding herd of 17 heads of Arabian
Oryx was released in 1990, which reached over 400 heads in 1999, then receded
to 346 in 2000, consecutive to a severe
drought; there were in addition some
800 Arabian sand gazelles (Gazella
subgurrurosa) [81]. In 2005, the population of the Arabian Oryx reached the
figure of 700 heads in addition to
2,000 gazelles while the number of plant
species recorded had increased fourfold,
showing a tremendous regeneration of the
Sécheresse vol. 17, n° 1-2, janvier-juin 2006
Box 4
Key target species of the reserve program
The key target species in the overall reserve program are as follows [81-85]:
• Large mammals
Hamadryas baboon: Papio hamadryas, Wild goat: Capra ibex nubiana, arabian
sand gazelle Gazella subgutturosa marica, dorcas gazelle: Gazella dorcas, mountain
gazelle: Gazella gazella, Arabian oryx: Oryx leucoryx, wild cat: Felis silvestris,
cheetah: Acinonyx jubatus, Arabian leopard: Panthera pardus nimr, caracal: Felis
caracal, sand cat: Felis margarita, red fox: Vulpes vulpes, Ruppell’s fox: Vulpes
ruppellii, wolf: Canis lupus, Asiatic jackal: Canis aureus, striped hyena: Hyaena
hyaena, African small-spotted genet: Genetta felina, ratel: Mellivora capensis, white
tailed mongoose: Ichneumia albicauda albicauda.
• Lagomorphs
Cape hare : Lepus capensis:
Insectivora: Ethiopian hedgehog: Paraechinus aethiopicus, Indian crested porcupine:
Hystrix indica.
• Rodents
Wagner gerbil: Gerbillus dasyurus, Cheesman’s gerbil: Gerbillus cheesmani, king jird:
Meriones rex, Egyptian spiny mouse: Acomys cahorinus, rock rat: Praomys fumatus,
lesser jerboa: Jaculus jaculus.
• Birds
Red necked ostrich: Struthio camelus camelus, Arabian ostrich: Struthio camelus
syriacus, houbara bustard: Chlamidotis undulata macquenii, sand partridge: Ammoperdix heyeri, hooded wheat eater: Oenanthe monacha, cream coloured cursor:
Cursorius cursor, trumpeter finch: Bucanetes githagineus, Yemen thrush: Turdus menachensis, Arabian serin: Serinus rothchildi, Yemen warbler: Parisoma buryi, Yemen
serin: Serinus menachensis, Arabian waxbill: Estrilda rufibarba, Yemen linnet: Carduelis yemenensis, Arabian woodpecker: Dendrocopos dorae, long legged buzzard:
Buteo rufinus, golden eagle Aquila chrysaetos, short-toed eagle: Circaetus gallicus,
sooty falcon: Falco concolor, lapped faced vulture: Torgos tracheliotus, black vulture:
Aegyptius monachus, Egyptian vulture: Neophron pernopterus.
• Reptiles
dhob or spiny-tailed lizard: Uromastyx ovcellatus & U. aegyptius, monitor lizard:
Varanus griseus, sand lizard: Scincus mitranus, Stenodactylus arabicus, Acanthodactylus gongorhynchatus, Cyrtodactylus sp. Phrenodcephalus arabicus, sand viper :
Cerastes cerastes gasparetti.
environment [86, 87]. The present stocking rate may thus be evaluated:
(2,000 × 25 kg) + 700 × 50 kg =
ca.85,000 kg Lwt ⁄ 224,000 hectares =
0.38 kg Lwt/ha or10.50 ha/OU − equivalent.
This corresponds to a consumed primary
production of some 44 kg DM/ha/yr.
Assuming a proper use factor of 50% the
corresponding Rain Use Efficiency (RUE)
would be:
88 kg DM/138mm = 0.6 kg DM/ha/yr/mm
suggesting a still large potential of future
improvement.
