Relationships between Change of Threatened Plant Species Penthorum Chinense Population and Management of Fallow Paddy Fields in the Nishida River Basin, Ibaraki Prefecture

Abstract

Relationships between change of threatened plant species Penthorum chinense population and management of fallow paddy fields in the Nishida river basin, Ibaraki prefecture were investigated. Soil water contents were significantly greater at the habitat of P. chinense. Plowing or mowing was practiced as management in fallow paddy fields where P. chinense was found. But when management was discontinued, P. chinense disappeared in a few years. Keeping soil in fallow paddy field wet and vegetation management were important to preserve P. chinense population.