Waves Under Control? A Meta‐Analysis of Morphological Restoration as a Strategy to Mitigate Navigation‐Induced Disturbances

ABSTRACT Ship‐induced waves significantly impact freshwater ecosystems, estuaries and tidal rivers by accelerating shoreline erosion and reducing aquatic biodiversity. Morphological protection measures are implemented to mitigate these adverse effects, but their effectiveness in preventing shoreline zone deterioration has not been systematically assessed. This meta‐analysis evaluates the performance of various measures in influencing hydraulic forces, abiotic processes and biological responses across primary producers, benthic invertebrates and fish. Our findings reveal that the effectiveness of these measures varies depending on the scale of investigation, ecosystem type and response variable. Offshore breakwaters were highly effective in reducing hydraulic forces in freshwater ecosystems (+756%) but had a limited impact in transitional ecosystems (+34%, not significant). In contrast, breakwaters positively influenced benthic invertebrates in transitional ecosystems (+6945%) but had negligible effects in freshwater ecosystems (+91%, n.s.). Increased shoreline complexity had overall positive effects in mesocosm‐based studies (+407%) but yielded limited benefits in freshwater field studies (+67%, n.s.). Moreover, the measures showed diverse responses across trophic levels within freshwater ecosystems. Shoreline complexity significantly benefited benthic invertebrates (+336%), while positive effects on fish were found for breakwaters (+74%) and side channels (+205%). These findings highlight the importance of implementing ecosystem‐specific management strategies tailored to the needs of target organisms. A combination of offshore breakwaters and increased shoreline complexity appears promising for mitigating the negative impacts of ship‐induced waves on all trophic levels in navigable rivers, lakes and estuaries.