This ecoregion encompasses the the coastal desert (sand dunes, solonchaks, clay takyrs) along the coast at the northern and eastern shores of the Caspian Sea, the largest inland water body in the world (400,000 square kilometers (km2)). The Caspian Sea is considered an independent zoogeographical region due to the diversity, specificity, and endemism of its fauna. Waters of the Caspian Sea house 400 endemic aquatic animal species, including the Caspian seal (Phoca caspica) and sturgeons (90% of the world catch). The sea coast provides important sites for many nesting and migratory birds such as flamingoes, geese, ducks, gulls, terns, swans. Many multinational companies are exploring the region for oil and gas.
Location and General Description
The Caspian Lowland lies on the northern and eastern shores of the Caspian Sea at elevations between -28 to 100 meters (m) above sea level. Four rivers traverse the region on their way to the Caspian Sea: Volga, Ural, and Emba from the north, and Atrek from the southeast. The shelf area of the sea adjacent to the Caspian shore is very shallow: the 10 m isobathe extends 10 to 20 kilometers (km) from shore. The coastal zone is built of Tertiary and Quaternary sea sediments. To the east of the Caspian Lowland in Turkmenistan lies low mountain ranges of Bolshoi and Malyi Balkhans; to the northeast stretch Krasnovodsk, Ustuyrt, and Mangyshlak plateaus. The plateaus often form spectacular escarpments (chinks). Especially impressive is the Kulandagh chink above the Kara-Bogaz-Gol Bay (300-320 m high). Most of the lowland was recently exposed by the sea. Sand ridges and unstabilized dune sands, salt desert, solonchaks (shors) and clay deserts (takyrs) are typical. Groundwater, at 0.3 to 2.0 m deep is often highly mineralized. Average annual temperature is 15.4° C. Annual precipitation is ca. 150 millimeters (mm); frostless period lasts 260 days. Shors (salt pans) 30 to 40 centimeters (cm) thick are often completely devoid of vegetation, exhibiting smooth salt-covered surfaces, that gleam brilliantly in the sunlight. Plateaus are occupied by stabilized sand massifs.
To the south of the Caspian Lowland in Turkmenistan lies the delta of the Atrek River – the only river to enter the Caspian Sea from the east. Most of its flow is used for irrigation so only flood waters actually reach the sea. The climate in the Atrek delta is milder than that to the north and classified as subtropical; average annual temperature is 17.1° C. Annual precipitation is 187 mm. A long frostless period (271 days) encourages cultivation of crops such as olive, fig, pomegranate, and date palm.
During the Tertiary, the Pontic-Caspian basin included the modern Caspian and Black Seas, and was connected to the Mediterranean. Fluctuations of the proto-Caspian Sea in the Neocene determined the modern geology of this ecoregion. In the Middle Pliocene, the sea receded, and only two small lakes remained as relicts of the ancient Pontic Sea. In the Upper Pliocene, the so-called Akchagylian Sea expanded over Turkmenistan, then receding back by the end of Pliocene. Aridization and erosion continued in the Quaternary, combined with continuing sea level fluctuations and aeolic relief formation. As the new land emerged, littoral flora gave rise to number of different types of xerophytes. Large ancient rivers, the Amu Darya and Uzboi, flowed to the Caspian Sea in the Quaternary period; later, the Uzboi disappeared, and the Amudarya changed its course to flow into the Aral Sea.
Although the vegetation of the coastal Caspian desert within Turkmenistan is impoverished, it consists of highly specialized halophytes (salt-resistant plants) represented by shrubs and semi-shrubs such as various sagebrushes (Artemisia), tetyr (Salsola gemmascens), kevreik (S. orientalis), boyalych (S. arbuscula), biyurgun (Anabasis salsa, A. ramosissimum), sarsazan (Halocnemum strobilaceum), Halostachys, Ceratocarpus, Nitraria, Kalidium. Herbaceous vegatation is represented by species of Aristida, Peganum, Agropyron, Anisantha, Eremopyrum. One of the most typical halophyte plant formations is dominated by tetyr (Salsola gemmascens), a 30-50 centimeters (cm) shrub, associated with low species diversity and sparse coverage. Solonchaks are sometimes occupied exclusively by sarsazan (Halocnemum strobilaceum).
