Fig. 3: Global predictions and latitudinal trends of mycorrhizal fungal endemism.
From: Global hotspots of mycorrhizal fungal richness are poorly protected
a,c, Endemism maps show the predicted rarity-weighted richness of AM fungal VT (a) and EcM fungal OTUs (c) per 100 m2 (pixels approximately 1 km2). Rarity-weighted richness is a unitless metric, and predicted values are capped at 0.26 (AM) and 1.5 (EcM) for visualization. These spatial predictions reflect the simulated high-sampling scenarios to limit unequal sampling effects on rarity patterns. Crosshatches are superimposed over areas that are underrepresented by the training data (highly extrapolated) where model predictions should be interpreted with caution. Plots show mean rarity trends across latitude (shaded area is ±2 s.e.m.). b,d, Bivariate maps show the combination of pixel-level uncertainty (orange gradient) and extrapolation (purple gradient) of AM (b) and EcM (d) fungi rarity-weighted richness predictions. Uncertainty is measured as the coefficient of variation across n = 100 bootstrapped model predictions. Extrapolation reflects the degree of environmental difference and geographical distance from samples in the training dataset. Histograms on the charts show the frequency of pixels in different uncertainty and extrapolation levels visualized here. Masked areas (grey) are sparsely vegetated zones and dense urban areas based on global land-cover data.
