Turnover and administrative boundaries
Heatmaps were generated by overlaying species ranges per taxon, representing species richness. To assess abrupt diversity changes, standard deviations for 10km blocks were calculated using block statistics in ArcMap. Maps were then classified into N=10 categories using the quartile function. Given varied maximum diversity and taxonomic representation, different numbers of richness categories were retained per group, following where borders emerged. This was then extracted using 1km buffers of national administrative boundaries to assess percentages of administrative boundaries overlapping turnover hotspots.