Data from: Habitat preferences and genetic diversity of the amphipod Gammarus roeselii across the Eastern Alps and western Pannonian Basin

We provide the data and R scripts used in the manuscript entitled Habitat preferences and genetic diversity of the amphipod Gammarus roeselii across the Eastern Alps and western Pannonian Basin. We investigated the distribution and genetic diversity of G. roeselii by sampling over 1,000 sites across the eastern Alps and the western Pannonian Basin. Cytochrome oxidase I barcoding assigned all sequenced G. roeselii to the Central-Western European lineage. For sites in Danube catchment we gathered information on the amphipod presence, type of habitat, river order and drainage size, the slope of the sections above and below the sampling sites, the elevation, and mean temperature of warmest quarter. The occurrence of G. roeselii was associated with low elevation, high summer temperature and gentle stream and river slopes and was biased towards downstream reaches and large drainage sizes. Its distribution partially overlapped with G. fossarum, which predominates in cooler, faster-flowing streams. Species distribution modelling using four bioclimate variables and several future climate scenarios predicted a future range expansion of G. roeselii into current G. fossarum habitat. Genetic diversity patterns, inferred using COI marker, are consistent with longstanding stable populations in the southwestern Pannonian Basin, a post-glacial range expansion across alpine forelands, and recent colonization of some alpine valleys.