In the north, within Russia, many rare and endemic plant are associated with intra-zonal communities of the Volga River delta and riparian forests of the Samur River delta. The Sarykum barkhan which is a unique refuge for flora adapted to the loose sands of the ancient Central Asian deserts. Rare aquatic plants of the Volga delta unclude Aldrovanda veiculosa and Nelumbo caspica. About 11 plant species are found in the Samur River delta, some forming a unique vine forest that dates back to the Tertiary period.
In the northern section of this ecoregion, typical mammals include wild boar (Sus scrofa), otter (Lutra lutra), weasel (Mustela nivalis), brown hare (Lepus europaeus), wild rabbit (Oryctolagus cuniculus), muskrat (Ondatra zibethica), many semi-desert rodents. Two species introduced from American are quite common: nutria (Myocastor coypus) and raccoon (Procyon lotor). Within Turkmenistan, common desert mammals include rodents (ground squirrels, gerbils, jerboas, mice, Indian porcupine), long-eared hedgehog (Hemiechinus), desert hare (Lepus tolai), jackal (Canis aureus), fox (Vulpes vulpes), corsac fox (V. corsac), weasel (Mustela nivalis), steppe ferret (M. eversmanni), marbled polecat (Vormela peregusna), ratel (Mellivora indica), badger (Meles meles), steppe cat (Felis libyca), dune cat (F. margaritata), caracal (F. caracal), saiga antelope (Saiga tatarica). Three herds of saiga live in the northern Caspian zone: the Ustyurt herd (between the Caspian and Aral Sea), Guriev herd (area between the Volga and Ural Rivers), and the Kalmyk herd. Most of them concentrate in southern Astrakhan. Since the ban on saiga hunting (in 1991) their numbers have increased to 300,000. Saigas may migrate up to 300-500 km. Recent winter migrations to the coast have been observed only among saiga herds living between the Volga and Ural Rivers.
Along the Atrek river down to its delta, one finds the Central Asian otter (Lutra lutra), jungle cat (Felis chaus), wild boar (Sus scrofa), turtles (Emys orbicularis, Mauremys caspica), and Coluber schmidti. This used to be the habitat for Turanian tiger (Pathera tigris virgata) as late as the 1950s; now this spectacular big cat is extinct. Other large mammals have recently been extirpated are dzheiran, or goitered gazelle (Gazella subgutturosa), leopard (Panthera pardus), and cheetah (Acinonyx jubatus).
The Caspian seal (Phoca caspica) is an endemic species of this ecoregion. It exhibits wide seasonal migrations around the Caspian Sea according to the dynamics of reproduction, molting, and feeding. It is a unique species among seals since it reproduces both on ice (in the northern Caspian, January-February) and on land (islands off the Turkmenistan shore). On Ogurchinsky Island there may be as many as 10,000 animals during the reproductive period. This species has been a traditional target for hunting, especially in Central and Northern Caspian. In 1997-1998, seal hunting was declared illegal by all Caspian littoral countries.
Coastal areas of the Caspian Sea are a "bird paradise" with many species of gulls, terns, waterfowl. The northern (especially Volga delta), northeastern, and eastern coasts of the Caspian Sea lie on a major migration route between Europe and Asia. Tens of millions migratory birds pass over the area twice a year, and hundreds of thousands are nesting. Many birds stay for winter, and the wintering population of waterfowl in the Khazar Reserve is estimated to be over 600,000 birds. Coot (Fulica atra) is a common wintering species with over 200,000 birds spend winter within the Khazar Reserve alone. Other common wintering species are goldeneye (Bucephala clangula), long-tailed duck (Clangula hyemalis), mute swan (Cygnus olor), whooper swan (C. cygnus), flamingo (Phoenicopterus roseus), grey-lag goose (Anser anser), mallard duck (Anas platyrhynchos), teals, and diving ducks. For flamingoes, the Turkmenistan shoreline is the most important wintering place in Central Asia. 25% of the global population of Sandwich tern (Thalasseus sandvicensis) breeds on the islands of the Khazar Reserve. The great black-headed gull (Larus ichthyaetus) is still common on the Caspian shores but its numbers are decreasing. Eagles are among the birds of prey (Haliaetus albicilla, Aquila heliaca, Circaetus gallicus).
