Difference of invasion behavior between two climax species, Castanopsis cuspidata var. sieboldii and Mechilus thunbergii, on lava flows on Miyakejima, Japan

The invasion behavior of two climax species, Machilus thunbergii Sieb. et Zucc. and Castanopsis cuspidata (Thunb.) Schottky var. sieboldii (Makino) Nakai, was studied on the 1874 and 1962 lava flows on Miyakejima, Japan. On the 1962 lava, zoochorous M. thunbergii appeared almost only under crowns of pioneering Alnus sieboldiana Matsum, while bolochorous C. cuspidata var. sieboldii occurred only along the borders of the lava. The three species, A. sieboldiana, M. thunbergii and C. cuspidata var. sieboldii, corresponded, in order, to the temporal sequence of invasion in the boundary forest and the spatial sequence from margin to center on the 1962 lava. Seed or fruit dispersion is important in primary succession in the case of large disturbances.