Tigris-Euphrates alluvial salt marsh

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Part of a former cradle of civilization (Mesopotamia), the ecoregion is surrounded by a vast region of desert and xeric shrubland. This complex of shallow freshwater lakes, swamps, marshes, and seasonally inundated plains is among the most important wintering areas for migratory birds in Eurasia.

  • Scientific Code
  • Ecoregion Category
  • Size
    13,700 square miles
  • Status
  • Habitats

Location and General Description
The vast deltaic plain of the Euphrates, Tigris and Karun rivers is located at the northern end of the Persian Gulf, in extreme eastern Iraq and southwestern Iran. This alluvial basin drains a large area of Turkey, Syria, Iraq, and the western Zagros Mountains of Iran, and the basin is covered in recent (Pleistocene and Holocene) alluvial sediments.

The ecoregion is a complex of shallow freshwater lakes, swamps, marshes, and seasonally inundated plains between the Tigris and Euphrates rivers. It includes huge permanent lakes of Haur al Hammar, the Central Marshes, and Haur al Hawizeh as well as more seasonal ‘ahrash’ forest of Populus and Tamarix on islands and banks of the great rivers (Evans 1994). The vegetation of the ecoregion is dominated by aquatic plants – Phragmites (reeds), Typha (rushes), and Cyperus (papyrus) (Stattersfield et al. 1998).

The climate of the region is subtropical, hot and arid. The hydrology of these vast marshes is extremely important to the ecology the entire upper Persian Gulf (Ramsar Convention Bureau 2001).

Biodiversity Features
The ecoregion is almost exactly equivalent to the Mesopotamian marshes Endemic Bird Area (EBA). EBAs represent areas that encompass the overlapping breeding area of at least two restricted-range bird species. The ecoregion, and the EBA, are the only breeding area of the Iraq babbler (Turdoides altirostris) and the Basra reed-warbler (Acrocephalus griseldis) (Stattersfield et al. 1998).

The region is among the most important wintering areas for migratory birds in Eurasia. Surveys in 1979 revealed internationally important wintering concentrations of at least 22 species (and possibly up to 70 species) of wintering waterfowl. The marshes support a number of globally threatened species on a seasonal basis including Dalmatian pelican (Pelecanus crispus), pygmy cormorant (Phalocrocorax pygmeus), imperial eagle (Aquila heliaca), white-tailed eagle (Haliaeetus albicilla), marbled duck (Marmaronetta angustirostris). Evans (1994) identified 12 Important Bird Areas in Mesopotamia as being of global and regional importance for birds.

A disjunct portion of the ecoregion also includes an Iranian area of marshes – the Shadegan Marshes and tidal mudflats of Khor-al Amaya and Khor Musa in Iran. Found in the southern portion of the extensive flood-plain and delta system of the Karun, Dez, and other major rivers that rise in the northwest Zagros Mountains. Higher portions dominated by Scirpus that give way to salt-tolerant vegetation and mudflats. Flooded in autumn and winter, with an abrupt onset of flooding in November. This Important Bird Area provides an important wintering ground for the Dalmatian pelican (Pelecanus crispus), imperial eagle (Aquila heliaca), white-tailed eagle (Haliaeetus albicilla), and marbled duck (Marmaronetta angustirostris) (Evans 1994). This areas of marshes is a RAMSAR site and are protected by a 296,000 ha wildlife refuge, encompassing all the main wetland areas and the coastal mudflats in the south, which was established in 1972 (Ramsar Convention Bureau 2001).

Unique to these wetlands are two species of mammals: Bunn's Short-tailed Bandicoot Rat (Erythronesokia bunnii) and Mesopotamian gerbil (Gerbillus mesopotamiae). More widespread freshwater-dependent mammals found in the ecoregion include wolves (Canis lupus), common otter (Lutra lutra), and a subspecies of smooth-coated otter (Lutra perspicillatamaxwelli maxwelli).

A relatively large population of feral Asian water buffalo (Bubalus bubalis); roams the marshes of the ecoregion. These animals, which may be related to some of the first-domesticated water buffalo (S. Hedges, pers.comm.), are associated with wet grasslands, swamps, and heavily vegetated river valleys. Up until relatively recently, wolves (Canis lupis) and wild boar (Sus scrofa) could be found roaming the marshes – depictions of wild boar hunts are found in rock reliefs in the region, but these have now been extirpated from the area (Humphreys & Kahrom 1995).

Current Status
There is no form of legal protection for biodiversity in any of Iraqi marshes of the region (Evans 1994), but there is an almost 3,000 km2 wildlife refuge in the Iranian marshes (Ramsar Convention Bureau 2001).

Types and Severity of Threats
Modifications to the hydrology of lower Iraq began in earnest in the 1950s (Evans 1994). Large-scale water diversion projects of all kinds are rapidly degrading the Tigris-Euphrates alluvial salt marsh. Changing the flow of both rivers with canals, dykes and dams has cut off river flow to a extensive areas of marshes, causing them to dry up. In addition, drainage canals flush salt from irrigated lands into the wetland system increasing the salinity of the area. Regional conflicts and increased settlement of the area have greatly increased pollution of the wetlands. All of these factors contribute to habitat loss and degradation (Evans 1994, Stattersfield et al. 1998).

Justification of Ecoregion Delineation
Ecoregion boundaries were formed using Zohary’s (1973) geobotanical map of the Middle East. In Iraq and Iran, the ecoregion corresponds to Zohary’s littoral saltland vegetation of Salicornietea europaeae and Irano-Turanian saltland vegetation of Halocnemetea strobilacei and Saharo-Arabian saltland vegetation of Suadetea deserta. The area from Zohary was expanded to capture the endemic bird area as defined by Birdlife International (Stattersfield et al. 1998).

Evans, M.I., compiler.1994. Important Birds Areas in the Middle East. Birdlife International, Cambridge, UK.

Humphreys, P.N. and E. Kahrom. 1995. The Lion and the Gazelle, Images Publishing, Bath, UK.

Ramsar Convention Bureau. 2001. Sixth Edition of the Directory of Wetlands of International Importance, Shadegan Marshes and mudflats of Khor-al Amaya and Khor Musa. http://www.wetlands.agro.nl/ramsar_database/Ramsar_Dir/Iran_Islamic_Republic/Ir006d99.doc, Ramsar Convention Bureau, Gland, Switzerland.

Stattersfield, A, M.J. Crosby, A.J. Long, D.C. Wege. 1998. Endemic Bird Areas of the World, Priorities for Biodiversity Conservation. Birdlife International, Cambridge, UK.

Zohary, M. 1973. Geobotanical foundations of the Middle East, volume1,2. Gustav Fischer Verlag, Stuttgart, Germany.

Prepared by: John Morrison
Reviewed by: In process