South Arabian fog woodlands, shrublands, and dune

The South Arabian fog woodlands, shrublands, and dune is an ecoregion in Oman and Yemen. The fog woodlands lie on mountainsides which slope southeastwards towards the Arabian Sea. The mountains intercept moisture-bearing winds from the Arabian Sea, creating orographic precipitation and frequent fogs that sustain unique woodlands and shrublands in a desert region.

South Arabian coastal fog woodlands, shrublands, and dune
Fog woodlands in the Dhofar Mountains near Salalah, Oman.
Ecology
RealmAfrotropical
BiomeTropical and subtropical grasslands, savannas, and shrublands
BordersArabian Peninsula coastal fog desert and Southwestern Arabian foothills savanna
Geography
Area19,913 km2 (7,688 sq mi)
CountriesOman and Yemen
Elevationsea level to 2100 m
Conservation
Conservation statuscritical/endangered
Protected685 km² (3%)[1]

Geography

The ecoregion occupies an area of 19,913 km² (7,688 sq mi) in eastern Yemen and southern Oman's Dhofar Governorate. The ecoregion covers four separate areas.

The westernmost is the Ureys (or Areys) range, a coastal mountain range that rises east of the town of Shuqrah, 150 km northeast of Aden. The range is made up of dark igneous rock, extending about 65 km east and west parallel to the coast. It is named for its tallest peak, Jabal Ureys (1735 m), which lies at the western end of the range close to the coast. The rest of the range is an east–west ridge 1500 to 1600 meters high, dropping to a dissected plateau 1200–1350 meters elevation and 2–3 km wide on the seaward (southern) side. There is a steep escarpment between the plateau and the coast.[2]

The largest area is in the Hadhramaut mountains of Yemen, on the mountainsides above Mukalla. The Hadhramaut mountains rise up to 2100 meters elevation. The eastern area is in the Dhofar Mountains, extending from easternmost Yemen to Ras ash Sharbatat in Oman. In between the Dhofar and Hahramaut is a small enclave on Jabal Fartak in Yemen, above the headland of Ras Fartak.

The ecoregion is bounded inland by the by the Southwestern Arabian foothills savanna ecoregion, which includes the drier foothill and mountain forests of southwest Arabia. The ecoregion is bounded on the ocean side by the Arabian Peninsula coastal fog desert, which occupies the coastal strip along the Arabian Sea.[3]

Flora

The predominant plant communities include deciduous woodland with trees Anogeissus, Acacia, and Commiphora, shrubland of Olea europaea, Dodonaea viscosa, Carissa edulis, and Rhus somalensis, succulent scrubland including Aloe, Caralluma, Euphorbia, Adenium, and Cissus, and semi-desert grassland.[4]

Anogeissus dhofarica is endemic to the ecoregion, and is the characteristic tree of the woodlands. A. dhofarica is a tall tree which can grow up to 12 meters in height. It is dry-season deciduous, losing its leaves in November or December at the start of the winter dry season, and re-leafing when the khareef (southwest monsoon) brings summer rains.[5] Anogeissus bentii is endemic to the Hadhramaut and Ras Fartak areas.[6]

In the Ureys range, semi-evergreen forests grow on the seaward plateau and escarpment between 800 and 1200 meters elevation, dominated by Olea europaea subsp. cuspidata and Tarchonanthus camphoratus, with Acokanthera schimperi, Cordia monoica, Euclea racemosa subsp. schimperi, Searsia flexicaulis, and Searsia glutinosa subsp. abyssinica. Escarpment gorges with more year-round water shelter evergreen trees Clerodendrum myricoides, Ficus ingens, Nuxia oppositifolia, and Mimusops laurifolia, which are generally found in the forests of eastern Africa.[7]

The ecoregion is home to 850 species of plants, of which 90 are endemic. There are one endemic genus, Dhofaria.[8] Other endemic species include Aloe dhofarensis, A. mahraensis, and Blepharis dhofarensis. Endemics in the Ureys range include Cystostemon kissenioides, Salvia areysiana, and Kleinia deflersii.[9]

The ecoregion is home to Boswellia sacra, the shrub from which aromatic frankincense is harvested.

Ecoregion delineation

In the 2001 Terrestrial Ecoregions of the World (TEOW) system, "a biogeographic regionalization of the Earth's terrestrial biodiversity", the region was divided between the Arabian Peninsula coastal fog desert and Southwestern Arabian foothills savanna ecoregions.[10][11][12][13]

In 2017, some of the authors of the 2001 system proposed a revised ecoregion system for the Arabian Peninsula, which designated the South Arabian fog woodlands, shrublands, and dune as a separate ecoregion.[14]

References
  1. 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; Supplemental material 2 table S1b.
  2. 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.
  3. "Ecoregions 2017". Accessed 25 April 2020
  4. Ghazanfar, S.A., and M. Fisher (1998). Vegetation of the Arabian Peninsula. Springer Science & Business Media, Aug 31, 1998.
  5. Christoph Oberprieler, Jörg Meister, Christine Schneider, and Norbert Killian (2009). "Genetic structure of Anogeissus dhofarica (Combretaceae) populations endemic to the monsoonal fog oases of the southern Arabian Peninsula". Biological Journal of the Linnean Society, 2009, 97, 40–51.
  6. Hegazy, Ahmad, and Jonathan Lovett-Doust (2016) Plant Ecology in the Middle East. Oxford University Press, Jan 14, 2016.
  7. 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.
  8. "Western Asia: Oman, Yemen, and Saudi Arabia". World Wildlife Fund. Accessed 25 April 2020.
  9. Hegazy, Ahmad, and Jonathan Lovett-Doust (2016) Plant Ecology in the Middle East. Oxford University Press, Jan 14, 2016.
  10. "Terrestrial Ecoregions of the World". World Wildlife Fund. Accessed 25 April 2020.
  11. "Arabian Peninsula: Yemen, Saudi Arabia, and Oman". World Wildlife Fund. Accessed 25 April 2020.
  12. Olson, D. M., Dinerstein, E., Wikramanayake, E. D., Burgess, N. D., Powell, G. V. N., Underwood, E. C., D'Amico, J. A., Itoua, I., Strand, H. E., Morrison, J. C., Loucks, C. J., Allnutt, T. F., Ricketts, T. H., Kura, Y., Lamoreux, J. F., Wettengel, W. W., Hedao, P., Kassem, K. R. 2001. Terrestrial ecoregions of the world: a new map of life on Earth. Bioscience 51(11):933-938.
  13. "Western Asia: Oman, Yemen, and Saudi Arabia". World Wildlife Fund. Accessed 25 April 2020.
  14. 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,
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