Background/Question/Methods Biotic interactions affect community level processes and structure. Through the study of metacommunities, which encompass networks of communities connected by dispersal, ecologists can advance our understanding of communities while incorporating landscape-scale processes. Investigating how multitrophic interactions, such as mutualistic and predatory interactions, structure metacommunities is an exciting frontier of knowledge. The exploration of this topic will not only further our understanding of ecological dynamics, but will also provide tools for conservation and restoration. We investigated the impacts of mutualistic partners and predators on a butterfly metacommunity, as well as the impacts that local and landscape characteristics have across three trophic levels: flowering plants, butterflies, and butterfly predators. Using data for butterfly diversity/richness, flowering plant diversity/richness, and butterfly predation (on clay butterfly models) across 15 grassland sites, we asked 3 questions: 1) How do mutualist metacommunity structure, predation pressure, and local and regional habitat characteristics affect butterfly metacommunity structure? 2) How do local and regional habitat characteristics affect flowering plant metacommunity structure? 3) How do local and regional habitat characteristics affect predation pressure? Results/Conclusions Floral diversity and richness had a positive effect on butterfly diversity and richness (Question 1). Site size positively affected floral diversity and richness (Question 2), and through this relationship site size had an indirect positive effect on butterfly diversity and richness (Question 1). In contrast with previous work, no other variables impacted butterfly diversity/richness. This result was particularly surprising for predation pressure: our results suggest that within our study system butterfly community diversity and richness is not strongly impacted by predation. Predator attacks occurred more in larger and more isolated sites (Question 3), suggesting that predators may be tracking the landscape rather than butterfly communities. This decoupling of predation pressure and butterfly communities suggests that conserving and restoring healthy predator populations may not negatively impact butterfly communities. In addition, our findings show that if diverse plant communities are maintained, even small and isolated habitat patches can be valuable for butterfly conservation, with implications for reserve design and habitat restoration.
