Figure 2

Population structure at macro-geographic, micro-geographic and temporal levels. Individual-based Bayesian clustering using STRUCTURE v.2.3.1[32, 33] to assess the genetic population structure at both A) macro-geographic and B) micro-geographic and temporal scales. For each scale, the number of genetic clusters (K), which was best supported by the procedure proposed by Evanno et al. (ΔK) [34] was represented (i.e. K = 3 for A and K = 4 for B). Different colours represent different genetic clusters in each figure. Code representing populations and hydrographic basins are given above graphs (see Table 1 for details). Results for different K are shown in Additional file 3.