We present a high-resolution 2000-year record of vegetation, fire and sedimentary change from near the forest-steppe ecotone in Región de la Araucanía, Chile. The region lies at the interface of two of the dominant regional climate systems in southern South America, the South Pacific Anticyclone (STA) and the Southern Hemisphere Westerly Winds (SWW), with current inter-annual climatic variability in this region strongly influenced by the El Niño– Southern Oscillation (ENSO). Dendrochronological and high-resolution lake sediment analyses from southern South America have revealed decadal to centennial scale climate changes over the last 1000 years that were apparently coeval with the northern hemisphere Little Ice Age (LIA) and Medieval Climate Anomaly (MCA). We analysed pollen, spore, charcoal and physical characteristics of lake sediments from Laguna San Pedro (38°26'S, 71°19"W), located close to the town of Lonquimay, a highly volcanic area within the Andes rain-shadow where continentally results in extreme weather conditions, in an attempt to discern between volcanic, human and climatic drivers of environmental change and to test whether lake-sediments from this region have potential as palaeoclimate indicators. We reveal a highly dynamic forest-steppe ecotone and lake sedimentary processes over the last 2000 years and identify phases that are remarkably consistent in direction of change and timing of the MCA and LIA in this part of southern South America, corroborating tree-ring analyses and giving us confidence in palaeoclimatic potential of this site. Further, we identify multi-decadal to centennial scale phases through the last 2000 years that are consistent with reconstructed ENSO variability. We conclude that, despite evidence for recurrent volcanic activity in the local region, the main drivers of environmental change recorded in Laguna San Pedro have been climate and humans.