Climatic data collection
To characterize patterns of spatial environmental variation among the
localities, the historical values (1970-2000) of 19 environmental
variables (bio 1 - bio 19) and elevation (Elv) were obtained using the
package raster v.2.7.15 and the Wordclim data of 2.5 arcmins (available
at http://worldclim.org/ ). We tested for covariation among
environmental variables using the vifcor () function from the
“usdm” R package (Naime et al., 2014). Variables presenting no strong
covariation (R <0.8; see Fitzpatrick and Keller, 2014) were
conserved for subsequent analyses (Supplementary table 1).