Mutualism increases diversity, stability, and function of multiplex networks that integrate pollinators into food webs

Ecosystems are composed of complex networks of many species interacting in different ways. While ecologists have long studied food webs of feeding interactions, recent studies increasingly focus on mutualistic networks including plants that exchange food for reproductive services provided by animals such as pollinators. Here, we synthesize both types of consumer-resource interactions to better understand the controversial effects of mutualism on ecosystems at the species, guild, and whole-community levels. We find that consumer-resource mechanisms underlying plant-pollinator mutualisms can increase persistence, productivity, abundance, and temporal stability of both mutualists and non-mutualists in food webs. These effects strongly increase with floral reward productivity and are qualitatively robust to variation in the prevalence of mutualism and pollinators feeding upon resources in addition to rewards. This work advances the ability of mechanistic network theory to synthesize different types of interactions and illustrates how mutualism can enhance the diversity, stability, and function of complex ecosystems. Aside from their pollination function, pollinators consume and are consumed by other members of ecological communities; these relationships could explain the controversial effects of pollinators on ecological networks. Here the authors show that when mutualists such as pollinators are introduced into food webs, they increase ecosystem biodiversity, stability, and function.

生态系统由许多物种以不同方式相互作用的复杂网络构成。虽然生态学家长期以来一直在研究摄食相互作用的食物网，但近期的研究越来越关注互利网络，包括植物用食物交换传粉者等动物提供的繁殖服务。在此，我们综合这两种消费者 - 资源相互作用类型，以便更好地理解互利共生在物种、类群和整个群落层面上对生态系统的有争议的影响。我们发现，植物 - 传粉者互利共生背后的消费者 - 资源机制能够提高食物网中互利共生者和非互利共生者的持久性、生产力、丰度和时间稳定性。这些影响随着花蜜奖励生产力的提高而显著增强，并且在互利共生的普遍程度以及传粉者除奖励外还摄取其他资源的变化情况下，在性质上是稳健的。这项工作提高了机制网络理论综合不同类型相互作用的能力，并阐明了互利共生如何增强复杂生态系统的多样性、稳定性和功能。除了传粉功能外，传粉者会被生态群落的其他成员捕食，同时也捕食其他成员；这些关系可以解释传粉者对生态网络的有争议的影响。在此，作者表明当像传粉者这样的互利共生者被引入食物网时，它们会提高生态系统的生物多样性、稳定性和功能。