Germination and emergence ofRumexin river flood-plains. I. Timing of germination and seedbank characteristics

Abstract

SUMMARY Field experiments were designed to determine the timing of germination and the character of the seedbank in relation to the field occurrence of three Rumex species, which are distributed in a gradient of intensity and predictability of floods in river flood-plains. Rumex acetosa is characterized by early autumn germination, a transient type of seedbank, flood-intolerant achenes and a lack of multiple post-flood germination cohorts. These traits fit well into the habitat of R. acetosa in river flood-plains: rarely flooded grasslands with a high level of competitive interactions. Both wetland species, R. crispus and R. palustris, are characterized by late spring germination, a persistent seedbank, flood-tolerant achenes and multiple post-flood germination cohorts. These traits fit into the habitats of both species which are characterized by harsh predictable winter floods and erratic catastrophic summer floods. Timing of germination and seedbank characteristics are important life-history traits, at least partly explaining the distribution of Rumex species in flood-dominated river flood-plains.