West Saharan montane xeric woodlands
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| Ecozone: | Palearctic |
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| Biome: | Deserts and xeric shrublands |
| Climate type: | extreme in the dry and hot climate |
| Soil types: | |
| Surface: | |
| Conservation status: | relatively intact |
| Global 200: | |
| Oceans or seas (borders): | |
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| Borders: | |
| Countries: | Northern Africa: Southeastern Algeria, northern Niger, Mali, and Mauritania |
The West Saharan montane xeric woodlands is an ecoregion covering part of the Sahara. Contrary to what its name suggests, it is not a land of woods. Xeric means "adapted to an extremely dry habitat" (generally referring to shrubs).
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[edit] Sahara desert, introduction
The Sahara is the world's second largest desert (after Antarctica) and is located in northern Africa. It stretches from the Red Sea to the highlands of Ethiopia. However, the Sahara encompasses regions significantly different from an ecological perspective. The surface of the desert ranges from large areas of sand dunes (which are called erg), to stone plateaus (hamadas), gravel plains (reg), dry valleys (wadis), and salt flats. The northern and southern margins also receive more rainfall and have greater vegetation than central Sahara. The very scarce rain (less than 25 mm and even less than 5 mm per annum in the east) can fall in any season and in a very irregular way: some areas may receive no rain for years and then suffer intense storms. Some areas encompass vast underground aquifers resulting in oases, while other regions severaly lack water reserves.
Some mountains (Ahaggar, Tassili N’Ajier, Tibesti, Aïr) also rise up in the desert and receive more rainfall and mostly present slightly cooler summer temperatures. For such reasons, the great Sahara may be divided in several ecoregions and each of them be separately described.
[edit] West Saharan montane xeric woodlands
The boundaries for the largest part of this ecoregion, which includes the Tassili-n-Ajjer Ahaggar and Aïr ou Azbine massifs, follow the 'regs,' 'hamadas' and 'wadis' above the 1000 m contour. This covers a good part of southeast Algeria. These areas are reaching almost 3000 meters Additional areas further south were included within this ecoregion, including the Aïr ou Azbine in northern Niger, Dhar Adrar in Mauritania, and Adrar des Iforas in Mali and Algeria, using the 500 m-elevation contour.
This ecoregion has an area of 258,100 km² (99,700 square miles)
The mountains of the West Saharan Montane Xeric Woodland ecoregion are found within the Sahara Desert and are predominantly of volcanic origin. They rise from the surrounding flat desert landscape or sand dunes and create islands of moister habitat (guelta) which support flora and fauna. The most important area is the Tassili-n-Ajjer Plateau, an outlier of the Ahaggar Mountains in Algeria which supports some near-endemic species and some globally threatened antelopes. The highest point of these mountains is 3003 meters (Mount Tahat).
Winters are quite rigorous, with amplitude in temperature over 20°C. Day temperatures may be over 20°C while nights are freezing. In summer, days are very hot, though less than in central Sahara. Rainfall is rare and sporadic.
The human population of the ecoregion is very small, with less than 5 persons per km². Many people are nomadic though some small cities also exist (ideles). The vegetation remains fairly intact.
