Predictive modelling of climax oak trees in southern Spain: insights in a scenario of global change

Predictions of an increase in mean temperatures and a widespread reduction in annual rainfall over the next few decades are consistent. Such drastic changes can have a serious, irreversible impact on the current distribution of trees and their ecosystems. Oaks are the most frequent trees in the better preserved areas of the Mediterranean basin; therefore, it is essential to understand potential shifts in their distribution for proper management and protection. The area studied in this work spans approximately 8.7 million hectares. The results obtained at 200 m resolution were subjected to logistic regression over four periods: current period (1961–2000), early twenty-first century (2011–2040), middle twenty-first century (2041–2070) and late twenty-first century (2071–2100). These periods were examined by using the CNCM3 model in an A1b scenario at 200 m resolution for the study area. Four of the five target species exhibited a narrower potential distribution in the twenty-first century. Cork oak and gall oak underwent a drastic potential reduction; on the other hand, Pyrenean oak and Algerian oak might find shelter at higher elevations. By exception, holm oak exhibited the opposite trend and was favoured by projected global warming. This projection is rather adverse for biodiversity and oak-dependent ecosystems. This study allowed an accurate prediction of the potential distribution of five different oak species and is therefore a promising, potentially effective tool for developing high-resolution reforestation programmes.