The Great Lakes Depression, also called the Great Lakes Hollow, is a large

semi-arid A semi-arid climate, semi-desert climate, or steppe climate is a aridity, dry climate sub-type. It is located on regions that receive precipitation below Evapotranspiration#Potential evapotranspiration, potential evapotranspiration, but not as l ...

depression in

Mongolia Mongolia is a landlocked country in East Asia, bordered by Russia to the north and China to the south and southeast. It covers an area of , with a population of 3.5 million, making it the world's List of countries and dependencies by po ...

that covers parts of the Uvs, Khovd, Bayan-Ölgii, Zavkhan and Govi-Altai '' aimags''. Bounded by the Altai in the West, Khangai in the East and

Tannu-Ola Mountains The Tannu-Ola mountains (, uniturk, Taᶇdь-Uula, – Tangdy-Uula mountains; , , , ) is a mountain range in southern Siberia, in the Tuva Republic of Russia. It extends in an east–west direction and curves along the Mongolian border. Its hig ...

in the North, it covers the area of over with elevations from . Small northern parts of the depression are part of

Russia Russia, or the Russian Federation, is a country spanning Eastern Europe and North Asia. It is the list of countries and dependencies by area, largest country in the world, and extends across Time in Russia, eleven time zones, sharing Borders ...

."Great Lakes Depression"
''

Great Soviet Encyclopedia The ''Great Soviet Encyclopedia'' (GSE; , ''BSE'') is one of the largest Russian-language encyclopedias, published in the Soviet Union from 1926 to 1990. After 2002, the encyclopedia's data was partially included into the later ''Great Russian Enc ...

'' The depression is named so because it contains six major Mongolian lakes: saline

Uvs Nuur Uvs Lake ( ) is a highly saline lake in an endorheic basin— Uvs Nuur Basin, primarily in Mongolia with a smaller part in Russia. It is the largest lake in Mongolia by surface area, covering 3,350 km2 at 759 m above sea level. The no ...

, Khyargas Nuur and Dörgön Nuur; and

freshwater Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. The term excludes seawater and brackish water, but it does include non-salty mi ...

Khar-Us Nuur, Khar Nuur and Airag Nuur, as well as a number of smaller ones. In addition, it includes of '' solonchaks'' and large

sand Sand is a granular material composed of finely divided mineral particles. Sand has various compositions but is usually defined by its grain size. Sand grains are smaller than gravel and coarser than silt. Sand can also refer to a textural ...

y areas. Northern parts are dominated by arid steppes, and southern by semideserts or deserts. The major rivers are Khovd River,

Zavkhan Gol Zavkhan River (, ) is a river in Mongolia. It flows from Khangai Mountains to Lake Khyargas, and has a draining area of over . The river forms most of the border between the Govi-Altai and Zavkhan aimags. The length of the river is . During ...

, and Tesiin Gol.

Ecology

The depression is a major

basin of Mongolia and contains important

wetland A wetland is a distinct semi-aquatic ecosystem whose groundcovers are flooded or saturated in water, either permanently, for years or decades, or only seasonally. Flooding results in oxygen-poor ( anoxic) processes taking place, especially ...

s of

Central Asia Central Asia is a region of Asia consisting of Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan, and Uzbekistan. The countries as a group are also colloquially referred to as the "-stans" as all have names ending with the Persian language, Pers ...

. The wetlands are based on the system of interconnected shallow lakes with wide reed belts within a generally

desert A desert is a landscape where little precipitation occurs and, consequently, living conditions create unique biomes and ecosystems. The lack of vegetation exposes the unprotected surface of the ground to denudation. About one-third of the la ...

steppe In physical geography, a steppe () is an ecoregion characterized by grassland plains without closed forests except near rivers and lakes. Steppe biomes may include: * the montane grasslands and shrublands biome * the tropical and subtropica ...

. The wetlands support a number of rare migrating birds:

Eurasian spoonbill The Eurasian spoonbill (''Platalea leucorodia''), or common spoonbill, is a wading bird of the ibis and spoonbill family Threskiornithidae, native to Europe, Africa and Asia. The species is partially migratory with the more northerly breeding popu ...

(''Platalea leucorodia''), black stork (''Ciconia nigra''),

osprey The osprey (; ''Pandion haliaetus''), historically known as sea hawk, river hawk, and fish hawk, is a diurnal, fish-eating bird of prey with a cosmopolitan range. It is a large raptor, reaching more than in length and a wingspan of . It ...

(''Pandion haliaetus''),

white-tailed eagle The white-tailed eagle (''Haliaeetus albicilla''), sometimes known as the 'sea eagle', is a large bird of prey, widely distributed across temperate Eurasia. Like all eagles, it is a member of the family Accipitridae (or accipitrids) which also ...

(''Haliaeetus albicilla''),

swan goose The swan goose (''Anser cygnoides'') is a large goose with a natural breeding range in inland Mongolia, Northeast China, and the Russian Far East. It is migratory and winters mainly in central and eastern China. Vagrant birds are encountered ...

(''Cygnopsis cygnoides''), and

bar-headed goose The bar-headed goose (''Anser indicus'') is a goose that breeds in Central Asia in colonies of thousands near mountain lakes and winters in South Asia, as far south as peninsular India. It lays three to eight eggs at a time in a ground nest. It ...

(''Anser indicus''). Only a few individuals of

great white pelican The great white pelican (''Pelecanus onocrotalus'') also known as the eastern white pelican, rosy pelican or simply white pelican is a bird in the pelican family. It breeds from southeastern Europe through Asia and Africa, in swamps and shallow ...

(''Pelecanus onocrotalus'') remain in the Great Lakes Basin in Mongolia. They nest in catchment areas of rivers and lakes that have abundant fish and vegetation. Although the total number of fish species in the region is low, a large percentage of those that do occur are

endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...

or near-endemic, especially from the genera '' Oreoleuciscus'' (Altai osmans), ''

Thymallus ''Thymallus'', commonly known as graylings, is a genus of freshwater ray-finned fish and the only genus within the subfamily Thymallinae of the family Salmonidae. Although all ''Thymallus'' species can be generically called graylings, withou ...

'' (graylings) and ''

Triplophysa ''Triplophysa'' is a genus of fish in the family Nemacheilidae found mainly in and around the Qinghai-Tibet Plateau in China, as well as inland waters of the larger part of central Asia. They can be distinguished from other genera of Nemacheilid ...

'' (a stone loach genus).

Notes

References

External links

Birdsview of the Great Lakes Depression
computer visualization generated from satellite data, showing (from front to back) Dörgön Nuur, Khar Nuur, Khovd, Khyargas Nuur, and

, as well as Üüreg Nuur left of Uvs Nuur. The green line on the left is the valley of the Khovd Gol with Khar-Us Nuur and Achit Nuur. {{Authority control Depressions of Mongolia Depressions of Russia