Characterization of the Distribution and the Habitat of Euphorbia Adenochlora as Landscape Resources in Ukiya no Sato, Kazo City, Saitama Prefecture

Abstract

The distribution of the wildfl ower Euphorbia adenochlora, a symbol of marshland, was investigated in the “Ukiya no Sato” rural landscape conservation area. The community scale of a total of 2,930 m was confi rmed at 8 points in the marsh with a rich spring fl ower landscape of the E. adenochlora community. The large population of E. adenochlora present was distributed over the area where the marsh has long not been reclaimed as a rice paddy; thus, it was considered that the marsh had functioned as an ecological refugium for this hydrophytic species. The tendency of high-density growth of E. adenochlora in relatively dry areas within the marsh was indicated as a result of the investigation by the grid lot in the habitat on the largest scale. Features of its location were a domination of Miscanthus saccharifl orus at the upper part, as well as high Saururus chinensis and Stachys aspera abundance. Although there was a similar external community on the site dominated by M. saccharifl orus in autumn, the fl oristic composition between abandoned paddy fi elds and habitats that continued to be marshland was different. Since Carex dispalata was dominant at lower-lying areas and the occurrence of E. adenochlora was rare in abandoned paddy fi elds, it was judged that the former was unsuitable habitat for this native wildfl ower. Conclusively, the distribution of E. adenochlora was a result of factors including a characteristic ecosystem with spring water sourced in a buried valley, the given history of rural development where non-reclaimed land has been left as refugium for a natural ecosystem to develop, as well as recent landscape conservation activities including burning by a landowner.