The transition from the Medieval Climate Anomaly (MCA, 950-1250 CE) to the Little Ice Age (LIA, 1350 to 1800 CE) is the largest pre-industrial climate shift within the last two millennia, offering an opportunity to study how vegetation responds to rapid climate change. We analyzed a sedimentary record from the Colombian Andes to reconstruct regional vegetation dynamics during this time interval, identify the modern environmental distribution of taxa present in the fossil record, and provide...