Theis Sebastian, Koops Marten A, Poesch Mark S
Department of Renewable Resources, University of Alberta, 433a South Academic Building, Edmonton, AB, Canada.
Fisheries and Oceans Canada (DFO), Great Lakes Laboratory for Fisheries and Aquatic Sciences (GLLFAS), Burlington, ON, Canada.
Environ Manage. 2022 Nov;70(5):793-807. doi: 10.1007/s00267-022-01703-x. Epub 2022 Aug 20.
Offsetting aims to compensate for negative impacts due to authorized anthropogenic impacts associated with development. While anchored into legislation, residual or chronic impacts can occur after offset establishment. Advice and best practice on how to approach these impacts is rare. To address this, we reviewed 30 projects based on a systematic review and meta-analysis in freshwater ecosystems dealing with residual or long-term negative impacts to provide application advice for: habitat creation, habitat restoration, and biological and chemical manipulation. Project information was obtained through Boolean search terms and web-scraping. Habitat creation projects had a pooled effect size of 0.8 and offsetting ratios of 1:5 with high biomass increases of >140% compared to pre-establishment, associated with them. Habitat restoration projects targeted a wide range of species and communities with a pooled effect size of 0.66, offset ratios ranging from 1:1.2 to 1:4.6, and biomass increases generally > 100% compared to pre-restoration. Biological manipulation had the lowest effect size (0.51) with stocking being highly variable both in terms of biomass benefits and project outcomes pointing towards being mostly applicable in cases of direct fish harm not related to habitat aspects. We conclude that (1) all three assessed approaches have a potential application use for offsetting residual or chronic harm with approach-specific caveats. (2) Implementation costs differ across offset methods, with connectivity and side-channel projects having the lowest biomass gain per area costs (3) Time to first benefits required one to two years with time lags needing to be accounted for in the implementation and monitoring process.
补偿旨在弥补与开发相关的经授权的人为影响所造成的负面影响。虽然补偿已被纳入立法，但在补偿措施确立后仍可能出现残余或长期影响。关于如何应对这些影响的建议和最佳实践很少见。为了解决这个问题，我们基于对淡水生态系统中处理残余或长期负面影响的30个项目进行的系统综述和荟萃分析，为栖息地创建、栖息地恢复以及生物和化学操纵提供应用建议。项目信息是通过布尔搜索词和网络爬虫获取的。栖息地创建项目的合并效应大小为0.8，补偿比例为1:5，与建立前相比，生物量增加超过140%。栖息地恢复项目针对广泛的物种和群落，合并效应大小为0.66，补偿比例从1:1.2到1:4.6不等，与恢复前相比，生物量通常增加超过100%。生物操纵的效应大小最低（0.51），放流在生物量效益和项目成果方面差异很大，表明主要适用于与栖息地方面无关的直接鱼类伤害情况。我们得出以下结论：（1）所有三种评估方法都有潜在的应用价值，可用于补偿残余或长期危害，但各方法有特定的注意事项。（2）不同补偿方法的实施成本不同，连通性和侧河道项目每单位面积成本的生物量增益最低。（3）首次产生效益的时间需要一到两年，在实施和监测过程中需要考虑时间滞后问题。
