Bascompte Jordi, Melián Carlos J, Sala Enric
Integrative Ecology Group, Estación Biológica de Doñana, Consejo Superior de Investigaciones Científicas, Apartado Postal 1056, E-41080 Seville, Spain.
Proc Natl Acad Sci U S A. 2005 Apr 12;102(15):5443-7. doi: 10.1073/pnas.0501562102. Epub 2005 Mar 31.
The stability of ecological communities largely depends on the strength of interactions between predators and their prey. Here we show that these interaction strengths are structured nonrandomly in a large Caribbean marine food web. Specifically, the cooccurrence of strong interactions on two consecutive levels of food chains occurs less frequently than expected by chance. Even when they occur, these strongly interacting chains are accompanied by strong omnivory more often than expected by chance. By using a food web model, we show that these interaction strength combinations reduce the likelihood of trophic cascades after the overfishing of top predators. However, fishing selectively removes predators that are overrepresented in strongly interacting chains. Hence, the potential for strong community-wide effects remains a threat.
生态群落的稳定性在很大程度上取决于捕食者与其猎物之间相互作用的强度。在此我们表明，在一个大型加勒比海海洋食物网中，这些相互作用强度的结构并非随机。具体而言，在食物链的两个连续层级上强相互作用同时出现的频率低于随机预期。即便它们出现了，这些强相互作用的链条比随机预期更常伴随着强烈的杂食现象。通过使用一个食物网模型，我们表明这些相互作用强度组合降低了顶级捕食者过度捕捞后营养级联效应发生的可能性。然而，捕鱼会选择性地移除在强相互作用链条中占比过高的捕食者。因此，强大的群落范围效应的可能性仍然是一个威胁。
