Investigación - COMPOSICIÓN BOTÁNICA DE LA DIETA DE ALPACAS (Lama pacos L.) Y LLAMAS (Lama glama L.) EN DOS ESTACIONES DEL AÑO, EN PRADERAS ALTIPLÁNICAS DE UN SECTOR DE LA PROVINCIA DE PARINACOTA, CHILE (Botanical composition of alpaca (Lama pacos L.) and llama (Lama glama L.) diets in two seasons of the year on highland ranges of Parinacota province, Chile.)

The botanical composition of alpaca (Lama pacos L.) and llama (Lama glama L.) diets was determined, grazing on a highland range of Parinacota, Chile (18°12' S lat; 69°16' W long; 4390 m.o.s.l.), using microhistological analysis of feces. The evaluations were carried out in dry-winter and rainy-summer seasons. The availability of dry matter (MS) and botanical composition (BC) of the main grassland, the "bofedal," was measured. The availability of DM varied between 1860 and 2940 kg ha-1, and the BC was dominated by Oxychloe andina (Cyperaceae) and Festuca nardifolia (Poaceae). Diets were dominated by species of the bofedal, especially by the grasses (F. nardifolia, Deschampsia caespitosa and Agrostis tolucensis ) and grass-like plants (O. andina), also being prominent, the "pajonal" and "tholar" species, Festuca orthophylla and Parastrephia lucida , respectively, especially in winter and in llama diets. Diets differed in their composition and diversity, there being an interaction between the type of herbivore and the season of the year, with a significant overlapping between 61.4% in summer and 73.6%, in winter, that suggests a differentiated grazing management of these camelids to avoid eventual competition. The Ivlev's selectivity index, highlighted the grass species A. tolucensis, D. caespitosa and the ranunculaceae Ranunculus uniflorus , which obtained positive values close to one, indicating a high preference by the herbivores. Whereas, the dominant species of bofedal, O. andina, obtained a negative value (rejection), and consequently, tended to dominate in the BC of grassland, having a negative effect on the grassland's condition