Null models for assembly rules: the Jack Horner effect is more insidious than the Narcissus effect
Null models for assembly rules: the Jack Horner effect is more insidious than the Narcissus effect
复制标题
装配规则的空模型：杰克霍纳效应比水仙效应更阴险
DOI：
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发表时间：
1995
期刊：
影响因子：
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通讯作者：
J. Wilson
中科院分区：
文献类型：
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作者：
J. Wilson
生物群落集会规则的存在一直存在争议，部分原因是对所使用的测试存在分歧。这里比较了威尔逊和福克斯分别设计的两种随机化测试，这两种测试都是为了寻找恒定行会代表的组装规则。所使用的零模型在物种频率方面的假设有所不同。结果表明，即使在随机分配物种出现的情况下，Fox的方法也能给出显著的结果。这是因为它主要测试行会在总体物种频率上是否相似，而不是像福克斯所希望的那样，测试“按照[a]规则指定的物种聚集的趋势”。因此，一个重要的结果可能只表明物种频率不相等。这种未能将众所周知的特征构建到零模型中，导致显而易见的演示的现象被称为“杰克·霍纳效应”。相比之下，威尔逊的方法给出了理论上预期的概率分布。当Fox和Brown的“内华达”数据集用这个空模型重新分析时，即考虑到物种之间的频率差异，组装规则就消失了。因此，福克斯对该数据集的组装规则最终只代表了物种在频率上的不同。有人建议，当唯一的选择是杰克·霍纳效应造成的生态虚假结果时，必须接受水仙花效应的危险。
The existence of assembly rules for biological communities has been controversial, partly because of disagreement on the tests used. Two randomisation tests are compared here, devised by Wilson and Fox respectively, both seeking assembly rules of constant guild representation. The null models used differ in their assumptions on species frequencies. It is demonstrated that Fox's method can give significant results even when species occurrences are allocated at random. This is because it tests mainly whether the guilds are similar in overall species frequency, rather than testing, as Fox intended, for a «tendencty for species to be assembled as specified by [a] rule». Therefore, a significant result is likely to demonstrate only that species frequencies are not equal. Such failure to build well-known features into a null model, resulting in a demonstration of the obvious, is termed the «Jack Horner» effect. In contrast, Wilson's method gives the theoretically expected probability distribution. When Fox and Brown's «Nevada» dataset is reanalysed with this null model, i.e. allowing for differences in frequency between species, the assembly rule disappears. Thus, Fox's assembly rule for that dataset turns out to represent only that species differ in frequency. It is suggested that danger of the Narcissus effect must be accepted when the only alternative is an ecologically spurious result caused by the Jack Horner effect