Modeling Current and Future Global Distribution of the Quarantine Pathogen Phytophthora ramorum Using MaxEnt

Phytophthora ramorum causes Sudden Oak Death, threatening global forests and nurseries. We modelled its current and future global distribution using an optimized MaxEnt model (mean AUC = 0.978). Temperature seasonality was the key driver (29.4%). Currently, suitable habitats (~42.48 million km2) concentrate in mid-latitude coastal regions (e.g., North America, Europe, East Asia). Future projections (SSP126-585) show no systematic contraction but rather significant spatial shifts: suitable areas expand poleward and upward in elevation while contracting in some current regions. High-suitability areas (5.52–6.40 million km2) change by −3% to +12%, with the centroid shifting northwestward, notably into the African Sahel under high emissions. Our findings indicate that, within the framework of the current modeling approach and the emission scenarios applied, climate warming is likely to lead to a net increase in the suitable habitat for this pathogen at the global scale, providing a critical scientific basis for the development of international phytosanitary strategies.