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Ecoregion Description

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Species Richness

# of Endemic Species


437: Orontes

Major Habitat Type:

temperate coastal rivers


Brian Coad


Lebanon; Syria; Turkey


This ecoregion includes the valley of the Orontes River of Lebanon and Syria, and northern tributaries of Turkey and Syria. It is surrounded by the Turkish mountain region to the north, the Jabal an Nusayriyah Mountains and Nur Daglari Mountains to the west, the Lebanon and Anti-Lebanon mountains to the south, and Jabal ar Ruwaq to the southeast. It is bounded by the Southern Anatolian ecoregion [432] to the north, Coastal Levant ecoregion [436] to the west, Upper Tigris & Euphrates ecoregion [442] to the east, and Arabian Interior ecoregion [440] to the east and south.

Drainages flowing into:

Mediterranean Sea

Main rivers or other water bodies:

The main rivers of the ecoregion include the Orontes River, the Afrin and Karasu rivers from the north, and the former Amik Lake.


The Jabal an Nusayriyah and Nur Daglari mountain ranges to the north and south of the Orontes sea outlet separate the basin from Mediterranean drainages, and plateau deserts to the east separate it from other basins. The highest elevations in the ecoregion occur in the Lebanon Mountains, with peaks above 2900 m.


The ecoregion falls within a semi-arid steppe zone. mean annual precipitation is 546 mm, with most rain falling between November and May. The Jabal an Nusayriyah catches most of the rains from the Mediterranean, producing a rainshadow effect to the area east of it.  The mean annual temperature is 16 ºC, but range from 2ºC in winter to 33 ºC in summer.

Freshwater habitats:

Amik Lake was once an important freshwater habitat, relatively unusual in Southwest Asia.

Terrestrial Habitats:

This area is a fertile valley surrounded by plateau and mountain ranges with desert and semi-desert conditions. It falls predominantly within the Eastern Mediterranean conifer-sclerophyllus broadleaf forests terrestrial ecoregion, with pockets of Southern Anatolian montane conifer and deciduous forests in the west, and an area of Eastern Anatolian deciduous forests in the north.

Fish Fauna:

The fauna comprises over 30 species in eight families; however, seven families have only one species. The fauna is dominated by Cyprinidae with 25 species, five of which are endemic. This is diverse for a basin of this size in Southwest Asia.

Description of endemic fishes:

There are no endemic genera, but the endemic species include five cyprinids (Acanthobrama centisquama, Alburnus orontis, Barbus lorteti, Chondrostoma kinzelbachi, Pseudophoxinus libani) and one balitorid (Schistura namiri).

Other noteworthy fishes:

Bahrat Homs, an old storage reservoir on the Orontes River, has introduced carp and is overfished. Other exotic fish species may be competing with native species.

Other noteworthy aquatic biotic elements:

Endemism in aquatic invertebrates, such as a snail, is known (Banarescu 1992).

Ecological phenomena:

The loss of the Amik Lake restricts knowledge of its fauna to historical documents, mostly from the nineteenth century. There was an extremely rich bird fauna with possible endemic taxa. Replacement of original marshes with irrigation channels impoverished the fish fauna in this basin.

Evolutionary phenomena:

The high number of endemics and the complex and disputed relationship to neighboring basins gives this small basin an unusually diverse fauna. 

Justification for delineation:

This ecoregion was delineated base on its high level of endemism and diverse fauna in a small basin. Bahrat Homs is an important wintering and staging area for migratory waterfowl.

Level of taxonomic exploration:



Banarescu, P. (1991). "Zoogeography of Fresh Waters, Volume 2: Distribution and Dispersal of Fresh Water Animals in North America and Eurasia" Weisbaden, Germany: AULA - Verlag.

Banarescu, P. (1992). "Zoogeography of Fresh Waters" 2 Weisbaden, Germany: AULA - Verlag.

Krupp, F. (1985). "Systematik und Zoogeographie der Süßwasserfische des levantinischen Grabenbruchsystems und der Ostküste des Mittelmeeres" Unpublished Thesis. Fachbereich Biologie der Johannes Gutenberg Universität in Mainz.

Por, F. D.,Dimentman, C. (1989). "The Legacy of Tethys: an aquatic biogeography of the Levant" 63 Dordrecht: Kluwer Academic Publishers.

Scott, D. A. (Ed.) (1995). "A Directory of Wetlands in the Middle East" Gland, Switzerland and Slimbridge, U.K: IUCN and International Waterfowl and Wetlands Research Bureau.

World Wildlife, Fund (2001). "Terrestrial Ecoregions of the World" 2005 (2005;

The Nature Conservancy World Wildlife Fund
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