Erba Stefania, Terranova Laura, Cazzola Marcello, Cason Manuela, Buffagni Andrea
Water Research Institute, National Research Council (CNR-IRSA), Via del Mulino 19, I-20861 Brugherio, MB, Italy.
Water Research Institute, National Research Council (CNR-IRSA), Via del Mulino 19, I-20861 Brugherio, MB, Italy.
Sci Total Environ. 2019 Sep 20;684:196-206. doi: 10.1016/j.scitotenv.2019.05.348. Epub 2019 May 24.
In relation to hydromorphological alteration the Water Framework Directive (WFD), a major piece of European legislation, has introduced the concept of Heavily Modified Water Bodies (HMWB). In water bodies falling in this category, hydromorphological modifications are permanent, significantly alter the character of the river and cannot be removed without compromising the use of the water body. In HMWBs a dedicated approach to the evaluation of their status is set, and their Ecological Potential must be assessed. Crucial to the process is the definition of Maximum Ecological Potential (MEP) as the reference conditions for HMWB. In the present paper we aim to define MEP conditions for Italian heavily modified lowland rivers, affected by strong bank protection (i.e. levees or bank reinforcement) in reason of flood protection and land drainage uses. The approach applied to identify MEP conditions follows the one considered for natural (not heavily modified) rivers in Italy and large part of Europe and bases on the identification of 'reference sites' representative for the river category and alteration. For the selection of MEP sites environmental features representing mitigation measures and/or expected natural features were considered. The ability of such features in discriminating MEP and disturbed sites was verified by multivariate analyses run on abiotic features (Principal Component Analysis) and biological communities (non-metric multidimensional scaling). We demonstrated differences both in terms of invertebrate community and biological metrics used to assess ecological status (and potential) between MEP and impaired river stretches. Finally, we recognized relevant habitat features able to clearly separate MEP reaches from nonMEP reaches with indication on the type and quantity of measures significant for benthic invertebrates and applicable in lowland Heavily Modified Water Bodies.
关于水文形态变化，欧洲一项主要立法《水框架指令》（WFD）引入了“严重改变的水体”（HMWB）这一概念。在属于此类别的水体中，水文形态变化是永久性的，显著改变了河流的特征，且在不影响水体使用功能的情况下无法消除。对于严重改变的水体，制定了专门的方法来评估其状况，并且必须评估其生态潜力。该过程的关键是将最大生态潜力（MEP）定义为严重改变的水体的参考条件。在本文中，我们旨在确定受防洪和土地排水用途影响而设有坚固河岸保护设施（即堤坝或河岸加固）的意大利严重改变的低地河流的最大生态潜力条件。用于确定最大生态潜力条件的方法遵循意大利以及欧洲大部分地区针对天然（未严重改变）河流所考虑的方法，其基础是识别代表河流类别和变化的“参考站点”。在选择最大生态潜力站点时，考虑了代表缓解措施和/或预期自然特征的环境特征。通过对非生物特征（主成分分析）和生物群落（非度量多维标度分析）进行多变量分析来验证这些特征区分最大生态潜力站点和受干扰站点的能力。我们展示了最大生态潜力河段与受损河段在无脊椎动物群落以及用于评估生态状况（和潜力）的生物指标方面的差异。最后，我们识别出了能够清晰区分最大生态潜力河段和非最大生态潜力河段的相关栖息地特征，并指出了对底栖无脊椎动物具有重要意义且适用于低地严重改变的水体的措施类型和数量。
