VARIABILITY ON STABLE ISOTOPES ( 13C, 15N) OF CAMELIDS BONE COLLAGEN: IMPLICATION TO HOLOCENE HUMAN PALEOECOLOGY

ADOLFO GIL; GUSTAVO NEME; CINTHIA ABBONA; ARMANDO DAUVERNÉ; GISELA QUIROGA; EVA PERALTA; CLARA OTAOLA

VIÑA DEL MAR

Conferencia; IsoEcol 2018; 2018

Camelids, mostly guanacos (Lama guanicoe) are the more prominent big sized herbivorous in South America and one of the most significant resource in human diet during pre-industrial time. The study of camelids isotopic diet is significant for different aspects. First, because it was a common resource for past human populations in south America; second, its high abundance during the Holocene make this specie a proxy for paleoecological reconstruction. Finally, isotopicinformation in this specie is useful for conservation biology as camelid are being displaced by human activities during the last century, today technical decision are being develop to protect and manage this species but lacking the general information about camelids strategies and its niche. All of this aspects can be considered based on stable isotope signal from bone collagen.Monte and Patagonia camelids differ in the manner expected, with Monte samples having more positive average values of ẟ13C and ẟ15N. The Altoandino samples, on the other hand, are similar to Patagonia but statistically not different with Monte. However, the small amount of samples can explain this statistical trend. The spatial pattern in ẟ13C show the enriched average localized in the Northeast quarter but as discontinuous areas intercept with a more depleted ẟ13C samples. At the same time, ẟ15N show a more variable and counterintuitive spatial pattern that do not follow theexpectation in Figure 2. On the other hand, the temporal trends show a new pattern previously ignored. There is some visual change through time that reject the idea of stable trends. Clearly, the high positive correlation between ẟ13C and ẟ15N could indicate an environmental/climatic variable is explaining the temporal trends. If so, it can be propose this variation through time is reflecting change in the ecosystems that could imply change in C3/C4 plants frequency and/or change in the isotopic value on the vegetation including the same photosynthetic way. The enriches ẟ13C during the early/middle Holocene, associated with a weak increase in 15N could confirm the increase in annual plants proposed by Markgraff (1983) reflecting and increasing of aridity. Clearly, an increase in the sample size and an improve in the study of relationship between ẟ13C bone collagen camelids and environment could confirm or reject this trends.