2006 Volume 69 Issue 5 Pages 577-580
A irrigation pond contributes to conservation of biodiversity in rural landscape to offer important standing water area greatly. Various aquatic plants utilize a irrigation pond as habitat, although recently decrease of a floating plant and a submerged plant is reported in each place. In Nakatado region of Kagawa Prefecture, we examined a role of irrigation pond for conservation of endangered submerged plants, which are sensitive for environmental change. The appearance frequency of a endangered submerged plant was high in a small irrigation pond less than 2.000m3 storage capacity from result of flora of 536 pond. Therefore we monitored population of Blxa aubertii and Ottelia japonica, which are belong Hydrocharitaceae of endangered submerged plants, and observation change of fluctuation pattern in water level and management situation of some irrigation ponds. As a result, it was considered that fluctuation in water level, supplied water use for irrigation, contributed to population preservation of submerged plants. It becomes clear that a role of the small irrigation pond is important for preserve of endangered submerged plant through maintained water use.