Concluding remarks
and recommendations
The vegetation in general and particularly
the tree flora have been extremely misused
and the rangelands degraded by man and
his livestock. The overgrazing of the range-
lands has been historic but what amounts
to destruction in many parts is recent,
following mechanized transport and feed
subsidy to the pastoralists. Similarly, destruction of woodlands and forests has
been historic but the rapidity and severity
of destruction has been more intense in
recent times following mechanized transport and increased human population and
human activity. In many of the rangelands,
simple protection for a few years accompanied by a reverse subsidy as incentive
to the true Bedouin shepherds to keep the
livestock numbers low can help maintain
sustained livestock productivity at the optimum carrying capacities of various rangelands. The rangelands are not in a state
beyond repair. To achieve such rehabilitation several socially acceptable and technically efficient “tools” are available including restoring the historical hima system
dating back to the Hegira period. Other
methods are planting adapted fodder
shrubs and establishing wildlife reserves
191
Copyright © 2017 John Libbey Eurotext. Téléchargé par un robot venant de 88.99.165.207 le 15/06/2017.
as already carried out on a large scale. To
achieve sustained productivity, optimum
carrying capacity for each kind/area of
rangeland will need to be determined
through further research and survey. In
affluent countries in the Arabian Peninsula
it should be possible for the governments
to develop regional range conservation
practices of the kind that would help
achieve sustained productivity as well as
serve as models to poorer countries in the
neighboring arid regions. Goatherds
should be cut back preferably to just small,
penned and not free-roaming, domestic
flocks for individual owners. The people in
Arabian Peninsula have in the past survived mostly on nature. Now is the time for
them to give back to nature what they have
so wantonly taken away from nature in the
recent past! ■
Acknowledgements
The authors shouldlike to express their gratitude to Ms. K. Tsagarakis, formerly librarian
with the National Wildlife Center, Taïf, for
kindly providing references to, and reports
on, wildlife in Saudi Arabia.
References
1. Chaudhary SA. Geography and geology, the
sand. In: Chaudhary SA, Juwaid AA, eds. Natural History of Saudi Arabia – An Introduction.
Riyadh: Ministry of Agriculture and Water,
1992.
2. Fisher M, Membery D. Climate. In: Ghazanfar SA, Fisher M, eds. Vegetation of the Arabian
Peninsula. Geobotany, n° 7. Dordrecht (The
Netherlands): Klüwer Academic Publishers,
1998.
3. Chaudhary SA, Juwaid AA. Vegetation of the
Kingdom of Saudi Arabia. Riyadh: Ministry of
Agriculture and Water, 1999.
4. Food and Agriculture Organisation (FAO).
Production yearbook, 2003. Rome: FAO, 2004.
5. Le Houérou HN. Atlas of climatic diagrams for
the isoclimatic Mediterranean zones. Montpellier: Copymania, 2005.
6. Le Houérou HN, Bingham R, Sherbek W.
Relationship between the variability of primary
production and the variability of annual rainfall
in world arid lands. J Arid Environ 1988; 13:
1-18.
7. Zaman S, Taha FK. Quantitative evaluation of
vegetation in two main steppes of Kuwait’s rangelands. In: Omar SAS, Razzaque MA, Alsdirawi F, eds. Range management in arid zones.
London: Kegan Paul International, 1995.
8. Allred BW. Range Management Training
Handbook for Saudi Arabia. Rome: Food and
agriculture organisation (FAO), 1968.
192
9. Le Houérou HN. Les pâturages de la Tunisie
aride et désertique. Tunis; Paris: Institut de sciences économiques appliquées (Isea), 1962.
10. Kingery CE. Report to the Government of
Saudi Arabia on proposals for expanding and
improving range, pasture and fodder development and management program. Rome: Food
and agriculture organisation (FAO), 1972.
11. Anon. AtlasEco. Paris: Nouvel Observateur,
2003.
12. Le Houérou HN, Boulos L. Bioclimatic and
phytogeographic characteristics of the arid rangelands of northern Africa and the Near East. In:
Gaston A, Kernick M, Le Houérou HN, eds. Proceedings of the IVth International Range
Congress. Vol. I. Montpellier: Centre de coopération internationale en recherche agronomique
pour le développement-unité centrale d’information scientifique et technique (Cirad-Ucist), 1991.
13. Zohary M. Geobotanical Foundation of the
Middle East. 2 Vols. Stuttgart: Fisher Verlag,
1973.
