Biology

Amur meadow steppe

caption Amur meadow steppe ecoregion. Source: WWF The Amur meadow steppe is a low-lying fertile floodplain and deciduous subtaiga forests along the middle reaches of the Amur River in southeastern Russia and northeast China. The areal extent of this palearctic ecoregion comprises a terrestrial extent of approximately 47,700 square miles; moreover, the geometry of the Amur meadow steppe is configured as a disjunctive set of two areas. This ecoregion is considered within the flooded grasslands and savanna biome.

Geology

caption Amur meadow steppe from space. Source: NASA The extensive meadows here are a product of the Amur River and its tributaries meandering during geologic time across the alluvial deposits in the Amur-Heilong valley. In ancient times the valley would have exhibited a gamut of broadleaf and pine trees along the dunes created by the river flow.

The Amur meadow steppe evinces two discrete units separated by a gorge within the Little Hingg'an Range.  The northwestern element of the Zeya-Bureya Plain was created around the lower reaches of these two main tributaries and the Amur River mainstem. The most intactThe condition of an ecological habitat being an undisturbed or natural environment wetland ecosystems of this unit is  situated in the Arkhara lowlands east of the discharge point of the Bureya River.

Biodiversity

The Pleistocene saw the Amur meadow steppe as generally unglaciated, so that the biota here are contiguous representatives of species found to the south on the Korean Peninsula and South China. The Amur meadow steppe evinces moderate levels of faunal species richness, hosting 376 distinct vertebrate taxa; however, endemism levels are low, owing to the lack of Pleistocene glaciation and absence of major [vicariance] between neighbouring ecoregions.

Vegetation

caption Korean Pine foliage. Source: J.C.Schou Forest cover in the Amur meadow steppe is compromised due to the historic flooding of the expansive plains, so that trees are generally limited to upland locations; furthermore, the steady intensification of agriculture has created deforestation pressure. While broadleaf deciduous trees are in the greatest dominance, there are also important conifer species stands such as the Korean Pine (Pinus koraiensis), whose presence is particularly evident in the Hingg'an Gorge and nearby Russian forests.

A refugium population of the Sacred Lotus (Nelumbo nucifera) is found within the Amur meadow steppe. Other less common flowering water-plants to northeast China are the Japanese Iris (Iris ensata), Spatter Dock (Nuphar luteum), and Pygmy Waterlily (Nymphaea tetragona). Another more widely occurring aquatic angiosperm is Watershield (Brasenia schreberi).

Mammals

caption Mountain Weasel. Source: David Blank Notable mammals in the Amur meadow steppe include the Chinese Goral (Naemorhedus caudatus, VU), the Mountain Weasel (Mustela altaica, NT), the Taiga Musk Deer (Moschus moschiferus, VU), Even-toothed Shrew (Sorex isodon), the Long-clawed Shrew (Sorex unguiculatus), the Grey Red-backed Vole (Myodes rufocanus), the Mongolian Vole (Microtus mongolicus), and the Korean Field Mouse (Apodemus peninsulae).

Amphibians

There are a number of amphibians in the Amur meadow steppe ecoregion including the Japanese Treefrog (Hyla japonica), the Siberian Wood Frog (Rana amurensis), the Oriental Fire-bellied Toad (Bombina orientalis), the Mongolian Toad (Pseudepidalea raddei).

Reptiles

Reptiles occurring in the Amur meadow steppe include the Rock Mamushi (Gloydius saxatilis), a upland member of the viper family found from the Selemdzha River in Siberia eastward to Korea; the Amur meadow steppe is the approximate northeastern species range limit for this snake. Another viper found on the Amur meadow steppe is the Japanese Mamushi (Gloydius blomhoffi). The Mongolia Racerunner (Eremias argus) is also found on the Amur steppe ecoregion as an element of its northeast range in China and Russia.

Birds

caption Red-crowned Cranes, Amur Basin wetland, northeast China. @ C.Michael Hogan A number of rare and threatened bird taxa are found in the Amur meadow steppe ecoregion, including the White-naped Crane (Grus vipio, VU), the Red-crowned Crane (Grus japonensis, EN), and the Chinese Scaly Merganser (Mergus squamatus, EN).

Conservation

The Amur meadow steppe is classifed as a Vulnerable ecoregion, chiefly due to the pressures to farm the fertile soils along the Amur floodplain, and the expanding human demand for food, spurring agriculture. The generally high water table deters more extensive forest succession of the level floodplain elements.

The Khingansky Zapovednik is a key protected area in Russia, having elements of a strict scientific national nature reserve, national wildlife reserve and Ramsar site. This site is one of the last strongholds of the Asian Black Bear (Ursus thibetanus), who has a disjunctive population here, and of the White-naped Crane (Grus vipio). Further de facto protection is accorded by the Russian military that maintains a border security force in this region, which deters entry.

There is a strong need to protect the area of the Hing'an gorge itself, which is a significant biological corridor; this faunal migration connects the upper Amur Basin with the expansive wetlands of the middle Amur reaches.

Ancient and medieval history

caption Map of the Liao, Song and Xixia Empires, 1111 AD. Source: Douglas Frankfort Between the fifth to tenth centuries AD the area within the Amur meadow was controlled by one of the semi-nomadic Bo Shiwei tribes, whose villages were situated at the north of the Yilehuli Mountains in the upper reaches of the Nenjiang River, but south of the Stanovoy Range, west of the Bureinsky and the Malyi Hingg'an ranges; their territory even extended to the Okhotsk Sea on the northeast. These tribal people paid tribute to the Tang Dynasty, but left little trace of their civilisation by about 900 AD, when the Liao Empire was founded.

By the Medieval period in the 1200s, the Daur people controlled the the middle-Amur Basin and the Zeya River Basin. The ancestral Daurs are considered to be closely related to the Khitan and the Mongol peoples.

References

  • Herbert Franke and Denis Twitchett. 1994. Introduction: The Cambridge History of China, Volume 6, Alien Regime and Border States, 907-1368 AD. Cambridge University Press, England  ISBN 0521243319.
  • René Grousset. 1970). The Empire of the Steppes: A History of Central Asia. Rutgers University Press, New Jersey. ISBN 0-8135-1304-9
  • Yaroslav V. Kuzmin. 2008. Geoarchaeology of prehistoric cultural complexes in the Russian Far East: Recent progress and problems. Bulletin of the Indo-Pacific  Prehistory Association
  • S. Kurnaev. 1990. Forest regionalization of the USSR (1:16,000,000)  Department of Geodesy and Cartography, Moscow, Russia
  • F.W. Mote. 1999. Imperial China: 900-1800 (AD). Harvard University Press.  ISBN 0-674-01212-7.
  • A.E. Volkov (ed.) 1996. Strict Nature Reserves (Zapovedniki) of Russia: Collection of Chronicle of Nature data for 1991-1992. Sabashnikov Publishers. Moscow, Russia  ISBN 5-8242-0051-3.
Glossary

Citation

Hogan, C. (2013). Amur meadow steppe. Retrieved from http://www.eoearth.org/view/article/51cbfb5f7896bb431f6bf4cf