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The West Saharan montane xeric woodlands is an
ecoregion An ecoregion (ecological region) or ecozone (ecological zone) is an ecologically and geographically defined area that is smaller than a bioregion, which in turn is smaller than a biogeographic realm. Ecoregions cover relatively large areas of ...
that extends across several highland regions in the
Sahara , photo = Sahara real color.jpg , photo_caption = The Sahara taken by Apollo 17 astronauts, 1972 , map = , map_image = , location = , country = , country1 = , ...
. Surrounded at lower elevations by the largely barren Sahara, the West Saharan montane xeric woodlands are isolated refuges of plants and animals that can survive in the higher humidity and lower temperatures of the highlands.


Setting

The Sahara is a vast desert, stretching across northern Africa from the
Atlantic Ocean The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe ...
to the
Red Sea The Red Sea ( ar, البحر الأحمر - بحر القلزم, translit=Modern: al-Baḥr al-ʾAḥmar, Medieval: Baḥr al-Qulzum; or ; Coptic: ⲫⲓⲟⲙ ⲛ̀ϩⲁϩ ''Phiom Enhah'' or ⲫⲓⲟⲙ ⲛ̀ϣⲁⲣⲓ ''Phiom ǹšari''; ...
. Some mountains ranges (such as the
Ahaggar The Hoggar Mountains ( ar, جبال هقار, Berber: ''idurar n Ahaggar'') are a highland region in the central Sahara in southern Algeria, along the Tropic of Cancer. The mountains cover an area of approximately 550,000 km. Geography This ...
,
Tassili n'Ajjer Tassili n'Ajjer ( Berber: ''Tassili n Ajjer'', ar, طاسيلي ناجر; "Plateau of rivers") is a national park in the Sahara desert, located on a vast plateau in southeastern Algeria. Having one of the most important groupings of prehistoric ...
,
Tibesti The Tibesti Mountains are a mountain range in the central Sahara, primarily located in the extreme north of Chad, with a small portion located in southern Libya. The highest peak in the range, Emi Koussi, lies to the south at a height of an ...
and Aïr) rise up from the desert and receive more rainfall and mostly present slightly cooler summer temperatures. These highlands support dry woodlands and shrublands distinct from the hot dry desert lowlands. This ecoregion has an area of . The boundaries for the largest part of this ecoregion, which includes the
Tassili n'Ajjer Tassili n'Ajjer ( Berber: ''Tassili n Ajjer'', ar, طاسيلي ناجر; "Plateau of rivers") is a national park in the Sahara desert, located on a vast plateau in southeastern Algeria. Having one of the most important groupings of prehistoric ...
Ahaggar The Hoggar Mountains ( ar, جبال هقار, Berber: ''idurar n Ahaggar'') are a highland region in the central Sahara in southern Algeria, along the Tropic of Cancer. The mountains cover an area of approximately 550,000 km. Geography This ...
and Aïr (or Azbine) massifs, follow the ' regs,' ' hamadas' and '
wadi Wadi ( ar, وَادِي, wādī), alternatively ''wād'' ( ar, وَاد), North African Arabic Oued, is the Arabic term traditionally referring to a valley. In some instances, it may refer to a wet (ephemeral) riverbed that contains water ...
s' above the 1,000 m contour. This covers a good part of southeast Algeria. These areas reach almost 3,000 meters in altitude. 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. 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 A guelta ( ar, قلتة, also transliterated qalta or galta; Berber: agelmam) is a pocket of water that forms in drainage canals or wadis in the Sahara. The size and duration will depend on the location and conditions. It may last year-round th ...
) which support flora and fauna. The most important area is the
Tassili n'Ajjer Tassili n'Ajjer ( Berber: ''Tassili n Ajjer'', ar, طاسيلي ناجر; "Plateau of rivers") is a national park in the Sahara desert, located on a vast plateau in southeastern Algeria. Having one of the most important groupings of prehistoric ...
Plateau, an outlier of the Ahaggar Mountains in Algeria which supports some near-endemic species and some globally threatened
antelope The term antelope is used to refer to many species of even-toed ruminant that are indigenous to various regions in Africa and Eurasia. Antelope comprise a wastebasket taxon defined as any of numerous Old World grazing and browsing hoofed mamm ...
s. The highest point of these mountains is 3,003 meters ( Mount Tahat). Winters are quite rigorous, with an amplitude in temperature of over 20°C. Day temperatures may be over 20°C while nights are freezing. In summer, days are very hot, though less so than in the central Sahara. Rainfall is rare and sporadic.


