Abstract
Clonal plants are very often among the first species to establish during primary succession. They may rapidly capture available space due to efficient vegetative propagation, but the question arises whether they may also rely on seed bank or seed rain during expansion and recovery after a possible disturbance. This question becomes increasingly important in extreme conditions of industrial deposit investigated in this study. We explored the two aforementioned seed sources in a clonal grass Calamagrostis epigejos within an ecotoxicologically stressed environment - abandoned tailings containment (former sedimentation basin) - from manganese-ore mining. Density of seeds found in seed rain was 617 seeds m-2, and in soil seed bank 220 seeds m-2, based on an autumn survey. Soil seed pool was almost depleted until the following spring as only 13 seeds m-2 were present. This pattern contrasted with the capacity of C. epigejos to build a persistent soil seed bank as shown by a burial experiment. Seed rain was thus identified to be the sole reliable seed source that may assist in recovery of this species after a possible disturbance