Location and General Description
The Pamir is a complex mountain region that extends about 275 km east-to-west and about 250 km north-to-south. It has been described as a "knot" and an "orographic crux" from which several of Asia’s main ranges—the Himalaya, Karakoram, Hindu Kush, Kunlun, and Tian Shan—radiate. Boundaries include Kashgar and the Tarim Basin to the east, the trans-Alai Mountains to the north, the Hindu Kush Range to the south and, to the west, a complex set of physiographic features that correspond to 73oE longitude. The local term pamir refers to the broad valleys and steeply rolling hills that characterize this plateau region. The Pamir is ecologically and physiographically similar to Tibet although, at 4,200 m average elevation, it is somewhat lower and therefore warmer than much of the Tibetan Plateau. It is also rougher with 1,000 to 1,500 m of vertical relief between valley and ridge. The highest peaks in this region exceed 7,400 m.
The grasslands and semi-deserts of this hilly plateau act as a major biogeographic barrier between Mediterranean-influenced Middle Asia, monsoonal South Asia, and the continental expanses of Central Asia. At the higher elevations, the flora is similar to that of the Tibetan Plateau, with which the Pamir shares a close geographic affinity, but there is a strong Mediterranean influence as well.
Climate is cold desert to semi-desert with mean temperature of 0 to –8oC. Mean summer temperatures are between 2 and 10oC., which means the Pamir is generally too frigid to support forest. Because the region is sunny and dry, diurnal temperature variations are especially large, as much as 60o C. Mean annual precipitation in the Pamir varies from 40 to 150 mm per year. Besides the cold, dry conditions, strong and steady winds are a major control inhibiting the growth of conventional plants, although the habitat is well-suited to plants with a cushion growth form.
The Pamir has a fairly distinct ecological zonation sequence with Mediterranean-type gravelly desert at the lowest elevations. This habitat is dominated by salt-tolerant taxa, such as Salicornia spp. Higher up, this is replaced by a lower open steppe and then, higher, by a Eurasian steppe belt. The lower open steppe is dominated by prickly cushion plants such as Acantholimon spp., wormwoods (Artemisia spp.), and needle grass (Stipa spp.). The higher Eurasian steppe supports needle grass and fescue grass (Festuca spp.). The highest zone, which is extensive throughout the Pamir, consists of alpine sedge-meadows (Kobresia spp. and Carex spp.) with many forb species and is similar to the vegetation over much the Tibetan Plateau and the Tian Shan. At 4,400 m, near the upper limit of vegetation, plant cover is sparse and consists of hardy perennial forbs like Rhodiola spp., Saussurea spp., Tanacetum spp., and Saxifraga spp., many of which have a cushion growth form and a stout, underground caudex, i.e., a woody taproot that stores carbohydrates when the plant dies back to ground level during winter.
The Pamir region has a strong phytogeographic affinity to the adjoining Tibetan Plateau, although its alpine flora is also influenced by Iranian-Afghan (i.e. Middle Asian) flora. Alpine species found here that come from Middle Asia rather than Tibet include Saponaria griffithiana, Arabis kokanica, Christolea pamirica, Didymophysa fedczenkoana, Rosularia paniculata, Astragalus ophiocarpus and many others. Some neoendemic species (i.e. endemics that have evolved recently and are closely related to more widespread taxa) with a Middle Asian affinity also occur here. They include Braya pamirica, Oxytropis bella, Astragalus alitschuri, Rhamus minuta, Hackelia testimudi, and Cousinia rava.
Most of the Pamir’s flora of 620 species, however, is comprised of Central Asian species that are common to the Tibetan Plateau. Dominant species that fall into this category include: Eurotia ceratoides, E. prostrata, Acantholimon diapensioides, Tanacetum gracile, T. xylorhizum, T. tibeticum, Carex pseudofoetida, Kobresia spp., Juncus thomsonii, Thylacospermum rupifragum, Christolea crassifolia, Oxytropis chiliophylla, Nepeta longibracteata, Dracocephalum heterophyllum, and Pedicularis chailanthifolia.
Several kinds of cold-desert plant associations have been identified for the Pamir region. They include low, branching shrubs, cushion plants, dense turf-forming grasses, alpine thin grass steppes, and Kobresia sedge barrens. Large areas are covered with gravel, talus, or rock and ice and are completely or nearly devoid of vegetation.
The eastern (Chinese) part of the Pamir supports extensive sedge barrens dominated by Kobresia spp. and Carex spp.with moisture-tolerant forbs like Ranunculus spp., Gentiana spp., Oxytropis spp., Potentilla spp., Primula spp., and Pedicularis spp. as well as grassy steppe vegetation (Festuca spp., Stipa spp., Poa spp., and Ptilagrostis spp.).
