Fig. 3. Management and environmental variables influencing vanilla yield in 30 vanilla agroforests in north-eastern Madagascar based on a linear mixed-effect model with yield sqrt-transformed.

Dots are raw data and solid and dashed lines indicate statistically significant (p < 0.050) and marginally significant effects (0.050 < p < 0.100), respectively. Trend lines show average values of the backtransformed model predictions of the final model after using likelihood ratio tests using maximum-likelihood estimation, shaded areas indicate 95% confidence intervals. The full model included: vanilla planting density, pollination labour input, vanilla vine length, vanilla plant age, soil characteristics, canopy closure, slope, landscape forest cover, understory vegetation cover, and elevation. The final model included: vanilla planting density, pollination labour input, vanilla vine length. Statistical test results in Supplementary Tables 6 and 7.