Response of guanacos to changes in land management in Península Valdés, Argentine Patagonia. Conservation implications.
BURGI M.V.; MARINO A.; RODRIGUEZ M.V.; PAZOS G.; BALDI R.
CAMBRIDGE UNIV PRESS
Año: 2011 vol. 46 p. 99 - 105
Guanacos were the only large native herbivore widely distributed across Patagonia until the introduction of sheep. Since then, guanaco population declined due to competition with sheep for forage, high hunting pressure and habitat degradation. Península Valdés is a UN Natural Heritage Site where sheep ranching is still the predominant activity. Alternatively, a ranch formerly dedicated to sheep production was converted into a private wildlife reserve, from which all the sheep were removed in 2005. This resulted in a unique opportunity to study both the response of guanacos and the vegetation to this drastic change in management. We studied the change in guanaco abundance inside and outside the reserve after sheep removal, and also plant cover of different vegetation types. We found that guanaco abundance was higher inside than outside the reserve, and increased by threefold within 3 years inside the reserve. Total plant cover and grass cover were higher inside than outside the reserve. Our results showed that guanacos reacted rapidly to changes in management, and suggest that even at a high density guanacos would not be as damaging as sheep to vegetation. Management changes did result in significant changes in guanaco abundance at the local scale. However as the size of protected areas influence the future persistence of wild populations, large herbivores like guanacos need to be managed across large areas. We understand it is necessary to implement a management plan for Península Valdés allowing for the coexistence of sustainable livestock production and healthy wildlife populations.