Persian Gulf desert and semi-desert
Located on the northeastern coast of the Arabian Peninsula on the Arabian Gulf, this ecoregion is made up of desert plains. The area serves as an important stop for birds migrating from Asia to wintering spots in Africa, and over 250 species of birds have been recorded. Threats to this ecoregion include feral rodents that disrupt the bird population, oil spills, overgrazing, and wildlife poaching.
Location and General Description
The ecoregion comprises part of the Eastern Province of Saudi Arabia, including its entire coastline along the Arabian Gulf, as well as Bahrain island, the coastline of Qatar and a small stretch of coastline belonging to the Abu Dhabi emirate of the United Arab Emirates (UAE). In the north, much of Kuwait is included. An inland finger projects south from Kuwait towards the great sand desert that dominates all of southern Arabia, the Rub'al-Khali.
The ecoregion is essentially a low desert plain extending from the Arabian Gulf coast westwards and inland towards Dahna, an area of high red-brown dunes rising above the surrounding plains. Its geology is of sedimentary marine deposits laid down during the late Tertiary, when the area was subject to intermittent submergence and deposition of sediments. This is very different from the ancient Precambrian complex of igneous and metamorphic rocks forming the western half of the Arabian Peninsula. Presenting some surface relief are various sedimentary formations although all are considerably eroded.
The inland finger stretching southward to the Rub'al-Khali is a landscape of plains affected by windblown sand. The sand accumulates at the base of plants, forming sand hummocks known as dikakah which can dominate stretches of inland areas. The indented coastline is characterised by shallow depressions of salt flats, or sabkhas. The sabkhas close to the coast may be flooded at high tide or following strong onshore winds. Intertidal mud flats and salt marshes are generally more extensive than on the Red Sea coast. The coastal sands are much whiter in appearance than the red sands of the Dahna and parts of the Rub'al-Khali. This is due to the limestone and sandstone formations containing microscopic shell material from which the sands are derived.
Inland a number of artesian springs occur, forming important oases whose relatively fresh water sustains large areas of cultivation, particularly date palm groves. These have been supplemented by numerous wells that draw upon underlying aquifers. These oases and areas of water outflow result in the growth of reeds such as Phragmites and mace (Typha spp.) and favor other planted vegetation such as Tamarix aphylla and Prosopis juliflora. This in turn creates important habitats for birds and other wildlife, including marsh frogs (Rana ridibunda) and Caspian pond turtles (Clemmys caspica).
The climate of the ecoregion is characterized by long, hot, rainless summers with northerly winds, often bringing sandstorms. Average regional rainfall is about 75 millimeters (mm), falling mainly in December and January, but is unpredictable and sometimes falls as localised heavy downpours. Typical annual values vary from 75 mm to 150 mm. Temperatures range from an average of 230C in winter to 350C in summer, although peaks of 500C can be recorded. The humidity along the coast is exceptionally high, often reaching 90% in summer.
Vegetation is characterised by a thin sprinkling of small shrubs, grass tussocks and occasionally large shrubby growth such as tamarisk. Variety is limited, with a small number of plants dominating the land. Zohary identifies an inland Sub-Sudanian vegetation association of Hammadetea salicornici and coastal zone vegetation comprised of mosaics of Haloxylotea salicornici and Suaedetea deserti. The most widespread shrubs are Rhanterium epapposum, Hammada elegans (previously recorded as Haloxylon salicornicum) and Calligonum comosum. The two main grasses are Panicum turgidum and Stipa capensis and a common sedge is Cyperus conglomeratus. In Kuwait, Halwagy et al. describe how a meagre annual rainfall of 115 mm allows for a poor scrub of shrubs, perennial herbs and spring ephemerals dominated by Cyperus conglomeratus, Rhanterium epapposum and Hammada salicornica. The very obvious salt tolerant plants belong to the family Chenopodiaceae. In the various muddy channels of the seashore and islands the black mangrove Avicennia marina is evident.
In Qatar and Bahrain terrestrial wildlife species diversity is low and there are few, if any, endemics. Most of Qatar, with its flat desert and scanty vegetation, supports only a sparse and restricted avifauna. Of 255 species recorded in the country, about 23 breed there, 78 are winter visitors and 104 are regular migrants. Bahrain was believed to be connected to the mainland of Arabia until 6,000 B.C. and its subsequent separation is cited as a reason for the low diversity of mammalian fauna.
The coastal zone with its intertidal mudflats and offshore islands is important for breeding sea birds and other migrating species, particularly as Saudi Arabia offers a land bridge connecting Africa with Eurasia. One site at Tarut Bay is considered to be the most important site on the Saudi Arabian Gulf Coast for wintering and migrating waders and other water birds, with a total of c. 58,000 waterbirds in 1991/92, and more than 20,000 present in April-May 1991. The houbara bustard (Chlamydotis undulata), a globally threatened species, occurs regularly in Bahrain as a passage migrant in autumn and a rare winter visitor to the open desert in the south of the island.
