Estimation of potential seed dispersal regions based on floating and ballochory of <i>Euphorbia adenochlora</i> capsules

Abstract The ability to disperse individuals and seeds among subpopulations is required for the sustainability of plant metapopulations. Understanding the mechanism of seed dispersal is essential for the conservation and restoration of plant diversity. In this study, Euphorbia adenochlora growing on floodplains was used as a research target to obtain new knowledge about hydrochory and ballochory and estimate potential dispersal range related to hydrological regimes. A wetland spreading around the Omi Maiko Inner Lake in Minami‐Komatsu, Otsu City, Shiga Prefecture, Japan, was the study site. Euphorbia adenochlora bear capsules, which have a three‐chambered hollow structure and which float on water up to 14 days, they can be dispersed by hydrochory. The capsule of E. adenochlora splits open when it dries, and ejects the seeds at a maximum distance of 4.1 m, indicating that the drifting capsule is capable for secondary dispersal by ballochory. At the study site, 2% of E. adenochlora subpopulations were within the range where fallen capsules could be dispersed by hydrochory, and 33% of E. adenochlora subpopulations could have been formed by ballochory from the drift line. Practical implications. These subpopulations are crucial for the conservation of E. adenochlora population at the study site. Furthermore, the fluctuating and maximum water levels from late May to mid‐June for E. adenochlora were considered important to the formation of new subpopulations.