EN
The effect of riparian ecotone functional complexity and stream hydraulics on an upland river ecosystem has been analysed. The amount of nutrients retained by the bottom sediment was lowest on a sandy substrate and highest in wetland bays. A stream bed covered by Berula erecta had about three times higher nutrient retentive capacity than did a sandy substrate. The trophic potential of CPOM, measured as total protein, was significantly correlated with the amount of deposited CPOM and depended on stream order. Macroinvertebrate biomass was highest at an intermediate riparian ecotone complexity with an adequate supply of organic matter and incident light. Fish biomass followed the same trend, being lowest in heavily shaded areas and in open channels without riparian vegetation, but highest in ecotones of intermediate complexity. These results indicate that the riparian ecotone structure and the heterogeneity of the stream channel may regulate biodiversity, productivity and nutrient retention in the fluvial corridor.