The mutual ecogeographical range and paleoclimatic reconstruction during the Late Pleistocene-Holocene in the Pampas (Argentina) using meso and microvertebrate fossils

摘要

The Pampas of Argentina is a large grassland ecosystem located in the oriental region southern of South America. As a study case, we present the results of the paleoclimatic analysis of the Tixi Cave site. This is a paleontological and archeological locality that shows a long chronologic sequence, with radiocarbon dates ranging from the Late Pleistocene to historical times, and one of the best records of meso and microvertebrate fossils in South America. Paleoclimatic reconstruction was assayed using the Mutual Ecogeographic Range method. Ecological niche models were made for each of the living representatives of the fossil taxa reported at the site. Potential distribution areas were superimposed to perform the paleoclimatic inference and to infer the annual average temperature and the annual average precipitation. During the Pleistocene-Holocene transition (12,287?±?212–11,609?±?218?ca BP) and in the Middle-Holocene (5592?±?79?ca BP), colder and drier climates appear in comparison to the present climate, the remaining of the Holocene (3496?±?81–160?±?120?ca BP) shows warmer and humid climates as compared to today’s climate conditions. Our results are in agreement with the paleoenvironmental inferences obtained by other proxies, such as deposition, paleosols, phytoliths, diatoms, ostracods, and pollen for Late Pleistocene -Holocene of the region, showing that the abundance of small mammals can accurately record the climatic fluctuations of the Late Pleistocene-Holocene in the Pampas of Argentina.