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The transferability of hydraulic microhabitat selection models among rivers has been largely debated. It can influence management decisions such as restoration measures or environmental flow definitions. We updated microhabitat selection models for 258 macroinvertebrate taxa, with 141 species, collected in 2128 Surber or Hess samples during 91 surveys (sites × dates) distributed in eleven small streams to large rivers of Germany and France. We compared microhabitat selection for four hydraulic variables, developed using mixed-effects models that account for the overdispersion of observed abundance, partly due to spatial aggregation. Models based on bed shear stress, water column velocity and Froude number showed comparable results and were stronger than models for water depth. For these velocity-related variables, 61–78% of models were significant and revealed variable response forms among taxa. The explanatory power of "average" microhabitat selection models, with response forms common to all surveys, was 78–83% of the explanatory power of more detailed models with variable response forms. Significant associations with biological traits such as locomotion, relation to substrate or food types suggested that microhabitat selection results from general biological processes. Our results indicate a high degree of transferability and can be useful in many basic and applied ecological studies. [ABSTRACT FROM AUTHOR]

River drying has drastic immediate effects on benthic invertebrates, but their high resilience reduces long-term effects on biodiversity and ecosystem functions (e.g. leaf litter decomposition). The hyporheic zone (saturated sediments below the riverbed) can be a refuge for invertebrates in dry rivers and a primary source of colonists supporting population resilience following flow resumption. However, factors such as the depth to the water table below the riverbed, which could determine the quality of the hyporheic refuge, are not well understood. We explored how depth to the water table (control, −5 cm, −30 cm and completely dry) during a 1-week drying event affected the survival and return to the substrate surface (%RTS) of Gammarus pulex (Crustacea : Amphipoda) using laboratory mesocosms. We measured litter decomposition and Gammarus energy stores to examine effects on ecosystem function and energetic costs for organisms crawling deeper into the hyporheic zone. Two populations, collected from intermittent and perennial rivers, were used to evaluate inter-population variability in response to drying. Survival and %RTS were reduced by ≤39% and 52%, respectively, in the −30 cm and dry treatments, and this had consequences for decomposition (≤46% reduction). Differences between populations in %RTS were high across treatments but did not generally affect survival and decomposition. Our results suggest that increases in depth to the water table during river drying, which often result from longer drying duration and water abstraction, could reduce invertebrate resilience and litter decomposition by diminishing the role of the hyporheic zone as a source of colonists. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The article focuses on the characteristic of the Chelicorophium sowinsky, which is first found in the French Rhone River in France. It discusses the morphological differences between Chelicorophium curvispinum and C. sowinskyi. It notes that C. curvispinum has more setae than C. sowinskyi, which is more hairy in appearance. It also tackles the difference between male and females C. sowinskyi and traces its invasion route.