Daurian Steppe Ecoregion

Mongolian Section Of The Amur/Heilong Ecoregion Complex (AHEC)

The total area of the Mongolian part of the Amur River Basin is 235,000km2 (15 % of Mongolian territory and about 11% of the total Amur River basin). The Mongolian part of the Amur River basin consists of four main rivers: The Onon, Ulz, Kherlen, and Khalkh Gol. Together with their 400 tributaries, the total length of permanent streams is approximately 2,000km. The Onon River has a basin area of about 30,000 km2.

All of the AHEC in Mongolia is contained within the ‘Zuun Bus’ economic area. The Mongolian portion of the AHEC also has a large overlap with the Mongolian part of the Daurian Steppe (a WWF Global 200 Eco-region).

Eastern Region (Zuun Bus) Of Mongolia
Mongolia’s more than 600,000 square miles of terrain is divided into 21 provinces called Aimags, meaning “tribe” in the parlance of the Altaic Mongol tongue. The three easternmost Aimags – Hentiy, Dornod, and Sukhbaatar – make up an economic zone of Mongolia known as the Zuun Bus. A 100,500 square mile (250,000 ha) swath of land inhabited by fewer than 200,000 people, the Zuun Bus is also one of the most ecologically important regions on the face of the Earth.

Daurian Steppe Ecoregion
This is one of the best, most intact examples of Eurasian steppe and grasslands. The Daurian steppe eco-region is made of the following terrestrial eco-regions: Daurian forest steppe and Mongolian-Manchurian grassland. It is a sea of grass that forms the best and most intact example of an undisturbed steppe ecosystem and is one of the last areas in the Palaearctic that still supports stable herds of larger vertebrates. The region has distinct flora and fauna, with a number of endemic species.

One of WWF Mongolia’s priority protected areas, contained wholly in the AHEC and largely in the Daurian Steppe, is the Onon-Balj National Park. Within the Onon River basin, the region is an important catchment area forming the headwaters of the Amur/Heilong River.

The Onon River Basin
The Onon River Basin is part of the Daurian Steppe Global 200 Eco-region identified by WWF. The Daurian Steppe Eco-region encompasses a large portion of Eastern Mongolia, as well as parts of the Russian Far East and North-Eastern China. The Onon River Basin is also a sub-unit of the much larger Amur River basin (see Figure 1) that forms the Amur/Heilongjiang Freshwater Eco-region of North-East Asia. The Onon River and its tributaries directly drain into the Amur through the Shilka River, all of which are ultimately destined for the Pacific Ocean.

The total area of the Mongolian part of the Amur River Basin is 235,000km2 (15% of the Mongolian land area). This makes up approximately 11% of the total Amur River Basin. The Mongolian part of Amur River Basin consists of four main rivers. The Onon River (with a basin area of about 30,000 km2), Ulz, Kherlen and Khalkh Gol, with their 400 tributaries and a total length of permanent streams of about 2,000km.

The Onon River originates on the North-East slope of the Khentii Mountain range with a total river basin of 94,000km2. 30,000km2 is located within Mongolian territory.  The total length of the Onon River is 808km with 298km in Mongolian territory. Several rivers on the Russian side, such as the Khuya, Ashinga, Balj, Agats, Kher and Teren drain into upper reaches of the Onon River. The confluence in Russia of the Ingode and Onon rivers forms the origin of the Shilka River. Upon convergence with the Argun River the Amur River is born.

The Onon-Balj National Park
The Onon-Balj National Park is a key part of the Onon River basin. Established in 2000, the area is of outstanding natural beauty with rich forests and water courses. These are very rare resources in Mongolia. The protected area is very close (30 km) to the Russian Sokhondo Biosphere (protected area) situated at the border of Mongolia and Russia. The total area of the Park is around 400,000ha. This covers the soums (territories) of Dadal, Bayan-Adarga, Binder and Norovlin within Khentii aimag (province) and Bayan-Uul soum in Dornod aimag (see Figure 2). It occupies the territories of the culturally rich and traditional Buriad communities, a minority ethnic group of Mongolia. The Russian side is also occupied by the Buriyads, forming the Chita oblast of Russia.

Climate of  the National Park is harsh continental, with mean annual air temperature varying from +0.50 to +30 С. The monthly mean temperature for January is between -200С and -240С. The monthly mean temperature in July is +160С to +220С. The lowest temperature is -40.10С to -46,70С and the warmest is +38.90С to +40.10С. The annual temperature variation may reach 700С. The number of days in a year where air temperature is below -300С in the winter period is 25-35 and the number of days in a year where the air temperature is above +300С in the summer season is 10-25 days.

The Onon-Balj area is dominated by forested mountains. Forest area covers around 40% (160,000ha) of the Onon-Balj national park. Mongolian-Daurian mountain forest steppe extends to the eastern side of the Khentii Mountain range along the Onon-Balj river basins. Larch, pine and birch forest dominate the back slopes of the hills. There is also pure pine forest growth along the sandy river valleys. In the forest, forest brown soil dominates. While on the southern slope of hills, mountain valleys, and on high floodplains, black soil is present. In the central valley regions, in relative lowlands, meadow and meadow-marsh soils can be observed. In this area, penetration of forest vegetation to the steppe side often occurs. In comparison with other regions of Mongolia, this region is more humid, with a higher annual precipitation of 350-450 mm.

Biodiversity of the National Park is unique and rich due the to its location in the transition zone – from Siberian taiga to Duarian and Manchurian dry steppe. There are 946 plant species recorded, 51 mammal species, 223 bird species and 23 fish species. Its plant coverage is particularly unique and 831 species of them are herbaceous. Three coniferous forest species, Krylovii pine, Daurian larch and Chekanovskii larch cannot be found anywhere in Mongolia outside the territory of the National Park.