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Previous research on intensification in hunter gatherer strategies from Central West Argentina ca. 2000 years BP states that human demographic packing and overhunting of guanacos ( Lama guanicoe ) may have caused resource depression of this large prey animal. As a result, people broadened their diet to include smaller prey animals. Evidence supporting this conclusion includes an increase in Shannon's Diversity Index and a decrease in the abundance of artiodactyl remains over time in southern Mendoza. However, these studies about change in diet breadth did not consider the importance of spatial scale on analysis of prey choice and diet breadth and used the entire region as a unit of analysis. This is problematic because southern Mendoza has a heterogeneous landscape. In this paper we analyze different faunal abundance indices considering different spatial scales and the representativeness of the zooarchaeological samples. The results of the analyses show distinctive patterns of resource use over time at the macro- and subregional scales. Some of the difference can be explained by environmental differences between subregions and others might relate to differences in sample representativeness between subregions. [ABSTRACT FROM AUTHOR]

This paper presents the results of a study on the isotopic ecology of guanacos in central western Argentina. We examine the historical population ecology of guanacos using stable isotope analysis of bone collagen from pre-Hispanic and modern guanaco populations (n = 129), considering variability in two ecoregions: the Monte hot desert and the Andean-Patagonian cold desert. Our study addresses the consistency of guanaco diets over time, evaluating palaeoecology to provide information for conservation of this taxon. We found significant differences in isotopic niche size between modern and archaeological guanacos. When analyzed by ecoregion, there were significant differences in niche size through time, indicating that guanacos had distinctive dietary habits and occupied different ecological niches across the ecoregions. Comparing Standard Ellipse Areas (SEA) through time and across space, we observed that the archaeological SEA for guanacos is smaller than its modern counterpart in the Andean-Patagonia ecoregion. Conversely, in Monte, the archaeological SEA is larger than the one established for modern samples. The contrast between pre-Hispanic and modern populations highlight the impact of human activity and conservation efforts on the distribution and ecology of guanacos. These findings have important implications for understanding guanaco ecology with consequences for conservation policies. [ABSTRACT FROM AUTHOR]

Zooarchaeologists have relied upon various approaches to study the impacts of harvest pressure and environmental change on ungulate populations, such as analysis of prey mortality patterns and morphometrics. Analysis of ancient DNA from ungulate bones and bone fragments from archaeological sites provides an additional means for studying prey population dynamics related to environmental change and human ecology over time. In this paper, we study the population history of the largest game animal in northwest Patagonia, the guanaco (Lama guanicoe). Our study relies on the use of Bayesian Skyline Plots to determine shifts in estimated guanaco population size based on analysis of ancient mitochondrial DNA. Our results indicate that hunting by humans in addition to increases in aridity during the late Holocene led to a decline in the guanaco population in the region, which is in contrast to the harvest and environmental history in other parts of Patagonia (south of our study area). Using a weight of evidence approach that includes proxies of environmental change, human population dynamics, exploitation of guanacos, and estimates of guanaco population size, we argue that the late Holocene shift in guanaco population size was a driving factor in subsistence and settlement change related to resource intensification during the late Holocene in northwest Patagonia. • Demographic reconstruction of guanaco population dynamics during the Holocene. •Estimated population size is based on ancient DNA analysis through Next Generation Sequencing. •There are key changes in guanaco population size during the late Holocene. •Late Holocene guanaco population relates to increased hunting pressure in northwest Patagonia. [ABSTRACT FROM AUTHOR]