The Mongolian-Manchurian grassland includes more than a million square kilometers of temperate grasslands on the inland side of Northeast China coastal mountain ranges and river basins. To the west are the desert regions of southern Mongolia and north-central China. The western arm of the Mongolian-Manchurian grassland ecoregion extends toward the Upper Selenga River Basin, which drains into Lake Baikal and then to the Arctic Ocean. A second arm extends southwest toward the deserts of north-central China. Much of the ecoregion consists of nearly flat or rolling grasslands. The southwestern uplands of the Great Hinggan Mountains are also included. Their western slopes are gently inclined toward Mongolia while the eastern slopes drop steeply to the Northeast China Plain.
Average elevation throughout the ecoregion is 1,000 to 1,300 m and the climate is temperate. The trans-montane grasslands northwest of the Great Hinggan Mountains have especially cold winters because there are no mountains to offer shelter from prevailing northwesterly winds. A "continental monsoon effect" – where low pressure over the South China Sea draws cold air toward the southeast from the high latitude regions of Central Asia – creates much colder winter temperatures than occur at other regions of similar latitude.
Dominant plant taxa in these grasslands include feather grass (Stipa baicalensis, S. capillata, and S. grandis), Festuca ovina, Aneurolepidium chinense, Filifolium sibiricuman, and Cleistogenes sqarrosa. Areas closer to the GobiDesert support desert steppe and have lower productivity. Dominant species here include drought-resistant feather grasses (Stipa gobica, S. breviflora, and S. glareosa), forbs (Reaumuria soongolica, Hippolytia trifida, and Ajania fruticosa), and small, spiny shrubs that are well adapted to arid conditions (Caragana microphylla, Ephedra equisetina, and E sinica).
Mongolian gazelle is the most abundant ungulate and in autumn and winter thousands of gazelle migrate and breed in these grasslands.
The western slope of the Great Hinggan Mountains, covering the Nomrog and Degee River basins on the Mongolia-China border, has many peculiar plants as white peony (Paeonia albiflora), grand lady’s slipper (Cypripedium macranthum), and gas plant (Dictamnus Dasycarpus). In Nomrog Protected Area there are 46 species of mammals and 260 species of birds, among which Ussurian moose, (Alces alces cameloides), Daurian hedge-hog (Erinaceus dauricus), Eurasian otter (Lutra lutra), Manchurian zokor (Mysospalax epsilanus), Eurasian Spoonbill (Platalea leucorodia), Baer’s Pochard (Aythya baeri), Mandarin Duck (Aix galericulata), Common Pheasant (Phasianus colchicus), and Asiatic Dowitcher (Limnodromus semipalmatus) are listed in the Red Data Book of Mongolia. Eurasian Otter, Baer’s Pochard, and Asiatic Dowitcher are IUCN listed as globally threatened.
Sheep-grazing is a dominant activity, although goats are more abundant in the rockier, mountainous areas. In recent years, the number of goats raised on the grasslands has increased considerably due to the high prices for cashmere wool, refined from goat fleeces. Because goats eat a wider range of plant species and forage more aggressively than sheep – and because goats consume the entire plant – this trend has contributed to the widespread degradation of these grasslands.
Wetland habitats (many brackish or saline) exist throughout these grasslands and many are important breeding habitat for Whooper Swan (Cygnus cygnus), Swan Goose (Anser cygnoides, IUCN Endangered), Red-crowned crane (Grus japonensis, IUCN Endangered), and relict gull (Larus relictus, IUCN Vulnerable). The Mongol Daguur Strictly Protected Area, which covers the lower Uldz River basin with 90 small lakes, rivers, springs and wetlands, is the breeding and stopover place for many migrating birds including several rare species of crane.
Among China's nature reserves Huihe National Nature Reserve is especially important for supporting populations of swan goose, cranes, and other wetland birds. A gazelle reserve west of Dalai Lake was established in China, while several reserves in the Kherlen River and Yakhi Lake basin exist within the Amur-Heilong basin in Mongolia. In 2005, Dornod Province petitioned the central government of Mongolia to establish a nature reserve adjacent to Buir Lake.