5 CONCLUSIONS
Our investigation revealed three well supported genetic clades in the Hainan island endemic plant P. heterotricha , and proposed hypotheses to construe the phylogeographic patterns detected (Figure 2 and 3). The genetic results highlight for the first time the critical role of riverine isolation caused by the Changhua and Wanglou Rivers in the patterns of intraspecific evolution of plant populations on Hainan Island. However, such barrier effects for the speciation mechanism of this island-endemic herb and other similar plants are still in need of further illumination, especially by reproductive studies, and enhanced mainland sampling. Both are important to construe the origins of the speciesʼ high current genetic diversity.
Importantly, the three groups of populations detected are genetically quite distinct, which calls for their independent management in any conservation strategy, in order to avoid disrupting their current genetic structure and their prospects of future evolution.