Global patterns and determinants of vascular plant diversity
(Kreft H, Jetz W PNAS 2007;104:5925-5930)
Fig. 3. Global patterns of vascular plant species richness. (a) The geographic distribution of the richness data of vascular plants for the 1,032 geographic regions analyzed in this study (each dot presents the mass centroid of a geographic entity; note that regions differ in size and that species counts have not been standardized). (b–d) The species-richness maps show area-standardized predictions of three different global models across an equal area grid (≈12,100 km2, ≈1° latitude × 1° longitude near the equator) based on the combined multipredictor model (b), ordinary kriging of species richness (where species richness is interpolated purely as a function of spatial autocorrelation in the response variable) (c), and ordinary cokriging (which incorporates both the spatial autocorrelation in species richness and the combined model as an underlying trend) (d).Global patterns and determinants of vascular plant