Trends in evergreen oak suitability from assembled species distribution models: assessing climate change in south-western Europe

This is the accepted manuscript of the paper "Trends in evergreen oak suitability from assembled species distribution models: assessing climate change in south-western Europe", published as final paper in "New Forests 49, 471–487 (2018). https://doi.org/10.1007/s11056-018-9629-5”. (The final publication is available at https://link.springer.com/article/10.1007%2Fs11056-018-9629-5)

Abstract
Questions: Will evergreen oaks be harmed or favoured by the expected global change? How could they interact? What is the trend along the twenty-first century regarding dominance or codominance among evergreen oaks?
Location: Western Europe.
Methods: We analysed four evergreen oaks (Quercus ilex subsp. ilex, Q. ilex subsp. ballota, Q. suber and Q. coccifera) by means of Species Distribution Models (SDMs). Three algorithms were used: Maximum Entropy (MaxEnt), Logistic Regression (LR) and Environmental Distance (EnvDis). Taxa occurrences were taken especially from the National Forests Inventories (NFI), whereas environmental data was retrieved from WorldClim 1.4 project. Present period and four future scenarios (RCP 4.5 2050, RCP 4.5 2070, RCP 8.5 2050 and RCP 8.5 2070) were studied. The latters were carried out by the average of thirteen Global Circulation Models (GCMs). Consensus maps were built taking into account AUC values, which also were necessary for validating the models. Finally, a map pointing out the dominance and codominance among evergreen oaks was developed.
Results: Evergreen oaks would be benefited from the forecasted environmental conditions according to our results. Due to their spread in Western Europe, evergreen oaks would find new suitable areas for growing, leading to an increment of mixed forests or, in other words, a raise in the codominance among them.
Conclusions: This work deals with the uncertain future on evergreen oaks facing climate change. The use of different algorithms and GCMs, as well as the high validation values obtained, confer robustness to this study. Oaks play a significant role in vegetation and forestry. Moreover, they are an important resource of income, especially Q. ilex subsp. ballota and Q. suber. Our findings might be highly useful for understanding the dynamics of evergreen oaks; the first step for carrying out management programmes, aiming to conserve this natural heritage.