Abstract :
Vicu˜na, 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 vicu˜nas at Laguna Blanca MAB-UNESCO Biosphere Reserve (Catamarca, Argentina),
within dry Puna environment. Vicu˜nas showed a stable diet throughout the year, with
marked differences at spatial scale. Diet of vicu˜nas included vegetation from all habitats,
all vegetation strata and all functional groups of plants, suggesting that vicu˜nas 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. Vicu˜nas consumed
large proportion of grasses (59–72%) and shrubs represented 16–19% of vicu˜na overall diet,
reaching 45% at local sites, so we proposed that in this puna ecosystem vicu˜nas do not
behave as strict grazers. Although vicu˜nas 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. Vicu˜nas 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. Vicu˜nas 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 vicu˜na, V. v. vicugna,
by researching botanical composition and nutritional quality of the diet. These features of
diet of vicu˜nas can be considered as part of its wide range of feeding responses to live in
the poor environment of altiplano
