Pseudois nayaur ssp. schaeferi
|Scientific Name:||Pseudois nayaur ssp. schaeferi Haltenorth, 1963|
See Pseudois nayaur
Pseudois schaeferi Haltenorth, 1963
|Taxonomic Notes:||The taxonomy of this taxon remains incompletely resolved. Although it has been recognized as a full species by some (Wang and Hoffman 1987, Wang et al. 2000, Liu et al. 2007, Wang and Xie 2009, Groves and Grubb 2011), recent molecular evidence (Feng et al. 2001, Cao et al. 2003, Zhou et al. 2003, Zeng et al. 2008, Tan et al. 2012) suggests that the most appropriate categorization at present is as a subspecies of Pseudois nayaur. Here, we consider the taxon P. n. schaeferi. While smaller size allows for some identification of specimens, sizes differences between this taxon and individuals recognzed as P. nayaur are no greater than among numerous groups of other artiodactyls that are currently recognized as subspecies. Much speculation has been given to whether, and if so, what generates reproductive isolation between P. n. schaeferi and P. nayaur, as they are geographically separated by a forest zone only 1,000 meters in elevation (Wang and Hoffmann 1987). Few studies have been conducted on P. n. shaeferi.|
|Red List Category & Criteria:||Endangered A2cd ver 3.1|
|Assessor(s):||Huffman, B. & Harris, R.|
|Reviewer(s):||Scott, M. & Zou, F.|
|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.
|Previously published Red List assessments:|
|Range Description:||This sub-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 Recently, populations have been reported from Deqin county, northwestern Yunnan (Wen Xiao, Dali University, unpublished data, 2007).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. 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 subspecies had 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. Wang and Xie (2009) considered the taxon to be declining, but declined to estimate abundance.|
|Current Population Trend:||Decreasing|
|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 asl; 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. nayaur schaeferi is isolated from the alpine habitat of P. nayaur by a belt of oak forest, into 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. (2006) 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).
|Generation Length (years):||7|
|Use and Trade:||This species is locally hunted for food.|
|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 and habitat degradation were identified as the primary threats by Wang et al. 2000.|
The subspecies is protected under Chinese national law as a Category II protected species under the wildlife protection law of 1988. Since the taxon was recognized as unique and important, a concerted effort has been made by scientists temporarily working in the area to educate local hunters. Conservation measures proposed: l) Continue to examine its taxonomic status. 2) If future research alters our current understanding and shows it to be more appropriately considered a full species, it 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).
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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.
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Smith, A.T. and Xie, Y. 2008. A Guide to the Mammals of China. Princeton University Press, Princeton, New Jersey.
Tan, S., Zou, D., Tang, L., Wang, G., Peng, Q., Zeng, B., Zhang, C. and Zou, F. 2012. Molecular evidence for the subspecfic differentiation of Blue Sheep (Pseudois nayaur) and polyphyletic origin of Dwarf Blue Sheep (Pseudois schaeferi) . Genetica 140: 159-167.
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Zeng, B., Xu, L., Yue, B., Li, Z. and Zou, F. 2008. Molecular phylogeography and genetic differentiation of Blue Sheep Pseudois nayaur szechuanensis and Pseudois schaeferi in China. Molecular Phylogenetics and Evolution 48: 387-395.
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. 2014. Pseudois nayaur ssp. schaeferi. The IUCN Red List of Threatened Species 2014: e.T18535A64313668.Downloaded on 22 September 2017.|