Krueger Kirk L, Bottom Daniel L, Hood W Gregory, Johnson Gary E, Jones Kim K, Thom Ronald M
Washington Department of Fish and Wildlife, 1111 Washington Street SE, Olympia, WA 98501, USA.
U.S. National Marine Fisheries Service National Oceanic and Atmospheric Administration (Retired), 2725 Montlake Blvd. E., Seattle, WA, 98112, USA.
J Environ Manage. 2017 Mar 1;188:337-350. doi: 10.1016/j.jenvman.2016.11.028. Epub 2016 Dec 19.
We describe a process for evaluating proposed ecosystem restoration projects intended to improve survival of juvenile salmon in the Columbia River estuary (CRE). Changes in the Columbia River basin (northwestern USA), including hydropower development, have contributed to the listing of 13 salmon stocks as endangered or threatened under the U.S. Endangered Species Act. Habitat restoration in the CRE, from Bonneville Dam to the ocean, is part of a basin-wide, legally mandated effort to mitigate federal hydropower impacts on salmon survival. An Expert Regional Technical Group (ERTG) was established in 2009 to improve and implement a process for assessing and assigning "survival benefit units" (SBUs) to restoration actions. The SBU concept assumes site-specific restoration projects will increase juvenile salmon survival during migration through the 234 km CRE. Assigned SBUs are used to inform selection of restoration projects and gauge mitigation progress. The ERTG standardized the SBU assessment process to improve its scientific integrity, repeatability, and transparency. In lieu of experimental data to quantify the survival benefits of individual restoration actions, the ERTG adopted a conceptual model composed of three assessment criteria-certainty of success, fish opportunity improvements, and habitat capacity improvements-to evaluate restoration projects. Based on these criteria, an algorithm assigned SBUs by integrating potential fish density as an indicator of salmon performance. Between 2009 and 2014, the ERTG assessed SBUs for 55 proposed projects involving a total of 181 restoration actions located across 8 of 9 reaches of the CRE, largely relying on information provided in a project template based on the conceptual model, presentations, discussions with project sponsors, and site visits. Most projects restored tidal inundation to emergent wetlands, improved riparian function, and removed invasive vegetation. The scientific relationship of geomorphic and salmonid responses to restoration actions remains the foremost concern. Although not designed to establish a broad strategy for estuary restoration, the scoring process has adaptively influenced the types, designs, and locations of restoration proposals. The ERTG process may be a useful model for others who have unique ecosystem restoration goals and share some of our common challenges.
我们描述了一个评估拟议的生态系统恢复项目的过程，这些项目旨在提高哥伦比亚河河口（CRE）幼鲑的存活率。哥伦比亚河流域（美国西北部）的变化，包括水电开发，导致13种鲑鱼种群被列入美国《濒危物种法》规定的濒危或受威胁物种名单。从邦纳维尔大坝到海洋的CRE栖息地恢复，是全流域依法规定的减轻联邦水电对鲑鱼生存影响的努力的一部分。2009年成立了一个专家区域技术小组（ERTG），以改进和实施一个评估和为恢复行动分配“生存效益单位”（SBU）的过程。SBU概念假定特定地点的恢复项目将增加幼鲑在穿越234公里CRE的洄游过程中的存活率。分配的SBU用于为恢复项目的选择提供信息并衡量缓解进展。ERTG对SBU评估过程进行了标准化，以提高其科学完整性、可重复性和透明度。由于缺乏量化单个恢复行动生存效益的实验数据，ERTG采用了一个概念模型，该模型由三个评估标准组成——成功的确定性、鱼类机会改善和栖息地容量改善——来评估恢复项目。基于这些标准，一种算法通过整合潜在鱼类密度作为鲑鱼表现的指标来分配SBU。在2009年至2014年期间，ERTG评估了55个拟议项目的SBU，这些项目总共涉及位于CRE 9个河段中8个河段的181项恢复行动，主要依靠基于概念模型的项目模板中提供的信息、演示文稿、与项目发起人的讨论以及实地考察。大多数项目恢复了潮水对新生湿地的淹没，改善了河岸功能，并清除了入侵植被。地貌和鲑鱼对恢复行动的反应之间的科学关系仍然是首要关注的问题。尽管该评分过程并非旨在制定河口恢复的广泛战略，但它已对恢复提案的类型、设计和地点产生了适应性影响。ERTG过程可能是其他有独特生态系统恢复目标并面临一些共同挑战的人的有用模型。
