Biological sustainability of live shearing of vicuña in Peru

  • Published source details Sahley C.T., Vargas J.T, & Valdivia J.S. (2007) Biological sustainability of live shearing of vicuña in Peru. Conservation Biology, 21, 98-105.


The vicuña Vicugna vicugna is a wild camelid that inhabits the high Andes. Its wool or fiber is highly valued as an export product (in 2004 fiber price $566/kg) that is made into luxury clothing. This makes the fiber a potentially important source of income for Andean agropastoral communities and serves as an incentive to allow vicuña grazing on landscapes also used for grazing of domestic stock e.g. sheep and llamas Lama glama. The supply of vicuña fiber may be sustainable if it is procured through live shearing, which should serve as a conservation tool; shorn vicuña have little value to poachers (the meat is of no value), so shearing could also serve as a disincentive to poaching and consequential evidence strongly supports this. In Peru, a system of capture and release adopted nationally in 1995 is borrowed from Inka tradition practiced for many hundreds of years, and is a combination of indigenous and modern technology and culture.

This study evaluated the effects of capture and shearing on the demography of vicuña in one site where vicuñas were captured and shorn in spring and then returned to the wild, and also the effect of capture and shearing on proportion of young born to shorn and unshorn females at a second site.

The effects of capture and shearing on the demography of vicuña was evaluated in one site located in the Salinas Aguada Blanca Reserve, Arequipa, Peru. Here vicuñas were captured and shorn in spring and then returned to the wild. Fixed-width line-transect censuses were undertaken from 1997 to 2003 to monitor this population. The proportion of young born to females that were shorn versus females that were unshorn for the 3 years in which shearing occurred was compared.

The effect of capture and shearing on the proportion of young born to shorn and unshorn vicuña females was also assessed at a second site, Picotani, Puno.

Estimate of carrying capacity: Average plant biomass for the month of least forage production (July 1997) was 9,900 kg/km². On the basis of a 10% consumption estimate, a carrying capacity of 9.9 vicuñas/km² was estimated. Average vicuña density in 1997 was 2.8/km². Although acknowledged to be a simplified estimate, carrying capacity estimates more than doubled over a year and between years. The plant biomass data indicated that the vicuña population was below carrying capacity in all years of this study. The population in Tambo Cañahuas suffered severe poaching in 1993 that reduced the population significantly. Therefore, calculations were purposefully conservative and supports the hypothesis that the population was under carrying capacity when this study began.

Population dynamics: Vicuñas at Tambo Cañahuas exhibited consistent population growth during the study regardless of whether or not capture and live shearing occurred (1997, 1999, 2000, 2002 were shearing years). Total numbers and average density/year increased over the length the study period. The exponential growth rate of the vicuña population at Tambo Cañahuas was 0.193 between 1997 and 2002.

Production of young in shorn vs. unshorn females: Data from reproductive-age females indicated that at both study sites, there was no significant difference in the number of young per female between shorn and unshorn females (n = 239)

Conclusions: The authors conclude that in spring, capture and live shearing of vicuñas can be sustainable. Winter shearing was not assessed.

Note: If using or referring to this published study, please read and quote the original paper, this can be viewed at:


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