Fig. 5: Altiplano history relating to climate, land use and deposition/erosion.

Timeline showing (a, b) ‘step change’ model and ‘spike’ model outputs as box-whisker plots (IQR and 5–95 percentile range, median black line). c Range of floodplain radiocarbon ages as box-whisker plot (±1 and ±2σ error), indicating increased sediment supply to valley floors via hillslope erosion. d Pollen and charcoal data⁶³, indicating onset of human-induced vegetation change from 4 ka, peak abundance of food-crop pollen (Chenopodiaceae/Amaranthaceae) and charcoal at ~2.6 ka (star) followed by decline in charcoal (despite high lake levels), implying comprehensive deforestation from ~2 ka. e Timing of the agropastoral transition start and end⁴⁴ as box-whisker plots (±1 and ±2σ error, and median black line). At base, schematic climate scenario describing mid-Holocene aridity (7.9–4.5 ka)^36,39 and succeeding wetter conditions that raised lake levels (~4.5–3.6 ka) in the Titicaca Basin.