Abstract
Land-use change around Sarobetsu Mire for agricultural purposes was started as an antidote project against food shortage after World War II. During 1961-1969, a short-cut channel was built to prevent the floods by lowering the water level. This led to the invasion by an exotic species of dwarf bamboo, Sasa kurilensis that prefer dry conditions in place of the native Sphagnum spp. The reduction in water levels were further affecting the water chemistry, creating ombrotrophic-minerotrophic gradient from east toward the western area. This study assessed the long-term changes in the composition of vegetation which accompanied by the changes in water chemistry regimes. Using canonical correspondence analysis (CCA), it was found that beside hydrological parameters, the succession of vegetation in this degraded bog was closely related to the nutrient contents and surface waters' mineral contents. The results also highlight the influence of hydrologic parameters on water chemistry regime; they control the chemical as well as biotic processes in mire ecosystems.
