Orumiyeh
ID
445
Author(s)
Brian Coad, Jennifer Hales
Countries
Iran
Turkey
Major Habitat Type
Xeric freshwaters and endorheic (closed) basins
Drainages flowing into
The basin is endorheic and all rivers terminate in the salt Lake Orumiyeh.
Main rivers to other water bodies
The basin comprises Lake Orumiyeh, brackish marshes, and tributary rivers. Prominent perennial streams include the Zarrineh River (230 km long), entering from the south with the Tata’u or Simineh River (145 km) as a major tributary; the saline Aji Chay or Talkheh (= bitter) River from the east, draining the flanks of Kuhha-ye Sabalan at 4810 m; Kuh-e Sahand at 3710 m; and smaller streams from the west. Lake Kobi (= Ghopi) is a Ramsar site lying at 1240 m altitude in this basin. The Shur Gol and the Yadergarlu and Dorgeh Sangi endorheic lakes are south of Lake Orumiyeh and northwest of Mahabad at 1290 m. Other small lakes and associated marshes are present in this basin. Gori Gol or Lake Gory at 37º5’N, 46º42’E is a fresh to brackish lake near Tabriz, occupying 120 ha at 1950 m asl. Qanats and dams are found throughout the basin.
Description
Boundaries
The ecoregion comprises the drainage basin of Lake Orumiyeh (= Reza’iyeh, Urmia, Urmi, Urumiyeh, or Darya-e Shahi), which lies in northwest Iran. It is bounded by the Caspian Highlands ecoregion [446] to the east and the Upper Tigris-Euphrates basin [442] to the west.
Topography
The area surrounding the lake includes some marshes and smaller lakes as noted above. The Sahand and Sabalan mountains reach 3710 and 4810 m, respectively, but much of the topography is rolling landscape.
Freshwater habitats
Lake Orumiyeh lies at about 1297-1300 m, is about 128-149 km long and 40-60 km wide. The lake has a surface area of 4750-6100 km2, a volume of 29.4 km3, a mean depth of 4.9-6.0 m, a maximum depth of 16 m, and a temperature range of -1.3−27.5°C. The lake level can rise as much as 2 m in one season, as it did in the winter of 1968-1969. It is a sodium chloride-sulphate system with a salinity up to 310.79 gl-1 (but mostly 217-235gl-1), and consequently is fishless. Brackish marshes in the northeast, northwest, and southern shores probably support some fishes as do all of the tributary rivers. The rivers are fed by seasonal snowmelt and rainfall recharge of groundwater. Lakes and marshes are also fed from local springs.
Terrestrial habitats
Much of the semi-arid steppe forest has been converted to wheat fields, but there are some remnants of pistachio forests on an island in the lake. The more forested areas occur to the west of the lake, whereas steppe is dominant to the east.
Description of endemic fishes
Almost half of the taxa are endemic, although there are no endemic genera. These species include Acanthalburnus urmianus, Alburnus atropatenae, Petroleuciscus ulanus, and Kura gudgeon (Romanogobio persus).
Other noteworthy fishes
The large Wels catfish (Silurus glanis) is found in this basin, as well as a distinct form (undescribed) of salmonid (the Liqvan Chai trout).
Justification for delineation
Lakes Gori, Kobi, Orumiyeh, Shur Gol, Yadergarlu, and Dorgeh Sangi are Ramsar sites. The basin has a high degree of endemicity.
Level of taxonomic exploration
Good
References
- Coad, B. W. (2002). "Freshwater Fishes of Iran" (www.briancoad.com).
- Saadati, M. A. G. (1977). "Taxonomy and distribution of the freshwater fishes of Iran" Unpublished Thesis. Colorado State University : Fort Collins
- Scott, D. A. (1995) A Directory of Wetlands in the Middle East IUCN and International Waterfowl and Wetlands Research Bureau : Gland, Switzerland and Slimbridge, U.K
- Hijmans, R. J., S. Cameron and Parra., J. (2004) \WorldClim, Version 1.4 (release 3). A square kilometer resolution database of global terrestrial surface climate\ "<"[http://www.worldclim.org]">" (16 July 2009)