Although the effects of species diversity on food web stability have long been recognized, relatively little is known about the influence of intraspecific diversity. Empirical work has found that intraspecific diversity can increase community resilience and resistance, but few theoretical studies have attempted to use modeling approaches to determine how intraspecific diversity will affect food web stability. To begin to address this knowledge gap, we added intraspecific diversity to May’s classic random food web model. We found that, like species diversity, intraspecific diversity decreased stability. These effects on stability were not simply attributable to changes in interaction strengths, suggesting that intraspecific diversity can have its own independent effects on stability. Its effect depends on the relationship between inter- and intra-genotype interactions; when competition within genotypes was stronger than among them, food webs were generally more stable than when the converse was true. Overall, our model suggests that determining the direction and the magnitude of intraspecific diversity’s effects on stability in natural systems will require more empirical information about how its inclusion alters patterns of interaction strength and food web topology.

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种内和种间多样性对食物网稳定性的影响

尽管人们早已认识到物种多样性对食物网稳定性的影响，但对种内多样性的影响知之甚少。经验工作发现种内多样性可以增加社区的适应力和抵抗力，但是很少有理论研究尝试使用建模方法来确定种内多样性如何影响食物网的稳定性。为了解决这一知识鸿沟，我们在May的经典随机食物网模型中添加了种内多样性。我们发现，像物种多样性一样，种内多样性降低了稳定性。这些对稳定性的影响不只是归因于相互作用强度的变化，这表明种内多样性可以对稳定性有其自己的独立影响。它的作用取决于基因型之间和基因内部相互作用之间的关系。当基因型内的竞争比基因型间的竞争更强时，食物网通常比相反时更稳定。总体而言，我们的模型表明，确定种内多样性对自然系统稳定性的影响的方向和幅度，将需要更多有关其如何改变相互作用强度和食物网拓扑模式的经验信息。