Identifying hotspots of non-indigenous species' high impact in the Maltese islands (Central Mediterranean Sea).

Several invasive non-indigenous species (NIS) cause ecological and socio-economic impacts. A good understanding of the impacts of invasive NIS in Mediterranean habitats is important for managing and prioritising measures in the marine environment. We applied a conservative additive model to sum up the Cumulative IMPacts of invasive Alien (CIMPAL) species of 19 invasive marine NIS on 13 habitats in Maltese waters. This analysis identified three hotspot areas of NIS' high impact and five top-priority together with four high-priority invasive NIS for management. By using CIMPAL, it was also possible to differentiate between areas within the same Marine Protected Area. CIMPAL is thus recommended as a good tool for managers and policy makers for prioritising measures as well as funds. Finally, recommendations are made with respect to future steps that are needed for the CIMPAL applicability, aiming to a more appropriate decision-making on prioritisation of hotspot areas and invasive marine NIS.