2021 FAROUK EL-BAZ AWARD: NEW FRONTIERS IN QUATERNARY PALEOECOLOGY OF THE ATACAMA DESERT

Our understanding of the Quaternary history of plant communities in the Atacama Desert accelerated with the discovery of the first rodent middens in the Atacama Desert more than 20 years ago. These organic deposits composed of feces, plant remains, insects, and bones encased in a matrix of crystallized urine, are true biological archives that endure for millennia in the caves and rock shelters. In addition to traditional paleoecological methods such as plant macrofossil and pollen analysis, the implementation of new techniques such as biomarkers, stable isotopes (δD, δ¹³C, δ¹⁵N), heavy metals and paleogenomics are generating a much broader view of ecosystem transformation during the last glacial-interglacial transition and the Holocene in northern Chile. In addition, new records of rodent body size changes garnered from ancient middens are being used to obtain a quantitative reconstruction of precipitation for the last 16,000 years, aiding a better understanding of the mechanisms of past climate variability and possible future changes in a warmer world.