Range inference
Predicted range #1 allowed to forecast 40.09% of the species’ range,
while 15.12% of such predicted range fell outside real range limits
(Fig. 3 and Fig. 4). ) Predicted range #2 (i.e. the range inferred by
extrapolating GEAM to include all grid cells suitable for any possible
combination of alleles at the four loci that significantly correlated
with environmental variables) was similar to the real species’ range.
All grid cells in predicted range #1 were included in predicted range
#2, accounting for 50.45% of its total amount. In turn, predicted
range #2 captured 77.46% of the actual distribution of P.
algirus , with 17.27% of inferred presences beyond real range limits.
The 22.54% fraction of the real distribution range unpredicted by GEAM
mostly corresponded to the northwest corner of the range, as well as to
a large number of small predicted gaps within it. Nevertheless,
predicted range #2 accurately reflected not only the northern and
southern edges of the real distribution range, but also many of the gaps
within it, both in northwest Africa (i.e. far from the sampled
populations) and in many Iberian mountain ranges (Fig. 3 and Fig. 4).
Because complete randomizations provided the most reliable null
hypothesis for EAAs, we used them to infer the species range following
the same procedure as described above. We ran a different EAA per fully
randomized dataset because each of them included a different set of
randomly generated ‘outliers’ (i.e. SNPs putatively under selection).
The mean percentage of inferred range was 41.39% (SD = 4.799, range =
40.09 - 81.27), roughly equivalent to predicted range #1 but smaller
than predicted range #2. Of the 500 complete randomization EAAs, only
one (P = 0.002, Fig. 5) was able to infer a larger proportion of the
species range (80.91%) than predicted range #2 (77.46%), but this was
at the cost of a large proportion of inferred presences beyond real
range limits (65.02%, vs. 17.27% for predicted range #2).