Use of food availability by guanacos (Lama guanicoe) and livestock in Northern Patagonia (Mendoza, Argentina)

PUIG, S.; FERNANDO VIDELA; MÓNICA I. CONA; MONGE S

JOURNAL OF ARID ENVIRONMENTS

ACADEMIC PRESS LTD-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2001

0140-1963

Grazing areas of a guanaco population were shared with introduced livestock ina protected area of Northern Patagonia. The diet of ungulates and the availabil-ity of food were compared to recognize interspecific overlaps and to detectpotential plant depletions. Seasonal faecal samples were analysed by microhis-tology, and food availability was analysed by point-quadrat transects in sandyand rocky habitats. Large ungulates were classified as ?strictly grazers?, whilesmall ungulates as ?grazer-browsers?. Food limitations constrained ungulatefeeding tendencies, in agreement with the selective quality hypothesis. Shareduse with a preference of scarce items, i.e. most forbs and four grasses, suggestthey are at risk of disappearance by overgrazing. Main dietary items annuallyshared were the grass Poa and the camephyte Hyalis, the conservation of whichwould be essential for the guanaco population. Despite their high dietarydiversity, guanacos could be affected especially by shared food use withsheep and horses in sandy habitats. Cattle would be the most affected byshared use with horses, sheep or goats. Fires and woody plant extractionscaused a decrease of shrubby stratum, food diversity and patchiness, and couldforce an increase of competitive risks. Management priorities should be tomonitor the plant cover and diversity, discourage a livestock carrying increase,avoid shrub extraction, and control fire generation.