Life history and demographic features of Aster kantoensis, an endangered local endemic of floodplains Original Research Article

Aster kantoensis, an endangered plant species, is a local endemic on floodplains of a few rivers in eastern central Japan. Three yearsʹ demographic study (1989–1991) on several subpopulations (discrete patches of the plants) revealed that it is a monocarpic perennial with a 2- to 4-year vegetative growth phase before flowering. Its distribution on the floodplain is restricted to sparsely vegetated gravelly areas. A relatively high light requirement and low competitive ability to gain light are likely to be responsible for the distribution pattern. Demographic parameters obtained for the studied period indicate a decline of the subpopulations of A. kantoensis. In a transect covering 76 m2, mean viable seed production per flowering plant was 450 (1990) and 780 (1991), but less than 0.027% of dispersed seeds survived to the reproductive stage. The spatial and temporal patterns of disturbance are of critical importance for the maintenance of the metapopulation of this short-lived species without a persistent seed bank or vegetative reproduction.