Al Hajar Al Gharbi montane woodlands

The Al Hajar montane woodlands is a temperate grasslands, savannas and shrublands ecoregion in the Al Hajar Mountains on the eastern Arabian Peninsula, which extends across portions of Oman and the United Arab Emirates.

Geography

The ecoregion includes the upper elevations of the Al Hajar Mountains in the eastern Arabian Peninsula. The mountains form an arc from northwest to southeast through portions of Oman and the United Arab Emirates, extending over 500 kilometres in length. The mountains run parallel to the coast of the Gulf of Oman, with the Al Batinah Region in the coastal plain between the mountains and the sea.

The Al Hajar al Gharbi, or western Hajar, extends from the Musandam Peninsula at the northeastern tip of the Arabian peninsula through the western UAE and northern Oman. The Al Hajar ash Sharqi, or eastern Hajar, extends eastwards towards Ras al Hadd, the easternmost point in Oman and the Arabian Peninsula. The Sama'il Gap separates the eastern and western portions of the range. The limestone massifs of Jebel Shams (2,997 metres) and Jebel Akhdar (2,980 metres), located in the western Hajar just west of the Sumail Gap, are the highest peaks in the range. The highest peak in the eastern Hajar is 2,152 metres.

The mountains are composed mostly of Cretaceous limestone, together with outcrops of metamorphic and igneous rocks, including grey-brown ophiolites.

The Gulf of Oman desert and semi-desert ecoregion surrounds the montane woodlands at lower elevations.

Climate

The ecoregion has a semi-arid temperate climate, transitioning to subtropical at lower elevations. The coolest months are December through March, when the mountains receive thunderstorms, rain, hailstorms and occasional snow, particularly at higher elevations. April to September are warmer, with occasional rainstorms brought by the Indian Ocean monsoons.

Flora

The natural vegetation types include shrubland and open woodland and the flora varies with elevation and underlying geology.

Open woodlands with '' Olea europaea'', '' Sideroxylon mascatense'' and ''Dodonaea viscosa'' extend from 1,100 to 2,500 metres elevation. ''Ziziphus spina-christi, Prosopis cineraria, Vachellia tortilis'' and ''Ficus salicifolia'' and other species of fig are found in seasonal watercourses (wadis). ''Euphorbia larica'' predominates on steep slopes, along with ''Vachellia tortilis'', ''V. gerardii'' and ''Periploca aphylla''.

Montane woodlands occur on the high peaks between 2,100 and 3,000 metres elevation. ''Juniperus seravschanica'') is the characteristic tree, sometimes mixed with ''Olea europaea''.

On the Musandam Peninsula, semi-evergreen woodlands above 1,300 metres elevation were formerly dominated by '' Sideroxylon mascatense'', but now ''Dodonaea viscosa'' is predominant in the degraded woodlands. Between 1,800 and 2,000 metres elevation, ''Prunus arabica'' forms woodlands with ''Ephedra pachyclada'' and a dense ground layer of the shrub ''Artemisia sieberi''.Kürschner H. (1998) Biogeography and Introduction to Vegetation. In: Ghazanfar S.A., Fisher M. (eds) Vegetation of the Arabian Peninsula. Geobotany, vol 25. Springer, Dordrecht.

''Ceratonia oreothauma'' ssp. ''oreothauma'' is an endemic subspecies of the tree found only in a single valley on Jebel Aswad in the eastern Hajar. The other subspecies occurs in Somalia.Hillcoat, D., G. Lewis, and B. Verdcourt. "A New Species of Ceratonia (Leguminosae-Caesalpinioideae) from Arabia and the Somali Republic." Kew Bulletin 35, no. 2 (1980): 261-71. Accessed December 4, 2020. .

Fauna

The Arabian Tahr (''Arabitragus jayakari'') is endemic to the region. Other large mammals occur in small numbers, including the Mountain Gazelle (''Gazella gazella''), particularly in the Wadi Sareen Reserve, Arabian Wolf (''Canis lupus arabs''), Striped Hyena (''Hyaena hyaena'') and Arabian wildcat (''Felis lybica lybica'').

Five species of lizards are endemic to the mountains – Emirati leaf-toed gecko (''Asaccus caudivolvulus''), Gallagher's Gecko (''Asaccus gallagheri''), Oman Rock Gecko (''Pristurus celerrimus''), Jayakar Lizard (''Omanosaura jayakari'') and Blue-tailed lizard (''Omanosaura cyanura''). '' Asaccus montanus, Asaccus platyrhynchus'' and '' Pristurus gallagheri'' are lizards endemic to Oman which live in the mountains.

71 bird species have been recorded around the Jebel Akdar, including 28 residents and 41 migrants. Resident birds include Lappet-faced Vulture (''Torgos tracheliotus''), Arabian Partridge (''Alectoris melanocephala''), Sand Partridge (''Ammoperdix heyi''), Pallid Scops Owl (''Otus brucei''), Hooded Wheatear (''Oenanthe monacha'') and Hume's Wheatear (''Oenanthe alboniger'').

Conservation and threats

The ecoregion is threatened by overgrazing from camels, goats and feral donkeys. Overgrazing has limited the ability of the ''Ceratonia'' woodlands and juniper woodlands below 2,400 metres to regenerate.

Protected areas

1.27% of the ecoregion is in protected areas. Protected areas include Hatta Protected Area (28 km²) in the United Arab Emirates and Al Jabal Al Akhdar Scenic Reserve (296 km²) in Oman.

References

External links

*{{WWF ecoregion, name=Al Hajar montane woodlands, id=at0801

Al Hajar montane woodlands (DOPA)

Al Hajar Al Gharbi montane woodlands (Encyclopedia of Earth)

Al Hajar Mountains
Ecoregions of Oman
Ecoregions of the United Arab Emirates
Afrotropical ecoregions
Temperate grasslands, savannas, and shrublands