Location and General Description
This ecoregion lies between the steppe and the taiga and includes the Orkhon and Selenge river basins. Average altitude of the mountains in the ecoregion is 1500-2000 m while mean altitude of the larger area is 800-1200 m. Groves, with areas of saline soil, continue into the vast mountain valley steppe. The northern and northwestern portions of the mountains that surround the basin support broadleaf forests (Murzaev 1962). At lower altitudes the forests are dominated by Rosa acicularis while Cotoneaster melanocapra are rare. Due to the landscape and humid climate caused by forest in delta of the Selenge River, there are gray, gray-muddy, and dark-gray soils.
The Orkhon-Selenge forest steppe experiences a dry climate similar to neighboring steppe regions. The hot, dry wind coming from the northeast steppe areas maintains the unique characteristics of the Orkhon-Selenge forest steppe. The winter season in the basin continues from mid-October to late March or early April. The average air temperature in January is –20° C to –25° C. Spring starts in early April and finishes late June. Strong winds and sudden cold continue to occur regularly until June. The summer season starts from mid-June and lasts 80-90 days. Summer precipitation is 250-300 mm while fall and winter precipitation is 150-200 mm. Fall starts mid-September and lasts about 65 days (UNDP 1998).
Coniferous forests are found on the northern slopes of the region’s mountains while the southern slopes are covered with open steppe vegetation. The open steppe vegetation is a combination of forest and steppe flora, including species such as pine (Pinus silvestris) and aspen (Populus tremula).
Dry steppe vegetation communities represent about 88 per cent of the total area. Stipa cleistogenes is found in approximately 40 percent of the area while in highly elevated areas herbs such as Cleistogenes gramineae are prevelant. Caragana stipa is distributed in small patches throughout the ecoregion. A unique feature of this ecoregion is small sandy areas with their own distinct floral composition. These sandy areas are characterized by trees such as Ulmus pumila, Populus tremula, and Padus asiatica, and several willow species (Salix pentandra, S. tenuifolia) in wetter locations.
The fauna of this ecoregion is characteristic of species found in the forests and steppes of the greater geographic region. The steppe areas are particularly rich in species diversity. All steppe areas are inhabited by numerous rodent species. The main representatives are the mountain hare (Lepus tolai), Korean field mouse (Apodemus peninsulae), squirrel (Sciurus vulgaris), and root vole (Microtus oeconomus). Other notable species are the Siberian chipmunk (Tamias sibiricus) and the Zabaikalian wild boar (Sus scrofa). The forest steppe areas are visited in winter by wolves (Canis lupus) and by bears (Ursus arctos) during migration (Priobrajenskii et al. 1959).
In the Selenge river basin there are 18 species of birds included in the Mongolian Red Data Book. Prominent species include: dalmation pelican (Pelicanus crispus), white spoonbill (Platalea leucorodia), black stork (Ciconia nigra), whooper swan (Cygnus cygnus), swan goose (Anser cygnoides), osprey (Pandion haliaetus), white-tailed eagle (Haliaeetus albicilla), Altai snowcock (Tetraogallus altaicus), white-naped crane (Grus vipio), Siberian crane (Grus Leucogeranus), Asiatic dowitcher (Limnodromus semipalmatus), great black-headed gull (Larus ichthyaetus), Hodgson’s stonechat (Saxicola insignis), Eurasian penduline (Remiz pendulinus), and Henderson’s ground jay (Podoces hendersoni) (Bold 2000).
Except for several smaller protected areas there is no broad protection for the ecological integrity of this region. The area is heavily settled by herders and animal husbandry is practiced widely. The low valleys of the Selenge basin are arid and fertile are used extensively for agriculture, hay making and livestock harvesting.
Types and Severity of Threats
Streams and rivers are threatened by gold panning, which is widely practiced.
The human population centers (e.g., Erdenet, Hutol and other county centers) in the region also bring associated industrial threats. Pressures resulting from railways, roads, and processing industries such as copper and cement are perhaps the most significant threat to this ecoregion and nature in Mongolia (Bold 2000).
Justification of Ecoregion Delineation
This steppe lies mostly in Mongolia between the Khangai and Khentii mountains. It is distinguished from the Daurian forest steppe as that ecoregion which plays a unique role as an area of biological exchange for the flora and fauna of Siberia and middle Asia. In Mongolia, the ecoregion boundaries are derived from the mountain forest steppe surrounding the Selenge and Orkhon (Hilbig 1995, Finch 1996). In Russia, ecoregion boundaries conform to the forest steppe zone within the Tuva-Buryat-Mongolian vegetation province in Kurnaev’s (1990) forest map of the USSR.
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Prepared by: Bolor Radnaabazar
Reviewed by: Batbold D. Otgoid