To determine the factors that promote the expansion of dwarf bamboo (Sasa palmate), an indicator of mesic vegetation, into bogs, a landscape-based approach was used to assess the geographical factors that are associated with, and contribute to, the propagation of Sasa in the Sarobetsu Mire, northern Japan. Using the "Sasa frontline" data obtained from aerial photographs taken during 2 different periods, the area expanded by Sasa in the past 23 years was determined. Next, distribution maps associated with geographical parameters, such as topography, hydrology, vegetation and soil, were created using remote sensing data (airborne LiDAR, ALOS/AVNIR-2, and ALOS/PALSAR). Using these geographical parameters as explanatory variables, the causes for Sasa expansion were analyzed by multiple linear regression analysis. It was shown that distance to natural ditches, gradient of ground surface, elevation, and carbon content are the largest contributors and that the hydrological factor is the one most associated with Sasa expansion. By using the landscape approach, 60% of the Sasa expansion factors could be explained. The analysis of the vegetation near the Sasa frontlines showed that the dynamics of sedge vegetation may serve as an indicator of potential Sasa expansion.
