Using motifs in ecological networks to identify the role of plants in crop margins for multiple agriculture functions

Abstract

Advances in network ecology offer new tools for the sustainable management of agroecosystems. Plants in field margins may be involved in different processes of agronomic importance - indirectly affecting crops by supporting shared pollinators, hosting natural enemies of pests or acting as pest reservoirs. In this work, we explored the use of motifs (patterns of interaction between a subset of species) in agricultural ecological networks incorporating multiple types of trophic interactions to identify plant species with a key role in field margins. We searched for plant species benefiting crops via (1) shared pollinators and (2) supporting parasitoids of crop pests; or (3) negatively affecting crops through attracting pest herbivore species. We focused on determining whether species’ showed consistent affiliation with these roles across the landscape and evaluated the potential of plant species to influence crops indirectly via shared insect partners. To showcase our framework, we used a unique data set of antagonistic and mutualistic interactions recorded in soybean crops and wild plant species in field margins, that despite its limitations (e.g., spanning one growing season) allowed us to test our approach using multiple types of interactions simultaneously. Here, we support the use of motifs in multi-trophic interaction networks in agroecosystems to reveal the role of key plant species in sustaining ecological functions involving crops and other plant species, enhancing the evidence base for management recommendations in the future.