Magurran Anne E, Henderson Peter A
Gatty Marine Laboratory, School of Biology, University of St Andrews, St Andrews, Fife KY16 8LB, UK.
Nature. 2003 Apr 17;422(6933):714-6. doi: 10.1038/nature01547.
The observation that a few species in ecological communities are exceptionally abundant, whereas most are rare, prompted the development of species abundance models. Nevertheless, despite the large literature on the commonness and rarity of species inspired by these pioneering studies, some widespread empirical patterns of species abundance resist easy explanation. Notable among these is the observation that in large assemblages there are more rare species than the log normal model predicts. Here we use a long-term (21-year) data set, from an estuarine fish community, to show how an ecological community can be separated into two components. Core species, which are persistent, abundant and biologically associated with estuarine habitats, are log normally distributed. Occasional species occur infrequently in the record, are typically low in abundance and have different habitat requirements; they follow a log series distribution. These distributions are overlaid, producing the negative skew that characterizes real data sets.
生态群落中少数物种极为丰富，而大多数物种稀少，这一观察结果促使了物种丰度模型的发展。然而，尽管有大量受这些开创性研究启发而产生的关于物种常见性和稀有性的文献，但一些广泛存在的物种丰度实证模式却难以轻易解释。其中值得注意的是，在大型群落中，稀有物种的数量比对数正态模型预测的要多。在此，我们利用一个来自河口鱼类群落的长期（21年）数据集，展示一个生态群落如何能够被分为两个部分。核心物种持久、丰富且在生物学上与河口栖息地相关联，呈对数正态分布。偶见物种在记录中出现频率低，通常数量较少且有不同的栖息地需求；它们遵循对数级数分布。这些分布相互叠加，产生了表征真实数据集的负偏态。
