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.