Figure 4 Genetic barriers obtained from BARRIER analysis based on nrDNA in the years of (a ) 2016 (note the third barrier indicated by the faint purple line between XA and WZ) and (b ) 2022 of Primulina heterotricha populations. Delaunay triangulation (black lines) and the bold lines (red, blue, and purple lines) indicate detected genetic barriers.
The barrier calculation based on the cpDNA sequence matrix showed similar patterns to those obtained with nrDNA. For the 2016 samples, the only difference was the location of the third barrier, which for the cpDNA separated YJ from BW and YG (Figure 5a). For the 2022 samples, the first barrier changed to be the reservoir but also included some sections of expressways 1 and 2 (Figure 5b). The second barrier corresponded well to the section of Expressway 1 lying between YG and WZ, while the third barrier was located between YJ and YG (Figure 5b).