Ryberg Wade A, Chase Jonathan M
Department of Biology, Washington University in St. Louis, St. Louis, Missouri 63130, USA.
Am Nat. 2007 Oct;170(4):636-42. doi: 10.1086/521228. Epub 2007 Aug 20.
In addition to having a positive effect on species richness (species-area relationships [SARs]), habitat area can influence the presence of predators, which can indirectly influence prey richness. While these direct and indirect effects of area on richness occur simultaneously, no research has examined how predation might contribute to SAR variation. We extend MacArthur and Wilson's equilibrium theory of island biogeography by including predation-induced shifts in prey extinction and predict that predators will reduce slopes of prey SARs. We provide support for this with data from two insular ecosystems: orthopteran richness in Ozark glades (rocky herbaceous communities within a forested matrix) with and without insectivorous lizards and zooplankton richness in freshwater ponds with and without zooplanktivorous fishes. Our results emphasize that anthropogenic activities yield simultaneous changes in processes altering diversity and that it is critical that we understand how these components of anthropogenic change interact to impact diversity.
除了对物种丰富度有积极影响（物种 - 面积关系[SARs]）外，栖息地面积还会影响捕食者的存在，而这又会间接影响猎物的丰富度。虽然面积对丰富度的这些直接和间接影响同时发生，但尚无研究探讨捕食如何导致物种 - 面积关系的变化。我们通过纳入捕食导致的猎物灭绝变化，扩展了麦克阿瑟和威尔逊的岛屿生物地理学平衡理论，并预测捕食者会降低猎物物种 - 面积关系曲线的斜率。我们利用来自两个岛屿生态系统的数据对此提供了支持：有食虫蜥蜴和没有食虫蜥蜴的奥扎克林间空地（森林基质中的岩石草本群落）中的直翅目昆虫丰富度，以及有浮游动物食性鱼类和没有浮游动物食性鱼类的淡水池塘中的浮游动物丰富度。我们的结果强调，人为活动会使改变多样性的过程同时发生变化，并且我们必须了解这些人为变化的组成部分如何相互作用以影响多样性，这一点至关重要。
