Aquatic insects in the Dinarides: identifying hotspots of endemism and species richness shaped by geological and hydrological history using Empididae (Diptera)

We identify local hotspots of elevated species richness and endemicity of aquatic insects in the Dinarides (Balkans) using aquatic Empididae (Diptera) as models and compared observed patterns with historical geological and hydrological changes in the region. We analysed species richness and reciprocal weighted endemicity. Parsimony analysis of endemism was used to generate an historical hypothesis of the relationships between the aquatic Empididae biotas of different regions of local endemism within the Dinarides and the results reconciled with the geological and hydrological history of the region. Hotspots of high endemicity were coincident with areas of elevated species richness and were located primarily in the northwest Dinarides, central Bosnia & Herzegovina, and southeast Montenegro. Parsimony analysis of endemism retrieved three weakly supported area clades comprising areas of southeast Dinarides together with disjunct areas at the western Dinarides, and central Bosnia & Herzegovina together with the disjunct northwest Dinarides. The aquatic Empididae fauna of the northwest Dinarides has been strongly influenced by dispersal from the European Alps, whereas that at the southern end of the range may have been shaped by immigration from ranges further south. In the central Dinarides, progressive fragmentation of the hydrological network through orogenesis, karstification, redistribution of flysch deposits, and saline ingressions may underlie current diversity patterns with populations becoming increasingly isolated and focused within refugia. Hotspots of endemism and diversity are not necessarily coincident with protected areas and further work will be needed if they are to be reconciled with future planning of conservation priorities.