Abstract
We investigated seasonal change of Ludwigia stipulacea communities and the relationship between growth of L. stipulacea and microtopography of sandbars at the Kashio River, Kanagawa Prefecture. We found out the pattern of seasonal change of L. stipulacea communities on sandbars that they grew rapidly in summer and declined in autumn. In addition, L. stipulacea grew well on gentle slopes of sandbars while the growth was poor on steep slopes. From these results, it was clarified that intensive growth of L. stipulacea on gentle slopes of sandbars affected by flooding was important to maintain their community. It was also suggested that the growth of L. stipulacea varied with microtopography of sandbars.
