|Scientific Name:||Pseudois schaeferi|
|Species Authority:||Haltenorth, 1963|
|Taxonomic Notes:||The separation of schaeferi into an independent species is controversial. While some believe that it is clearly an independent taxa (Wang et al. 2003, Liu et al. 2007), others claim that it should be designated as a subspecies of P. nayaur (Feng et al. 2001). Recent molecular evidence (Cao et al. 2003, Zhou et al. 2003) did not support the independent species status of schaeferi. Feng et al. (2001) found an average 12.21% sequence divergence in mitochondrial DNA between P. schaeferi and P. nayaur - disproving Allen's 1940 suggestion that the observed difference between the two species of the genus Pseudois was an environmental effect, and supporting at least a subspecific ranking for the Dwarf Blue Sheep. However, there was weak differentiation between the two species based on ZFY introns (nuclear Y-linked genes), leading the study to conclude that Pseudois schaeferi should not be a separate species, but considered to be a subspecies of Pseudois nayaur. Much speculation has been given to what maintains the reproductive isolation between the two species of Pseudois, as they are geographically separated by a forest zone only 1,000 meters in altitudinal height (Wang and Hoffmann 1987). Wang and Hoffmann (1987) also suggest that the Dwarf Blue Sheep may be a peripheral, isolated population undergoing speciation. As a result, it is treated as a full species in this account. The dwarf blue sheep is monotypic (Wang and Hoffmann 1987). Few studies have been conducted on P. shaeferi, and much of the available data merely compares this species with P. nayaur.|
|Red List Category & Criteria:||Endangered A2cd ver 3.1|
|Assessor/s:||Huffman, B. & Harris, R.|
|Contributor/s:||Wang Yu & Xiao Wen|
Listed as Endangered because of a serious population decline, estimated to be more than 50% over the last three generations (approximately 21 years), due to over-hunting and habitat destruction and/or degradation.
|Range Description:||This species is found in China (Upper Yangtze Gorge in west Sichuan and adjacent parts of Tibet and north Yunnan) (Grubb 2005). Recently, populations have been reported from Deqin county, northwestern Yunnan (Wen Xiao, Dali University, unpublished data, 2007). Its primary range is in a narrow area along the Jinshajiang Valley, which forms part of the upper reaches of the Changjiang (Yangtse) river. Specimens have been collected from Batang (Sichuan), and Baiyu, to the north of Batang (Cai et al. 1990). Local hunters claim it is found in Derong (southwestern Sichuan), in Deqin (northwestern Yunnan), and in Markam (eastern Xizang); areas that are all to the west and south of Batang (Wu et al. 1990, Wang and Wang 2003). Wang et al. (2000) doubted the presence of Dwarf Blue Sheep in Baiyu County (believing these animals to be Blue Sheep, as well as the reports of Dwarf Blue Sheep from Markam (in eastern Tibet; Wang and Wang 2003). The status of Dwarf Blue Sheep in Deqin County, Yunnan is in some dispute, and requires more investigation.|
Native:China (Sichuan, Tibet [or Xizang], Yunnan)
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||Hu (1998) believed there were approximately 7,000 individuals in the mid-1990s, although this seems difficult to square with the reports of only a few hundred by Wang et al. (2000). Local hunters report that the numbers of this species have fallen drastically; previously observed group size ranges of 10 to 36 have dropped to three to eight animals in recent years. Density estimates of only 0.5 to 1.0 sheep/km² also suggest low numbers (Wu et al. 1990, Wang and Wang 2003). Smith and Xie (2008) also repeated concerns of a drastic decline in numbers.|
|Habitat and Ecology:||
Dwarf Blue Sheep inhabit rugged valley terrain along the Yangtze River valley. They live among very steep rocky slopes between 2,700-3,200 m; occasionally range into conifer forest and forest clearings. Blue Sheep may live in same region at higher altitudes (Wu et al. 1990, Wang et al. 2000, Wang and Wang 2003, Shen et al. 2007). This valley habitat is dry with sparse vegetation cover; common species include grasses (Cymbopogon distans and Themeda hooderi), low shrubs (Berberis spp., Rosa spp., Cotoneaster spp., Cladrastis spp., Ephedra spp., and Rhododendron spp.), and clubmoss (Selaginella sanguinolenta) (Wang et al. 2000). P. schaeferi is isolated from the alpine habitat of P. nayaur by a belt of oak forest, in which they have not been documented to enter (Groves 1978, Wang et al. 2000). Diet consists of grasses, low shrubs, club moss and lichens. They feed and rest alternately throughout the day on the grassy slopes of mountains. Group sizes were formerly 10-36 animals, but now usually less than 15, or even fewer as a result of over-hunting and competition with livestock. Males sometimes form all male groups or sometimes mix with females and young. The largest herd reported by locals was 25 animals, although this was seen in the 1950s (Wang et al. 2000). These same locals also stated that herd size has been declining since then - due primarily to hunting and competing with livestock, but also due to habitat loss. Contrary to Schäfer's original reports (1937), neither Wu et al. (1990) nor Wang et al. (2000) ever observed solitary individuals. Population densities range between 0.5-1.0 individuals per square kilometer (Wu et al. 1990, Wang and Wang 2003).
