The occurrence of Phytophthora cinnamomi in southern Spain: Presence – absence records and potential distribution area

Abstract: Phytophthora cinnamomi is an alien species, which causes root rot and decline in cork oak (Quercus suber) and holm oak (Quercus ilex) native forests and agroecosystems in the Iberian Peninsula. However, there is little reliable and accessible data on the presence and absence of this soil borne pathogen in Spain. For this reason, we applied the Environmental Niche Models to predict the potential distribution of P. cinnamomi in Andalusia (southern Spain). Firstly, we developed a georeferenced database about presence-absence records of P. cinnamomi in the study area based on published data and from our research projects. Secondly, we developed a set of environmental variables at a resolution of 250 meters. Thirdly, the inferential approach was based on the regression methods using presence-absence data, and the machine learning algorithms using presence-background data, and evaluated the models using ROC/AUC. Finally, we ensembled the best models to mapping the results in one consensus model. The result showed a large potential distribution area of P. cinnamomi in Andalusia, from one-third to one-half of the region and connected areas.