This EBA comprises the Asir mountains of south-west Saudi Arabia and the highlands of southern and western Yemen. In the west, just inland and east of the Red Sea and Gulf of Aden, an escarpment rises to a high plateau, which drops to the sandy Rub' al Khali (or Empty Quarter) in the interior of southern Arabia.

Formerly, large areas of the EBA were forested, but agricultural activities over millenia, including exploitation for timber, charcoal and firewood, have diminished this habitat. Patches of forest still survive in deep valleys (wadis) and on some steep slopes, and well-developed juniper Juniperus forest remains intact in the Asir mountains above c.1,900 m. The most widespread vegetation today is deciduous woodland, often characterized by Acacia, with many endemic plants (WWF/IUCN 1994).

Arabia lies at the junction of three distinct biogeographical realms: the Afrotropical to the west, the western Palearctic to the north and the Oriental to the east. The avifaunal interest of the south-western part of the peninsula has long been recognized, though there have been relatively few studies because of (until fairly recently) problems of access.

The restricted-ranges species occur throughout the EBA apart from Prunella fagani, which is confined to the Yemen highlands, and Estrilda rufibarba, which has not been recorded in the Asir mountains. Most are found in deciduous woodland and scrub, and can be widespread in secondary vegetation (see Sandgrouse 1987, 9).

Several other birds are also largely confined to this region but were judged to have ranges which exceed 50,000 km ² and therefore do not qualify as restricted-range species: they include Arabian Partridge Alectoris melanocephala, Arabian Woodpecker Dendrocopos dorae, South Arabian Wheatear Oenanthe (lugens) lugentoides, Arabian Golden Sparrow Passer euchlorus (adjacent lowlands only), Arabian Warbler Sylvia leucomelaena, Arabian Serin Serinus rothschildi and Golden-winged Grosbeak Rhynchostruthus socotranus (see Jennings 1991).

During recent decades roads have improved access to the mountains and, in some areas, economic activity has shifted from agriculture to local tourism. Consequently, traditional cultivated terracing (and associated uncultivated scrub), which can provide important habitats for some birds, are deteriorating and are subject to severe soil erosion on steeper slopes; habitat is further degraded as a result of uncontrolled cutting of fuelwood and timber and overgrazing (Jennings et al. 1988, WWF/IUCN 1994). More insidiously, however, in many areas mature trees are currently known to suffer from die-back; this may have resulted from climate change (reduced precipitation or drought) exacerbated by a range of other biological stresses (Gardner and Fisher 1994). Both Turdus menachensis and Sylvia (Parisoma) buryi are considered threatened because they occur at low densities and are thus most at risk from continuing loss of habitat.

As well as being important for restricted-range species, the Arabian peninsula is a major flyway for migrating birds: it has been estimated that some two to three billion migrants of up to 200 species pass through Saudi Arabia during both spring and autumn en route between sub-Saharan Africa and the Palearctic; the mountains no doubt provide vital habitat for feeding and resting. The region is also an important flyway for birds of prey that cross the Red Sea at and around the Bab al Mandab, the narrowest crossing point between the peninsula and Africa (Welch and Welch 1992). Threatened passage or wintering birds include Greater Spotted Eagle Aquila clanga, Imperial Eagle A. heliaca and Lesser Kestrel Falco naumanni, all classified as Vulnerable. The main problem facing these raptors on migration is persecution, although definitive published evidence for this (in this EBA) appears to be lacking (Rands 1989).

The Critical-but historically widespread-Northern Bald Ibis Geronticus eremita has been recorded as a rare spring passage migrant and non-breeding visitor at a few sites in the EBA (in both Saudi Arabia and Yemen). The species is known to survive only at a few breeding colonies in Morocco, and the wintering of birds in this EBA suggests either that some of the birds from the extinct breeding colony in Turkey have remained in the winter quarters over several years, or that an undiscovered breeding area exists in Turkey, Oman, Ethiopia, Syria or Iraq, or even in south-west Arabia.

Within the Saudi Arabian part of the EBA there are several protected areas. One of these, Asir National Park (4,150 km², established in 1981), is actually more of an umbrella organization promoting tourism and recreation in a generally unprotected area of outstanding natural beauty. However, the special nature reserve which protects the Raydah escarpment (c.12 km²) encompasses one of the best-preserved tracts of juniper forest (Newton and Newton 1996) and is possibly the most important compact site in Saudi Arabia for the endemic birds (Evans 1994). There are no protected areas in Yemen but a network of reserves has been recommended by UNEP/IUCN, and some areas-scattered throughout the western highlands and believed to be managed for their traditional resources (e.g. for bee-keeping and grazing)-offer improved habitat quality for some of the endemics. Evans (1994) identified some 25 Important Bird Areas (including the Raydah escarpment) in this EBA, and an assessment of the biological diversity of Yemen has been made by Varisco et al. (1992).

Recommended citation
BirdLife International (2024) Endemic Bird Area factsheet: South-west Arabian mountains. Downloaded from https://datazone.birdlife.org/eba/factsheet/90 on 23/11/2024.