Abstract Many streams and rivers worldwide are restored with the intention to mitigate degradation caused by human activities, but these rehabilitation projects often involve physical instream work with diggers or other heavy machinery. The short-term effects of such restoration works on stream ecosystems are rarely investigated. The primary aim of our study was to assess the short-term effects of physical instream restoration works (which likely increased instream fine sediment load temporarily) on the benthic macroinvertebrate community in a lowland soft-bottomed stream, and our second aim was to compare the results of semi-quantitative kick-net and quantitative Surber sampling in this assessment. Invertebrates were collected using these two methods from three Control and three Impact sites, before and two days after recontouring the stream banks and installing instream woody cover features. Three of seven macroinvertebrate community-level indexes suggested positive short-term effects of the restoration works, whereas none indicated negative effects. By contrast, seven of the 14 most common taxa were negatively affected by the restoration works, possibly due to increased fine sediment levels reducing habitat quality for these taxa. These differences imply that taxon-specific invertebrate responses may be more suitable for detecting short-term impacts of instream restoration works than community-level metrics. Community indexes and common taxa were also likely affected by a drought in the spring and summer before restoration, which may have obscured some effects of the restoration works. Finally, kick-net and Surber sampling methods yielded similar findings for the community-level metrics but differed more for the common taxa, probably because the two methods sampled different microhabitats within the stream. Consequently, we recommend that for routine monitoring of macroinvertebrate communities in lowland soft-bottomed streams, the semi-quantitative kick-net sampling method should be used.

中文翻译：

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河内栖息地恢复对大型无脊椎动物的短期影响和采样方法的比较

摘要 世界各地的许多溪流和河流都经过修复，旨在减轻人类活动造成的退化，但这些修复项目通常涉及使用挖掘机或其他重型机械进行的体力工作。此类修复工程对河流生态系统的短期影响很少被调查。我们研究的主要目的是评估河内物理恢复工程（可能暂时增加河内细粒沉积物负荷）对低地软底河流中底栖大型无脊椎动物群落的短期影响，我们的第二个目的是比较本评估中半定量踢网和定量 Surber 抽样的结果。使用这两种方法从三个控制点和三个影响点收集无脊椎动物，在重新塑造河岸并安装河内木质覆盖特征之前和两天之后。七个大型无脊椎动物社区水平指数中的三个表明修复工作的短期积极影响，而没有一个表明负面影响。相比之下，14 个最常见的分类群中有 7 个受到恢复工程的负面影响，这可能是由于细粒沉积物水平的增加降低了这些分类群的栖息地质量。这些差异意味着特定于分类群的无脊椎动物反应可能比社区级指标更适合检测河流恢复工作的短期影响。群落指数和常见分类群也可能受到恢复前春夏干旱的影响，这可能掩盖了恢复工作的一些影响。最后，kick-net 和 Surber 采样方法对社区层面的指标产生了类似的发现，但对常见分类群的差异更大，可能是因为这两种方法对溪流中的不同微生境进行了采样。因此，我们建议对低地软底溪流中的大型无脊椎动物群落进行常规监测，应使用半定量踢网采样方法。