Bud banks of two perennial grasses: Composition, size, dynamics and contribution to population maintenance during the flooded restoration succession on the Songnen Meadow, China

To describe the composition, size, temporal dynamics of bud banks of both perennial rhizomatous herbaceous Leymus chinensis and Carex duriuscula and to explore the contributions of bud banks to aboveground population persistence during the flooded restoration succession. Soil blocks 25 x 25 x 30 cm(3) were sampled during two growing seasons from June to September. The total rhizome buds comprised the largest proportion of L. chinensis bud banks except for September of 2004 (juvenile tillers were the most). The top rhizome buds were the most of C. duriuscula bud banks. The percentages of total buds derived from tiller nodes and rhizomes of both species were nearly equal in the two-year study period. The productivity of L. chinensis and contribution of bud banks to population persistence were higher than those of C. duriuscula. Size of bud banks of L. chinensis was not significant between the end of two sampling seasons (1039.2 and 1232.0 buds/m(2)), and buds significantly decreased in C. duriuscula (1140.0 and 581.6 buds/m(2)). Over the two studied seasons, decreasing number of buds and low productivity as well as small contribution indicate that C. duriuscula which spread after flood event will be successively replaced by L. chinensis.