Climate-Driven Invasion Risks of Japanese Beetle (Popillia japonica Newman) in Europe Predicted Through Species Distribution Modelling

Invasive species pose a growing threat to global biodiversity, agricultural productivity, and ecosystem health, as climate change worsens their spread. This study focused on modelling the current and projected distribution of the Japanese beetle (Popillia japonica Newman), an invasive pest with potentially devastating impacts on crops and natural vegetation across Europe. Using the MaxEnt species distribution model, we integrated beetle occurrence data with bioclimatic variables, analyzing current and future climate scenarios based on Shared Socio-economic Pathways (SSP1-2.6, SSP2-4.5, SSP5-8.5) for near-term (2021–2040) and mid-term (2041–2060) periods. By reclassifying the model results, we identified European regions with negligible, low, medium, and high exposure to this invasive pest under climate change pathways. The results identified regions in central Europe covering an area of 83,807 km2 that are currently at medium to high risk of Japanese beetle infestation. Future projections suggest northward expansion with suitable areas potentially increasing to 120,436 km2 in the worst-case scenario, particularly in northern Italy, southern Germany, the Western Balkans, and parts of France. These spatially explicit findings can inform targeted monitoring, early detection, and management strategies to mitigate the economic and ecological threats posed by the Japanese beetle. Integrating species distribution modelling with climate change scenarios is imperative for science-based policies to tackle the growing challenge of biological invasions. This research provides a framework for assessing invasion risks at the European scale and guiding adaptive responses in agricultural and natural systems.