Schoener’s D and Niche similarity significance levels relative to ordination methods and Species Distribution Models used to carry out niche comparison.

LDA = Linear Discriminant Analysis; Maxent 1 and 2 = Maximum Entropy Algorithm analysis made using in turn one of the two Maxent outputs generated by either population (or species) as the comparison background against which the output of the remainder was contrasted; MDS = Multidimensional scaling; PCA environmental = Principal Component Analysis calibrated on the whole environmental space including the presence records where the species occur; PCA occurrence = Principal Component Analysis calibrated with EGV values associated with the occurrences of the species; Within environmental = Within-group calibrated on the whole environmental space. + = similarity; − = dissimilarity.Schoener’s D and Niche similarity significance levels relative to ordination methods and Species Distribution Models used to carry out niche comparison.