Fig. S4.

Chronology of megafaunal extinctions plotted against climate change as indicated by oxygen isotope and pollen data (left colored bands, where blue is cool and red is warm); vegetation change [right colored bands, with yellow equating to cold grassland dominance, yellowish green representing mixed grasslands and Nothofagus forest, and olive green (younger than ∼11,000 ka) indicating predominance of Nothofagus forest]; and timing of increase in fire frequency (dotted-line box). See Figs. S2 and S3 for more details on vegetation change and fire frequency indicators. The megafaunal extinction chronology and the chronology of human arrival is based on dates listed in ref. 21; all dates were vetted for robustness, with only those of rank 11 (as explained in ref. 21) or higher used. The timing of local ice-free conditions is taken from ref. 72 (light blue rectangle). Also shown is the timing of the Reclús Volcano eruption (red line), which although it distributed considerable ash in the region, had no apparent effect on the timing of the faunal or vegetation changes (23). The time axis is in calibrated years before present. For the radiocarbon dates on megafauna and human occupation, the dots (or triangles for humans) show the median and the whiskers show the 2-σ probability. Distributions indicating the probability of timing of extinction for megafauna and first arrival for humans were calculated using the GRIWM best-estimate method; see ref. 68 for explanation and R-code. Dietary preferences are indicated in brackets by C (carnivore), M (mixed feeder herbivore), G (grazer), and U (unknown) (40, 73–75). Reproduced with permission from ref. 23.