Abstract Herbivory assays are a valuable tool used by field ecologists to understand many of the patterns and processes affecting herbivory, a widely recognized driving force in marine communities. However, methods vary substantially among studies in both design and operation, and the effect of these differences has yet to be evaluated. We assessed the effects of several key components of assay design on estimates of herbivory on a tropical reef, a system characterized by strong herbivory pressure by highly mobile grazers. Based on our results, we offer four recommendations. First, we found assays out-planted on sequential days in both predictable and random locations within a 60m2 site experienced temporal increases in herbivory by an increasingly diverse assemblage of fishes. Thus, we strongly advise against placing herbivory assays in the same site over a series of days. Second, we found while the amount of biomass consumed in assays was density-dependent, but the percent loss was not. Thus, it is our opinion that researchers should report percent consumption because this metric is robust to differences in biomass offered and will facilitate comparisons across studies. Third, we found associational effects, where proximity of species of differing palatabilities impacted estimates of herbivory rate on one or both species, but these impacts were not consistent across species or sites. Thus, we recommend the effect of association be directly tested for multi-species herbivory assays. Fourth, we found no effect of attachment method on estimates of herbivory rate and recommend researchers continue to use the attachment method in which they are most confident. We hope our experimental results prove useful in the future when designing, conducting, and interpreting herbivory assays.

中文翻译：

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测试野外食草试验的概念和操作基础：资源可预测性、试验设计和部署方法的变化是否会影响结果？

摘要食草动物分析是野外生态学家用来了解许多影响食草动物的模式和过程的宝贵工具，食草动物是海洋社区中公认的驱动力。然而，不同研究在设计和操作方面的方法差异很大，这些差异的影响还有待评估。我们评估了分析设计的几个关键组成部分对热带珊瑚礁食草动物估计的影响，该系统的特点是高度移动的食草动物对食草动物的压力很大。根据我们的结果，我们提出四项建议。首先，我们发现在一个 60 平方米的场地内连续几天在可预测和随机位置种植的化验物经历了越来越多样化的鱼类组合带来的食草动物的时间增加。因此，我们强烈建议不要连续几天在同一地点进行食草动物试验。其次，我们发现虽然分析中消耗的生物量与密度有关，但损失百分比却不是。因此，我们认为研究人员应该报告消耗百分比，因为该指标对所提供的生物量差异具有稳健性，并将有助于跨研究进行比较。第三，我们发现了关联效应，其中不同适口性的物种的接近程度影响了对一个或两个物种的食草率的估计，但这些影响在不同物种或地点之间并不一致。因此，我们建议直接测试关联的效果以进行多物种食草试验。第四，我们发现附着方法对食草率的估计没有影响，并建议研究人员继续使用他们最有信心的附着方法。我们希望我们的实验结果在未来设计、实施和解释食草动物试验时被证明是有用的。