Southwestern Arabian foothills savanna

Source: Wikipedia, the free encyclopedia.
Southwestern Arabian foothills savanna
Geography
Area275,270 km2 (106,280 sq mi)
Countries
Conservation
Conservation statuscritical/endangered[1]
Protected1.37%[2]

The Southwestern Arabian foothills savanna, also known as the Southwestern Arabian Escarpment shrublands and woodlands,[3] is a desert and xeric shrubland ecoregion of the southern Arabian Peninsula, covering portions of Saudi Arabia, Yemen, and Oman.

Geography

The ecoregion occupies moderate elevations in the peninsula's mountainous southwest, including the Hijaz and Asir Mountains of Saudi Arabia, the Sarawat Mountains of Yemen, and the Dhofar Mountains of southwestern Oman.

The foothills savanna is bounded on the west and south by the

Red Sea Nubo-Sindian tropical desert and semi-desert lies to the northwest along the Red Sea coast, and wraps around the north and east between the foothill savanna and the hyper-arid Arabian Desert ecoregion of Central Arabia.[2]

The mountains rise from the Red Sea and Gulf of Aden in a series of escarpments. The highest peaks are in southwest Yemen, and the mountains generally diminish in height to the north and east. The rocks are generally Precambrian, and include granite, gneiss, and schist. In places they are overlain by areas of younger volcanic rock, known as harrats. The Hadhramaut and Dhofar mountains are mostly sedimentary rocks, including limestones, marls, sandstones, bauxitic clay, evaporites, shales, turbidites and conglomerates over a base of older Precambrian igneous and metamorphic rocks.[4]

Climate

The climate is tropical to subtropical and semi-arid. Average annual rainfall is generally 250 mm or less, and with areas of higher rainfall in the southeastern mountains. Marine upwelling along the Arabian Sea coast chills the air above sea's surface, creating fog during the summer months that cools and provides moisture to southeastward-facing mountain slopes in Dhofar and southern Yemen.[5]

Flora

The principal plant communities include drought-deciduous open thorn woodlands, drought-deciduous woodlands, evergreen woodlands, shrublands, and dry grasslands. The vegetation varies with elevation, rainfall, and soils, and has been extensively altered by livestock grazing and human use.[6]

Acacia-Commiphora woodlands predominate up to 1000 meters elevation. They consist of drought-deciduous open woodlands and thorn scrub, with species of the genera

Boswellia carteri, Maerua crassifolia, and Sterculia africana.[6]

On certain seaward-facing slopes facing the Arabian Sea, moisture-bearing winds from the Arabian Sea create

Hadramaut mountains in southeastern Yemen, and the Dhofar Mountains in southwestern Oman.[7] Some authors classify these distinctive subhumid woodlands and shrublands as a separate ecoregion, the South Arabian fog woodlands, shrublands, and dune.[8]

Acacia-Commiphora woodlands continue up to 1800 meters elevation, and these higher-elevation woodlands are characterized by Senegalia asak, S. etbaica, Vachellia tortilis, Commiphora gileadensis, C. myrrha,

.

Seasonal watercourses, or wadis, are lined with

Breonadia salicina, Cordia abyssinica, Ficus vasta, and Mimusops laurifolia.[6] In a few sheltered wadis with year-round moisture on the western slopes of the escarpment, including Jabal Fayfa, Mimusops laurifolia, an evergreen tree, has grown to great age and large size, and these trees are the largest in Saudi Arabia.[9][10]

Semi-evergreen woodlands of

Olea europaea are found between 1800 and 2200 meters elevation, and form the transition between the Acacia-Commiphora woodlands at lower elevations and the high-elevation Juniper woodlands of Southwestern Arabian montane woodlands ecoregion.[6]

The flora of the ecoregion has many affinities to that of tropical East Africa. Acacia-Commiphora woodlands are characteristic of the dry East African lowlands and foothills, and the Southwestern Arabian woodlands and savannas share many species. Southwestern Arabia's high-elevation forests and humid forests at lower elevations share many Afromontane species with the high mountains of Eastern Africa.[6]

Fauna

The ecoregion is home to the critically-endangered

long-tailed jird (Meriones crassus), Cape hare (Lepus capensis), and Indian crested porcupine (Hystrix indica).[12][13]

Several species of birds are endemic to the mountains of southwestern Arabia. They include

