Hydromorphological conditions, potential fish habitats and the fish community in a mountain river subjected to variable human impacts, the Czarny Dunajec, Polish Carpathians

摘要: The Czarny Dunajec River, Polish Carpathians, has been considerably modified by channelization and gravel mining-induced channel incision it varies in morphology from a single-thread, incised or regulated to an unmanaged, multi-thread channel. For twelve cross-sections with between 1 4 flow threads, the abundance diversity of fish fauna were determined electrofishing compared assessment hydromorphological river quality variation depth, velocity bed material size. Hydromorphological varied high-status conditions (Class 1) varying proportions islands Class channelized cross-sections. increased number low-flow channels cross-section was associated larger aggregated width greater Single-thread hosted only 2 species 13 individuals on average, whereas 3―4 82 average recorded four channels. Regression analysis indicated that both linearly increasing depth within exponentially improving quality, while they unrelated width, suggesting is increase variability habitat rather than simple enlargement, supported This study shows simplification pattern resultant degradation caused human impacts, reflected remarkable impoverishment communities recovery these will require morphological complexity river.