Canadian Journal of Fisheries and Aquatic Sciences, Ahead of Print.
Before–after, control–impact (BACI) experimental designs are commonly used in large-scale environmental experiments, but these designs can be confounded by location and time interactions. Staircase designs, where replicate treatments are staggered temporally, have been suggested as an alternative to BACI designs. We performed a simulation study based on data from an ongoing watershed-scale restoration experiment within three streams to test the effectiveness of adding large wood to increase habitat complexity and abundance and productivity of juvenile steelhead (Oncorhynchus mykiss). We compared the power of two asymmetric BACI (aBACI) designs with two staircase designs for detecting changes in the density of steelhead (fish·m–2). A staircase design where treatments were temporally staggered in one treatment section in each stream had the highest power and best precision, especially when the innate spatial and temporal variances of steelhead density were large. A traditional BACI performed the worst, and a variation on another BACI and staircase design had intermediate performance. Multistream staircase designs are also more logistically and economically feasible and can maximize learning by replicating experiments across different stream types.

中文翻译：

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比较楼梯和非对称前后碰撞控制实验（aBACI）的实验设计，以测试在增加幼龄钢头密度时流恢复的有效性

《加拿大渔业和水生科学杂志》，印刷前。
在此之前，在大型环境实验中通常使用控制影响（BACI）实验设计，但是这些设计可能会因位置和时间相互作用而混淆。有人建议在楼梯设计中暂时重复进行重复治疗，以作为BACI设计的替代方案。我们基于正在进行的流域规模恢复实验的数据，在三个溪流中进行了模拟研究，以测试添加大木材以增加栖息地的复杂性以及少年硬头（Oncorhynchus mykiss）的丰度和生产力的有效性。我们比较了两种非对称BACI（aBACI）设计和两种阶梯设计用于检测钢头密度（fish·m-2）的变化的能力。在阶梯流设计中，每条水流在一个处理段中的处理时间在时间​​上错开，具有最高的功效和最佳的精度，尤其是当杆头密度的固有时空变化较大时。传统的BACI表现最差，而另一个BACI和楼梯设计的变体则表现出中等的表现。多流楼梯设计在物流和经济上也更可行，并且可以通过在不同流类型之间复制实验来最大化学习效果。