Arabian accentor (Prunella fagani), Arabian waxbill (Estrilda rufibarba), Yemen serin (Crithagra menachensis), and Yemen linnet (Linaria yemenensis). Other native bird species with a wider range include the Arabian partridge (Alectoris melanocephala), Arabian woodpecker (Dendrocopos dorae), Arabian wheatear (Oenanthe lugentoides), Arabian golden sparrow (Passer euchlorus), Arabian warbler (Curruca leucomelaena), Arabian serin (Crithagra rothschildi), and Arabian golden-winged grosbeak (Rhynchostruthus percivali).[14]

Mafhaq (1,550 meters elevation) in northern Yemen.[15]

Human use

The ecoregion has been settled for millennia. Archeological evidence of settled agriculture dates back more than 5000 years.[16] Local people created terraced fields on steep slopes in areas of relatively high rainfall, and irrigated farms in the lower reaches of streams descending from the mountains. The mountains are also used for grazing livestock, including cattle, sheep, goats, and camels.

Boswellia sacra is a shrub or small tree that grows on drier northern slopes in the Hadramaut and Dhofar mountains and in northern Somalia. It is the source of frankincense, and aromatic resin, which has been harvested and traded for centuries. Myrrh is another aromatic resin gathered from Commiphora myrrha.[17][18]

The woodlands have been degraded and reduced in area by overharvesting trees for timber and firewood, livestock grazing, and conversion to agriculture, particularly around the ecoregion's cities.[6]

Protected areas

1.37% of the ecoregion is in protected areas. Protected areas include

Jabal Shada al-A‘la Resource Use Reserve, and Raydah Natural Reserve.[2]

See also

References

  1. ^ "Southwestern Arabian foothills savanna". Terrestrial Ecoregions. World Wildlife Fund.
  2. ^ a b c "Southwestern Arabian foothills savanna". DOPA explorer. Accessed 31 January 2021. [1]
  3. ^ Eric Dinerstein, David Olson, et al. (2017). An Ecoregion-Based Approach to Protecting Half the Terrestrial Realm, BioScience, Volume 67, Issue 6, June 2017, Pages 534–545 [2].
  4. ^
  5. ^ Kilian, Norbert, Peter Hein and Mohamed Ali Hubaishan (2004). "Further Notes on the Flora of the Southern Coastal Mountains of Yemen". Willdenowia Bd. 34, H. 1 (Aug. 25, 2004), pp. 159-182.
  6. ^ Eric Dinerstein, David Olson, et al. (2017). An Ecoregion-Based Approach to Protecting Half the Terrestrial Realm, BioScience, Volume 67, Issue 6, June 2017, Pages 534–545, [3]
  7. ^ Hall, M., Neale, S., Al‐Abbasi, T.M. and Miller, A.G. (2010). "Arabia's tallest trees: ecology, distribution and conservation status of the regionally endangered tree species Mimusops laurifolia." Nordic Journal of Botany, 28: 240-245. https://doi.org/10.1111/j.1756-1051.2009.00560.x
  8. ^ BirdLife International (2021) Important Bird Areas factsheet: Jabal Fayfa. Downloaded from http://www.birdlife.org on 03/02/2021.
  9. ^ Boug, Ahmed & Islam, Zafar-ul & Shehri, Abdulla. (2009). Captive-breeding of Arabian Leopard in Saudi Arabia.
  10. ^ Michael C. Jennings, Amar R. H. Al-Momen and Jabr S. Y. Haresi (2010). The Birds of the Highlands of South-West Saudi Arabia and Adjacent Parts of the Tihama: July 2010 (ABBA SURVEY 42). December 2010. Accessed 1 February 2021. [4]
  11. ^ BirdLife International (2021) Important Bird Areas factsheet: Raydah escarpment. Downloaded from http://www.birdlife.org on 03/02/2021.
  12. ^ BirdLife International (2021) Endemic Bird Areas factsheet: South-west Arabian mountains. Downloaded from http://www.birdlife.org on 01/02/2021.
  13. ^ Andrew Gardner, Theodore Papenfuss, Steven Anderson, Matthias Stöck, Sergius Kuzmin. 2004. Duttaphrynus scorteccii. The IUCN Red List of Threatened Species 2004: e.T54758A11200539. https://dx.doi.org/10.2305/IUCN.UK.2004.RLTS.T54758A11200539.en. Downloaded on 13 February 2021.
  14. ^ Wilkinson, Tony (1999). “Settlement, Soil Erosion and Terraced Agriculture in Highland Yemen: a Preliminary Statement.” Proceedings of the Seminar for Arabian Studies, vol. 29, 1999, pp. 183–191.
  15. ^ Nabhan, Gary Paul (2014). Cumin, Camels, and Caravans: a Spice Odyssey. University of California Press, 2014.

External links