The EEICAT framework.

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.