Pollinators in food webs: Mutualistic interactions increase diversity, stability, and function in multiplex networks

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 such as those of plants who 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 complex ecosystems. Contrary to classic theory, we find that the dynamics of pollination mutualisms can increase the diversity, stability, and several ecosystem functions of multiplex ecological networks. These effects strongly increase with floral reward productivity and are qualitatively robust to variation in the prevalence of mutualism and pollinators feeding upon vegetation and other species in addition to floral rewards. This work advances the ability of mechanistic network theory to synthesize different types of ecological interactions and illustrates how mutualism can enhance the diversity, stability, and function of complex ecosystems.