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Ecoregion Description

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Species Richness

# of Endemic Species


442: Upper Tigris & Euphrates

Major Habitat Type:

temperate floodplain rivers and wetlands


Brian Coad


Iran; Iraq; Syria; Turkey


This ecoregion includes essentially the upper sections of the Tigris and Euphrates rivers and their tributaries, with adjacent drainages in Iran that flow into the northern Gulf and other neighboring internal basins, and the Quwaiq River basin in Syria. It is bounded by the Orontes [437], Southern Anatolia [432], and Lower Tigris & Euprates [441] ecoregions to the west; northern Anatolia [430] and Western Transcaucasia [433] ecoregions to the north; Lake Van [444], Orumiyeh [445], Caspian Highlands [446], Namak [447], Esfahan [449], and Kavir & Lut Deserts [448] to the east; and Persian (= Arabian Gulf) and Northern Hormuz Drainages [451] to the south.

Drainages flowing into:

Persian (= Arabian ) Gulf

Main rivers or other water bodies:

This ecoregion encompasses the upper sections of the Tigris and Euphrates rivers, with tributaries including the Murat, Great Zab, Little Zab, Diyala rivers. The ecoregion also includes the Karun, Zohreh, Mand, and Kor rivers in Iran. The southern Iranian parts of this basin have large salt lakes, fed by fresh springs and rivers. Lake Zaribar in Iran is a deep, freshwater upland lake, which is comparatively rare in the Middle East.


The topography of the Upper Tigris and Euphrates is characterized by the Zagros Mountains in the south that extend to 4548 m, the mountains of Kurdistan and their intervening valleys, and low-lying coastal plains at the head of the Gulf in Iran.


This ecoregion’s climate varies from Mediterranean to semi-arid. The mean annual precipitation is 456 mm, but exceeds 1000 mm in the north. The mean annual temperature is 15 ºC, but ranges between a mean minimum of -2 ºC to mean maximum of 36 ºC.

Freshwater habitats:

The ecoregion comprises the upper reaches of large rivers such as the Tigris and Euphrates. There are occasional smaller lakes, but no extensive marsh/lake habitats like those found in the Lower Tigris & Euphrates ecoregion [441]. In the upper reaches on the plateau of Iran, springs and qanats are important habitats.

Terrestrial Habitats:

The terrestrial habitats are characterized by deciduous and conifer sclerophyllus-broadleaf forests in the northwest, montane steppe in the northeast, stone desert in the south near the coast, and steppe further inland. The landscape is mountainous with valleys of various sizes. It is heavily deforested at lower elevations; however, some original pistachio-almond and oak forests remain, but these are often sparsely vegetated. Dry farming occurs at higher elevations and in the north, as well as some tree crops. There are also patches of irrigated farming in the south.

Fish Fauna:

There are about 70 species in the ecoregion, which is very diverse compared to many other ecoregions in the Middle East. Over half of these species are found in the family Cyprinidae, with Balitoridae and Cyprinodontidae a distant second and third. Lake Zaribar has seven introduced fish species that has affected the natural fauna deleteriously.

Description of endemic fishes:

Nearly a third of the species in the ecoregion are endemic, most of which occur in the genera Aphanius, Glyptothorax, Cobitis, Orthrias, and Schistura. Iranocypris is a monotypic genus endemic to this ecoregion.

Other noteworthy fishes:

The ecoregion includes two blind cave fish, Iran cave barb (Iranocypris typhlops) and blind loach (Paracobitis smithi), recorded from Iran at a single locality and listed as Vulnerable in the IUCN Red List.

Other noteworthy aquatic biotic elements:

The salt lakes are important areas for waterfowl. For example, Lake Parishan and Dasht-e Arjan are Important Bird Areas (IBAs) for wintering and breeding waterfowl such as Dalmatian pelican (Pelecanus crispus) and white-headed duck (Oxyura leucocephala). Two globally threatened species, lesser white-fronted goose (Anser erythropus) and imperial eagle (Aquila heliaca), are found in the Kamjan marshes in winter.

Evolutionary phenomena:

The cave fishes are important in evolutionary studies since they are depigmented and lack eyes.

Justification for delineation:

This ecoregion contains mostly riverine fauna comprising species shared with the Lower Tigris & Euphrates ecoregion [441], but with many endemics not found in these lowlands. The saline Sabkhat al-Jabbul Nature Reserve in Syria is a Ramsar site, as are the salt lakes Neyriz (and Kamjan marshes), Parishan, and Dasht-e Arjan in southern Iran.

Level of taxonomic exploration:



Coad, B. W. (2002). "Freshwater Fishes of Iran" (

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.

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