Surface area: 10,189 ha
Elevation: 1,332-1,454 m
Protection status: Unprotected.
Site description: Ugii Lake is located 352km west of Ulaanbaatar in Orkhon River valley. There are 3 rivers that flow in the west side of the lake, of which Khugshin Orkhon or Nariinii River enters to the lake from its west. Khooloin river flows out from the northwest of the lake, then flows into Orkhon River. The surrounding area of the lake is characterized by grassy steppe and river meadow vegetation zones. There also can be found grassy wetlands and small ponds along tributary of the lake, located in the west. The rest areas of the site are characterized by dry steppe zone. Small gravels are common along the lake shores. There are low cliffs along its eastern and southeastern shores. The small lake called Baga Lake forms in the east of the lake when the water level decreases. A small-scale fishery practices at the site and it is one of popular sport fishing destinations of Mongolia. There are many herders around the site and there is small area in the Orkhon River valley used for agriculture. The major threats at the site are degradation of the land due to overgrazing, drought, poorly managed tourism and wildfire.
Importance for birds: Globally threatened bird species such as Dalmatian Pelican (Pelecanus crispus), Swan Goose (Anser cygnoides), Baikal Teal (Anas Formosa), Pallas’s Fisheagle (Haliaeetus leucoryphus), Lesser Kestrel (Falco naumanni), Siberian Crane (Grus leucogeranus), White-naped Crane (G. vipio), Hooded Crane (G. monacha), Great Bustard (Otis tarda) and Relict Gull (Larus relictus) are common at the site. Every year thousands of waterbirds stopover during autumn and spring migration. Of which, Great Crested Grebe (Podiceps cristatus), Whooper Swan (Cygnus Cygnus), Swan Goose (Anser cygnoides), Bar-headed Goose (Anser indicus), Ruddy Shelduck (Tadorna ferruginea), Common Goldeneye (Bucephala clangula), Common Crane (Grus grus) and Northern Lapwing (Vanellus vanellus) gather here in flocks, exceeding 1% of their flyway populations.
Special flora and fauna: Tarbagan marmot (Marmota sibirica), Grey Wolf (Canis lupus), Corsac Fox (Vulpes corsac) and Red Fox (V. vulpes) occur at the site. Rare fish species such as Lenok (Brachymystax lenok) and Mongolian Grayling (Thymallus revirostris) are live here. Potamogeton prolongus can be found only in Ugii Lake.