1 - ((s – min(s)) / (max(s)- min(s)))
Where “s ” corresponds to the suitability values obtained from
the raster projections, and “min(s) ” and “max(s) ”
correspond to the minimum and maximum suitability values from the model,
respectively. Then, we calculated the kernel density distribution of
marginality within the suitable conditions with the “density” function
in R, which represents the relative amount of area of different
marginality values within suitable conditions. The calculation of the
density distribution of marginality was done for the present-day and LGM
distribution models. Then, we calculated the change in the marginality
distribution between LGM and present by subtracting the kernel density
curves from both time periods. Finally, to identify clusters of taxa
that showed similar changes in their marginality density distribution
between LGM and present, the density curves were hierarchically
clustered with the “dad” package (Boumaza et al. 2021) in R by
calculating the Hellinger’s distance between density curve pairs.