Regional impact risk classification (RIRC): a predictive framework for plant invasion impacts

Regional prediction of impact risk is essential for prioritizing targeted management of invasive alien plants. We present the Regional Impact Risk Classification (RIRC) framework, which combines the Environmental Impact Classification for Alien Taxa (EICAT) with species distribution models (SDMs) to connect ecological impact severity with the spatial likelihood of establishment and spread under current and future climates. Applying RIRC to 20 alien plants in Iran, we produced species-specific and aggregated regional maps, along with detailed climatic suitability projections. The analysis revealed significant regional contrasts: very high to extreme risks for salt- and drought-tolerant taxa along the southern coasts, a dominance of tree invaders in the southwestern lowlands and the Zagros, and hotspots of trees, woody climbers, and aquatic species in the northern provinces. Aggregated maps identified the Caspian coast and southern regions as hotspots for invasion risk. Under RCP 4.5 and 8.5 climate scenarios, RIRC levels increase along the northern and southern coasts but decline in central deserts, with species-specific responses ranging from strong expansions (e.g., Cynanchum acutum ) to projected contractions (e.g., Paulownia fortunei ). By linking impact severity with spatial dynamics, RIRC provides a scalable decision-support framework for guiding invasion management and conservation planning under current and future climates.