FIGURE 1.

Density distribution of the increase in alien species compared to the current conditions required to cause major impacts on biodiversity, as estimated by 36 experts. Vertical red lines indicate the median value of the density distributions. Columns correspond to zonobiomes, taxonomic groups, realms and socio‐economic development (from left to right); see Supplementary Material 4. Uncertainty estimates are the mean uncertainty values provided by the experts using a five‐point Likert scale