Foraging ecology of Vicuña, Vicugna vicugna, in dry Puna of Argentina

Abstract

Vicuña, Vicugna vicugna, is one of the few large native herbivores of South American and it is considered a keystone resource for the Andean Region. We studied foraging ecology of free ranging vicuñas at Laguna Blanca MAB-UNESCO Biosphere Reserve (Catamarca, Argentina), within dry Puna environment. Vicuñas showed a stable diet throughout the year, with marked differences at spatial scale. Diet of vicuñas included vegetation from all habitats, all vegetation strata and all functional groups of plants, suggesting that vicuñas can use a large range of plant species that are distributed in almost all portions of their range (they used 39 of 75 available plant species), behaving as a generalist ungulate. Vicuñas consumed large proportion of grasses (59–72%) and shrubs represented 16–19% of vicuña overall diet, reaching 45% at local sites, so we proposed that in this puna ecosystem vicuñas do not behave as strict grazers. Although vicuñas showed high diet plasticity, only two grasses, Panicum chloroleucum and Distichlis spp. represented nearly 50% of the diet. In relation to photosynthesis pathways of the plants, C4 grasses contributed higher to proportions in diet than C3 grasses. Vicuñas showed a selectivity foraging behaviour by consuming swamp forages, low and medium vegetation strata, and a few plant species in more proportion to their availability. Vicuñas did not eat plant species with more overall nutritional quality in higher proportion than species with less nutritional contents. However, the consumption of steppe grasses was in direct proportion to its crude protein content. This work brings a broad description of the foraging ecology of southern subspecies of vicuña, V. v. vicugna, by researching botanical composition and nutritional quality of the diet. These features of diet of vicuñas can be considered as part of its wide range of feeding responses to live in the poor environment of altiplano.