a, Drought sensitivity as the slope (β) in an ordinary least-squares linear regression of an index of the variation in aboveground plant water content at midday compared to night (regression: VODmidday = β × VODnight + ε). b, Native plant species richness (percentage of maximum; data from http://ecotope.org/anthromes/biodiversity/plants/data/). c–h, Ordinary least-squares linear regressions between these two variables for six major biomes. c, Tropical and subtropical moist broadleaf forests (n = 1,380 grid cells). d, Tropical and subtropical dry broadleaf forests (n = 241 grid cells). e, Temperate broadleaf and mixed forests (n = 1,289 grid cells). f, Temperate coniferous forests (n = 318 grid cells). g, Boreal forests (n = 1,784 grid cells). h, Mediterranean-type forests, woodlands and shrub (n = 319 grid cells). Each point represents an individual grid cell from the map and colours that are more red indicate a higher density of points. Red lines show the best fit of ordinary least-squares linear regression lines.