Predicting climate change impacts on native and invasive tree species using radial growth and twenty-first century climate scenarios

The climatic conditions predicted for the twenty-first century may aggravate the extent and impacts of plant invasions, by favouring those invaders more adapted to altered conditions or by hampering the native flora. We aim to predict the fate of native and invasive tree species in the oak forests of Northwest Spain, where the exotic invaders Acacia dealbata and Eucalyptus globulus co-occur with the natives Quercus robur and Quercus pyrenaica and the naturalized Pinus pinaster. We selected adult, dominant trees of each species, collected increment cores, measured the ring width and estimated the basal area increment (BAI, cm2 year−1). Climate/growth models were built by using linear mixed-effect models, where the previous-year BAI and seasonal temperature and precipitation were the fixed factors and the individual the random factor. These models were run to project the fate of studied species in the A2 and B2 CO2 emission scenarios until 2100. The models explained over 50 % of BAI variance in all species but E. globulus, where growth probably occurs whenever a minimum environmental requirement is met. Warm autumns favoured BAI of both natives, probably due to an extension of leaf lifespan, but hampered A. dealbata and P. pinaster BAI, maybe because of water imbalance and/or the depletion of carbon reserves. The projections yielded a positive BAI trend for both Quercus along the twenty-first century, but negative for the invader A. dealbata and clearly declining for the naturalized P. pinaster. Our results disagree with previous literature pointing at climate change as a driver of invasive species’ success and call for further studies regarding the effect of climate change on co-occurring natives and invaders.