Limited validation of forecasted northward range shift in ten European tree species from a common garden experiment

Abstract As climate change leads to global warming and modified precipitation patterns, the distribution of forest biomes and tree species is expected to shift towards higher latitudes and altitudes. Such shifts are currently projected by species distribution models fitted to different climate change scenarios. Field validation of these models for several life stages of different tree species is a necessity to adapt forest management and understand the future of forest ecosystems. The study presented here aims to assess whether signs of the projected near-future range shift, contraction or expansion of ten European forest tree species are already observable in survival and growth of their seedlings at the core, leading and trailing edges of their distribution. The results show limited validation of the projected near-future changes in spatial distribution: seedling survival and growth paralleled modelled near-future habitat suitability for the three Mediterranean/Southern species, whereas cold-adapted species showed limited validation of model projections with lower growth and survival at their trailing edge; and widespread species showed inconsistent performance with model projections. Individuals of contrasting provenances did not show strong differences in survival; however they did show substantial differences in growth. The role of extreme events and biotic interactions might prove to be more important factors into shaping the future realized niche and the distribution of these species and thus should be investigated to complete the current studies on latitudinal and altitudinal shifts in relation to climate change.