Expected impacts on Mediterranean forest species under climate change

Abstract

Climate change affects tree species, altering their growth and distribution, with effects varying by region, although mostly negative in the Mediterranean. This study examines 27 tree species in central Iberia, in a continental Mediterranean climate, using GISs and climate models. It investigates changes in net primary productivity (NPP) under different climate scenarios, identifying species that are endangered or vulnerable. Currently, only 2.4% of forest stands are endangered, but 51.2% are vulnerable; by 2100, these figures could rise to 35.4% and 85.2%, respectively. A correlation between altitude and threat level was found, with mountain species facing lower risks. Species with higher threat levels are linked to high NPP or low NPP variability. Four species currently have no threatened stands, though they may in the future, except one introduced in high-elevation areas, which will be favoured by climate change. Climate change will induce migrations to higher altitudes, but these movements depend on the rate of change, population size, fragmentation, and human alteration of the environment. Migration will be more challenging for low-altitude species in heavily human-impacted areas.