Determinants on Sphagnum Block Transplantation Success After Peat Mining in Sarobetsu Mire, Northern Japan

Aims Succession in post‐mined bogs is often stagnant, limiting natural recovery. Sphagnum mosses play a pivotal role in peatland restoration, but their establishment is constrained by the respective successional stages. We evaluated whether Sphagnum moss transplantation accelerated succession in degraded bog habitats and identified habitats supporting successful moss growth. Location Sarobetsu mire, northern Japan. Methods We transplanted 3‐ l blocks of Sphagnum moss into four successional habitats in Sarobetsu mire, northern Japan: bareground (early stage), sedgeland, grassland, and Sphagnum vegetation (late stage). Moss growth was monitored over 3 years by productivity, shoot elongation, NDVI, capitulum density, and Sphagnum cover. Environmental factors including water table, peat moisture, pH, temperature, and light intensity were measured. Vegetation surveys were conducted to evaluate species richness and plant cover in each habitat. Results No Sphagnum emerged in non‐transplanted controls. Transplanted mosses reduced productivity in the first year but recovered in all habitats except bareground. A few transplanted‐origin species grew but rarely persisted. Species richness increased only in later‐successional habitats. Growth patterns varied across habitats, with high elongation and density in Sphagnum vegetation, vigorous elongation and cover increase in grassland, and steady productivity increase in sedgeland. Aboveground factors varied among habitats, while belowground conditions remained relatively stable. Conclusion Sphagnum transplantation effectively accelerated succession in vegetated habitats with moderate shading. Bareground sites were unsuitable due to desiccation and instability. Microclimatic buffering and biotic context were critical for transplant success. Vegetation‐mediated shading and microclimatic buffering were the key determinants of transplantation success, whereas bareground failed due to desiccation and unstable peat surfaces. However, the increase in species richness is not expected.