放棄された谷戸田におけるハンゲションの保全に関する生態学的研究

Abstract

Understanding the ecological features of wetland plants is essential to establish a conservation plan for quickly decreasing wetlands in the suburbs. We analyzed the relationships between environmental factors and the sprouting, the growth, and the flowering of Saururus chinensis in abandoned paddy fields on valley bottoms with the aim of deriving guidelines for the wetland conservation using this species. We achieved three results: (1) Sprouting in the next spring is promoted by thinning high plants in fall. (2) The higher the water contents in soil, the more the number of sprouting is. (3) Lower vegetation coverage in shrub layers helps its growing, however the growth is restricted under the environment of the low sun radiation or the low soil water contents. (4) Flowering is promoted by higher sun radiation. Thinning shrubs and trees in and by abandoned rice paddy fields on valley bottoms will extend the habitat of Saururus chinensis, keep the soil water contents higher, and keep the sun radiation higher, therefore, will promote the sprouting, the growth, and the flowering of this species.