Abstract :
Live shearing of wild guanacos (Lama guanicoe) is promoted as an alternative to livestock
production and a conservation tool in the Argentinean Patagonia. However, biological sustainability
of guanaco shearing has not been evaluated. We studied movements, population
trends, survival, and yearling recruitment of guanacos, comparing sections with and without
roundups on a Patagonian sheep ranch. A total of 2900 guanaco captures occurred in
10 roundups from 2003 to 2007. We estimated guanaco density and yearling/adult ratios
with line transect surveys. We evaluated if guanacos left the section with roundups through
direct observation of tagged guanacos and radiotelemetry. We estimated survival rate of
shorn guanacos using 1334 capture–recapture histories. Guanaco population trends in sections
with and without roundups were stable throughout a normal-rainfall period and
declined during the drought that followed. Roundups were followed by temporary declines
in density estimates probably associated with altered guanaco behavior. Tagged guanacos
were rarely observed outside the section with roundups and none of the radiocollared
guanacos permanently left the section. We estimated a constant annual survival rate for
shorn guanacos (82% SE = 0.01) that was independent of sex and age. Yearling proportions
declined in the section with roundups 2–3 months after summer roundups. Our results
suggest that, under conditions similar to those of our study (i.e. following animal welfare
practices in a ranch with moderate livestock densities and sections without livestock), live
shearing would not imperil wild guanacos if roundups were conducted in spring and during
normal-rainfall periods.
