Species distribution models and a 60‐year‐old transplant experiment reveal inhibited forest plant range shifts under climate change

Aim Climate change causes species to shift their distributions. Individual species, however, greatly vary in their capacity to track the macroclimatic temperature increase due to differences in demography and dispersal. To better predict range shifts to climate change we need a complementary integration of long-term empirical data and predictive modelling. Location Belgium and North-West Europe. Taxon Hyacinthoides non-scripta, forest understorey plants. Methods Complementing species distribution models with demographic data from an exceptional 60-year-old over-the-range-edge transplant experiment measured not less than 45 and 60 years after installation, we evaluated the long-term consequences of climate change on one of the most emblematic but also among the slowest colonizing plant species of European forests, bluebell Hyacinthoides non-scripta. Results We found bluebell able to establish viable populations beyond its natural range. These results were confirmed by the SDM, showing that bluebell's potential range is considerably larger than its current range. Colonization rates of only 2 m century(-1) were observed in the transplanted populations. Beyond bluebell's current range, we observed decreasing trends in population growth rates over the past 15 years. By the end of the 21st century, substantial decreases in the southern parts of bluebell's range were predicted. Main conclusions Based on empirical and modelling results, we expect serious population declines in large parts of its current natural distribution of bluebell. Although the species is able to establish viable populations beyond the natural range edge, slow demography and local colonization rates four orders of magnitude lower than the velocity of climate change make fast enough range shifts virtually impossible in this species.