Forested riparian corridors are a key management solution for halting the global trend of declining ecological status of freshwater ecosystems. There is an increasing body of evidence related to the efficacy of these corridors at the local scale, but knowledge is inadequate concerning the effectiveness of riparian forests in terms of protecting streams from harmful impacts across larger scales. In this study, nationwide assessment results comprising more than 900 river water bodies in Finland were used to examine the importance of adjacent land use to river ecological status estimates. Random forest models and partial dependence functions were used to quantify the independent effect of adjacent land use on river ecological status after accounting for the effects of other factors. The proportion of adjacent forested land along a river had the strongest independent positive effect on ecological status for small to medium size rivers that were in agricultural landscapes. Ecological quality increased by almost one status class when the adjacent forest cover increased from 10 to 60%. In contrast, for large rivers, adjacent forested land did not show an independent positive effect on ecological status. This study has major implications for managing river basins to achieve the EU Water Framework Directive (WFD) goal of obtaining good ecological status of rivers. The results from the nationwide assessment demonstrate that forested riparian zones can have an independent positive effect on the ecological status of rivers, indicating the importance of riparian forests in mitigating the impacts of catchment-level stressors. Therefore, forested buffer zones should be more strongly considered as part of river basin management.

森林河岸走廊是阻止淡水生态系统生态状况下降的全球趋势的关键管理解决方案。越来越多的证据表明这些走廊在当地的有效性，但关于河岸森林在保护河流免受更大规模有害影响方面的有效性的知识不足。在这项研究中，包括芬兰 900 多个河流水体在内的全国性评估结果被用来检验相邻土地利用对河流生态状况评估的重要性。在考虑了其他因素的影响后，利用随机森林模型和偏依赖函数来量化相邻土地利用对河流生态状况的独立影响。对于农业景观中的中小型河流，沿河相邻林地的比例对生态状况的独立正向影响最强。当相邻森林覆盖率从 10% 增加到 60% 时，生态质量几乎提高了一级。相比之下，对于大型河流，相邻的林地对生态状况没有表现出独立的积极影响。这项研究对管理河流流域以实现欧盟水框架指令 (WFD) 获得良好河流生态状况的目标具有重要意义。全国评估的结果表明，森林河岸带可以对河流的生态状况产生独立的积极影响，表明河岸森林在减轻流域级压力源的影响方面的重要性。所以，