DIVERSITY & ENDEMISM
As a result of the dramatic differences in topography, climate and vegetation and the physical barriers between its regions, the Mountains of Southwest China Hotspot has evolved a cluster of distinctive mini-hotspots, each with its own unique flora and fauna.
This hotspot is arguably the most botanically rich temperate region in the world, even though its species richness is not fully documented. Vascular plant diversity is estimated at about 12,000 species, representing as much as 40 percent of all the species in China. Of these, about 3,500 species (29 percent) and at least 20 genera are endemic, including about 100 endemic ferns and 20 endemic gymnosperms. Two plant families are endemic to the hotspot: the Circaeasteraceae and the monotypic Acanthochlamydaceae.
The region provides a refugium for several ancient plant species found nowhere else in the world, including representatives from the genera Rhododendron, Rhodiola, Kingdonia, and Circaeaster. More than a quarter of the world's rhododendron species are represented in the Heng Duan Shan, an astounding 230 different species, many of which are endemic and quite rare. Some of the larger rhododendrons can grow as tall as 20 meters or more.
Of the more than 600 bird species occurring in the hotspot, only a single bird species is endemic – the white-speckled laughingthrush (Garrulax bieti, VU). Nevertheless, four Endemic Bird Areas (EBAs), identified by BirdLife International, largely overlap with the hotspot and are home to a number of restricted range and endemic species, including the Sichuan partridge (Arborophila rufipectus, EN). While species such as the white-eared pheasant (Crossoptilon crossoptilon) are not technically endemic to the hotspot, they are important species endemic to Southwest China.
The region has the richest variety of pheasants and their relatives in the world, with around 25 species in total, including Lady Amherst pheasant (Chrysolophus amherstiae). Two iridescent monal pheasants, Sclater’s monal (Lophophorus sclateri, VU) and the Chinese monal (L. lhuysii, VU), are perhaps the most brilliant.
More than 230 mammal species inhabit the hotspot, although only five are endemic, including the Gaoligong pika (Ochotona gaoligongensis) and Chinese dormouse (Dryomys sichuanensis, EN), the latter known only from the Wanglang Nature Reserve.
The giant panda (Ailuropoda melanoleuca, EN), which is almost entirely restricted to the shrinking forests of this hotspot, is the world's best-known flagship species for conservation. As with several bird species, the giant panda has a range that is not much larger than the boundaries of the hotspot. This species survives in fragmented populations confined to over 40 reserves stretching from western Sichuan to southern Gansu and southern Shaanxi. The red panda (Ailurus fulgens, EN), a smaller relative of the giant panda, is also found in this hotspot.
Other important mammal flagships include the golden monkey (Rhinopithecus roxellana, VU) and the Yunnan or black snub-nosed monkey (R. bieti, EN), which lives at higher altitudes than any other non-human primate (ranging as high as 4,500 meters). These monkeys are among the few truly temperate monkey species in the world. Several distinctive ungulate herbivores are endemic to this hotspot, including the takin (Budorcas taxicolor, VU), an unusual 300-kilogram goat antelope, the red or Bailey's goral (Nemorhaedus baileyi, VU), which is endemic to the Gaoligong Shan, and the Chinese forest musk deer (Moschus berezovskii). These herbivores provide prey for a number of large predators, including the magnificent snow leopard (Panthera uncia, EN).
Given its size and temperate climate, the Mountains of Southwest China hotspot is also home to a surprisingly wide diversity of reptiles and amphibians. There are more than 90 reptile species in the hotspot, comprising a little over 20 lizard species, and nearly 70 species of snakes. About 15 species are endemic, including the Szechwan pit viper (Trimeresurus xiangchengensis) and Kingdonward's bloodsucker (Calotes kingdonwardi).
Amphibians are represented by around 90 species in the hotspot, with the genera Scutiger, Oreolalax and Amolops being particularly well represented. Some of these species occur at very high altitudes; for example, the Xizang alpine toad (Scutiger boulengeri) is found to elevations of more than 5,000 meters above sea level. Of the eight species known to be endemic, three are threatened: Oreolalax liangbeiensis (CR), restricted to Puxiong in Yuexi County, in southern Sichuan province, from 2,850 to 3,000 meters; Scutiger gongshanensis (VU), known from Gongshan and Biluoxueshan, in northwestern Yunnan province; and Rana chevronta (CR), known from Mount Emei, in Sichuan Province, and not recorded since 1983.
The hotspot has more than 90 freshwater fish species, almost a quarter of which are endemic, including two endemic genera. The majority of fish in the hotspot are from two families, Cyprinidae and Balitoridae, while most of the endemic fish are from two genera, Schizothorax and Triplophysa.