The Yarlung Tsangpo arid steppe
ecoregion
An ecoregion (ecological region) or ecozone (ecological zone) is an ecologically and geographically defined area that is smaller than a bioregion, which in turn is smaller than a biogeographic realm. Ecoregions cover relatively large areas of ...
(WWF ID: PA1022) covers the river valley of the
Yarlung Tsangpo
The Yarlung Tsangpo, also called Yarlung Zangbo () is the upper stream of the Brahmaputra River located in the Tibet Autonomous Region, China. It is the longest river of Tibet and the fifth longest in China. The upper section is also called D ...
River on the southern edge of
Tibet
Tibet (; ''Böd''; ) is a region in East Asia, covering much of the Tibetan Plateau and spanning about . It is the traditional homeland of the Tibetan people. Also resident on the plateau are some other ethnic groups such as Monpa, Taman ...
. The river runs parallel to the northern borders of
Nepal
Nepal (; ne, :ne:नेपाल, नेपाल ), formerly the Federal Democratic Republic of Nepal ( ne,
सङ्घीय लोकतान्त्रिक गणतन्त्र नेपाल ), is a landlocked country in S ...
,
Bhutan
Bhutan (; dz, འབྲུག་ཡུལ་, Druk Yul ), officially the Kingdom of Bhutan,), is a landlocked country in South Asia. It is situated in the Eastern Himalayas, between China in the north and India in the south. A mountainou ...
and
India
India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...
, between the
Himalayas
The Himalayas, or Himalaya (; ; ), is a mountain range in Asia, separating the plains of the Indian subcontinent from the Tibetan Plateau. The range has some of the planet's highest peaks, including the very highest, Mount Everest. Over 10 ...
to the south and the
Tibet Plateau to the north.
The river valleys are the most populated areas of Tibet, putting pressure on wildlife. The area ranges from cold desert in the west to steppe shrub land in the east; the few trees are in the lowest river valleys to the east.
Location and description
The Yarlung Tsangpo runs west to east for along the north slope of the Himalayas, but south of the
Transhimalaya
The Transhimalaya (also spelled Trans-Himalaya), or "Gangdise – Nyenchen Tanglha range" ( zh, s=冈底斯-念青唐古拉山脉, p=Gāngdǐsī-Niànqīngtánggǔlā Shānmài), is a mountain range in China, India and Nepal, extending in a wes ...
ranges of the
Gangdise Shan
The Kailash Range, Kailas Range, Gangdisi Mountains, Gangdese Range, Gangdisê Range or Gangdise Shan, is a mountain range on the Tibetan Plateau in Tibet and the Tibet Autonomous Region.
Geography
It is the western subrange of the Transhimalaya ...
and
Nyenchen Tanglha Mountains
The Nyenchen Tanglha Mountains (officially spelt Nyainqêntanglha Mountains in Chinese) are a long mountain range, and subrange of the Transhimalaya System, located in Tibet and the Tibet Autonomous Region of China.
Geography
One source ...
. The ecoregion mostly follows the river valley and short tributary valleys, including the area north to
Lhasa
Lhasa (; Lhasa dialect: ; bo, text=ལྷ་ས, translation=Place of Gods) is the urban center of the prefecture-level Lhasa City and the administrative capital of Tibet Autonomous Region in Southwest China. The inner urban area of Lhas ...
.
Yamdrok Lake
Yamdrok Lake (also known as Yamdrok Yumtso or Yamzho Yumco; ; ) is a freshwater lake in Tibet, it is one of the three largest sacred lakes in Tibet. It is over long. The lake is surrounded by many snow-capped mountains and is fed by numerous sm ...
, one of the largest lakes of the Tibetan Plateau is in the region, and at Lhasa is an urban impoundment of water now protected as the
Lalu Wetlands National Nature Preserve.
Climate
The climate of the valleys of the ecoregion have a ''
Subarctic climate, dry winter'' (
Köppen climate classification
The Köppen climate classification is one of the most widely used climate classification systems. It was first published by German-Russian climatologist Wladimir Köppen (1846–1940) in 1884, with several later modifications by Köppen, notabl ...
Subarctic climate (Dwc)). This climate is characterized by mild summers (only 1–3 months above ) and cold winters having monthly precipitation less than one-tenth of the wettest summer month.
Precipitation in the ecoregion is 200–500 mm/year, increasing from west to east. The valleys also benefit from the drying and warming effects of the
katabatic wind
A katabatic wind (named from the Greek word κατάβασις ''katabasis'', meaning "descending") is a drainage wind, a wind that carries high-density air from a higher elevation down a slope under the force of gravity. Such winds are sometim ...
.
Flora and fauna
Vegetation in the region changes from west to east, as the river valley gently descends from cold desert, through steppe and deciduous shrub areas, to some areas of conifer-rhododendron forest in the east. The temperate slopes above the valley floors in the middle of the ecoregion are steppe and shrub communities, with species of feather grass (''
Stipa
''Stipa'' is a genus of around 300 large perennial hermaphroditic grasses collectively known as feather grass, needle grass, and spear grass. They are placed in the subfamily Pooideae and the tribe Stipeae, which also contains many species for ...
bungeana''), fountain grass (''
Pennisetum flaccidum''), needlegrass (''
Aristida
''Aristida'' is a very nearly cosmopolitan genus of plants in the grass family. ''Aristida'' is distinguished by having three awns (bristles) on each lemma of each floret. The genus includes about 300 species found worldwide, often in arid warm ...
triesta''), and other grasses and shrubs. Above 4,400 meters, vegetation grades into cold steppe species of feather grass (''
Stipa
''Stipa'' is a genus of around 300 large perennial hermaphroditic grasses collectively known as feather grass, needle grass, and spear grass. They are placed in the subfamily Pooideae and the tribe Stipeae, which also contains many species for ...
purpurea'') and shrubs such as shrubby cinquefoil (''
Potentilla
''Potentilla'' is a genus containing over 300Guillén, A., et al. (2005)Reproductive biology of the Iberian species of ''Potentilla'' L. (Rosaceae).''Anales del Jardín Botánico de Madrid'' 1(62) 9–21. species of annual, biennial and perenni ...
fruticosa'') and honeysuckles (''
Lonicera
Honeysuckles are arching shrubs or twining vines in the genus ''Lonicera'' () of the family Caprifoliaceae, native to northern latitudes in North America and Eurasia. Approximately 180 species of honeysuckle have been identified in both contin ...
tibetica''). Above 5,000 meters, some areas of stable soil support species of ''
Kobresia
''Kobresia'' is a genus of plants in the sedge family. They are sometimes called bog sedges. These perennial sedges are quite similar to ''Carex'' species in appearance. The genus is widespread across much of Europe, Asia and North America, with ...
'' sedges, and cushion plants.
See also
*
List of ecoregions in China {{Short description, none
The following is a list of terrestrial ecoregions of the People's Republic of China and the Republic of China, according to the World Wide Fund for Nature.
The transition between two of the planet's eight terrestrial bioge ...
References
{{reflist
Palearctic ecoregions
Ecoregions of China