Small mammals can be used as environmental indicators and have been intensively studied in fragmented landscapes of Atlantic Forest, with a wide range of field methods. Our aim in this study was two-fold: we tested for the effects of methods and for the effects of the main environmental variables on observed small mammal richness in fragments of Atlantic Forest. We gathered information on small mammal richness, methods and environmental variables from 122 fragments of Atlantic Forest through literature review. These data were analysed using linear models and model selection based on AIC values along with a regression tree analysis. We found that studies will record more species with bigger trapping effort, using pitfall traps and sampling all forest strata. We also confirmed two important ecological assumptions: fragments at lower latitudes and bigger fragments were the ones with higher species richness. Methodological and environmental variables were analysed together on a regression tree, where trapping effort was the most important variable, surpassing any environmental effect. Considering that a significant number of the studies on Atlantic Forest fragments did not use pitfall traps or sample all forest strata, their results on forest fragmentation were affected by sampling bias.

中文翻译：

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大西洋森林碎片中的小型哺乳动物：物种丰富度与野外方法和环境有关

小型哺乳动物可用作环境指标，并已在大西洋森林的碎片化景观中进行了深入研究，并采用了广泛的野外方法。我们在这项研究中的目的有两个：我们测试了方法的影响和主要环境变量对大西洋森林碎片中观察到的小型哺乳动物丰富度的影响。我们通过文献回顾从大西洋森林的 122 个碎片中收集了有关小型哺乳动物丰富度、方法和环境变量的信息。使用线性模型和基于 AIC 值的模型选择以及回归树分析来分析这些数据。我们发现，研究将使用陷阱陷阱和对所有森林地层进行采样，以更大的诱捕努力记录更多的物种。我们还确认了两个重要的生态假设：较低纬度的碎片和较大的碎片是物种丰富度较高的碎片。方法和环境变量在回归树上一起分析，其中诱捕努力是最重要的变量，超过了任何环境影响。考虑到大量关于大西洋森林碎片的研究没有使用陷阱或对所有森林层进行抽样，他们关于森林碎片的结果受到抽样偏差的影响。