Central Tien Shan BioProvince
The BioProvince of Central Tien Shan (from Chinese ‘Divine or Celestial’ Mountains) is still unclearly defined but according to Armen Takhtajan it definitely includes the central ranges of the Tien Shan, part of the Alai Range and the Alai Valley. On its northern boundary it includes the Issyk-Kul Basin and its surrounding slopes and extends along the Kirgizian Range and the Kungei Ala-Tau, while the southern boundary roughly coincides with the crest of the Transalai (Zaalai) Range. In the west it follows the Fergana Range, the Susamyr Tau and the Talassian Ala-Tau. The climate is continental and extremely severe with respect to both temperature and aridity. There is little cloud cover resulting in high fluctuations in daily and annual temperatures and the air is often very dry. Summers are hot in the foothills and valleys, cool in nival and subnival zones, but winters are very severe. There is widespread permafrost above 3000 m and the short growing season ranges from about six months at 3000 m to just six weeks at 4000 m. The mountain rocks mainly comprise crystalline and sedimentary rocks of the Paleozoic Era. A more recent geological process, characterized by sudden movements of the Earth’s crust, started in the middle Tertiary period and continues to the present time. As a result loose fragments of rock have accumulated in valleys. In the Fergana Valley, for example, these are now almost 8 km thick. Shallow lakes also formed in many valleys later evaporating leaving saline deposits. Subsequently, glaciers have produced moraines of boulder-rich sediments in the mountains and gravel and loess (wind-deposited sediment) have accumulated in the valleys. The flora is not particularly rich, despite the size of the area, with no more than about 1800 species, but it includes one endemic genus (Tianschaniella) and a fair number of endemic species such as Ammopiptanthus nanus (Fabaceae) and Zygophyllum kaschgaricum (Zygophyllaceae).
The following accounts for this BioProvince have been written or will be written with particular reference to endemic and locally important species. Accounts available are displayed in green or yellow. Those displayed in red are either in the pipeline or awaiting expert contributions.
|Endemic Vascular Plant Flora|