These sheep are known to consume more than twenty species of plants (Wu et al. 1990); according to the observations made by Wang et al. (2000), they feed primarily on grasses (e.g., Pennisetum flaccidum and Setarica glauca), though other plants like club moss (Selaginella sanguinolenta) are also eaten. Predators include Wolf (Canis lupus), Dhole (Cuon alpinus), Leopard (Panthera pardus), and large raptors (Wang et al. 2000).
Usually single young (rarely twins) are born in May or June after a gestation of 160 days. Young are weaned within six months and reach maturity at 1.5 years. Males may take seven years to reach full size (Wang and Hu 2004).
|Major Threat(s):||Hunting is a major threat to these animals, and if effective protection measures are not adopted quickly, the taxon will disappear in the near future. Humans and/or their livestock are present throughout the range of this species. Over-hunting is a serious threat, as is habitat degradation (Wang et al. 2000).|
There is no formal legislation for its protection in China because when the national protection list was established, this species was considered to be P. nayaur and placed in Class II (although Smith and Xie 2008 show it as listed under Class II). Since Dwarf Blue Sheep was recognized as a separate species, a concerted effort has been made by scientists temporarily working in the area to educate local hunters. The species does receive protection from local people in Baiyu (Sichuan) because of their religious beliefs (Cai et al. 1990). Conservation measures proposed: l) Re-assess its taxonomic status. 2) If it proves to be a separate species, Dwarf Blue Sheep should be raised to a Class I species in the national protection list. 3) Protected areas need to be established. Reserves at Batang, or in adjacent areas where the population is still relatively abundant, have been suggested (Wu et al. 1990). 4) At the same time, surveys are essential to determine status and total distribution throughout its suspected range.
In 1995, a prefectural reserve covering 142.4 km² (which was enlarged to about 300 km² in 2007) around Zhubalong was established for the protection of this species (Wang et al. 2000). However, many human activities such as mushroom gathering, livestock grazing, and illegal hunting continue to occur in the core zone and thus threaten the populations here (Wang et al. 2000).
Cai Changping, Hu Jinchu and Pong Jitai. 1990. The Dwarf Blue Sheep of the Western Sichuan.
Cao Li-Rong, Wang Xiao-Ming and Fang Sheng-guo. 2003. A molecular phylogeny of Bharal and dwarf blue sheep based on mitochondrial cytochrome b gene sequences. Acta Zoologica Sinica 49(2): 198-204.
Feng, J., Lajia, C., Taylor, D.J. and Webster, M.S. 2001. Genetic distinctiveness of endangered dwarf blue sheep (Pseudois nayaur schaeferi): Evidence from mitochondrial control region and Y-linked ZFY intron sequences. Journal of Heredity 92(1): 9-15.
Groves, C. P. 1978. The taxonomic status of the dwarf blue sheep (Artiodacytla; Bovidae). Seaugetierkundliche Mitteilungen 26: 177-183.
Grubb, P. 2005. Artiodactyla. In: D. E. Wilson and D. M. Reeder (eds), Mammal Species of the World. A Taxonomic and Geographic Reference (3rd ed), pp. 637-722. Johns Hopkins University Press, Baltimore, USA.
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Schafer, E. 1937. Über das Zwergblauschaf (Pseudois spec. nov.) und das Grossblauscha (Pseudois nahoor Hdgs.) in Tibet. Zoologische Garten 9: 263-278.
Shen D. J., Wang Y., Zeren J. M., Zeng G. W.,Huang Y. C., Li, K. J. and Tang, L. 2007. Primary Study on Behavior of Dwarf Blue Sheep (Pseudois schaeferi). Sichuan Journal of Zoology 26(4): 774-776.
Smith, A. and Xie, Y. 2008. The Mammals of China. Princeton University Press, Princeton, New Jersey.
Wang, X. and Hoffmann, R. S. 1987. Pseudois nayaur and Pseudois schaeferi. Mammalian Species 278: 1-6.
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Wang Y. and Wang X. M. 2000. Population ecology of dwarf blue sheep (Pseudois schaeferi). Biodiversity Science 11(1): 59-62.
Wang, Y., Zheng, H., Zhao, J. H., Xu, H. F., Zhang, H. F., Zeren, J. M., Zeng, G. W., Huang, Y. C. and Wu, J. D. 2006. Grouping Behavior of Dwarf Blue Sheep in Batang County China. Journal of Henan University (Natural Science) 2: 73-75.
Wu Yi, Yuan Chonggui, Hu Jinchu, Peng Jitai and Tao Peilin. 1990. A biological study of dwarf blue sheep. Acta Theriologica Sinica 10: 185-188.
Zhou, L. Q., Zhou, K. Y. and Hu, J. C. 2003. On the potential to use cyctochrome-b to assess the specific status of dwarf blue sheep. Chinese Journal of Zoology 49: 578-584.
|Citation:||Huffman, B. & Harris, R. 2013. Pseudois schaeferi. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.2. <www.iucnredlist.org>. Downloaded on 21 April 2014.|