The colder and drier eastern Pamir supports fewer bird species, although brown-headed gulls (Larus brunnicephalus) and bar-headed geese (Anser indicus) nest at 4,000 m along the shores of some of the high lakes of this region. Two species of snowcock (Tetraogallus himalayensis and T. tibetanus) nest on rocky hillsides. The western Pamir is richer in species, due to increased topographic relief and proximity to the diverse Middle Asian floristic province.
Endangered mammals include the Tian Shan subspecies of brown bear Ursus arctos isabellinus, endemic to the mountains of Central Asia, and snow leopards Uncia uncia. A few wolves Canis lupus occur in Taxkorgan Nature Reserve (14,000 km2), located in western Xinjiang, China near the southeastern margin of the Pamir alpine desert and tundra, while they are common in the Tajik part of Pamir. Several species of wild sheep and goats are numerous in the Pamir alpine desert and tundra. The most abundant is Siberian ibex Capra ibex sibirica, while endangered species include the markhor C. Falconeri (Tian-Shan part of the ecoregion) and an argali subspecies referred to as Marco Polo sheep Ovis ammon polii.
Schaller’s (1987) survey of the Taxkorgan Nature Reserve near the southeastern edge of the Pamir found a single viable population of 150 Marco Polo sheep as well as ibex and blue sheep, (Pseudois nayaur), the most abundant wild ungulate in the region. The reserve also supports an estimated 50-75 snow leopards and a few wolves and brown bears. The abundant marmots (Marmota caudata) are an important prey item for these predatory mammals.
Many plant species of Central Asian affinity occur in the Pamir, but are not found in Tibet because the Pamir’s more complex topography offers some habitat types that are absent from the Tibetan Plateau. Another reason is that, unlike western Tibet, the Pamir, at least the southeastern portion, was not scoured by glaciers during the Pleistocene. These species include the streamside willows Salix pycnostachia, and S. fedtschenkoi, currants Ribes spp., Comarum salesvovianum, Dasiphora dryadanthoides, Cotoneaster uniflora, Rosa spp., Caragana jubata, Spiraea spp., and Betula spp.
The unique nature of the West and East Pamirs is protected in the Pamir National Park (Tajikistan) which occupies more than 2,6 million ha (11% of the area of Tajikistan). The network of complex natural refuges exists in the Pamirs: the Pamir refuge which includes the Lake Kara-Kul; the Zorkul refuge with the Zorkul lake system; the Muzkol refuge established between the Trans-Alai and Muzkol Ranges; and the Sanglyar refuge on the slopes of the Peter the First Range. In China, the Taxkorgan Nature Reserve provides important protection for many characteristic species.
Types and Severity of Threats
Taxkorgan Nature Reserve is inhabited by 7,500 people and 70,000 domestic animals. These people hunt ungulates for meat, and they hunt predators in response to depredation of livestock. Desertification of the alpine steppe habitat is also occurring as a result of overgrazing and fuelwood collection. Schaller (1987) recommends that rules be enforced against killing wildlife, and that solar cookers be used to reduce pressure on local wood supplies.
Justification of Ecoregion Delineation
Centered in Tadjikistan, this ecoregion consists of alpine vegetation in the dry, rocky, high altitude desert of the Pamir and the inner Tian Shan mountains. Ecoregion boundaries were adapted from lines delineating the high mountain meadows, deserts and cryophytic steppes of Gissaro-Darvas, Badakhshan, Alai-Turkestanik, and East Pamir regions according to Pereladova’s (1998) map of Central Asian ecosystems. The ecoregion extends into China down to approximately 3000 meters of elevation to include the glacial highlands of the northwest extension of the Kunlun Shan. In the Afghanistan panhandle, the Pamirs are separated from the Karakoram and Hindu Kush by the Wakhan Corridor.
Grubov, V.I. 1999. Plants of Central Asia, vol. 1 Science Publishers, Inc., Enfield, New Hampshire, USA. (translated from: Rasteniya Central’nov Asii, vol. 1, 1963. Nauka Publishers, Leningrad)
Knystautas, Algirdas. 1987. The Natural History of the USSR. McGraw-Hill Book Company, New York.
MacDonald, D., editor. 1999. The Encyclopedia of Mammals. Barnes and Noble Books.
Pereladova, O., V. Krever and M. Williams. 1997. Biodiversity Conservation in Central Asia. Moscow.
Schaller, G.B. 1977. Mountain monarchs: Wild sheep and goats of the Himalaya. The University of Chicago Press, Chicago and London.
Schaller, G. B, Li Hong, Lu Hua, Ren Junrang, Qiu Mingjiang, and Wang Haibin. 1987. Status of Large Mammals in the Taxkorgan Reerve, Xinjiang, China. Biological Conservation 42: 53-71.
Prepared by: C. Carpenter
Reviewed by: K.Rachkovskaja, O.Pereladova