Diet and habitat of the guanaco (Lama guanicoe) in the past and present at the Colhué Huapi and Musters lakes (Patagonia, Argentina), based on stable carbon and nitrogen isotope analysis of bone collagen

Abstract

The analysis of δ 13C and δ 15N values in collagen obtained from the Lama guanicoe modern and archaeological bones (N = 26) from the Sarmiento Basin area (Colhué Huapi and Musters Lakes, central Patagonia) indicates a diet based on C3 plants (Calvin–Benson photosynthetic carbon xation cycle). Within this group of plants, a marked increase in grass consumption during the recent lapse (post–1 500 years BP) is recorded. In contrast, a strong signal of higher woody plant consumption is recorded between 3 844-1 920 years BP (i.e., shrubs) and among modern individuals (i.e., subshrubs). It is proposed that when the valley oors of the Colhué Huapi and Musters Lakes were exposed (post-1 500 years BP), there was greater availability of wetlands and grasslands.El análisis de los valores de δ 13C y δ 15N obtenidos de colágeno de huesos modernos y arqueológicos de Lama guanicoe (N = 26) de los lagos Colhué Huapi y Musters en el área de la Cuenca de Sarmiento (Patagonia central) indica una dieta basada en plantas C3 (ciclo de jación fotosintética del carbono de Calvin–Benson). Dentro de este grupo de plantas, se observa un marcado incremento en el consumo de gramíneas durante el lapso reciente (posterior a 1 500 años AP). En contraste, se registra un mayor consumo de plantas leñosas entre 3 844-1 920 años AP (i.e., arbustos) y entre los individuos modernos (i.e., subarbustos). Se propone que cuando los fondos de los valles de los lagos Colhué Huapi y Musters quedaron expuestos (posterior a 1 500 años AP), hubo una mayor disponibilidad de humedales y pastizales.