Typical Turanian desert reptiles found here include Central Asian tortoise (Testudo horsfieldi), Elaphe quatuorlineata, toad agama (Phrynocephalus ocellatus), runner Eremias arguta, gecko Alsophylax pipiens; in sand massifs, skink gecko (Teratoscincus scincus). Among common invertebrate species are typical desert beetles (Tenebrionidae, Scrabaeidae, Carabidae, Curculionidae), scorpions (Mesobuthus eupeus, M. caucasicus, Orthochirus scrobliculosus), many desert spiders (Artema transcaspica, Dysdera aculeata, Oecobius nadiae, Latrodectus tridecemguttatus, Argiope lobata, Lycosa alticeps, Drassodes proximus, Pseuducius cinctus, Yllenus bajan).
Many rare and endemic animal species are on IUCN or local Red Data Lists: honey badger (Mellivora capensis), otter (Lutra lutra seistanica; in the Atrek river valley), corsac fox (Vulpes corsac), sand lynx, or caracal (Caracal caracal michaelis), kulan (Equus hemionus), dzheiran (Gazella subgutturosa), Ustyurt wild sheep (Ovis vignei arcal), black vulture (Aegypius monachus), imperial eagle (Aquila heliaca), short-toed eagle (Circaetus gallicus), lesser kestrel (Falco naumanni), Central Asian desert monitor (Varanus griseus caspius). A very common species of reptiles is the central Asian tortoise (Testudo horsfieldii) included in the IUCN Red Data list.
Specially protected coastal and delta areas in this ecoregion include Astrakhan Reserve in Russia, and Khazar (former Krasnovodsk) Reserve in Turkmenistan. The Astrakhan Biosphere Reserve in the lower part of Volga Delta, represents a wetland area of international significance. The Reserve was organized in 1919 and protects 30 species of mammals and about 230 species of birds. About 60% of the Khazar (former Krasnovodsk) Reserve area lies within the aquatory of the Caspian Sea. It also includes freshwater ecosystems of the Atrek delta, and Maloe and Bolshoe Delili Lakes. The Reserve was organized in 1932 to protect the large wintering place for aquatic birds. It houses 50 species of mammals, almost 300 species of birds (50 nesting), 35 species of reptiles, and 30 species of fish.
The Caspian Sea is the largest inland water body in the world, with the total surface area of 400,000 km2. The biodiversity of the Caspian aquatic environment is derived from its long history and isolation, allowing ample time for speciation. The number of endemic aquatic taxa is over 400. Of 124 species of molluscs, 119 are endemic or subendemic. There are 115 species of fish, of which many are anadromous and migrate from the Caspian up the rivers to spawn. The endemic Caspian seal (Phoca caspica) is one of only two existing freshwater seal species (the other is found in Lake Baikal). The sea coast provides many important sites for a number of nesting and migratory birds.
The Caspian has been separated from the other seas since the last glacial period. It has not only preserved the rich late Tertiary flora and fauna but has also been influenced by later inputs, particularly of freshwater origin. The Caspian Sea is noted for a great number of endemic species of fauna. It is considered an independent zoogeographical region due to the diversity, specificity and endemism of its fauna. Most of the Caspian fish endemics belong to the herring and bullhead families of which seven species and subspecies of sturgeon are of importance. The Caspian is the only area with a significant sturgeon fishery, which represents up to 90% of the world catch. Among Caspian [mollusk|molluscs]], 119 endemic and subendemic species belong to two families of Bivalvia (Dreissenidae and Lymnocarduidae) and seven families of Gastropoda.
