Abstract
The ecological impacts of biological invasions vary widely in type, scale, and severity, highlighting the need for consistent assessment tools. The Environmental Impact Classification for Alien Taxa (EICAT) provides a standardized framework for assessing their effects, but focuses mainly on population-level impacts. We introduce the Extended EICAT (EEICAT), which incorporates impacts across three ecological dimensions, from individuals to ecosystems, with an impact-based approach. EEICAT enables classification of 19 impact types at the invasion-event level, making it suitable for primary research, synthesis, and management. This framework aims to improve the detection, comparison, and communication of complex ecological impacts caused by biological invasions.