The Kagamiganaru Marsh is located in the Daisen-Hiruzen area of the Daisen-Oki National Park in south-western Honshu Island, Japan. For many years, the groundwater level may have been dropping due to the drainage route and there has been the invasion of woody plants into the marsh due to a management policy that has excluded human disturbance. Consequently, it is feared that the marshy ecosystem has deteriorated. Projects for marsh restoration have been undertaken since 2000, but the marsh has not yet been successfully restored. In this study, therefore, the authors aimed to redesigned restoration planning of the marsh based on identifying essential factors of the ecosystem’s degradation. The authors surveyed relative accumulated solar radiation, groundwater level below ground surface level, water quality, potential waterway mapping based on hydrological analysis using LIDAR data and vegetation mapping. The water quality was poor enough to be suitable for low-stem wet grasses. In 84 % of the surveyed area, the groundwater level is too low to maintain marsh vegetation. In only 18% of the surveyed area, solar radiation was more than 50% (measured at points 30 cm above ground), i.e . suitable for maintaining wet grassland. The vegetation was classified into 12 communities, and wet grassland communities existed only in small areas. Based on the survey, the project site was divided into three areas by marsh restoration potential, mainly by the present groundwater level and the solar radiation availability. The site was then divided into eight sub-areas by present vegetation type, vegetation management history, existence of Ilex crenata var. paludosa communities and the location of potential waterways, and measures for restoration were suggested for each area.

To establish the mitigation methods for the endangered perennial Solanum maximowiczii Koidz, the seed sowing test, the transplanting test, the transplanting test of their sticking shoots and the test for preventing the feeding damages were examined. Our results indicate that the individuals that were grown until their diameter at the ground level reached more that 1.0 cm are suitable for transplanting to the natural sites. Further, those individuals can be flowered and fruited. However, those developed individuals should be transplanted the site where are surrounded with the equipments that can prevent the feeding damages. Thus, the transplanting those developed individuals to the sites within the equipments that can prevent the feeding damages is thought to be the effective way to mitigate the speceis.