The role of intra-guild indirect interactions in assembling plant-pollinator networks

Abstract

Understanding the assembly of plant-pollinator communities has become critical to their conservation given the rise of species invasions, extirpations, and species’ range shifts. Dynamic network analyses can advance such understanding by elucidating the effects of species’ direct and indirect interactions on network assembly. We investigate the role of intra-guild indirect interactions on assembling plant-pollinator networks by developing: 1) an assembly model that includes population dynamics and adaptive foraging, and 2) a motif analysis tracking the effects of colonizing species throughout assembly. Motifs — networks’ building blocks — allow an in-depth analysis of indirect interactions. We found that adaptive foraging reduces the otherwise strong effect of indirect competition for shared mutualistic resources on community assembly. This allows for coexistence between specialist and generalist species within the same guild and the emergence of nested networks. Further, by maintaining the persistence of specialist species, who are most vulnerable to competitive exclusion, adaptive foraging allows for the development of richer and less connected networks which is consistent with empirical pollination networks. Our work contributes new understanding and methods to study the effects of species’ indirect interactions on community assembly.