Irstea, UR EABX, av. de Verdun, F-33612 Cestas, France.
AZTI, Marine Research Division, Herrera Kaia, Portualdea s/n, 20110 Pasaia, Spain.
Sci Total Environ. 2016 Jan 15;542(Pt A):383-93. doi: 10.1016/j.scitotenv.2015.10.068. Epub 2015 Nov 3.
Estuaries are subjected to multiple anthropogenic stressors, which have additive, antagonistic or synergistic effects. Current challenges include the use of large databases of biological monitoring surveys (e.g. the European Water Framework Directive) to help environmental managers prioritizing restoration measures. This study investigated the impact of nine stressor categories on the fish ecological status derived from 90 estuaries of the North East Atlantic countries. We used a random forest model to: 1) detect the dominant stressors and their non-linear effects; 2) evaluate the ecological benefits expected from reducing pressure from stressors; and 3) investigate the interactions among stressors. Results showed that largest restoration benefits were expected when mitigating water pollution and oxygen depletion. Non-additive effects represented half of pairwise interactions among stressors, and antagonisms were the most common. Dredged sediments, flow changes and oxygen depletion were predominantly implicated in non-additive interactions, whereas the remainder stressors often showed additive impacts. The prevalence of interactive impacts reflects a complex scenario for estuaries management; hence, we proposed a step-by-step restoration scheme focusing on the mitigation of stressors providing the maximum of restoration benefits under a multi-stress context.
河口受到多种人为胁迫的影响，这些胁迫具有加性、拮抗或协同作用。当前的挑战包括利用生物监测调查的大型数据库（例如欧洲水框架指令）来帮助环境管理者优先考虑恢复措施。本研究调查了来自东北大西洋国家的 90 个河口的鱼类生态状况的 9 个胁迫类别对其的影响。我们使用随机森林模型来：1）检测主要胁迫及其非线性效应；2）评估减少胁迫压力的预期生态效益；3）研究胁迫之间的相互作用。结果表明，在减轻水污染和缺氧方面，预计会有最大的恢复效益。非加性效应占胁迫之间成对相互作用的一半，拮抗作用最为常见。疏浚沉积物、水流变化和缺氧主要与非加性相互作用有关，而其余胁迫通常表现出加性影响。相互作用的普遍性反映了河口管理的复杂情况；因此，我们提出了一个分步恢复计划，重点是减轻胁迫，在多胁迫情况下提供最大的恢复效益。
