Hengduan Mountains

The Hengduan Mountains () are a group of mountain ranges in southwest China that connect the southeast portions of the Tibetan Plateau with the Yunnan–Guizhou Plateau. The Hengduan Mountains are primarily large north-south mountain ranges that effectively separate lowlands in northern Myanmar from the lowlands of the Sichuan Basin. These ranges are characterized by significant vertical relief originating from the Indian subcontinent's collision with the Eurasian Plate, and further carved out by the major rivers draining the eastern Tibetan Plateau. These rivers, the Yangtze, Mekong, and Salween, are recognized today as the Three Parallel Rivers UNESCO World Heritage Site.

The Hengduan Mountains cover much of western present-day Sichuan province as well as the northwestern portions of Yunnan, the easternmost section of the Tibet Autonomous Region, and touching upon parts of southern Qinghai. Additionally, some parts of eastern Kachin State in neighbouring Myanmar are considered part of the Hengduan group. The Hengduan Mountains are approximately long, stretching from 33°N to 25°N. Depending on extent of the definition, the Hengduan Mountains are also approximately wide under the narrowest definition, ranging from 98°E to 102°E. The area covered by these ranges roughly corresponds with the Tibetan region known as Kham.

The Hengduan Mountains subalpine conifer forests is a palaearctic ecoregion in the Temperate coniferous forests biome that covers portions of the mountains.

Geography

The Hengduan Mountain system consists of many component mountain ranges, most of which run roughly north to south. These mountain ranges, in turn, can be further divided into various subranges. The component ranges of the Hengduan are separated by deep river valleys that channel the waters of many of Southeast Asia's great rivers. The core of the Hengduan Mountains can be divided into four major component ranges, described below.

* The westernmost primary range of the Hengduan runs north-south between the Salween (Nu) and Mekong (Lancang) Rivers. The northern half of this range, found in the Tibet Autonomous Region, is called the Taniantaweng Mountains while the southern half, in Yunnan, is called the Nu Mountains. A major subrange along this system is the Meili Snow Mountains and their highest peak, Kawagebo.
*Moving eastward, the next major subsection of the Hengduan Mountains is the range running between the Mekong (Lancang) and Yangtze (Jinsha) Rivers. The northernmost parts of this range are called the Mangkam Mountains, the middle section is known as the Ninchin Mountains, and the southern end is called the Yun Range. The Yulong Mountains are a subrange of this system and the highest peak here is Jade Dragon Snow Mountain's Shanzidou. Eastern Himalaya, part of larger Himalaya mountains, is Hengduan Mountain's immediate neighbor to its west.
* The third primary component of the Hengduan ranges is the section running between the Yangtze (Jinsha) and Yalong Rivers. This section is known for almost its entire length as the Shaluli Mountains except for the northernmost subrange that is called the Chola Mountains. The highest point of this entire section is the Ge'nyen Massif.
* The easternmost of the Hengduan core ranges is the Daxue Mountains between the Yalong River and Dadu River. This range is dominated by Mount Gongga, the highest peak in the entire Hengduan group as well as the highest peak east of the Himalayas.
* In addition to the four core systems, described above, some adjacent ranges are also sometimes included as part of the Hengduan group. To the west, the Gaoligong Mountains form an additional barrier along the Salween's western edge, but are more accurately described as an extension of the Baxoila Range connecting with the eastern Nyenchen Tanglha Mountains across central Tibet. To the east, the Qionglai Mountains and the Min Mountains are sometimes included as part of the Hengduan Mountains as these two ranges form the eastern edges of the Tibetan Plateau.

Ecosystems

The Hengduan Mountains support a range of habitats, from subtropical to temperate to montane biomes. The mountains are largely covered by subalpine coniferous forests.http://researcharchive.calacademy.org/research/cnhp/glgs/PDF/ChaplinG.2005_opt.pdf Physical Geography of the Gaoligong Shan Area of Southwest China in Relation to Biodiversity Elevations range from . The dense, pristine forests, the relative isolation, and the fact that most of the area remained free from glaciation during the ice ages provides a very complex habitat with a high degree of biological diversity.

