Fig. 4.

Detailed comparison of the Lake Barombi vegetation changes and the archaeological record of WCA during the past 5,000 y. ($A$) Lake Barombi ${\delta }^{13}$${\text{C}}_{n-\text{C}31}$ indicating vegetation changes. ${\delta }^{13}$${\text{C}}_{n-\text{C}31}$ values have been corrected for the Suess effect for the last 160 y (SI Appendix). Dots are the raw measured data; line indicates median probability; envelopes reflect 68% (dark) and 95% (light) confidence intervals in the reconstruction, based on analytical and age model errors. ($B$ and $C$) Archaeological synthesis of WCA. All presented archaeological data rely on the SPD of calibrated ¹⁴C dates that were binned in space using 10-km radii and time using 200-y intervals (SI Appendix). SPDs were plotted with a 200-y moving average to prevent overinterpretation of smaller-scale variability (53–55) and are shown either as a gray scale [($B$) black represents maximum probability, white represents null probability] or as a line ($C$). ($B$) Evidence of human activity. ($C$) SPD-inferred population dynamics: SPD of ¹⁴C dates (thick line) was compared against an exponential model used as a conservative null hypothesis reflecting both the long-term population rise observed in prehistoric populations and temporally increasing taphonomic loss (53–55) (SI Appendix). The dark gray area represents the 95% confidence intervals for the null model. Red and blue areas represent intervals with significant positive and negative deviations, respectively. Regional cultural timeline (13) shown at bottom (EIA, Early Iron Age; LIA, Late Iron Age; LSA, Late Stone Age; Neolithic S., Neolithic Stage). Vertical yellow band indicates the timing of the Lake Barombi LHRC.