Indices of climatic (a) and vegetation (b) dissimilarity between populations of Ensatina within California. White bars correspond to all possible pairwise comparisons between the 20 populations and reflect the underlying ecological variation intrinsic to the geographic area occupied by Ensatina in California. Black bars correspond to the dissimilarity indices from pairs of populations that contact around or across the ring distribution.
Pereira et al. BMC Evolutionary Biology 2011 11:194 doi:10.1186/1471-2148-11-194