Extended Data Fig. 4: Hotspot and coldspot maps for alpha diversity (left) and community dissimilarity (right).

The Getis-Ord Gi* statistic was calculated for each location (0.25x0.25 deg pixel size) in the dataset 1–3. The resulting z-scores were used to estimate if a given location has statistically high or low values and if these values are spatially clustered. This is done by assessing each location within the context of neighbouring locations. Statistically significant positive z-scores indicate clustering of high values (hotspot) and statistically significant negative z-scores the clustering of low values (coldspot). Values are plotted for both positive (hotspots) and negative (coldspots) 99%, 95%, and 90% confidence levels.