Ecology of Dryas octopetala sensu lato, a relict plant in the Tateyama Mountains in the North Alps of Japan:Comparison between mid-latitude alpine and arctic tundra populations.

To understand the adaptation of a plant found in different environments, I focused on the circumarctic plant Dryas octopetala sensu lato, which is widely distributed from mid-latitude mountains to the high arctic tundra. A comparison was made of environmental conditions, leaf and floral traits, and genetic diversity between populations from the mid-latitude Mt. Tateyama in central Japan and the high arctic Ny-Ålesund in Svalbard, in order to examine ecological and genetic variations in this species. Accumulated temperature during the summer in Tateyama was 3.1 times as high as that in Ny-Alesund, while global radiation was almost the same at both sites. LMA (leaf mass per area) was lower, and leaf N concentration higher in Dryas populations of Tateyama and in other mid-latitude alpines than in plants of Ny-Alesund and the sub-arctic tundra. Based on the relationship between flower weight and resource allocation to female function within a hermaphrodite flower, gender variation in this species appeared to be lower in the population from Tateyama than in that from Ny-Ålesund. Moreover, genetic diversity within a population was lower in Tateyama than in Ny-Ålesund. Finally, the results are discussed in relation to the response of plants to climate change and global warming, and several traits are highlighted in order to predict the population dynamics of D. octopetala in the mid-latitude mountains of central Japan.