Spatial Foodweb Ecology Group, Department of Ecology, Swedish University of Agricultural Sciences, Post Office Box 7044, SE-750 07 Uppsala, Sweden.
Spatial Foodweb Ecology Group, Department of Agricultural Sciences, Post Office Box 27, FI-00014 University of Helsinki, Finland.
Science. 2017 May 19;356(6339):742-744. doi: 10.1126/science.aaj1631.
Biotic interactions underlie ecosystem structure and function, but predicting interaction outcomes is difficult. We tested the hypothesis that biotic interaction strength increases toward the equator, using a global experiment with model caterpillars to measure predation risk. Across an 11,660-kilometer latitudinal gradient spanning six continents, we found increasing predation toward the equator, with a parallel pattern of increasing predation toward lower elevations. Patterns across both latitude and elevation were driven by arthropod predators, with no systematic trend in attack rates by birds or mammals. These matching gradients at global and regional scales suggest consistent drivers of biotic interaction strength, a finding that needs to be integrated into general theories of herbivory, community organization, and life-history evolution.
生物相互作用是生态系统结构和功能的基础，但预测相互作用的结果却很困难。我们通过一项全球实验来检验生物相互作用强度随纬度增加而增加的假设，该实验使用了模型毛虫来测量捕食风险。在跨越六大洲、11660 公里的纬度梯度上，我们发现捕食风险随着纬度向赤道增加，与随着海拔降低而增加的模式平行。纬度和海拔两个方向的模式都是由节肢动物捕食者驱动的，鸟类或哺乳动物的攻击率没有系统的趋势。这些在全球和区域尺度上的匹配梯度表明，生物相互作用强度存在一致的驱动因素，这一发现需要被纳入关于食草作用、群落组织和生活史进化的一般理论中。
