Location and General Description
The Eastern Gobi Desert Steppe extends from the Inner Mongolian Plateau (China), situated at 1,000 to 1,500 m elevation, northward into Mongolia. It is a broad ecotone. Boundaries are determined to the east and north by the relatively moist grasslands of Mongolia and Manchuria, and to the west and south by the extensive semi-deserts of the Alashan Plateau. This ecoregion includes the Yin Shan, a mountain range that rises to an elevation of 1,500 to 2,200 m, and many low-lying areas with salt pans and small ponds. Although the region appears rather desolate, it provides potential habitat for many wildlife species and a human population of semi-nomadic herders.
The climate here is continental. Summers are warm to hot, depending on elevation, and winters are intensely cold. Winter conditions are harsher here than other parts of China at similar altitude and latitude because there are no mountains to shelter the region from cold northerly winds. The mean annual temperature varies from -2 to -6oC, with January mean temperatures of -20 to -28oC. Annual precipitation here is about 100 to 150 mm, although total precipitation varies considerably from one year to the next. Most of this precipitation falls during summer.
Vegetation tends to be homogenous across vast areas of the Eastern Gobi Desert Steppe and distinct from the vegetation of grasslands to the east and deserts to the west. It consists of drought-adapted shrubs and thinly distributed low grasses. Dominant shrubs include two Caragana species (C. bungei and C. leucocephala). This shrubby legume is also dominant over much of the Tibetan Plateau in the transitional area between the cold, moist grasslands of the east and the cold deserts of the western plateau. Other shrubs include gray sparrow’s saltwort (Salsola passerina), gray sagebrush (Artemisia xerophytics), Potaninia mongolica, and Nitraria sibirica. Low grasses include needle grass (Stipa gobica and S. glareosa) and bridlegrass (Cleistogenes soongorica).
Mammals characteristic of the Eastern Gobi Desert Steppe include Asian wild ass (Equus hemionus), Saiga antelope (Saiga tartarica mongolica), black-tailed gazelle (Gazella subgutturosa), marbled polecat (Vormela peregusna), and several species of Jerboa (Zapodidae). Jerboas comprise a small family of mammals that are adapted to burrowing and jumping in sandy habitats. Their hind legs are as much as five times the length of their forelegs. They have long, flexible tails, and are capable of jumping up to 3 m. Several species are endemic to the deserts of Central Asian, and include the long-eared jerboa (Euchoreutus naso), Kozlov's pygmy jerboa (Salpingotus kozlovi), Mongolian jerboa (Stylodipus andewsi), and Gobi jerboa (Allactaga bullata). The mountains of this ecoregion include potential habitat for snow leopards (Uncia uncia) although it is uncertain whether any snow leopards survive here.
Birds characteristic of the desert steppe include Houbara bustard (Chlamydotis undulata), Pallas sandgrouse (Syrrhaptes paradoxus), Henderson's ground jay (Podoces hendersoni), greater plover (Charadrius leschenaultii), Mongolian desert finch (Bucanetes mongolicus), chukar (Alectoris chukar), lammergeier (Gypaetus barbatus), and Cinereous vulture (Aegypius monachus).
In general, the portion of this ecoregion that lies in Mongolian has been less heavily influenced by people and supports more intact wildlife populations than does the portion located within China.
Desert steppe vegetation is susceptible to damage caused by trampling (livestock or off-road vehicles) and overgrazing, particularly by goats. Because the Eastern Gobi Desert steppes receive more precipitation and are more productive than the desert regions to the west, this ecoregion receives a greater human impact. Mongolia’s system of national parks and nature reserves does not cover this area adequately, as most of the protected areas are located in the most arid, mountainous places or in the taiga of northern Mongolia. The portion of this ecoregion that lies within China is similarly devoid of nature protection areas, although de facto wildlands do exist here because the area is so marginal.
Types and Severity of Threats
In recent years, the number of goats raised on the grasslands has increased considerably due to the high prices for cashmere wool, which comes from goats. Because goats eat a wider range of plant species, forage more aggressively and tend to consume the whole plant, this trend has contributed to degradation of the grasslands over a widespread area.
In Mongolia, economic trends of livestock privatization and the collapse of the urban economy have caused people to return to rural lifestyles, a movement contrary to the global trend toward urbanization. As a result, the number of herdsmen in Mongolia is reported to have tripled in the past decade to more than 450,000 and the number of livestock has increased by 30 percent.
Justification of Ecoregion Delineation
This ecoregion represents a transitional zone between Mongolian-Manchurian grassland and Alashan Plateau semi-desert. Shrub semi-desert cover the northern part of the region transitioning into more xerophytic communities on sandy, rubble soils to the south. The boundary is based on CVMCC (1979) Vegetation Map of China classes of desert steppe (45,46, 47). This is comparable to the southwestern section of the Mongolian steppe biogeographic subunit in the Mongolian-Manchurian Desert according to Mackinnon et al. (1996).
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Prepared by: Chris Carpenter
Reviewed by: Batbold D. Otgoid