Flora and fauna

Vegetation varies greatly depending on altitude and landscape, in particular wind protection. It is often composed of
relict A relict is a surviving remnant of a natural phenomenon. Biology A relict (or relic) is an organism that at an earlier time was abundant in a large area but now occurs at only one or a few small areas. Geology and geomorphology In geology, a r ...
mediterranean The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on ...
vegetation. In the gueltas, vegetation is very diverse and hosts many animals. Trees may be found at lower elevations, while higher areas mostly host bushes. It is possible to find wild olive trees, or '' Olea lapperrini''. Endemic and rare species include the
Saharan Cypress ''Cupressus dupreziana'', the Saharan cypress, or tarout, is a very rare coniferous tree native to the Tassili n'Ajjer mountains in the central Sahara desert, southeast Algeria, where it forms a unique population of trees hundreds of kilometres f ...
(“tarout”) ''(Cupressus dupreziana)'' and
Saharan Myrtle ''Myrtus'' (commonly called myrtle) is a genus of flowering plants in the family Myrtaceae. It was first described by Swedish botanist Linnaeus in 1753. Over 600 names have been proposed in the genus, but nearly all have either been moved ...
''(Myrtus nivellei)'', both of which are relict Saharan-Mediterranean species. Olive and myrtle trees grow at the bottom of
wadi Wadi ( ar, وَادِي, wādī), alternatively ''wād'' ( ar, وَاد), North African Arabic Oued, is the Arabic term traditionally referring to a valley. In some instances, it may refer to a wet (ephemeral) riverbed that contains water ...
s, intermittent stream valleys, or beside
guelta A guelta ( ar, قلتة, also transliterated qalta or galta; Berber: agelmam) is a pocket of water that forms in drainage canals or wadis in the Sahara. The size and duration will depend on the location and conditions. It may last year-round th ...
s and permanent or temporary waterholes. Other species with a preference for moist habitats are '' Trianthema pentandra'', ''
Lupinus pilosus ''Lupinus pilosus'', commonly known as blue lupine, ( he, תורמוס ההרים, ar, ترمس برّي) is a species of flowering plant from the family Fabaceae which is endemic to Israel where it is found in Mediterranean scrubland. It has a ...
'', and '' Convolvulus fatmensis''. '' Silene kiliani'', ''
Acacia laeta ''Senegalia laeta'', the gay acacia or daga, is a legume found in the family Fabaceae. It was formerly included in the genus ''Acacia''. Description ''Senegalia laeta'' is a perennial shrub or small tree growing to a height of 4–10 m with a g ...
'', '' A. scorpiodes'', and '' Cordia rochii'' grow in wadis. Other representatives of the 28 national Algerian plant rarities found on Tassili n'Ajjer include '' Ficus ingens'' and ''Anticharis glandulosa''.


Population and conservation

The human population of the ecoregion is very small, with fewer than 5 persons per square kilometre. Many people are nomadic though some small cities also exist (such as
Idlès Idlès (Arabic: إدلس) is a municipality in Tazrouk District, Tamanrasset Province, Algeria. According to the 2008 census it has a population of 4,945, up from 3,791 in 1998, with an annual growth rate of 2.7%. Its postal code is 11110 and i ...
). The vegetation remains fairly intact.


References

{{reflist Deserts and xeric shrublands Ecoregions of Algeria Ecoregions of Mali Ecoregions of Mauritania Ecoregions of Niger Flora of Algeria Flora of Mali Flora of Mauritania Flora of Niger Geography of Mali Geography of Mauritania Palearctic ecoregions Tuareg