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.

Geography

The ecoregion occupies an area of 19,913 km² in eastern Yemen and southern Oman's Dhofar Governorate. The ecoregion covers four separate areas.
The westernmost is the Ureys 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, 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 side. There is a steep escarpment between the plateau and the coast.
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 on the ocean side by the Southwest Arabian coastal xeric shrublands, which occupy the coastal strip along the Arabian Sea. Inland, the ecoregion is bounded by the South Arabian plains and plateau desert ecoregion.

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.
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 brings summer rains. Anogeissus bentii is endemic to the Hadhramaut and Ras Fartak areas.
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.
The ecoregion is home to 850 species of plants, of which 90 are endemic. There are one endemic genus, Dhofaria. Other endemic species include Aloe dhofarensis, A. mahraensis, and Blepharis dhofarensis. Endemics in the Ureys range include Cystostemon kissenioides, Salvia areysiana, and Kleinia deflersii.
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 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.
In 2017, 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.