Dominant drivers of tree species richness in forested areas worldwide
a, Driver dominance was derived for each pixel from four driver categories (that is, bioclimatic, topographic, anthropogenic and soil) and co-limitation, which represents a lack of clear dominance among the four foregoing categories. The pixel-level drivers were then aggregated by 0.5° latitudinal bins to show the percentage prevalence of dominant drivers by latitude (top left). b, The violin charts show the kernel probability density of tree species richness per ha for different drivers. Inside boxes indicate the median (line in the centre) and interquartile range (bounds of boxes). The numbers on top of the violin charts indicate the percentage of forested pixels globally that corresponds to each driver category. The red line represents the mean and 95% confidence interval of tree species richness per ha (81.1 ± 0.1) for all the 0.025° × 0.025° pixels of co-limitation. The vertical axis is on a logarithmic scale for better illustration.