Ecological characteristics of the coastal dune plant <i>Artemisia stelleriana</i> , along with genetic diversity of populations at Niigata Prefecture in Japan

Abstract Coastal dune plants play an important role in maintaining the stability of coastal dune areas. Artemisia stelleriana Besser. is a coastal dune plant with a northern distribution, and populations are scattered and isolated in Japan due to habitat loss, leading to its classification as an endangered species in several prefectures. However, very few ecological and genetic studies of A . stelleriana have been conducted worldwide. This study was performed to investigate the self‐compatibility, flower structure, and flowering phenology, seed thalassochory potential, and clonal propagation ability of A . stelleriana, along with the genetic diversity of four populations in Niigata Prefecture. Our results showed that A . stelleriana is self‐compatible, with a flower head composed of female and hermaphrodite florets that have overlapping flowering periods. The species also exhibits a relatively short seed floating period, which leads to limited seed dispersal by sea currents, and possesses a weak clonal structure due to its low ability for clonal propagation. In four populations in Niigata Prefecture, most individuals were fixed for a single homozygous genotype at all loci. Artemisia stelleriana is considered to have a flower structure suitable for self‐pollination, and it is assumed that this extremely low genetic diversity has been established through repeated self‐pollination within the population, with little gene flow between populations. Investigation of the genetic diversity and structure is necessary in the other four prefectures, where A. stelleriana is classified as an endangered species, in the future.