Incorporating the effects of generalist seed predators into plant community theory

1. Post-dispersal seed predators contribute substantially to seed loss across many ecosystems. Most research has focused on understanding sources of variation in seed loss, without appreciating the implications of seed predation for plant coexistence, community assembly and broader community theory. Meanwhile, research aimed at understanding coexistence and community assembly processes in plant communities has focused on axes of dispersal and resource competition and the traits influencing these processes, without accounting for the role of generalist seed predators. 2. We review the unique features of post-dispersal seed predation and assess the implications of seed loss on three critical components of plant community organization - coexistence, community structure and plant invasions - pointing to both important gaps in theory and empirical knowledge. We highlight how understanding fundamental controls on plant recruitment is central to determining how seed predation affects plant recruitment and coexistence. We discuss how accounting for seed predator foraging strategies may shift trait-based inferences of community assembly. 3. Synthesis. We argue that seed predation by generalist consumers, which is pervasive in temperate communities, should be better incorporated into plant community theory. Experiments that specifically incorporate the presence and attributes of the seed predator community and that follow seed fate would fill important knowledge gaps. Particularly needed are studies focused on strengthening the connections between seed removal and plant establishment and linking selective and density-dependent foraging strategies to plant traits. Advancing our understanding of the processes regulating plant coexistence and community assembly requires that future research not only acknowledge but also incorporate generalist consumers' effects on plant communities.