Boundaries

This ecoregion includes the entire Sungari (also known as the Songhua Jiang) River drainage. In the north, the border moves along the Malyy Khigan Range (also known as Xiao Hinggan Ling) where headwaters of the Nen Jiang and Hulan He rivers are located. In the northeast, the ecoregion is separated from the Ussuri River drainage [616] by the Nadan-Khada-Alin (or Wanda Shan) Range. Further south, these two ecoregions are divided by the Laoelin (or Laoye Ling) Range between the Mulin He (Dalin He) River and the Mudan Jiang River. In the south, the ecoregion is contiguous with the Yalu Jiang (or Amnok-kang) [638] and Liao He [637] drainages. In the west, the Bolshoy Khingan (or Da Hinggan Ling] Range divides the Sungari drainage and the Haylar (or Hailar He) drainage [618].

Topography

The Songhua River runs through northeast China, and is the largest tributary of the Heilong (Amur) River, flowing about 1,927 km from the Changbai Mountains through the Heilongjiang and Jilin provinces.

The Sungari River drainage encompasses nearly the entire northern Manchuria, excluding the western slopes of the Great Khingan Mountains in the Argun River drainage, the northern slopes of the Great Khingan Mountains, as well as the Little Khingan Mountains.  Except for the eastern mountains near Khanka Lake and the Ussuri River, the region’s mountains contribute several small rivers that flow directly into the Amur River.

The river drains 212,000 square miles of land. The river has a dam at Fengman, which is used for hydroelectricity production. It forms a lake that stretches 150 km upstream. Below the dam, the river flows northwest until its largest tributary, the Nen River, joins it near Daan. The Nen River drains the northern Manchurian Plain. The river travels east until it joins the Hulan River near Harbin. Then it passes between the northern end of the eastern Manchurian mountain system and the Lesser Khingan Range. The river then flows into the Amur River valley. It joins the Amur at the town of Dongjiang.

The majority of small tributaries of the Sungari River are mountainous or semi-mountainous.  They flow rapidly, and carry large amounts of suspended particles. Larger tributaries, like the left-bank Nen Jiang River and the right-bank tributaries (Lalin He and Mudan Jiang rivers), run mostly through valleys, forming numerous floodplain bodies. A large number of these water bodies (anabranches, bayous, backwaters, lakes, etc.)—connected with the Sungari River by a system of anabranches either permanently or during floods—are formed downstream from the upper Sungari River’s confluence with the Nonni River.

Freshwater habitats

The Sungari River’s average water flow is roughly 2500 m³ s^-1. It freezes from late November until March, and experiences its highest flows when the mountain snow melts during the spring thaw. Disastrous floods tend to occur during periods of high summer rainfall. Large-scale floods occurred in the Songhua Jiang valley in 1995 and 1998, and the river still carries large amounts of suspended debris.

In November 2005, the river was contaminated with benzene, leading to a shutdown of Harbin’s water supply and threats of a Russian lawsuit against China.

Fengman Dam is one of the region’s three large dams.

Terrestrial habitats

Numerous streams join the Sungari River’s tributaries in forming a fan that begins in the highlands of the Bolshoy Khingan (or Da Hinggan Ling), Malyy Khigan (or Xiao Hinggan Ling), Nadan-Khada-Alin (or Wanda Shan), and the Laoelin (Laoye Ling) ranges.  The waters flow through a series of relatively narrow, forested valleys. The major part of the river system drains the Manchurian Plain. Its characteristic feature is a well developed system of floodplain water bodies. The once swampy lowlands have been altered by agriculture.

Description of endemic fishes

The ecoregion contains three endemics: Abbottina lalinensis, roundtail paradisefish (Macropodus ocellatus), and Micropercops cinctus. Abbottina lalinensis (gudgeon) is the only known endemic in the Lalin He River (a tributary of the Sungari).

Other noteworthy fishes

Rhodeus mantschuricus was once described as a distinct species. This information may be correct, but further research is needed to confirm it is not simply part of a larger group.

Lefua costata (Kessler 1876) was commonly considered a wide-ranging species that spanned the whole Amur catchment. However, the complex "Lefua costata" needs extra study, with more concrete information about its range. It has been already published that in Sungari there are two different species of Lefua identified as L. castata and L. pleskei. The representatives of this genus are small-sized loaches with patchy coloration.  They differ by relative size of body parts and vertebral counts, as well as the position of their fins.

Justification for delineation

The Sungari (or Songhua Jiang) River is a southern tributary of the Amur, and is the largest drainage within the Amur catchment. Its ichthyofauna is poorly known. However, this ecoregion ranks among the highest for species richness in North Asia and is only comparable with the Lower Amur ecoregion [616]. In general, the Sungari River’s fish fauna have a more "southern" character relative to that of the Lower Amur. It lacks most salmonids, but has more diverse and abundant cultrins and xenocyprinins (Cyprinidae).

Level of taxonomic exploration

Poor