Risk of invasiveness of non-native aquatic species in the eastern Mediterranean region under current and projected climate conditions

Abstract

Human-induced biological introductions pose a major threat to global biodiversity, and this is especially frequent in the eastern Mediterranean region, which is a globally important biodiversity hotspot area of high conservation value. To predict at which level introduced species in this region might become invasive under current and projected climate conditions, 232 non-native aquatic organisms were screened using the Aquatic Species Invasiveness Screening Kit. Based on receiver operative characteristic curve analysis, thresholds were identified to distinguish between low, medium and high risk species. The “top invasive” (very high risk) species identified were: brown bullhead Ameiurus nebulosus, blue crab Callinectes sapidus, gibel carp Carassius gibelio, Philippine catfish Clarias batrachus, Chinese mitten crab Eriocheir sinensis, bluespotted cornetfish Fistularia commersonii, silver carp Hypophthalmichthys molitrix, silver-cheeked toadfish Lagocephalus sceleratus, half-smooth golden pufferfish Lagocephalus spadiceus, Suez pufferfish Lagocephalus suezensis, signal crayfish Pacifastacus leniusculus, fathead minnow Pimephales promelas, channeled applesnail Pomacea canaliculata, red swamp crayfish Procambarus clarkii, devil firefish Pterois miles and European catfish Silurus glanis. The risk of being invasive of more than half of the screened species increased after taking global warming predictions into account, and several species considered to be globally invasive (cf. high risk) were classified as posing only a medium risk for the eastern Mediterranean region. Region-specific risk screenings, as implemented in this study, are therefore essential for setting priorities in preventative management for the conservation of key biodiversity hotspots and the optimal allocation of resources in view of full risk assessment for the species identified as (very) high risk.