Long-term changes in mire vegetation since 915 CE reconstructed from plot-based pollen and vegetation analysis

Abstract

The aim of this study was to reconstruct millennium-scale changes in mire vegetation.　Local components determined by plot-based pollen and vegetation analysis represent the positions of local plants and the mire margin.　The components allowed reconstruction of the changes in the local vegetation and the areal extent of a montane oligotrophic mire, Mae-yachi Mire, in 915 CE.　The mire was drier and species such as Vaccinium oxycoccus, Andromeda polifolia, Sanguisorba tenuifolia and Sieversia pentapetala were more common.　It has changed to a wetter one with abundant Sphagnum species.　The extent of the mire has advanced more than 5 m, although the margin around the eastern end has been stable.　The comparison between four mires in the same area showed that they had different vegetation histories during the last millennium.　These empirical knowledges of the actual mire history provide the basic information for proper conservation procedures.