Differentiation of foraging areas of Lama guanicoe (Camelidae) in Patagonia using multiproxy analysis of feces: Modern reference dataset for paleoecological reconstruction

Abstract

Paleoecological studies based on camelid coprolites analysis provide valuable information about diet, vegetation, and habitats. In Patagonia, Argentina, relationships between humans and camelids date back to the early Holocene. The archeological site Cueva Milodón Norte 1 (CMN1), Pueyrredón lake, contains camelid coprolites and evidence of human occupation since 8600 years cal. BP. Environmental changes and lake-level fluctuations have influenced the landscape and resource availability. Actualistic studies are essential for building reference models that improve paleoecological interpretations of Holocene coprolites in Patagonia. The aim of this study was to identify and differentiate the foraging areas of guanaco (Lama guanicoe) through the analysis of phytoliths, pollen, and plant fragments from modern feces collected in two distinct environments: the shrub-grass steppe surrounding CMN1, and the sub-shrub steppe near Salitroso lake (SAL), within the lake Posadas-Pueyrredón basin. Multiproxy protocol was applied to identified plant taxa consumed by L. guanicoe. Also, a plant phytolith reference collection was built for this study. The results of the combined analyses of the three proxies in modern feces identified representative taxa for each environment: Poeae, Cerastium arvense, Colobanthus lycopodioides, Colliguaja, Azorella, Fabaceae, and Asteraceae at CMN1 site, and Stipeae, Verbenaceae, Nassauvia, Atriplex sagittifolia, Senecio and Nardophyllum at SAL site, among others. Principal component analyses based on each proxy showed a differentiation between feces from CMN1 and SAL, supporting the identification of discrete foraging areas. These results demonstrate the value of multiproxy approaches in building reference models for interpreting past camelid diets and habitat use in southern Patagonia.