Hydro-morphological stressors reduce distribution range and affect population status of cyprinid fishes in Austria

• DOI: 10.3389/fenvs.2022.991722
• Publication Date: 2022-10-03T04:54:32Z
• Authors: Daniel S. Hayes; Gregor Schaufler; Stefan Schmutz; Günther Unfer; Simon Führer; Stefan Auer; Carina Seliger
• Keywords: Barbel; Leuciscus

Rivers worldwide have been transformed into fragmented, impounded, channelized, and flow-regulated ecosystems. These anthropogenic transformations can reduce fish distribution population status, especially of those species belonging to medium- or long-distance migratory guilds dependent on free-flowing rivers intact sediment habitat conditions. Here, we aim understand how different hydro-morphological pressure types affect the status key potamodromous rheophilic lithophilic guilds, barbel ( Barbus barbus ) nase Chondrostoma nasus ). We also assess chub Squalius cephalus include a less sensitive degradation. For first time, assembled an extensive Austrian-wide GIS-based sampling database with hundreds biological surveys, allowing us analyze quantitatively >4,000 river kilometers for presence/absence target fishes status. The data reveal that range decreased by around 40–60% compared their natural ranges according reference standard (Leitbild). Hydro-morphological pressures species’ biomass, trends between impact be detected. Chub exhibit highest median biomass in residual flow reaches, followed reservoir sections. Of all types, is lowest hydropeaked stretches. Nase has grand 0.0 kg/ha across sites, showing hardly any differences types. Overall, our results show drastic shrinkage three cyprinid previously prominent Austria. By linking current vitality stressors ecological assessments, this study sets baseline data-based conservation actions (Red-listed) as well policy management frameworks.