14. Le Houérou HN. The Isoclimatic mediterranean biomes: bioclimatology, diversity and phytogeography. 2 Vols. Montpellier: Copymania,
2005.
15. Le Houérou HN. Bioclimatology and phytogeography of the Red Sea and Aden Gulf basins:
A Monograph (with particular reference to the
highland evergreen sclerophylls and lowland
halophytes). Arid Land Res Manage 2003; 17:
177-225.
16. Boudet G, De Wispelaere G, Dulieu D, et al.
Range survey of the Saq (Saudi Arabia). Vols I, II,
III, IV, V. Maisons-Alfort: Institut d’élevage et de
médecine vétérinaire des pays tropicaux
(IEMVT), 1982.
17. Le Houérou HN. Rangeland Management in
Northern Africa and the Near East: evolution,
trends and development outlook. In: Gaston A,
Kernick M, Le Houérou HN, eds. Proceedings of
the IVth International Range Congress. Vol. I.
Montpellier: Centre de coopération internationale en recherche agronomique pour le
développement-unité centrale d’information
scientifique et technique (Cirad-Ucist), 1991.
18. Le Houérou HN. Bioclimatologie et biogéographie des steppes arides du Nord de l’Afrique.
Options Méditerranéennes Ser B 1995; 10:
1-396.
19. Heemstra HH, Al Hassan OL, Minwar FS.
Plants of Saudi Arabia. Al-Jouf (Saudi Arabia):
Range and Animal Development Research Center, Ministry of Agriculture and Water, 1990.
20. Mandaville JP. Flora of Eastern Saudi Arabia. London: Kegan Paul International, 1990.
23. Ghazanfar SA, Fisher M, eds. Vegetation of
the Arabian Peninsula. Geobotany, n° 7. Dordrecht (The Netherlands): Klüwer Academic
Publishers, 1998.
24. Jongbloed M. Guide to the wild flowers of the
United Arab Emirates. Abu Dhabi: Environment
and Wildlife Development Agency (ERDWA),
2003.
25. Collenette S. An illustrated guide to the
flowers of Saudi Arabia. London: Scorpion
Publishing, 1985.
26. Collenette S. Wild flowers of Saudi Arabia.
Riyadh: National Commission for Wildlife
Conservation and Development (NWCD)), 1999.
27. Chaudhary SA. Vegetation Communities. In:
Ministry of Agriculture and Water, ed. Land
Resources. Riyadh: Ministry of Agriculture and
Water, 1995.
28. Chaudhary SA, ed. Flora of the Kingdom of
Saudi Arabia. Illustrated. Vols. I, II, III. Riyadh:
National Herbarium, Ministry Agriculture and
Water, 1999-2001.
29. Abd El Rahman AA. The deserts of the Arabian Peninsula. In: Evenari M, Noy-Meir I, Goodall DW, eds. Hot Deserts and Arid Shrublands.
Vol 12 B. Amsterdam: Elsevier, 1986.
30. Popov G, Zeller W. Ecological survey in the
Arabian Peninsula. United Nations Special Fund
(UNSF) Desert Locust Project. Rome: Food and
agriculture organisation (FAO), 1963.
31. Chaudhary SA. Rangeland grazing and
effects on vegetation and biodiversity in Arabia.
Paper presented at Quest 2002, International
Symposium on Rangelands, Vegetation and Biodiversity in Arabia, Doha, Qatar, 2001 (unpublished).
32. Mikesell MN. The Deforestation of Mount
Lebanon. Geogr Rev 1969; 54: 1-8.
33. Fischer M. Decline in juniper woodlands of
Riyadh Reserve in southwestern Saudi Arabia; a
response to climate changes? Global Ecol Biogeogr Lett 1997; 6: 379-86.
34. Fischer M, Gardner AS. The status and ecology of Juniperus excelsa ssp. Polycarpos woodland in the northern mountains of Oman. Vegetatio 1995; 119: 33-51.
35. Hepper FN. Outline of the vegetation of
Yemen Arab Republic. Cairo Univ Herbarium
Bull 1977; 7-8: 307-22.
