Phylogeography and refugia of the Japanese endemic alpine plant, Phyllodoce nipponica Makino (Ericaceae)

Aim: This study aims to elucidate the phylogeography of the Japanese endemic alpine plant, Phyllodoce nipponica Makino (Ericaceae) and to infer the location of refugia of alpine plants in Japan during climatic oscillations. Location: Alpine zone in the Japanese archipelago. Methods: We determined the chloroplast (cp) DNA haplotypes of 155 individuals (22 populations) based on sequence data from the trnL-F and trnT-L intergenic spacers and the trnL intron, whose phylogenetic relationships were analysed using the program tcs. To examine the genetic structure, analysis of molecular variance (amova) was carried out and the population differentiation was shown by the parameters G_ST and N_ST. Results: The haplotype composition and the results of amova showed that populations in the Japanese Central Mountain Region (JCMR) and in the westernmost region were highly divergent (18.8%). The diversity within populations was very high in the JCMR (h_S = 0.421); less variation was found within populations located in other regions at lower elevations. Main conclusions: Phyllodoce nipponica survived climatic changes during the Quaternary in the JCMR and the westernmost region. Most of the distribution range was colonized during only one range expansion. The source location from which the range expansion occurred was unclear.