Figure 1.
Maps illustrating geographical locations of individuals analyzed for this study.
Note that in the case of S. occidentalis caurina and P. monticola, genetic data reflected the presence of a single phylogenetic lineage or phenetic cluster within the geographical range displayed. In contrast, previous genetic analyses of A. longicaudus and R. variegatus indicated the presence of separate “northern” and “southern” haplotype lineages in western Oregon (labeled with ‘N’ and ‘S’, respectively). For our analyses, only haplotypes corresponding to “southern” lineages were included in analyses of these two species (unlabeled locations on R. variegatus map and locations labeled with an “S” on A. longicaudus map). See text for more information.
Figure 2.
Results of Mantel tests (left column) and spatial autocorrelation analyses (right column) for four species investigated.
Panels A and B: S. o. caurina. Panels C and D: P. monticola, Panels E and F: R. variegatus, Panels G and H: A. longicaudus. Distance classes in spatial autocorrelations that showed significantly larger or smaller values at the α = 0.05 level than average (indicated by horizontal dashed lines) are marked with asterisks.
Figure 3.
Results of Genetic Landscape Shape interpolations.
Panel A: S. o. caurina, Panel B: P. monticola, Panel C: A. longicaudus, Panel D: R. variegates, Panel E: a randomly selected simulated data set using δ = 1.5 and µ = 10−4 during simulation runs. Surface plot heights reflect genetic distance (and genetic diversity) patterns over the geographical landscape examined.
Figure 4.
Results of regression/correlation analyses designed to confirm patterns observed in Genetic Landscape Shape analyses (Fig. 3).
Analyses of S. occidentalis caurina and P. monticola show significant negative correlations between genetic distance patterns and UTM northing coordinates. In contrast, R. variegatus and A. longicaudus both show positive correlations between genetic distance patterns and UTM northing coordinates.
Table 1.
Proportion of 25 simulated range expansion event replicates where a significant negative correlation at the α = 0.05 level was observed between landscape coordinates along a South to North transect and pairwise genetic distances.