Leibniz-Institute of Freshwater Ecology and Inland Fisheries IGB, Müggelseedamm 310, 12587 Berlin, Germany.
Leibniz-Institute of Freshwater Ecology and Inland Fisheries IGB, Müggelseedamm 310, 12587 Berlin, Germany; Society to Save the Sturgeon, Rostock, Germany.
Sci Total Environ. 2016 Aug 1;560-561:266-73. doi: 10.1016/j.scitotenv.2016.03.232. Epub 2016 Apr 19.
Ineffectiveness of current river restoration practices hinders the achievement of ecological quality targets set by country-specific regulations. Recent advances in river restoration help planning efforts more systematically to reach ecological targets at the least costs. However, such approaches are often desktop-based and overlook real-world constraints. We argue that combining two techniques commonly used in the conservation arena - expert judgement and systematic planning - will deliver cost-effective restoration plans with a high potential for implementation. We tested this idea targeting the restoration of spawning habitat, i.e. gravel bars, for 11 rheophilic fish species along a river system in Germany (Havel-Spree rivers). With a group of local fish experts, we identified the location and extent of potential gravel bars along the rivers and necessary improvements to migration barriers to ensure fish passage. Restoration cost of each gravel bar included the cost of the action itself plus a fraction of the cost necessary to ensure longitudinal connectivity by upgrading or building fish passages located downstream. We set restoration targets according to the EU Water Framework Directive, i.e. relative abundance of 11 fish species in the reference community and optimised a restoration plan by prioritising a subset of restoration sites from the full set of identified sites, using the conservation planning software Marxan. Out of the 66 potential gravel bars, 36 sites which were mainly located in the downstream section of the system were selected, reflecting their cost-effectiveness given that fewer barriers needed intervention. Due to the limited overall number of sites that experts identified as being suitable for restoring spawning habitat, reaching abundance-targets was challenged. We conclude that coupling systematic river restoration planning with expert judgement produces optimised restoration plans that account for on-the-ground implementation constraints. If applied, this approach has a high potential to enhance overall efficiency of future restoration efforts.
当前河流修复实践的无效性阻碍了实现特定国家法规设定的生态质量目标。河流修复的最新进展有助于更系统地规划工作，以最低成本达到生态目标。然而，这些方法通常是基于桌面的，忽略了现实世界的限制。我们认为，将保护领域中常用的两种技术——专家判断和系统规划——结合起来，将提供具有高实施潜力的具有成本效益的修复计划。我们针对德国哈韦尔-施普雷河流系统中的 11 种洄游鱼类的产卵栖息地（砾石滩）的恢复，测试了这一想法。我们与一组当地鱼类专家一起，确定了河流中潜在砾石滩的位置和范围，以及必要的改进措施以消除洄游障碍，确保鱼类洄游。每个砾石滩的修复成本包括行动本身的成本，以及为确保位于下游的鱼类通道的纵向连通性而升级或建造所需的一部分成本。我们根据欧盟水框架指令设定了修复目标，即参考群落中 11 种鱼类的相对丰度，并通过使用保护规划软件 Marxan 从全部分辨出的地点中优先选择修复地点子集，优化了修复计划。在 66 个潜在的砾石滩中，选择了 36 个主要位于系统下游部分的地点，这反映了它们的成本效益，因为需要干预的障碍较少。由于专家确定适合恢复产卵栖息地的地点总数有限，因此达到丰度目标具有挑战性。我们得出的结论是，将系统的河流修复规划与专家判断相结合，可以生成考虑到实地实施限制的优化修复计划。如果应用这种方法，它有很大的潜力提高未来修复工作的整体效率。
