Mylius S D, Klumpers K, de Roos A M, Persson L
Population Biology Section, University of Amsterdam, P.O. Box 94084, NL-1090 GB Amsterdam, The Netherlands.
Am Nat. 2001 Sep;158(3):259-76. doi: 10.1086/321321.
We analyze the consequences of intraguild predation and stage structure for the possible composition of a three-species community consisting of resource, consumer, and predator. Intraguild predation, a special case of omnivory, induces two major differences with traditional linear food chain models: the potential for the occurrence of two alternative stable equilibria at intermediate levels of resource productivity and the extinction of the consumer at high productivities. At low productivities, the consumer dominates, while at intermediate productivities, the predator and the consumer can coexist. The qualitative behavior of the model is robust against addition of an invulnerable size class for the consumer population and against addition of an initial, nonpredatory stage for the predator population, which means that the addition of stage structure does not change the pattern. Unless the top predator is substantially less efficient on the bottom resource, it tends to drive the intermediate species extinct over a surprisingly large range of productivities, thus making coexistence generally impossible. These theoretical results indicate that the conditions for stable food chains involving intraguild predation cannot involve strong competition for the bottommost resource.
我们分析了集团内捕食和阶段结构对于一个由资源、消费者和捕食者组成的三物种群落可能的组成结构所产生的影响。集团内捕食作为杂食性的一种特殊情况，与传统的线性食物链模型存在两个主要差异：在资源生产力处于中等水平时可能出现两种替代稳定平衡状态，以及在高生产力水平时消费者会灭绝。在低生产力水平下，消费者占据主导地位，而在中等生产力水平时，捕食者和消费者能够共存。该模型的定性行为对于为消费者群体添加一个无懈可击的体型类别以及为捕食者群体添加一个初始的非捕食阶段具有鲁棒性，这意味着添加阶段结构不会改变模式。除非顶级捕食者对底层资源的捕食效率大幅降低，否则它往往会在相当大的生产力范围内驱使中间物种灭绝，从而使得共存通常变得不可能。这些理论结果表明，涉及集团内捕食的稳定食物链的条件不能涉及对最底层资源的激烈竞争。
