Boundaries

This ecoregion runs along the southern and western fringes of the Arabian Peninsula, bounded by the Red Sea to the west, the Gulf of Aden to the south and the An-Nafud and Rub’ al-Khali deserts of the Arabian interior to the east and north. It includes the narrow coastal plain called the Tihamah, which extends along the Red Sea escarpment.

Topography

Tihamah is a narrow coastal plain backed by the Hijaz Mountains in the north and Asir Mountains in southwest Arabia. Elevation reach 3760 m near San’a in the Asir Mountains.

Freshwater habitats

Small streams are subject to intermittent flow and flash floods. The water table of many natural streams is being lowered by groundwater pumping for irrigation.

Terrestrial habitats

Much of the northern coast and interior of the ecoregion is characterized by Red Sea Nubo-Sindian tropical desert and semi-desert, with some patches of rain-fed and irrigated cultivation. The Arabaian Peninsula coastal fog desert lines the southern coast, rising to the Southwestern Arabian foothills savanna, and Southwestern Arabian montane woodlands in the Asir Mountains.

The Tihamah coastal plain includes sandy wadis and stony plains with halophytic and xerophytic plant associations and open Commiphora and Acacia woodlands. Doum palms (Hyphaene thebaica) and tamarisks (Tamarix spp) are also common. The Asir Mountains experience a zonation of vegetation, including evergreen forest and scrub between 2000 – 2500 m, and Afroalpine vegetation, such as Juniperus procera, at elevations above 2500 m (WWF 2001).

Description of endemic fishes

There are no endemic genera, but 70% of the cyprinids are endemic, four in a single genus. Endemics include Acanthobrama hadiyahensis, Carasobarbus exulatus, Cyprinion acinaces, Garra dunsirei, G. lautior, G. mamshuqa, and G. sahilia. Garra dunsirei is in the IUCN RedList.

Other noteworthy fishes

Acanthobrama hadiyahensis is the southernmost representative of the genus.

Justification for delineation

This ecoregion was delineated based on high endemism among its fish fauna.

Level of taxonomic exploration

Good