Format: ORAL

Ivan M. De-la-Cruz1, Anne Muola2, 3 and Johan A. Stenberg1

1 Swedish University of Agricultural Sciences, Alnarp, Sweden 2 Norwegian Institute of Bioeconomy Research, Tromsø, Norway 3 University of Turku, Turku, Finland

Climate change, including increased temperature and altered precipitation, is likely to advance spring phenology and cause poleward range expansions of many plant species but also herbivores. This is likely to profoundly alter both abiotic and biotic natural selection on and evolution of plant traits in local plant populations. We used latitudinal gradient across the continental Europe as a space-for-time approach to mimic future climates, i.e. current southern ecosystems represent the abiotic and biotic conditions of more northerly habitats in the future. Genotypes of the woodland strawberry (Fragaria vesca; Rosaceae) originating from this gradient were replicated to five separate experimental sites placed across a north-south latitudinal gradient within Europe. Additionally, at each site, half of the plants were exposed to a drought treatment. By using this framework, we studied biotic and abiotic natural selection on plant traits. Herbivore pressure was higher at mid-latitudes compared to the extremes of the latitudinal distribution of F. vesca in Europe. In the Arctic, F. vesca genotypes from southern and central Europe had delayed flowering onset compared to when they grew at more southern sites. However, northern F. vesca genotypes showed remarkable flexibility in their ability to time flowering onset according to local conditions. Plants subjected to drought experienced more herbivory, accelerated flowering in most of the sites, and grew larger and produced more fruits and runners at some sites. However, at the driest site, there was a decrease in fruit production and chewing damage. Indication of a trade-off was found between reproduction, growth, and defense at several of the sites, being evident almost only under drought. Our results provide timely insights on how plant adaptations to climate change should be studied in combination with plant adaptations to biotic interactions, which also are affected by changing environments.