Multi-population approach in seed germination ecology: evidence from Ranunculus ficaria

In temperate deciduous forests recruitment from seed is believed to play a lesser role in population and community ecology. Our aim was to assess seed germination of Ranunculus ficaria subsp. bulbilifer as this species is traditionally considered to rely predominantly on clonal reproduction and to have limited seed-mediated recruitment. We adopted a multi-population approach to generalize our findings and to further evaluate the extent to which germination responses vary among populations. From 25 forest populations embedded in different landscape types (urban, rural, forest) we collected seeds originating from one flower from 10 individuals per population and followed their germination under laboratory conditions. We also cultivated individuals in our experimental garden under uniform conditions and performed germination trials accordingly. We retrieved seeds from 109 out of 250 individuals in the field and 297 out of 513 collected seeds germinated. We also collected seeds from 209 individuals in the experimental garden. Close to 60% of seeds from the field and 75% of garden collected seeds germinated. In general, over 80% of sampled individuals bore seeds that were able to germinate. We found differences in seed mass, number and germination efficiency between experimental conditions but no differences in germination response between populations, however seeds from all populations germinated directly indicating that the species seed germination is general. The species’ ability to colonize new sites could explain why population origin had no influence on germination characteristics. Seed germination may indeed be more important for the clonal forest floor plant species than vegetative propagation.