Assessment of the future stability of cork oak (Quercus suber L.) afforestation under climate change scenarios in Southwest Spain

摘要

Intensive afforestation programmes were developed in Spain during the end of the 20th century and the beginning of the 21st, under the European Economic Community's (EEC) agricultural reforestation directives. However, these afforestations were performed without considering future climate change scenarios and now these areas have to cope with more-severe climatic conditions. We used ensemble Species Distribution Models (SDMs) to study the future stability of cork oak (Quercus sober L.) plantations established in Andalusia between 1993 and 2000. We used presence/absence data from the national forest inventory and RED SEDA Network, together with survival rate data from 2008 for cork oak afforestations planted between 1993 and 2000, to forecast the potential optimal distribution of cork oak and to model the distribution of the survival rate of cork oak afforestations. We evaluated the change over time of the volume overlap of the environmental space between the potential distribution and the afforestations. The ensemble modelling approach gave highly-accurate results for the current potential distribution of cork oak in Andalusia (AUC = 0.943, TSS = 0.718, Kappa = 0.718) and moderately-accurate estimations of the distribution of the survival rate of cork oak afforestations in Andalusia (RMSE = 0.290). We found that 10% of the cork oak afforestations planted between 1993 and 2000 were established in the optimal area of occurrence of cork oak (probability of presence above 70%) and presented an acceptable survival rate (& 50%); also, the volume of the environmental space defined by cork oak afforestation decreased over time. We have confirmed the potential of SDMs to predict the distribution of the survival rate of cork oak afforestations and to assess their future stability. In the worst scenario, 3% of the cork oak afforestations would withstand climate change.