Stream and river restoration practices have become common in many parts of the world. To answer the question whether such restoration measures improve freshwater biotic assemblages or functions over time, and if not, can general reasons be identified for such outcomes, we conducted a literature survey and review of studies in which different types of stream restorations were conducted and outcomes assessed. In the first paper, we reviewed studies of culvert restorations, acid mine drainage or industrial pollution restoration; and urban stream restoration projects. Here, we review studies of restoration via dam removal, changes in dam operation or fish passage structures; instream habitat modification; riparian restoration or woody material addition; channel restoration and multiple restoration measures and develop some general conclusions from these reviews. Biomonitoring in different studies detected improvements for some restoration measures; other studies found minimal or no statistically significant increases in biotic assemblage richness, abundances or functions. In some cases, untreated stressors may have influenced the outcomes of the restoration, but in many cases, there were mismatches in the temporal or spatial scale of the restoration measure undertaken and associated monitoring. For example, either biomonitoring to measure restoration effects was conducted over a too short a time period after restoration for effects to be observed, or the sources and stressors needing remediation occurred at a larger catchment scale than the restoration. Also, many restoration measures lack observations from unimpaired reference sites for use in predicting how much of a beneficial effect might be expected.

中文翻译：

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考虑河流恢复和生物监测的空间和时间尺度以评估恢复结果：文献综述，第 2 部分


溪流和河流修复实践在世界许多地方已经变得普遍。为了回答这样的恢复措施是否会随着时间的推移改善淡水生物组合或功能，如果不能，是否可以确定造成这种结果的一般原因，我们进行了文献调查和回顾，其中进行了不同类型的河流恢复和结果评估。在第一篇论文中，我们回顾了涵洞修复、酸性矿山排水或工业污染修复的研究；和城市河流修复项目。在这里，我们回顾了通过拆除大坝、改变大坝运行或鱼道结构进行恢复的研究；河道内栖息地改造；河岸恢复或木质材料添加；渠道恢复和多种恢复措施，并从这些审查中得出一些一般性结论。不同研究中的生物监测发现一些恢复措施有所改善；其他研究发现，生物组合的丰富度、丰度或功能几乎没有或没有统计学上的显着增加。在某些情况下，未经处理的压力源可能会影响恢复的结果，但在许多情况下，所采取的恢复措施和相关监测的时间或空间规模不匹配。例如，测量恢复效果的生物监测要么在恢复后的短时间内进行，无法观察到效果，要么需要修复的来源和压力源发生在比恢复更大的流域范围内。此外，许多恢复措施缺乏来自未受损参考地点的观察结果，无法用于预测预期的有益效果有多大。