Assessing Natura 2000 coverage of river fish species in Greece: What do field surveys show?

Europe’s Natura 2000 network (N2K), based on the EU Birds and Habitat Directives, has rapidly expanded protected areas targeting species and habitat types. In Greece, 52.4% of native freshwater fish are considered as species of EU community interest within the Habitats Directive (HD). However, 31.3% of all threatened fish species at a global level and 32.0% at a national level, are not included in the Habitat Directives Annex lists. Fishes in Greece’s rivers are understudied, precise knowledge of their distributions is poor for most species. We utilize a large set of site-based electrofishing samples to explore the coverage of these species by the country’s Natura 2000 sites. Field surveys recorded 102 species inhabiting rivers within 645 sampling sites. Although the majority of the HD listed, threatened and endemic freshwater fish species exist within the current N2K network, important gaps are evident and four HD species were not found within any Natura 2000 sites. In analyzing fish densities from field sampling, only two upland-stream species, Salmo farioides and Barbus strumicae, show significantly higher abundance inside N2K sites. Applying a Combined Index utilizing IUCN vulnerability status, species rarity and richness, we identified 161 hotspot sites for riverine fishes; 50.9 % of all hotspots are located outside of N2K network, especially in lowland areas. Unprotected areas with a high concentration of hotspots are mapped; the river basins with the highest number of such unprotected hotspots belong to the Strymonas, Pinios, Evrotas and Aoos rivers. With concern for the EU’s revised biodiversity conservation strategy, our screening level assessment provides insights for unmet conservation needs and the method is readily transferable to other states and protected area jurisdictions.