Enhancing weed multifunctionality at a landscape scale: A simulation study

Abstract

There is a pressing need for research guiding the design and management of multifunctional landscapes that combine the delivery of production services and that of other ecosystem services. Arable weeds are an interesting model as they can impact negatively crop production but also contribute to maintain pollination and pest control services. Here, we assessed weed multifunctionality using weed data recorded within a small landscape, in the field edge and field core of 97 fields over six consecutive years. We detected a general positive correlation between harmfulness and services provision, at the field-scale and at the landscape scale. At the field scale, the flora of field edges strongly contributed to the delivery of (dis)services; some fields delivered interesting trade-offs, and this was only weakly explained by the crop management strategy. At the landscape scale, we explored through scenarii the impact of changes in the composition (proportional cover of the different crop management strategies) and structure (field size, i.e. length of field edges) of the land-use mosaics on weed multifunctionality. Land–use mosaics offering interesting trade-offs were for the most part characterised by an even representation of the different crop management strategies. Small-grained landscapes did not offer better trade–offs than the current landscape structure, but slightly improved the inter-annual stability of services. Our results support the idea that promoting the co-existence of various cropping strategies within landscape is a good option to reconcile the positive and negative impacts of weeds.