Assessment of barriers to gene flow in S. hesperis
A partial mantel test indicated that lineage distance (same vs. different lineage) was not significantly related to resistance distance (r = -0.111; p = 0.987) after partialling out the relationship between lineage distance and Euclidean distance. This result suggests that, although dispersing individuals of each lineage are less likely to contact individuals of the other lineage, this is best attributed to the geographic separation of the ranges of the lineages (i.e., parapatry) and not to arrangements of suitable habitat that might present significant barriers to dispersal.