Regional specificity without methodological fragmentation: a perspective on invasion-risk screening of Mediterranean freshwater fishes

Lorenzo Vilizzi

Regional ecological context is essential in invasion-risk screening but need not require development of a region-specific decision-support tool. The Mediterranean specificity of the Hellenic Risk Assessment (HeRA), developed for freshwater fishes in Greece, has been presented as a principal advantage over the globally employed Invasiveness Screening Kit (ISK) tools. In this Perspective, I show that the supporting literature does not demonstrate that ISK-type screening under- or overestimates risk in the Mediterranean region; Greek ISK applications instead provide evidence of statistically robust risk discrimination following risk assessment area-specific calibration. I also identify tension between claims of Mediterranean specificity and transferability beyond Greece, and correct inaccuracies in the reported history, structure and implementation of the ISK tools. Species-level comparisons reveal broad rank concordance but substantial categorical divergence and inconsistencies in HeRA grouping. Regional specificity, transferability and methodological standardisation should be treated as complementary objectives in the risk identification of non-native species.