Evans cites the Gulf coastline in this ecoregion to be especially important for the black-necked grebe (Podiceps nigricollis), great crested grebe (P. cristatus), socotra cormorant (Phalacrocorax nigrogularis), broad-billed sandpiper (Limicola falcinellus) and Saunders' little tern (Sterna saundersi). The breeding population of Phalacrocorax nigrogularis in this area, which is thought to be over 95% of the world population, exceeds 220,000 pairs.
Inland, and particularly striking when seen from the air, are isolated circles of green in otherwise barren areas of desert. These are sites of intensive cultivation of alfalfa and winter wheat, irrigated by artesian water sprayed form hugh booms rotating around a central pivot. Trans-desert migrants are attracted to the greenery of these sites, which are the only known breeding site in the Eastern Province for quail (Coturnix coturnix), spotted sandgrouse (Pterocles senegallus), and great grey shrike (Lanius excubitor).
The rare Asiatic jackal (Canis aureus ssp. aureus) is known to occur in this ecoregion but there is little recent evidence to confirm its presence. Characteristic mammals of the ecoregion include the red fox (Vulpes vulpes), Cape hare (Lepus capensis), and Ethiopian hedgehog (Paraechinus aethiopicus.
The National Centre for Wildlife Conservation and Development (NCWCD) is responsible for nature conservation in Saudi Arabia and various sites along the coast are under protection or being considered for protection under the NCWCD System Plan for Protected Areas. The Gulf Coral Islands have been designated as a protected area and are managed by this body. In Qatar, nature conservation is the responsibility of the Environment Protection Committee (EPC). Research into fauna and flora is also conducted by the Scientific and Applied Research Centre of Qatar University, but there are no protected areas for nature conservation (Evans 1994). On Bahrain island, the Environmental Protection Committee is the government body responsible for environmental matters and protected areas for nature conservation. Al-Areen Wildlife Reserve on Bahrain island, established in 1976, was built as a sanctuary to conserve vegetation and also functions as a wildlife captive-breeding centre. The Environmental Research and Wildlife Development Agency (ERWDA) is in charge of biodiversity conservation along the short section of Abu Dhabi coastline in the UAE.
Types and Severity of Threats
The entire 1,200 kilometers (km) coastline of this ecoregion is vulnerable to major oil spills . Hill indicates that Phalacrocorax nigrogularis is one of the most commonly found oiled dead birds around the Bahrain coastline. Overgrazing by camels, goats and sheep is a common threat to the area's vegetation. The mangroves are under pressure in some areas from overgrazing by camels. Disturbance from fisherman, recreational campers and divers, and the military is a threat along various coastal stretches and islands. However, in some areas the military has fenced off certain sites, protecting the vegetation and eliminating grazing pressure. Feral mice are reported to be a threat, particularly when their population peaks coincide with the tern breeding season on Saudi Arabia's Gulf Coral Islands. Land reclamation and dredging poses a threat to various sites on Bahrain island.
Justification of Ecoregion Delineation
This ecoregion boundary was formed using Zohary's geobotanical map of the Middle East. It corresponds to Zohary's sub-Sudanian desert vegetation of Hammadetea salicornici, at times mixed with Acacietea tortilis, and his mosaics of Haloxylotea salicornici and Suaedatea deserti, occasionally mixed with A. tortilis sub-sudanica.
Additional Information on this Ecoregion
- For a shorter summary of this entry, see the WWF WildWorld profile of this ecoregion.
- To see the species that live in this ecoregion, including images and threat levels, see the WWF Wildfinder description of this ecoregion.
- World Wildlife Fund Homepage
- Al-Khalili, A.D. 1999. New records and review of the mammalian fauna of the State of Bahrain, Arabian Gulf region. Pages 43-53 in Wildlife of Bahrain, Bahrain Natural History Society. Fifth edition.
- Aspinall, S. 1996. Status and conservation of the breeding birds of the United Arab Emirates. Hobby Publications.
- Bundy, G., R.J. Connor, and C.J.O Harrison. 1989. Birds of the Eastern province of Saudi Arabia. Witherby, London, England and Saudi Aramco, Dhahran, Saudi Arabia. ISBN0854931805
- Child, G., and J. Grainger. 1990. A system plan for protected areas for wildlife conservation and sustainable rural development in Saudi Arabia. National Commission for Wildlife Conservation and Development, Riyadh, Saudi Arabia.
- Evans, M.I. 1994. Important bird areas in the Middle East. Birdlife International, Cambridge, England. ISBN: 0946888280
- Halwagy, R., A.F. Moustafa, and S.M. Kamel. 1982. On the ecology of the desert vegetation in Kuwait. Journal of Arid Environments 5:95-107.
- Hill, M. 1995/6. Socotra Cormorants. Arabian Wildlife 2(3): 8-10.
- Nader, I.A. 1996. Distribution and status of five species of predators in Saudi Arabia. Journal of Wildlife Reseach 1(2):210-214.
- Zohary, M. 1973. Geobotanical foundations of the Middle East. Vols. 1 and II. Stuttgart: Gustav Fisher Verlag.
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