Global warming is taking place at an unprecedented rate, and the consequent shifts in species’ distributional ranges will have enormous ecological consequences in forest ecosystems. However, the outcome of such changes is highly uncertain, and most work done to date has focused on long-term predictions, e.g., centuries, and at broad spatial scales, e.g., continents. We lack information on what we should expect in the next few decades at a regional level. In this study we combined extensive field-based experimentation with a powerful statistical analysis of the data to achieve a more realistic understanding of species’ potential to track global warming in the Great Lakes region for the next few decades.
We carried out a translocation experiment where several temperate deciduous species (two species of Carya and Quercus, and Nyssa sylvatica) were planted within and beyond the northern limit of their distributional ranges together with locally abundant species (two species of Acer, Betula and Pine and one species of Quercus, Q. rubra). Experimental plots were setup under a gradient of environmental conditions and were divided between control and treatment (fungicide application) conditions to test for the effects of environmental variables together with plant-soil interactions on seedlings establishment. Survival data were then analyzed as a function of the environment and the treatments using a frailty or risk model (parametric survival with individual random effects) within a multilevel framework.
Results/Conclusions
Results for the Carya and Quercus species and N. sylvatica show higher establishment rates in plots outside their distributional range, and a benefit from the fungicide treatment, indicating that they could be released of some of their soil pathogens during the colonization process. On the other hand, the local species, Acer, Betula and Pine performer better in control plots, which led us to think that the fungicide treatment might have affected beneficial fungi. Overall, results show that the response to the region of planting, the environmental conditions and to the fungicide treatment varied among species, and indicates the need to evaluate in situ species-specific responses to global warming.
