Abstract
This study focused on 3 groups of rare plants that are recognized as being difficult to transplant, in order to develop conservation techniques for these plants. We categorized the groups (i.e., epiphytic, mixotrophic, and mycoheterotrophic plants) as difficult-to-transplant species, based on previous studies. We analyzed practical examples of transplantation in 179 road projects around the nation to examine the current status, issues, and best practices of transplantation, to provide insights into effective transplantation techniques. According to our results, all 26 species belonging to 8 families of the difficult-to-transplant plant groups were transplanted in road projects around the nation: 4 epiphytic species on a tree trunk, 6 epiphytic species in a rocky area, and 9 mixotrophic species and 7 mycoheterotrophic species. Epiphytic species in a rocky area showed the favorable survival rate after transplantation. The survival rates of both epiphytic species on a tree trunk and mixotrophic species differed greatly between species. Although the survival rate of mycoheterotrophic species could not be estimated, the scape was found in about 10 - 20 percent of transplantation cases. We also observed some effective transplantation techniques, such as the transplantation of epiphytic plants on tree trunks using wires and Sphagnum spp. in order to prevent detachment and drying, respectively, and the transplantation of mixotrophic and mycoheterotrophic plants with surrounding soil using a void tube or plastic basket in order to maintain symbiosis with mycorrhizal fungi. In addition, we did not find a example of transplantation using disseminules (e.g., seeds), although by this method, transplantation can be carried out without causing damage to the plant body. In future, it is important to gain knowledge of effective transplantation techniques and adopt the practice of transplantation using disseminules.
