The interaction between competition and predation: A meta-analysis of field experiments
The interaction between competition and predation: A meta-analysis of field experiments
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DOI：
10.1086/303337
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发表时间：
2000-04-01
影响因子：
2.9
通讯作者：
Hedges, LV
中科院分区：
文献类型：
--
作者：
Gurevitch, J;Morrison, JA;Hedges, LV
生态学家研究了一系列生物和环境，进行了可操作的野外实验，使我们能够提出有关竞争和捕食（包括食草）之间的相互作用以及野外竞争和捕食的相对强度的问题。综合评估，这样的研究集合可以深入了解这些因素在自然界中的重要性和功能。利用一种新的因子荟萃分析技术，我们结合了20篇文章的结果，报告了39个已发表的野外实验，以询问捕食者的存在是否影响竞争效应的强度，并比较了竞争和捕食的平均效应。在所有研究中，捕食者存在时的竞争效应小于没有捕食者时的竞争效应，并且大多数反应变量的竞争和捕食之间的相互作用在统计上是显著的。除去竞争对手比排除捕食者对生物的生长和质量有更积极的影响。与竞争相比，排除捕食者对生物生存的有利影响要大得多。竞争和捕食对密度的平均影响没有差异。不同营养水平的结果不同。进一步的理解将从更多的现场实验中受益匪浅，这些实验可以操纵竞争和捕食，关注更广泛的生物和环境，关注密度等种群水平参数，更完整地报告结果，包括样本大小和方差等数据。
Ecologists working with a range of organisms and environments have carried out manipulative field experiments that enable us to ask questions about the interaction between competition and predation (including herbivory) and about the relative strength of competition and predation in the field. Evaluated together, such a collection of studies can offer insight into the importance and function of these factors in nature. Using a new factorial metaanalysis technique, we combined the results of 20 articles reporting on 39 published field experiments to ask whether the presence of predators affects the intensity of competitive effects and to compare the average effects of competition and predation. Across all studies, the effects of competition in the presence of predators were less than in the absence of predators, and the interaction between competition and predation for most response variables was statistically significant. Removal of competitors had much more positive effects on organisms' growth and mass than did exclusion of predators. Predator exclusion had much more beneficial effects on organisms' survival than did competition. The mean effects of competition and predation on density did not differ from one another. The results differed among trophic levels. Further understanding would benefit greatly from more field experiments that manipulate both competition and predation, that focus on a wider range of organisms and environments, that focus on population-level parameters such as density, and that report results more completely, including data such as sample sizes and variances.