Wetlands are crucial ecosystems providing diverse ecological services, represented by large carbon storage and biodiversity. Sarobetsu Mire located in northern Hokkaido is one of the largest bogs dominated by Sphagnum mosses in Japan and suffered large-scale peat mining from 1970 until 2003. In Sarobetsu mire, the ordinal successional sere after peat mining is: bare ground – Rhynchospora alba sedgeland – Moliniopsis japonica grassland – Sphagnum mat. However, the succession is often stagnant and Sphagnum mosses have not recovered for a few decades or longer. Therefore, the active restoration of bogs is an urgent task. The transplantation of keystone species has been often conducted as an active regeneration. In most wetlands dominated by Sphagnum, Sphagnum is considered as an ecological engineer. 
    The aims of this study are to clarify what vegetation is suitable for the transplantation of Sphagnum mosses to promote succession after peat mining. To detect suitable habitats, six 1.5 m × 1.5 m plots (large plots) with different vegetation types were established. One plot was established as control where Sphagnum mosses were dominant. In each plot, four 50 cm × 50 cm plots (medium) were set up. In each medium plot, four 16 cm × 12 cm plots (small) were established. Sphagnum mosses, which were sampled from the adjacent areas, were transplanted into each small plot. The transplantation of Sphagnum mosses was undertaken in early November 2023 and monitored at about one-month intervals from May to October during snow-free periods in 2024. On the transplanted Sphagnum mosses in each census, vertical shoot growth, NDVI (normalized difference vegetation index), capitulum density and cover were measured to evaluate the effectiveness of transplantation. As environmental factors, water table, light intensity and temperature on the ground surface were monitored.
    Transplanted Sphagnum mosses showed high capitulum density and vertical growth in plots dominated by M. japonica. However, the horizontal growth, i.e., cover increase, of Sphagnum in these plots was lower than plots with less M. japonica. The horizontal growth of Sphagnum in plots dominated by R. alba or dominated both R. alba and M. japonica was fast. NDVI was high in plots with dense R. alba. In summer, the temperature averaged over 20°C and peat moisture decreased. The capitulum density of Sphagnum mosses tended to be decreased in summer. Overall, the transplanted Sphagnum mosses exhibited variations in growth rate, but the survival rate was high.