The ecoregions that coincide with the Hengduan Mountains are:
*The Southeast Tibet shrub and meadows in the higher elevation and northern parts of the Hengduan
*The Hengduan Mountains subalpine conifer forests in northern Yunnan and western Sichuan parts of the central Hengduan
*The Nujiang Langcang Gorge alpine conifer and mixed forests along the westernmost ranges of the Hengduan
*The Qionglai-Minshan conifer forests in the east parts of the Hengduan along the edge of the Sichuan Basin
*The Yunnan Plateau subtropical evergreen forests at the southern parts of the Hengduan where the mountains transition to the Yungui Plateau
*The Northern Indochina subtropical forests in the Nu Mountains, a southwestern component range of the Hengduan in Yunnan

Additionally, the lowest elevation portions of the Jinsha (Yangtze) River and Nu (Salween) River valleys in the southern Hengduan ranges are classified by the Chinese government as a tropical savanna environment.

The easternmost ranges of the Hengduan are home to the rare and endangered giant panda. Other species native to the mountains are the Chinese yew (''Taxus chinensis'') and various other rare plants, deer, and primates.

Gallery

File:Hailuogou glacier.JPG, Hailuogou glacier, slopes of Mount Gongga (Minya Konka), Sichuan province.
File:Yading - panoramio (1).jpg, Mount Chenrezig, seen from Yading Xin river, southwest Sichuan. Highest peak of Yading range.
File:Yading Jampelyang-Yangmaiyong.jpg, Mount Jampelyang, Yading range, southwest Sichuan.
File:Yading Chanadorje-Xianuoduoji Chonggu Grassland.jpg, Chonggu grassland and conifer-clad foothills of Mount Chanadorje, snow-clad in background. Yading range.
File:雪山的眼泪 - Tears of the Snow Mountains - 2012.10 - panoramio.jpg, Lake at foot of Mount Chanadorje, Yading range, southwestern Sichuan.
File:Chola Mountain.jpg, Wooded slopes of Chola Mountains, Sichuan province.
File:Litang Ge'nyen 2014.09.16 09-11-25.jpg, Panorama of Ge'nyen massif, Sichuan province.
File:Yulong xue shan.jpg, Lijiang, Yunnan province, (only city within Hengduan Shan) dwarfed by Jade Dragon Snow Mountain.
File:Meili Snow Mountain, Deqin County, Yunnan.jpg, Meili range, border of Dêqên County, Yunnan with Tibet.
File:梅里雪山.jpg, Kawagarbo, highest peak of Meili range, Yunnan/Tibet border.
File:Gaoligongshan IMGP5778.jpeg, Gaoligong range, border of western Yunnan and Myanmar (Burma).
File:高黎贡山隧道08.jpg, Gaoligong railway tunnel, Yunnan / Myanmar.
File:Yangzi River gorge.jpg, Jagged peaks rising from Yangtze River gorge Yunnan province.
File:Micro-hydro Salween River in Yunnan Province, China.jpg, Trial hydroelectric installation, Salween River gorge, Yunnan province.
File:Lancang River in Baoshan.jpg, Valley of the Lancang (upper Mekong) River, Baoshan, Yunnan.
File:Hengduan conifer forests.jpg, Hengduan conifer forests, Dêgê County, northwest of Sichuan province.

See also

* Global 200
* The Hump

References

External links

Biodiversity of the Hengduan Mountains and adjacent areas of south-central China
- a research project at Harvard University
PBS NOVA's First Flower discusses botanical diversity in the Hengduan Shan

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Transhimalayas
Mountain ranges of Myanmar
Mountain ranges of Tibet
Mountain ranges of Sichuan
Mountain ranges of Yunnan