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Ecoregion Description


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Species Richness


# of Endemic Species


Threats

446: Caspian Highlands

Major Habitat Type:

xeric freshwaters and endorheic (closed) basins

Author:

Brian Coad

Countries:

Iran

Boundaries:

This ecoregion includes the upper rivers and tributaries of the Caspian Sea basin on the plateau of Iran (including the upper basin of the Safid River).  It is bounded on the north by the Kura-South Caspian Drainages [434] and a small section of the Turan Plain [450], to the south by the Kavir & Lut Deserts [448] and Lake Namak [447] ecoregions, and to the west by the Upper Tigris & Euphrates [442] and Orumiyeh [445] ecoregions.

Drainages flowing into:

Caspian Sea

Main rivers or other water bodies:

The upper basin of the Safid (Sefid) River, with its major tributaries the Qezel Owzan (Qizil Uzun) and Shah River.

Topography:

The ecoregion lies on the western side of the Iranian plateau, and has altitudes reaching 5601 m at Damavand and 4819 m at Takht-e Suleiman along the Alborz Mountain range. Most of the smaller rivers have deep valleys. The Qezel Owzan and Shah rivers are also deeply incised in parts, but also have more open valleys and drain large steppe plains.

Climate:

The climate to the south of the Caspian Sea is generally warm. The mean annual temperature for the ecoregion is roughly 10 °C, with minimum temperatures averaging -7 °C, and maximum temperatures averaging 31 °C. The mean annual precipitation is 362 mm.

Freshwater habitats:

The amount of freshwater vegetation in the ecoregion is poor. There is a lot of erosion and consequent siltation; for example, the dam at Manjil is dredged.

Terrestrial Habitats:

The ecoregion is predominantly semi-desert steppe on the plateau of Iran, exluding the Caspian lowland forests. Most vegetation is scrub, although there is some mixed forest at higher elevations. Dry farming and irrigated farming occurs, as well as tree crops.

Fish Fauna:

The upper reaches of rivers support migratory and commercially important species from the lower reaches. The fauna is dominated by cyprinids and is mostly ostariophysan in composition. Remnants of native trout may survive in the higher tributaries.

Description of endemic fishes:

There are no endemic species in this ecoregion. Mursa (Barbus mursa) is a near-endemic to this ecoregion and the Kura-South Caspian Drainages ecoregion [434].

Other noteworthy fishes:

The dam at Manjil and other rivers have introduced taxa including pike-perch (Sander lucioperca), common whitefish (Coregonus lavaretus), silver carp (Hypophthalmichthys molitrix), rainbow trout (Oncorhynchus mykiss), and eastern mosquitofish (Gambusia holbrooki). Survival of first two taxa in the dam is unknown.

Justification for delineation:

This ecoregion comprises a subset of the Kura-South Caspian Drainages ecoregion [434], but without migratory and semi-migratory species. 

Level of taxonomic exploration:

Good

References/sources:

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

The Nature Conservancy World Wildlife Fund
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