Fig. 3. Importance of variables in predicting threatened vertebrate species richness in different zoogeographic regions.

Variables are grouped into broader classes, which are indicated by the capital letters on the side of the variable names: Total Species Richness (S), Environmental (E), and Human Impact (H) covariates. The mean importance of each variable from the models of threatened vertebrate species richness is indicated by the yellow (low importance) to black (high importance) colour gradient. Variables are ordered from top to bottom first by group, and then according to their importance in the global model of threatened vertebrate species richness. Average performance of each regional set of models, measured with R², is indicated at the top of each column, with regional models ranked by decreasing mean R². Heat maps of variable importance for the individual taxonomic groups can be found in Supplementary Figs. 5–8. Source data are provided as a Source Data file.