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.