Contrasting the roles of section length and instream habitat enhancement for river restoration success: a field study of 20 European restoration projects

摘要: Restoration of river hydromorphology often has limited detected effects on biota. One frequently discussed reason is that the restored length insufficient to allow populations develop and give room for geomorphological processes occur. We investigated ten pairs sections which one was a large project involving long, intensively section represented smaller restoration effort. The effect quantified by comparing each an upstream non-restored section. sampled following response variables: habitat composition in its floodplain, three aquatic organism groups (aquatic macrophytes, benthic invertebrates fish), two floodplain-inhabiting (floodplain vegetation, ground beetles), as well food web land-water interactions reflected stable isotopes. For variable, we compared difference dissimilarity nearby between larger projects. In second step, regrouped with changes substrate those small changes. When all sections, beetles were most strongly responding restoration, followed fish, floodplain macrophytes. Aquatic habitats isotope signatures responded less strongly. grouping size, there no projects targeting long short regard any measured variables except nitrogen isotopic composition. contrast, when composition, responses invertebrates, vegetation greater Synthesis applications. hydromorphological measures biota depend creation organisms, or not present prior restoration. These positive are necessarily related length. Therefore, recommend focus enhancement