Anti-predator defence and the complexity-stability relationship of food webs
Anti-predator defence and the complexity-stability relationship of food webs
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DOI：
10.1098/rspb.2007.0335
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发表时间：
2007-07-07
影响因子：
4.7
通讯作者：
Kondoh, Michio
中科院分区：
文献类型：
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作者：
Kondoh, Michio
维持复杂食物网的机制一直是生态学的中心问题，因为理论经常预测复杂性(物种丰富度越高，相互作用越多)会破坏食物网的稳定。尽管有人提出捕食者的反捕食者防御可能会影响捕食者-捕食者动态的稳定性，但这些研究假设食物网结构的变化有限且相对简单。在这里，利用数学模型，我报告了由捕食者反捕食者防御产生的食物网灵活性在更复杂的系统中提高了社区水平的稳定性(群落持久性和稳健性)，甚至改变了复杂性-稳定性关系。模型分析表明，在广泛的食物网复杂程度和拓扑结构下，针对捕食者的适应性防御增强了群落水平的稳定性，而一般防御不能。此外，虽然在没有防御适应的情况下，或在存在普遍防御的情况下，不断增加的食物网复杂性对社区一级的稳定性有轻微或负面的影响，但在存在捕食者特有的防御时，连接-稳定关系可能成为单峰关系。相比之下，物种丰富度的增加总是会降低群落水平的稳定性。然而，出现积极的连接-稳定关系需要食物网分区、高防御效率和低防御成本，这表明只有在有限的条件下才会出现这种关系。
The mechanism for maintaining complex food webs has been a central issue in ecology because theory often predicts that complexity (higher the species richness, more the interactions) destabilizes food webs. Although it has been proposed that prey anti-predator defence may affect the stability of prey-predator dynamics, such studies assumed a limited and relatively simpler variation in the food-web structure. Here, using mathematical models, I report that food-web flexibility arising from prey anti-predator defence enhances community-level stability (community persistence and robustness) in more complex systems and even changes the complexity-stability relationship. The model analysis shows that adaptive predator-specific defence enhances community-level stability under a wide range of food-web complexity levels and topologies, while generalized defence does not. Furthermore, while increasing food-web complexity has minor or negative effects on community-level stability in the absence of defence adaptation, or in the presence of generalized defence, in the presence of predator-specific defence, the connectance-stability relationship may become unimodal. Increasing species richness, in contrast, always lowers community-level stability. The emergence of a positive connectance-stability relationship however necessitates food-web compartmentalization, high defence efficiency and low defence cost, suggesting that it only occurs under a restricted condition.