Centennial-scale climate variability and human land-use shaped vegetation and lake dynamics in southern Spain over the past three millennia

Mediterranean vegetation has been profoundly shaped by the interaction of climate variability and human activities, and understanding the timing, magnitude, and drivers of these transformations is essential for predicting ecosystem responses in an especially climate-sensitive region. In this study we present a high-resolution palynological record spanning the last ~3150 years from Laguna Grande de Archidona (LGA), a lake in southern Spain, to reconstruct vegetation history, fire activity, identify major Late Holocene climatic and lake-environment phases, and disentangle the relative roles of climate variability and human activity in controlling landscape evolution. Quantitative temperatures were estimated by a calibration derived from the Eurasian Modern Pollen Database v2 (EMPDv2) using the Weighted Averaging-Partial Least Squares (WA-PLS) calibrated regression method. Temperature primarily controlled elevational shifts of vegetation belts, while variations in effective moisture (precipitation minus evaporation) governed lake level fluctuations in the study area. Temperatures were highest coinciding with a period of higher humidity during the Iberian Roman Humid Period (IRHP). Subsequently, cooling is observed during the Early Middle Ages (EMA) and the Little Ice Age (LIA). The alternation of persistent North Atlantic Oscillation (NAO) modes probably played an important role in controlling the humid-arid cycles observed at LGA. Anthropogenic impact in the area becomes particularly clear during the last millennium, when intensified olive cultivation progressively transformed the landscape .