A consistent metric for nestedness analysis in ecological systems: reconciling concept and measurement
A consistent metric for nestedness analysis in ecological systems: reconciling concept and measurement
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DOI：
10.1111/j.0030-1299.2008.16644.x
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发表时间：
2008-08-01
期刊：
影响因子：
3.4
通讯作者：
Ulrich, Werner
中科院分区：
文献类型：
--
作者：
Almeida-Neto, Mario;Guimaraes, Paulo;Ulrich, Werner
嵌套性已经被广泛报道的metacquireities和网络的相互作用的物种。尽管这种生态模式的概念已经得到了很好的定义，但有几个指标可以对其进行量化。我们注意到，当前的指标没有正确量化嵌套的两个主要属性：（1）列和/或行之间的边际总数（即填充）是否不同，以及（2）填充较少的列和行中的存在（1）是否分别与填充较多的列和行中的存在一致。我们提出了一个新的度量直接基于这些属性，并比较其行为与最常用的度量，使用一组模型矩阵，从高度嵌套的替代结构，其中没有嵌套应检测。我们还使用了一个经验数据集来探索指标产生的可能偏差，并评估指标之间的相关性。我们发现，嵌套已被量化的指标，不适当地检测这种模式，即使是矩阵中没有嵌套。此外，最常用的度量容易出现I型统计错误，而我们的新度量具有更好的统计特性，并始终拒绝不同类型的随机矩阵的嵌套模式。实证数据的分析表明，两个嵌套度量，矩阵温度和差异的措施，往往高估了嵌套的程度，在元集聚。我们强调并讨论了这些偏见的理论理解的过程中形成的物种相互作用网络和亚稳态结构的影响。
Nestedness has been widely reported for both metacommunities and networks of interacting species. Even though the concept of this ecological pattern has been well-defined, there are several metrics by which it can be quantified. We noted that current metrics do not correctly quantify two major properties of nestedness: (1) whether marginal totals (i.e. fills) differ among columns and/or among rows, and (2) whether the presences (1's) in less-filled columns and rows coincide, respectively, with those found in the more-filled columns and rows. We propose a new metric directly based on these properties and compare its behavior with that of the most used metrics, using a set of model matrices ranging from highly-nested to alternative structures in which no nestedness should be detected. We also used an empirical dataset to explore possible biases generated by the metrics as well as to evaluate correlations between metrics. We found that nestedness has been quantified by metrics that inappropriately detect this pattern, even for matrices in which there is no nestedness. In addition, the most used metrics are prone to type I statistical errors while our new metric has better statistical properties and consistently rejects a nested pattern for different types of random matrices. The analysis of the empirical data showed that two nestedness metrics, matrix temperature and the discrepancy measure, tend to overestimate the degrees of nestedness in metacommunities. We emphasize and discuss some implications of these biases for the theoretical understanding of the processes shaping species interaction networks and metacommunity structure.