36. Halwagy R, Halwagy M. Ecological studies
on the desert of Kuwait. 1 – Physical Environment.
2 - The vegetation. J Univ Kuwait (Science) 1974;
1: 75-95.
21. Ghazanfar SA. An annotated catalogue of
the vascular plants of Oman. Scripta Botanica
n°2. Meise: National Botanic Garden, 1992.
37. Halwagy R, Halwagy M. Ecological studies
on the desert of Kuwait. 3. The vegetation of
coastal salt marshes. J Univ Kuwait (Science)
1977; 5: 95-107.
22. Ghazanfar SA. Flora of Oman. Vol. 1.
Scripta Botanica Belgica n° 25. Meise: National
Botanic Garden, 2003.
38. Halwagy R, Moustafa AF, Kamal S. On the
ecology of desert vegetation in Kuwait. J Arid
Environ 1982; 5: 95-107.
Sécheresse vol. 17, n° 1-2, janvier-juin 2006
39. Vesey-Fitzgerald DF. Vegetation of the Red
Sea coast south of Jeddah, Saudi Artabia. J Ecol
1955; 43: 477-89.
Copyright © 2017 John Libbey Eurotext. Téléchargé par un robot venant de 88.99.165.207 le 15/06/2017.
40. Vesey-Fitzgerald DF. Vegetation of the Red
Sea coast north of Jeddah, Saudi Arabia. J Ecol
1957; 45: 547-62.
54. Italconsult. Water and agricultural surveys for
areas II, III and IV. Final report. Grazing resources inventory, vegetation and range units map.
Rome; Riyadh: Italconsult; Ministry of Agriculture
and Water, 1969.
41. Vesey-Fitzgerald DF. The vegetation of central and eastern Arabia. J Ecol 1957; 45: 77998.
55. Klemme M. Report to the Government of
Saudi Arabia on pasture development and range
management (with respect to increasing livestock
production). EPTE Report n° 1633. Rome: Food
and agriculture organisation (FAO), 1965.
42. Heady HF. Grazing resources and problems.
Report to the Government of Saudi Arabia.
Expanded Program of Technical Assistance,
Report n° 1614. Rome: Food and agriculture
organisation (FAO), 1963.
56. Mirreh MM, Darin MS. The effect of three
years protection on vegetation of WadiTamaryaat. Working Paper No. TW-2. Al Jouf (Saudi
Arabia): Range and Animal Development
Research Center, 1986 (unpublished report).
43. Alwelaeie AN. Factors contributing to the
degradation of the environment in Central Eastern and Northern Saudi Arabia. In: Abuzinadah AA, et al. Wildlife Conservation and Development in Saudi Arabia. Riyadh: National
Commission for Wildlife Conservation and Development (NCWCD), 1989.
57. Mirreh MM. Al-Diran 0MS. Effects of grazing
pressure in the desert rangelands of Al Jouf
Region, Saudi Arabia. In: Omar SAS, et al., eds.
Range Management in Arid Zones. London:
Kegan Paul, 1995.
44. Chaudhary SA. Acacia and other genera of
Mimosoideae in Saudi Arabia. Riyadh: Regional
Agriculture and Water Research Center, ministry
of Agriculture, 1983.
45. Zahran MA. Vegetation types of Saudi Arabia. Introduction to Plant Ecology and Vegetation
Types of Saudi Arabia. Jeddah: King Abdulaziz
University, 1982.
46. Abo Hasan AA, et al. Natural forests in the
Kingdom of Saudi Arabia and their potential use.
Riyadh: Saudi Arabia National Center for
Science and Technology (SANCST), 1984 (in
Arabic).
47. Wood JR. A handbook of the Yemen flora.
Richmond (Great Britain): Royal Botanic Gardens, Kew, 1997.
48. König P. Zonation of vegetation in the mountainous region of southwestern Saudi Arabia
(Asir, Tihama). In: Kurschner H, ed. Contribution
to the vegetation of southwest Asia. Wiesbaden
(Germany): Reichert verlag, 1986.
49. König P. Vegetation und Flora im sudwestlichen Saudi Arabien (Asir, Tihama). Dissertationes Botanicae, 101. Stuttgart: Borntraeger
Verlagbuchhandlung; Schweizerbart’sche Verlagbuchhandlung, 1987.
