Current and future distribution of the invasive oak processionary moth

Predicting shifts in the distribution and abundance of pest organisms relies on an accurate forecasting of their response to climate change. The oak processionary moth (OPM) Thaumetopoea processionea causes serious damages to oak trees in forest, urban and other landscapes as well as severe allergic reactions to humans and animals. In the 1990's and 2000's, the OPM extended its range from mainland Europe and the Middle East into northern Europe. In 2005, it was also accidentally introduced in the United Kingdom. Moreover, the intensity and the frequency of OPM outbreaks are thought to have recently increased in several countries of Europe including Belgium, the Netherlands, Germany and Austria. In the present study, we aimed at forecasting the potential distribution of the OPM in Europe under current and future climate conditions. We thoroughly compiled available records of established populations all across Europe and fitted MaxEnt and BIOCLIM models to infer bioclimatic requirements for this species. Both models showed good predictive performance under current climate conditions. In particular, the surroundings of London where the OPM recently got established were predicted as highly climatically suitable. Models also predicted that many parts of northern Europe where the OPM currently does not occur (e.g. central UK, Wales, Ireland, southern Scotland, Denmark, southern part of the Scandinavian Peninsula, etc.) might become climatically suitable by 2050. Our predictions warrant the need for proper communication and management planning around the risks associated with the potential expansion of the OPM in Europe.