Yoshida Takehito, Jones Laura E, Ellner Stephen P, Hairston Nelson G
Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, New York 14853-2701, USA.
Nature. 2006 Jan 5;439(7072):E1-2; discussion E2. doi: 10.1038/nature04526.
A variety of mechanisms can theoretically produce competitive coexistence in nature, making it hard to identify a single explanation for the maintenance of diversity in any particular system. Based on laboratory experiments with a consumer-resource system of crustacean Daphnia eating algae, Nelson et al. suggest that maintenance of genetic diversity in the consumer populations they studied depends only on the dynamics of the population structure of the consumer. We suggest that the differences in Daphnia genetic diversity that they find for different experimental treatments could equally be explained by a simple, well known mechanism: the number of coexisting competitors cannot exceed the number of shared resources. Here we confirm this possibility by using a simple mathematical model and suggest that more than one mechanism may account for the maintenance of genetic diversity observed by Nelson et al. in their system.
理论上，多种机制可以在自然界中产生竞争性共存，这使得很难为任何特定系统中多样性的维持确定单一的解释。基于对甲壳类水蚤食用藻类的消费者 - 资源系统进行的实验室实验，尼尔森等人认为，他们所研究的消费者群体中遗传多样性的维持仅取决于消费者种群结构的动态变化。我们认为，他们在不同实验处理中发现的水蚤遗传多样性差异同样可以用一个简单且广为人知的机制来解释：共存竞争者的数量不能超过共享资源的数量。在这里，我们通过使用一个简单的数学模型证实了这种可能性，并表明可能有不止一种机制可以解释尼尔森等人在其系统中观察到的遗传多样性的维持。
