Included here are the deserts and semi-deserts of eastern Transcaucasia, the precaspian lowlands including the lower reaches of the Volga and Ural rivers, the eastern shores of the Caspian Sea to the basin of Lake Ala Kul, the Ust Urt Plateau, the Turan lowland around the Aral Sea, the Karakum and Kyzyl Kum deserts, the Muyunkum Sands, Bet-Pak-Dola and the Sary-Ishikotrau sands, the footshills of the Piedmont Plains along the Kopet Dagh and extending along the Pamiro-Alai and along the western Tien Shan, the intermontane valleys of the Mirzachcul, the Karshingsky Steppe and other plains of southern Uzbekistan.

Turanian Halophilic (salt-loving) Shrubland

This is mainly restricted to depressions where the groundwater is close to the surface and in zones around salt lakes where salt-rich soils know as solochaks occur. Chenopods are the predominant group with Salicornia herbacea, Halocnemum strobilaceum and the endemic Halostachys caspica and Seidlitzia rosmarinus (Chenopodiaceae) being some of the more characteristic species. Most are succulents but there are also woody plants such as Haloxylon and Kalidium. Haloxylon ammodendron is a tree reaching heights of 14 m. The halophilic grasses present include Alopecurus ventricosus, Puccinellia fomini and P. scleroides. Formations dominated by Salsola gemmascens (tetyr formations) represent one of the more typical of the desert halophyte communities and occurs in the Uzboi dry beds, on the southern Ustyurt and Krasnovodsk plateaus near Karabogazgol Bay in the Caspian and in the Trans-Unguz area. Patches are also found in the Karakum Desert. The dominant shrub, Salsola gemmascens, can live for up to 25 years and reach heights of 40 cm, but is usually much more stunted especially in gypsum-bearing soils. Other common shrubs include Salsola arbuscula and S. orientalis. Floristically, however, this formation is relatively poor with no more than about 35 species and certain shrubs such as Hypoxylon aphyllum and the endemic Calligonum setosum (Polygonaceae) are so depressed in that they rarely reach heights of more than about 50 cm. The vertical structure is also poorly developed with just two tiers. Lower level species reach about 20 cm in height and are mainly composed of ephemeral or annual species. The desert sedge Carex pachystylis often dominates while other common low-level species include Ceratocephala falcata, Eremopyrum orientale and Leptaleum filifolium. In summer a significant number of annuals make their appearence such as Salsola sclerantra and the endemic or near endemic Halimocnemus karelinii (family?).

A more widespread formation is characterized by Anabasis salsa (biyurgun formation). It extends over wide areas of Middle Asia and Kazakhstan. Anabasis salsa can grow to heights of 40 cm and can reach densities of up to 50,000 plants per ha. Other shrubs include Anabasis eriopoda, Atraphaxis spinosa and Nanophyton erinaceum. A lower herbaceous layer may sometimes be present with species like Arnebia decumbens, Lepitium perfoliatum and endemic or near endemic Amberboa turanica (Asteraceae). Salsola orientalis can also occasionally occur as a dominant species (kevreik formation) such as on the ancient alluvial plain of the Kunyadarya River and on the Meshed-Messerian Plain. Far more widespread is the succulent-halophytic desert formation dominated by Halocnemum strobilaceum (sarsazan). This is typical of solonchak depressions and small salt hills (chukalaks). The largest expanses occur on the ancient delta of the Atrek River, the Kelkor Solonchaks and on the shores of the Karabogazgal Bay. The dominant species, Halimocnemum strobilaceum, is a stem succulent, leafless sub shrub and can reach heights of about 40 cm. Structurally these formations are usually simple and rarely have more than one layer, but in areas of reduced salt content a greater variety of species can be found such as Limonium subfruticosum, Tamarix hispida and the endemic or near endemic Halimocnemum longifolia (Chenopodiaceae) and Halostachys caspica (Chenopodiaceae).

One final vegetation type covered here is the so-called black sakaul formation named after the dominant Haloxylon aphyllum. It is primarily associated with river deltas and desert depressions. In Turkmenistan major stands are associated with the ancient alluvial deposits along the Amudarya River and the Assake-Audan and Sarykamysh depressions. Haloxylon aphyllum dispays remarkable ecological plasticity. In depressions with shallow water tables it develops in to a tree reaching heights of 9 m, but where the water supply is less reliable it forms small shrubs little more than 1 m high. The species diversity of these formations can be relatively high with up to 140 species recorded in some localities, but their vertical structure is fairly simple. There is usually an upper layer of H. aphyllum, which is sometime accompanied by shrubs such as Reaumuria oxiana, Salsola richteri and the endemic Smirnovia turkestana (Fabaceae). The second layer (30-40 cm high) is usually composed of small semi shrubs such as Artemisia badhysi and Salsola gemmascens, but with low density and abundance. The third layer is largely composed of annual or ephemeral herbaceous species such as Allium sabulosum, Ferula assafoetida and the endemic Streptoloma desertorum (Brassicaceae).  Other endemic or near endemic species generally associated with solochak soils include Arthrophyton lehmanniana (Chenopodiaceae), Euphorbia sororia (Euphorbiaceae), Kalidium caspicum (Amaranthaceae), Lepidium borsczovi (Brassicaceae), Limonium caspium (Plumbaginaceae), Alexandra lehmanni, Bienertia cycloptera, Ofaiston monandrum, Petrosimonia squarrosa, Piptoptera turkestana, Suaeda microsperma, Salsola kasakorum (Chenopodiaceae) and Zygophyllum oxianum (Zygophyllaceae).

References

Chemonics International Inc. Washington, DC. 2001. Biodiversity Assessment for Turkmenistan. Submitted to USAID Central Asian Republics Mission, Almaty, Kazakhstan.

Fet, V. & Atamuradov, K. I. 1994. Biogeography and Ecology of Turkmenistan. Kluwer Academic Publishers.

Paulsen, O. 1913. Transcaspian Vegetation. Journal of Ecology, 1: 133-134.

Shokri, M., Safaian, N. & Ahmadi, M. Z. 2004. An ecological look at saline wetlands. Acta Agronomica Hungarica, 52: 37-44.

Walter, H. & Box, E. O. 1983. Central Kazakhstan. In: Ecosystems of the World 5 - Temperate Deserts and Semi-Deserts. Ed. N. E. West. Elsevier Scientific Publishing Company.

Walter, H. & Box, E. O. 1983. Middle Asian Deserts. In: Ecosystems of the World 5 - Temperate Deserts and Semi-Deserts. Ed. N. E. West. Elsevier Scientific Publishing Company.

Walter, H. & Box, E. O. 1983. The Karakum Desert. In: Ecosystems of the World 5 - Temperate Deserts and Semi-Deserts. Ed. N. E. West. Elsevier Scientific Publishing Company.

Walter, H. & Box, E. O. 1983. Orobiomes of Middle Asia. In: Ecosystems of the World 5 - Temperate Deserts and Semi-Deserts. Ed. N. E. West. Elsevier Scientific Publishing Company.

Walter, H. & Box, E. O. 1983. Caspian Lowland Biome. In: Ecosystems of the World 5 - Temperate Deserts and Semi-Deserts. Ed. N. E. West. Elsevier Scientific Publishing Company.

Wendelbo, P. 1971. Some distributional patterns within the flora Iranica area. In: Plant Life of South-West Asia. Eds. P. H. Davies, P. C. Harper & I. C. Hedge. The Botanical Society of Edinburgh.