Damming-associated landscape change benefits a wind-dispersed pioneer plant species

Landscape changes by anthropologic activities such as damming threaten local biodiversity through deforestation and subsequent geographic isolation. Ecological restoration through planting pioneer species could buffer the negative effects of landscape changes. As genetic variation of a species is important for its long-term persistence in the face of land use change, the temporal genetic variation of a pioneer plant species must be evaluated. Yet, it has received little attention. In this study, we used nuclear microsatellites to study the genetic variation of a wind-pollinated and wind-dispersed pioneer tree Pinus massoniana (Pinaceae) on islands in the Thousand-island Lake (TIL) formed by damming in 1959. Overall, high genetic diversity was observed in all individuals (H_E = 0.692), which is positively related to island size and independent of geographic isolation. Additionally, similar genetic diversity and differentiation was observed between old (within 5 generations after damming) and young cohorts (around 5–10 generations after damming). These results imply that P. massoniana did not lose genetic variation after the formation of the TIL. Furthermore, smaller variance in genetic differentiation that is dependent on geographic distance was found in the young cohort suggesting gene flow was maintained in the face of geographic isolation after damming. Overall, our findings revealed that pioneer wind-pollinated and wind-dispersed plant species are resistant to the negative effects of damming, and they could be used to restore disturbed habitats caused by anthropogenic landscape changes.