Millennium-scale changes in mire vegetation reconstructed from plot-based pollen and vegetation analysis and their implications for conservation

Abstract

Historical perspective helps ecologists and conservationists to better understand modern processes and potential future changes, but collecting long-term ecological data with fine spatiotemporal resolution is challenging. The aim of this study was to reconstruct mire vegetation about 1100 years ago by applying local components that represent the positions of local plants and the mire margin. From the plot-based comparison between modern pollen and vegetation, Sanguisorba, other Rosaceae, Ericaceae and Sphagnum were considered to be local components that signify the position of source plants within about 1 m. Ilex, Acer and Lysichiton were estimated to have attributes of both local and extra-local components and to indicate the mire margin with a few metres’ resolution. These results allowed reconstruction of the millennium-scale changes in the mire’s areal extent and local vegetation. The site was a wetter Sphagnum mire in 915 CE and has changed to a drier one, with Geum pentapetalum now more common. The maximum extent of the mire has retreated about 5 m, although the margin around the depressed northern end has slightly expanded. Nevertheless, the mire has maintained a peatland of similar size during the last millennium. Plot-based pollen and vegetation analysis is useful and can assist ecologists and conservationists to choose the proper conservation procedures.

Keywords

• japan
• modern pollen
• palynology
• peat
• tephrochronology