Mechanism of formation and continuity of fen meadow communities at a lowland peat-forming mire in Pacific coast, northern Japan

点击翻译按钮获取中文摘要

This study aims to clarify the mechanism of formation and continuity of the fen meadow communities, which have to conserve because they were rapidly decreased. Fen meadow communities rapidly decreased between 1975 and 2009, since Alnus forest replaced them. The rapid change of communities suggests that fen meadow communities are temporally formed by the degradation of fens owing to the decline of water level begun before 1960. Hydrochemical conditions which sustain fen meadow communities were intermediate in water level between Alnus forest and fens, and low concentrations of major minerals and nitrogen, indicating fen meadow communities are low productive. Water of rivers in this area contained much minerals and nutrients. On the other hand, after flooding of Utonai lake in August 2010, the concentrations of minerals and nutrients fen meadow areas did not rise. Accordingly, water supply by increasing water level of Utonai pond would be most effective, because this method can maintain oligotrophic condition.