Projection to present-day and LGM climates
The niche ellipsoid of each genetic clade, corresponding to the model with the highest AUC value, was projected onto the present-day geography to obtain each clade’s predicted distribution. Distribution models were binarized between suitable and non-suitable conditions by using a 10% of omission criterion. Then, we projected the niche ellipsoid to LGM climate using MIROC and CCSM GCMs. The amount of geographic area corresponding to suitable conditions for each clade was calculated for present-day and LGM climate in R with the “landscapemetrics” package (Hesselbarth et al., 2019). Further, we calculated the proportional change in area for each clade by dividing the LGM-predicted area by the present-day predicted area. Significant differences in the proportional change in area were tested among clade location (north, south, or unstructured), taxonomic groups (mammal, plant, or reptile), and elevation (highland or lowland), using a single GLMM in R with “lme4” using a “gamma” distribution and “inverse” link function, including each taxon as a random variable.