50. Heady HF. Comments on range management
technical assistance in the Middle East, with special reference to Saudi Arabia. J Range Manage
1963; 16: 317-21.
51. Chaudhary SA. The northern rangelands. In:
Chaudhary SA, Juwaid AA, eds. Natural History
of Saudi Arabia – An Introduction. Riyadh:
Ministry of Agriculture and Water, 1992.
52. Baierle HU, El-Sheikh AM, Frey W. Vegetation und flora im mittleren Saudi-Arabien (AtTaif-ar-Riyadd). Wiesbaden: Ludwid Reichert
Verlag, 1985.
53. De Marco G, Dinelli A. First contribution to
the floristic knowledge of Saudi Arabia. Annali di
Botanica (Roma) 1974; 33: 211-36.
Sécheresse vol. 17, n° 1-2, janvier-juin 2006
58. Kernick MD. Report to the Government of
Kuwait on plant resources, range ecology and
fodder plant introduction. Report of Technical
Assistance n° 218. Rome: Food and agriculture
organisation (FAO), 1966.
59. Draz O. The Hema system of range reserves
in the Arabian Peninsula. AGP. Rome: Food and
agriculture organisation (FAO), 1969.
60. Chaudhary SA. Desert environment and
plant adaptations. In: Chaudhary SA, Juwaid AA, eds. Natural History of Saudi Arabia – An
Introduction. Riyadh: Ministry of Agriculture and
Water, 1992.
61. Le Houérou HN. The grazing lands ecosystems of the African Sahel. Ecological Studies
n°75. Heidelberg: Springer Verlag, 1989.
62. Chaudhary SA. Understanding the desert
range plants of Saudi Arabia. In: Abuzinadah AA, et al. Wildlife Conservation and Development in Saudi Arabia. Riyadh: National Commission for Wildlife Conservation and Development
(NWCD), 1989.
63. Chaudhary SA. The Empty Quarter. In:
Chaudhary SA, Juwaid AA, eds. Natural History
of Saudi Arabia – An Introduction. Riyadh:
Ministry of Agriculture and Water, 1992.
64. McClure HA. Radiocarbon Chronology of
Late Quaternary Lakes in the Arabian Desert.
Nature 1976; 263: 755-6.
65. McClure HA. Ar Rub’ Al Khali. In:
Al-Sayari SS, Zotl JG, eds. Quaternary Periodin
Saudi Arabia. Wien; New York: SpringerVerlag, 1978.
66. Batanouny KH. Natural History of Saudi Arabia. A bibliography. Jeddah: King Abdulaziz
University, 1978.
67. Le Houérou HN. Long-term dynamics in aridland vegetation and ecosystems of North Africa.
In: Goodall DW, Perry RA, eds. Arid Lands Ecosystems: their structure, functioning and management. 2. International Biological Programmes 17.
Cambridge: Cambridge University Press, 1981.
68. Le Houérou HN. Rain Use Efficiency, a unifying concept in arid land ecology. J Arid Environ
1984; 7: 213-47.
69. Le Houérou HN. La régénération des steppes
algériennes. Paris: Institut national de la recherche agronomique (Inra), Département des Relations extérieures, 1985.
70. Le Houérou HN. Inter-annual variability of
rainfall and its ecological and managerial consequences on natural vegetation, crops and livestock. In: Di Castri F, Floret C, Rambal S, Roy J,
eds. Time scale and water stress. Paris: International Union of Biological Sciences, 1988.
71. Le Houérou HN. A probabilistic approach to
assessing arid rangelands productivity, carrying
capacity and stocking rates. In: Squires VR, Sidahmed A, eds. Sustainable use of arid lands.
Rome: International Fund for Agricultural Development (IFAD), 1998.
72. Le Houérou HN. Outline of a strategy for
rangeland and feed resources development in the
Arabian Peninsula. Arabian Peninsula Regional
program (APRP). Dubai: International Center for
Agricultural Research in the Dry Areas (ICARDA),
1998 (unpublished).
