Potential Distribution of Invasive Boxwood Blight Pathogen (Calonectriapseudonaviculata) as Predicted by Process-Based and Correlative Models

Abstract

Boxwood blight caused by <i>Cps</i> is an emerging disease that has had devastating impacts on <i>Buxus</i> spp. in the horticultural sector, landscapes, and native ecosystems. In this study, we produced a process-based climatic suitability model in the CLIMEX program and combined outputs of four different correlative modeling algorithms to generate an ensemble correlative model. All models were fit and validated using a presence record dataset comprised of <i>Cps</i> detections across its entire known invaded range. Evaluations of model performance provided validation of good model fit for all models. A consensus map of CLIMEX and ensemble correlative model predictions indicated that not-yet-invaded areas in eastern and southern Europe and in the southeastern, midwestern, and Pacific coast regions of North America are climatically suitable for <i>Cps</i> establishment. Most regions of the world where <i>Buxus</i> and its congeners are native are also at risk of establishment. These findings provide the first insights into <i>Cps</i> global invasion threat, suggesting that this invasive pathogen has the potential to significantly expand its range.