Conservation measures leading to sustainability are implemented but insufficient; a number of recent regionwide international initiatives exist. It is believed that nesting and migratory birds are adequately protected in the nature reserves.
Types and Severity of Threats
Oil pollution is one of the largest threats. The northern part of the Caspian Sea holds reserves of 3 to 3.5 billion tons of oil, and 2 to 2.5 trillion cubic meters of natural gas.
In Kazakhstan, western Atyrau and Mangistau Regions bordering the Caspian Sea are major producers of oil and natural gas, with production rapidly increasing.
Justification of Ecoregion Delineation
This ecoregion encompasses the Caspian depression of Kazakhstan, the Karabogaz Kol in Turkmenistan and includes the Volga Delta and surrounding semi-desert. Within Central Asia, it is defined by deserts and halophytic regions of the syrt regions according to Pereladova’s map of Central Asian ecosystems. Adjacent Iranian littoral saltland vegetation from Zohary’s geobotanical map of the Middle East is also included since it represents a similar halophytic environment. The European portions of the ecoregion consist of Bohn et al.’s northern lowland dwarf semi-shrub deserts and small areas of floodplain vegetation and coastal and inland halophytic vegetation north of the Caspian Sea.
Additional Information on this Ecoregion
- For a shorter summary of this entry, see the WWF WildWorld profile of this ecoregion.
- To see the species that live in this ecoregion, including images and threat levels, see the WWF Wildfinder description of this ecoregion.
- World Wildlife Fund Homepage
- Atamuradov, K. I. 1994. Paleogeography of Turkmenistan. Pp. 49-64 in: V. Fet & K. I. Atamuradov, editors, Biogeography and Ecology of Turkmenistan. Kluwer Academic Publishers: Dordrecht. ISBN: 0792327381
- Babaev, A. 1994. Landscapes of Turkmenistan. Pp. 5-22 in: V. Fet & K. I. Atamuradov, editors, Biogeography and Ecology of Turkmenistan. Kluwer Academic Publishers: Dordrecht. ISBN: 0792327381
- Bohn, Udo, Gisela Gollub, and Christoph Hettwer. 2000. Reduced general map of the natural vegetation of Europe. 1:10 million. Bonn-Bad Godesberg.
- Lisitsyna, T. Yu. 1995. The Caspian seal. Pp. 201-211 in: Mlekopitayushchie Turkmenistana (Mammals of Turkmenistan) Vol. 1. Khishchniki, lastonogie, kopytnye (Carnivores, pinnipeds, ungulates). Ylym, Ashgabat (in Russian).
- Kalustov, A. M. 1995. The marbled polecat. Pp. 201-111 in: Mlekopitayushchie Turkmenistana (Mammals of Turkmenistan) Vol. 1. Khishchniki, lastonogie, kopytnye (Carnivores, pinnipeds, ungulates). Ylym, Ashgabat (in Russian).
- Mikhailov, K. G. & Fet, V. 1994. Fauna and Zoogeography of Spiders (Aranei) of Turkmenistan. Pp. 499-524 in: V. Fet & K. I. Atamuradov, editors, Biogeography and Ecology of Turkmenistan. Kluwer Academic Publishers: Dordrecht. ISBN: 0792327381
- Pereladova, O., V. Krever and M. Williams. 1997. Biodiversity Conservation in Central Asia. Moscow.
- Rachkovskaya, E. I., editor. 1995. Vegetation of Kazakhstan and Middle Asia (desert region). Explanatory text and legend to the map, scale 1:2,500,000. St. Petersburg, Botanical Institute Russian Acad. Sci., 128 pp.
- Starobogatov, Ya. I. 1994. Fauna and Zoogeography of Molluscs of Turkmenistan. Pp. 535-543 in: V. Fet & K. I. Atamuradov, editors, Biogeography and Ecology of Turkmenistan. Kluwer Academic Publishers: Dordrecht. ISBN: 0792327381
- Zohary, M. 1973. Geobotanical foundations of the Middle East, volume1,2. Gustav Fischer Verlag, Stuttgart, Germany. ISBN: 9026501579
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