Seed germination and seedling development ecology in world-wide populations of a circumboreal Tertiary relict

摘要: Background and aims Temperate forests are disjunct in the Northern Hemisphere, having become fragmented from earlier widespread (Tertiary) boreotropical forest. We asked ‘What contemporary patterns of population variation ecological traits a Tertiary relict macroecological context?’. This issue underpins our understanding populations occurring same biome but on different continents. Methodology examined characters associated with root shoot emergences among Viburnum opulus temperate Asia, North America Europe. species has complex seedling emergence extending over several years requiring various temperature cues. Principal results Populations varied germination responses clustered into groups that were only partly related to varietal status. Whereas roots (at warm temperatures) shoots (following cold period) simultaneously emerged seeds all when simulated dispersal occurred winter, they delayed some summer. Conclusions populations, separated by 10 300 km, showed high similarity development phenology, we suggest stabilizing selection played key role maintaining similar dormancy mechanisms. Nevertheless, there was degree other characters, suggesting local adaptation.