According to Vasily Kryuchkov, approximately 31,000 square kilometers of the Russian Arctic has subjected to severe environmental disturbance. Fauna Birds Order Galliformes Family Tetraonidae Hazel grouse Siberian grouse Black grouse Black-billed capercaillie Western capercaillie Willow ptarmigan Rock ptarmigan Family Phasianidae Daurian partridge Grey partridge Altai snowcock Japanese quail Common quail Ring-necked pheasant Mammals Order Artiodactyla Moose Bactrian camel Wisent (European bison) Red deer Wild boar Siberian roe deer Manchurian wapiti Siberian musk deer Order Carnivora Family Canidae Grey wolf Tundra wolf Arctic fox Red fox Family Felidae Snow leopard Amur leopard Siberian tiger Eurasian lynx Pallas cat Family Mustelidae Least weasel Stoat Mountain weasel Siberian weasel Steppe polecat Sable Eurasian river otter Asian badger Wolverine Family Ursidae Asian black bear Brown bear Polar bear Flora Larix sibirica Larix gmelinii Picea obovata Pinus pumila Politics Notable sovereign states in Siberia Xianbei state (1st–3rd century CE) First Turkic Khaganate (6th–7th century) Eastern Turkic Khaganate (7th century) Second Turkic Khaganate (7th–8th century) Mongol Empire (13th–14th century) Khanate of Sibir (1468–1598) Tsardom of Russia (1598–1721) Russian Empire (1721–1917) Russian Republic (1917–1918) Russian Socialist Federative Soviet Republic (1918–1922) Far Eastern Republic (1920–1922) Tuvan People's Republic (1921–1944) Soviet Union (1922–1991) Russian Soviet Federative Socialist Republic (1922–1991) Russian Federation (1991–present) Borders and administrative division The term "Siberia" has both a long history and wide significance, and association. The understanding, and association of "Siberia" have gradually changed during the ages. Historically, Siberia was defined as the whole part of Russia and North Kazakhstan to the east of Ural Mountains, including the Russian Far East. According to this definition, Siberia extended eastward from the Ural Mountains to the Pacific coast, and southward from the Arctic Ocean to the border of Central Asia and the national borders of both Mongolia and China. Soviet-era sources (Great Soviet Encyclopedia and others) and modern Russian ones usually define Siberia as a region extending eastward from the Ural Mountains to the watershed between Pacific and Arctic drainage basins, and southward from the Arctic Ocean to the hills of north-central Kazakhstan and the national borders of both Mongolia and China. By this definition, Siberia includes the federal subjects of the Siberian Federal District, and some of the Ural Federal District, as well as Sakha (Yakutia) Republic, which is a part of the Far Eastern Federal District. Geographically, this definition includes subdivisions of several other subjects of Urals and Far Eastern federal districts, but they are