2021 Volume 38 Issue 2 Pages 191-208
Vegetation and soil characteristics of two physiognomic types of young Pinus thunbergii-dominated stands, that is, naturally recovered type on beach ridge and sand dune （RS;five sites） and afforested type on artificial mounds （AS;four sites）, were compared along Sendai Bay after the Great East Japan Earthquake and Tsunami in 2011. Of the 111 vascular plants found, 34 were found only in RS and 27 were found only in AS. The percentages of perennials, annuals, alien species, and coastal species were 50.5%, 29.7%, 25.2%, and 9.9% of the total species, respectively. Seven vegetation types were classified using modified TWINSPAN. In the first division, 54 surveyed stands were divided into two groups:one group mainly contained AS stands indicated by alien species, while the other group mainly contained RS stands indicated by coastal species. Stands of RS and AS were plotted along nMDS axis 1, which was correlated with vegetation cover and number of woody species. Stands of RS were widely dispersed along nMDS axis 2, which was correlated with the number of coastal plant species. Soil pH, water permeability, and electrical conductivity differed among the different stands （n = 20）, however, no significant difference was observed between RS and AS groups. Weak correlations were found between total number of species and the particle diameter value of D20 and number of coastal species and electric conductivity. AS with artificial mounds was poor in coastal and woody species except the planted pine saplings, probably owing to the absence of reproductive sources. Laying coastal sand increased the number of coastal plants in AS on artificial mounding. Therefore, artificial mounding and afforestation will have striking impacts on coastal vegetation. The impacts, however, may be mitigated by laying local sand containing propagules of coastal and woody species.