73. Le Houérou HN. Range Rehabilitation in
Kuwait. Kuwait: Kuwait Institute for Scientific
Research, 2003 (unpublished).
74. Peacock JM, Ferguson ME, Alhadrami GA, et
al. Conservation through utilization: a case study
of the indigenous forage grasses of the Arabian
Peninsula. Proceedings of the International
Conference on the Conservation of Biodiversity in
Arid Regions, Kuwait, March 27-29, 2000.
75. Chaudhary SA. Grasses of Saudi Arabia.
Riyadh: Ministry of Agriculture and Water,
1989.
76. Chaudhary SA, Cope TA. A checklist of grasses of Saudi Arabia (Studies in Flora of Arabia,
VI). Arab Gulf J Scientific Res 1983; 1: 313-53.
77. Dakheel A, Ferguson ME, Al Hadrami G,
Saleh A, Mc Cann IR, Peacock JM. Desert Forages of the Arabian Peninsula. The sustainable use
of salt-affected soils through conservation and
evaluation. Proceedings of the International
Seminar on Prospects for Saline Agriculture,
April 10-12, Islamabad, Pakistan. Aleppo
(Syria); Patancheru (Andra Predesh, India): International Center for Agricultural Research in the
Dry Areas (ICARDA); International Crops
Research Institute for the Semi-Arid Tropics (ICRISAT), 2000.
78. Zaroug MG. The status of rangelands of the
southern region of the Sultanate of Oman (Dhofar) and prospects for their conservation and
sustained development. Rome: Food and Agriculture Organisation (FAO), 1983.
79. Zaroug MG. Rangelands of the southern
region of Oman. Their characteristics and development aspects. Rome: United Nations Development Program (UNDP); Food and Agriculture
Organisation (FAO), Office Muscat, 1990.
193
80. Anon. Agricultural Statistics Yearbooks. Vols.
12-16. Riyadh: Ministry of Agriculture and
Water, Department of Economic Studies and Statistics, 1982-2003.
81. Teyde AC, Williams JB, Bedin E, et al. In
search of the optimal management strategy foe
Arabian Oryx in Mahazat as-Sayd, Said Arabia.
Taif: National Commission for Wildlife Conservation and Development (NCWCD), 2000.
84. Abuzinada AH, Llewellyn OA. Designing a
system of protected areas to reverse environmental degradation in Saudi Arabia. IUCN General
Assembly Workshop on Conservation and Sustainable Development in the Sahel and other Arid
Regions, Perth, Australia. NCWCD Report.
Riyadh: National Commission for Wildlife
Conservation and Development (NCWCD),
1990.
85. Jungius H. The establishment of national
parks and protected areas in the arid zone: a
contribution to conservation and rational utilization of natural resources. In: Abuzinada AH,
Goriup PD, Nader IA, eds. Wildlife conservation
and Development in Saudi Arabia. Proceedings
of the first symposium on the potential of Wildlife
conservation and developmlent in Saudi Arabia.
Riyadh: National Commission for Wildlife
Conservation and Development (NCWCD),
1988.
86. Ostrowski S. Ajustements écophysiologiques
des antilopes aux contraintes du milieu désertique. Thèse, université Claude Bernard, Lyon,
2006.
87. Ostrowski S, Williams JB, Mésochina P,
Sauerwein H. Physiological acclimation of a
desert antelope, Arabian oryx (Oryx leucoryx) to
long-term food and water restriction. J Compared Physiol 2006; 176: 191-201.
Copyright © 2017 John Libbey Eurotext. Téléchargé par un robot venant de 88.99.165.207 le 15/06/2017.
82. Abuzinada AH. Protected areas and conversion of desert ecosystems. In: Batanouny KH,
Ghabbour SI, eds. Proceedings of the workshop
on Arid Lands Biodiversity in North Africa. Cairo:
Academy of Scientific Research and Technology,
University of Cairo, 1996.
83. Abuzinada AH. Protected areas management and sustained rural development: the Saudi
Arabia experience. Riyadh: National Commission for Wildlife Conservation and Development
(NCWCD)), 1997.
194
Sécheresse vol. 17, n° 1-2, janvier-juin 2006