日本の湿原

摘要

Mires in the volcanic area of Aso-Kujyu region experience frequent volcanic activity such as volcanicash deposition, inundation by spring water with high concentration of sulfur or catastrophic disturbance by scoria.Vegetation of the mires are affected by chemical environment of soil, however, the relationship between vegetationand environmental parameters is not evident. Frequent change in soil chemical and physical environment caused bydisturbance by volcanic activity will show the time delay of vegetation change caused by the environmental change.Chronological change of macrofossil in peat in Tadewara mire revealed the frequent vegetation change of the mire.After the deposition of sulfur rich volcanic ash initiates the retrogressive vegetation change from Sphagnum vegeta-tion to Phragmites community via Moliniopsis vegetation. Volcanic ash deposition causes the increase of exchange-able cations in peat due to the decomposition of organic materials by aeration. Artificial fire on mires in Tadewaraand Bougatsuru would disturb the succession of mires to forest community. Removal of nutrients by burning senes-cent vegetation could be effective for maintaining mires in nutrient poor condition, however, fire management ofmires should be considered from the biogeochemical point of view.