Wednesday, August 6, 2014

Northern Deserts of Central Asia

Introduction

The Central Asian Northern Deserts are a mosaic of clay, stone, salt and sand and together with the Central Asian southern desert, supports the highest level of biological richness of all Eurasian deserts. The region is populated by middle Asian and north Caucasus species and is closer in nature to the Turanian subtropical realm. The area is dominated by rarefied semi-shrub communities formed by the perennial saltworts (Chenopodiacea) and sagebrushes (Artemisia spp.). Northern Turanian or Kazakhstanian species of plants are the dominant flora. Two prominent small mammals in this eco-region are jerboa and gerbil. The latter digs deep burrows which become critical for vegetation growth. Rare but still found are the goitered gazelle, marbled polecat, saxaul jay, Asian desert sparrow, and Houbara bustard.

Location and General Description

Photo: Usturt Plateau

The Northern Desert includes the Kazakh territory of Mangyshlak, the central part of the Ustyurt plateau (including a large part of the territory of Karakalpakstan) streatching across again into Kazakhstan and the northern and southern areas near Balkhash Lake. The northern deserts are distinguished the following climatic parameters: total solar radiation 130-140 kilocalories (kkal) per square centimeter (cm2) and the radiating balance 45 - 50 kcal./cm2. The mean temperature in January is –10 to -15oC and in July from 24 to 26oC.

The precipitation is distributed evenly across seasons with some increase observed in the spring. The quantity of precipitation compounds 100-150 millimeters (mm) per one year (for separate years up to 200mm). The influence of the Asian anticyclone begins to develop in this territory.

The relief of the Northern Desert is varied in form and origin. Low littoral plains near the Caspian Sea, arid denudational plateaus (northern part of Ustyurt and western part of Betpakdala), stony plains, and melkosopochnik - a highly eroded plateau (Mangyshlak, eastern part of Betpakdala and northern part near Balkhash Lake) are represented here. There are also sandy deserts (Muyunkum), and sandy regions near the northern part of Aral Sea and near Balkhash Lake. These vast areas are composed of the clay alluvial and alluvial-delta plains found in the lower reaches of the Chu, Ili and Emba rivers.

Perennial saltworts predominate in the Northern deserts. Species that prevail on clay soils of the region include Anabasis salsa, Salsola orientalis, and sagebrushes such as artemisia terrae albae, A. turanica, and A. gurganica to the west. The plant communities from Salsola arbusculae formis and Nanophyton erinaceum are typical in stony soils. Typical for sandy soils are psammophitic semi-shrubs such as Ceratoides papposa, Artemisia terrae albae, var. massagetovii, A. santolina, and A. songarica, and shrubs such as Calligonum aphyllum, Ephedra lomatolepis and psammophitic grasses (Agropyron fragile).

The spring flora of ephemers and ephemeroids aren’t as richly represented in the northern desert as in the southern deserts, however the colorful tulips (Tulipa greigii, T. albertii) decorate these areas in some years. The halophytic succulent semi-shrubs such as Halimione verrucifera, Kalidium folitum, K. Schrenkianum, anc Halocnemum strobilaceum, and annual saltworts (species of Petrosimonia, Climacoptera, Suaeda) dominate on solonchaks. Spireanthus schrenkianus (relic of Tertiary time) is
a rare plant growing in the central area of Betpakdala. It is associated with a specific community of species peculiar to chink ecosystems found in Mangyshlak, Ustyurt Plateau, and Ili depressions.

Biodiversity Features

The most common northern desert mammals are the long-eared hedgehog (Erinaceus auritus), long-quilled hedgehog (Piracohinus hypomelas), and tolai hare (Lepus tolai). Yellow gopher (suslik) is characteristic of the clay desert and feeds on the ephemeral plants. A variety of rodents such as gerbils (Rhombomys, Meriones), and more than ten species of jerboas (Allactaga, Dipus, Paradipus, Eremodipus, Stylodipus) are found here. Both gerbils and jerboas play an important role in the biological functioning of the clay desert. Numerous, deep burrows by the gerbils are critical for vegetation growth. Both form a significant part of the diet of nocturnal predators such as owl, steppe ferret (Mustela eversmanni) and corsac fox (Vulpes corsac). Endemic jerboas include the selevinia (Selevinia betpakdalensis), comb-toed jerboa (Paradipus ctenodactylus), and the three-toed and five-toed dwarf jerboas (Salpingotus heptneri, salpingotus pallidus, Cardiocranius). Also endemic are representatives of several mammalian genera (e.g., Diplomesodon, Spermophilopsis, Pyderethmus, Allactodipus, Eremodipus).

Saiga (Saiga tatarica) were once quite common throughout these deserts, coming here for winter periods. Their population size has been significantly reduced however. The goitered gazelle or djeiran (Gazella subgutturosa subgutturosa) and marbled polecat (Vormela peregusna) are also rare and endangered. First attempts to reintroduce Asiatic wild ass (kulan) (Equus hemionus) were undertaken here in the 1980s. Until only recently, there was a chance that cheetah (Acinonyx jubatus) continued to survive in some parts of this ecoregion.

Photo: Saiga http://www.fauna-flora.org/explore/kazakhstan/

Larger birds of the ecoregion include the houbara bustard (Chlamydotis undulata), black-bellied and pin-tailed sandgrouse (Pterocles alcata, P. orientalis), cream-colored courser (Cursorius cursor), golden eagle (Aquila chrysaetus), short-toed eagle (Circaetus gallicus), steppe eagle, (Aquila rapax), Egyptian vulture (Neophron percnopterus), and saker falcon (Falco cherrug). Among the more common bird species are wheatears (Oenanthe isabellina, O. deserti), desert warbler (Sylvia nana), the desert lark (Ammomanes deserti), desert raven (Corvus ruficollis), and desert shrike (Lanius excubitor). Pander’s ground jay or saxaul jay (Podoces panderi) is a rare and unusual member of the crow family. Asian desert sparrow (Passer zarudnyi) is also rare. Houboara bustard is one of the most endangered bird species in this region. It migrates from Saudi Arabia through Iran and Pakistan to Uzbekistan, Kazakhstan, and Turkmenistan. It is threatened by elite hunters who spend large amounts of money for the opportunity to hunt it.

The list of desert reptiles includes a number of species of toad agamas, namely: Khentau toad agama (Phrynocephalus rossikowi), Molchanov's toad agama (P. moltschanovi), Strauch's toad agama (P. strauchi), spotted toad agama (P. maculatus), Sogdian toad agama (P. sogdianus), Said-Aliev's toad agama (P. helioscopus saidalievi). Other reptiles include gekkos (Alsophylax pipiens, A. laevis), Rustamov's skink gekko (Teratoscincus scincus rustamovi), Chernov's snake-lizard (Ophimorus chernovi), Ferghana sand lizard (Eremias scripta pherganensis), black-eyed lizard (Eremias nigrocellata), gray monitor (Varanus griseus), Afghan lytorhynch (Lytorhynchus ridgewayi), four-lined snake (Elaphe quatuorlineata), and the cobra (Naja naja oxiana). The invertebrate fauna of the sandy deserts is especially rich, represented by species such as grasshoppers, darkling beetles, scarabaeid beetles, butterflies, termites and ants.

The main anthropogenic threats are agriculture, hunting and poaching, and overuse of woody plants for firewood. Overgrazing of livestock is the main threat in non-irrigated areas. Biodiversity in the deserts of this region are adversely affected by desertification and localalised degradation of soils. Irrigated agriculture in marginal lands has significantly accelerated wind erosion and salinisation of soils.

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