7.3.2. Ecosystems
- The region is characterized by arid and semi-arid lands, on which it
depends for much of its economic activity (e.g., agriculture and livestock
grazing in rangelands). These ecosystems are under extreme pressure from human
activities and current climatic conditions (e.g., high temperatures and prolonged
droughts). Because of the current marginality of soil-water and nutrient reserves,
some ecosystems in semi-arid regions may be among the first to show the effects
of climate change. However, a number of management options (e.g., better stock
management, more-integrated agroecosystems) could improve land conditions.
- The relatively hospitable mountain regions are under particular pressure
from human settlements and commercial cultivation, which have led to land
degradation and adverse effects on water supply. Glacial melt is forecast
to increase under climate change, which would lead to increased summer flows
in some river systems for a few decades, followed by a reduction in flow as
the glaciers disappear.
- A tenth of the world's known species of higher plants and animals occurs
in this region. Some countries (particularly Turkey and Tajikistan) are centers
of origin for many crop and fruit-tree species; as such, they are important
sources of genes for the wild relatives. Few studies are available to assess
the impact of climate change on the biodiversity of the region; given its
importance, however, there is a need for such studies. Biodiversity is being
lost in the region because of human activities, especially land degradation
and the overuse of resources.
7.3.2.1. Grasslands, Rangelands, Woodlands, and Deserts
Half of the region (see Table 7-1) is classified
as arid land, much of which is true desert (i.e., extremely arid, as defined
in IPCC 1996, WG II, Chapter 3). Another tenth of the region is classified as
semi-arid rangeland, dominated by grasslands or shrublands. About 10% of the
arid and semi-arid land is classified as having some soil constraints, indicating
either that it shows significant soil degradation or that it is desertified
(see Table 7-1). The region's major deserts and
some of their characteristics are listed in Table 7-2,
along with their classification (i.e., semi-arid, arid, or extremely arid, as
defined in IPCC 1996, WG II, Chapter 3). For comparative purposes, deserts in
adjoining regions (e.g., the Gobi desert from the Temperate Asia region) are
included. Deserts are classified as cold deserts (e.g., upland deserts of Middle
Asia that are 1,200 m above sea level) or hot deserts (e.g., those in the Middle
East). The seasonality of the deserts' rainfall varies; some receive predominantly
winter rain, whereas others receive mostly summer rain. Deserts with very sporadic
rain events are classified as aseasonal.
| Table 7-2: Geophysical characteristics
of deserts in the Middle East and Arid Asia region. |
|
| Desert (Country) |
Aridity
|
Main Rainy Season
|
Temperature of Coldest Month/ Absolute Min (°C)
|
Temperature of Warmest Month/ Absolute Max (°C)
|
Latitude
|
Elevation (m)
|
Precipitation (mm/yr)
|
Area (000s km2)
|
|
| Arabian Desert |
Extreme Arid/
|
Aseasonal
|
0-10/10-20/
|
20-0/>30
|
15-31°N
|
0-1,200
|
25-150
|
800
|
| (includes Rub al Khali and Nafud) |
Arid/Semi-Arid
|
Winter
|
20-30
|
|
|
|
|
|
| |
|
|
|
|
|
|
|
|
| Iranian Desert |
Extreme Arid
|
Winter
|
0-10/-10
|
20-30/+45
|
27-36°N
|
200-800
|
50-100
|
135
|
| (includes Dasht-i-Margo, Dasht-e-Naomid, Dasht-e-Kavir, Dasht-e-Lut) |
Semi-Arid/Arid
|
|
|
|
|
|
|
|
| |
|
|
|
|
|
|
|
|
| Negev (Israel) |
Arid
|
Winter
|
10-20
|
20-30/>30
|
|
|
|
|
| |
|
|
|
|
|
|
|
|
| Syria, Iraq, N. Arabian, Jordanian Deserts |
Arid
|
Winter
|
0-10/-11
|
20-0/+470
|
31-37°N
|
200-800
|
100-150
|
|
| |
|
|
|
|
|
|
|
|
| Registan (Afghanistan) |
Extreme Arid
|
Winter
|
/-19
|
/+42
|
29-32°N
|
500-1,500
|
50-100
|
40
|
| |
|
|
|
|
|
|
|
|
| Middle Asia (1) and Kazakstan |
|
|
|
|
|
|
|
|
| Garagum |
Extreme Arid/Arid
|
Biseasonal/Spring
|
-5-10/-35
|
+27 +30/+ 50
|
37-42°N
|
100-500
|
70-100
|
350
|
| Ustjurt and Mangyshlak |
Arid/Semi-Arid
|
Biseasonal/Spring
|
-5-10/-40
|
+26+28/+42
|
42-45°N
|
200-300
|
80-150
|
200
|
| Qizilkum |
Extreme Arid/ Arid/Semi-Arid
|
Biseasonal/ Spring
|
-4-8/-32
|
+28+30/+45
|
42-44°N
|
50-300
|
70-180
|
300
|
| Priaralski Garagum |
Arid
|
Biseasonal/Spring
|
-11-14/-42
|
+26+28/+42
|
46-48°N
|
400
|
130-200
|
35
|
| Betpaqdala |
Arid
|
Biseasonal/Spring
|
-12-13/-38
|
+26+28/+43
|
44-46°N
|
300-350
|
100-150
|
75
|
| Mujunkum |
Arid/Semi-Arid
|
Biseasonal
|
-2-3/-45
|
+24+28/+40
|
43-44°N
|
100-660
|
170-300
|
40
|
| Moinkum |
Semi-Arid
|
Biseasonal/Spring
|
-7-11
|
+25+27
|
43-45°N
|
300-700
|
250-300
|
80
|
| Saryesik-Atyrau |
Arid
|
Biseasonal
|
-14-15
|
+23+25
|
45-46°N
|
300-500
|
150-200
|
|
| Bolshie and Malye Barsuki |
Arid
|
Biseasonal/Spring
|
-12-15
|
+25+27
|
46-48°N
|
100-200
|
150-200
|
40
|
| Naryn-Peski |
Semi-Arid
|
Biseasonal
|
-9-12
|
+23+25
|
46-50°N
|
0-50
|
250
|
200
|
| |
|
|
|
|
|
|
|
|
| Others Adjacent to the Region |
|
|
|
|
|
|
|
|
| Gobi (China, Mongolia) (2) |
Semi-Arid/Extreme Arid
|
Biseasonal
|
/-40
|
/+45
|
42-47°N
|
900-1,200
|
50-200
|
1050
|
| Ordos (China, Mongolia) |
Arid/Semi-Arid
|
Summer
|
/-21
|
/+42
|
38-40°N
|
1,100-1,500
|
150-300
|
95
|
| Sinai (Egypt) |
Extreme Arid/Arid
|
Aseasonal
|
10-20
|
20-30
|
|
|
|
|
| Takla Makan (China) (2) |
Semi-Arid/Extreme Arid
|
Biseasonal
|
-10-20 /-27
|
/+37
|
36-43°N
|
800-1,500
|
50-75
|
271
|
| Thar (India, Pakistan) (2) |
Arid/Semi-Arid
|
Summer/Aseasonal
|
10-20/-1
|
>30/+48
|
24-31°N
|
0-800
|
150-500
|
300
|
| Thal (Pakistan) |
Arid
|
Summer
|
/-2
|
/+49
|
30-32°N
|
100-200
|
50-200
|
26
|
|
|
Sources: McGinnies et al., 1968; Wilson, 1976; Walter et al., 1983; Evenari
et al., 1985; Babaev et al., 1986.
(1) Includes FSU.
(2) Not in this region.
|
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|
