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Intensified agriculture, a driver of biodiversity loss, can diminish ecosystem functions and their stability. Biodiversity can increase functional redundancy and is expected to stabilize ecosystem functions. Few studies, however, have explored how agricultural intensity affects functional redundancy and its link with ecosystem function stability. Here, within a continental‐wide study, we assess how functional redundancy of seed predation is affected by agricultural intensity and landscape simplification. By combining carabid abundances with molecular gut content data, functional redundancy of seed predation was quantified for 65 weed genera across 60 fields in four European countries. Across weed genera, functional redundancy was reduced with high field management intensity and simplified crop rotations. Moreover, functional redundancy increased the spatial stability of weed seed predation at the field scale. We found that ecosystem functions are vulnerable to disturbances in intensively managed agroecosystems, providing empirical evidence of the importance of biodiversity for stable ecosystem functions across space. [ABSTRACT FROM AUTHOR]

Seed predation can reduce the abundance and spread of unwanted vegetation in agricultural and other semi‐natural ecosystems. However, knowledge of how variations in seed predation rates affect plant species population dynamics is needed for decision making and knowledge‐based ecosystem management.We developed a stage‐classified stochastic matrix population model for Alopecurus myosuroides Huds. (blackgrass), an annual plant species thriving as a weed in temperate agroecosystems of Western and Northern Europe. The model was parameterised using empirical demographic data from long‐term experiments in Swedish winter wheat fields, including information on post‐dispersal seed losses by vertebrate and invertebrate seed predators.For agroecosystems with highly effective weed control measures (e.g. chemical and mechanical weed control), model simulations showed that seed losses via seed predation need to reach at least 78% at peak seed shedding to suppress population growth of A. myosuroides.The field experiment showed that vertebrates were most important for seed predation in July, at peak seed shedding. In August, after crop harvest, invertebrates were responsible for almost all seed predation. The model indicated that weed seed predation was much more important for weed regulation when it occurred before crop harvest in July. Vertebrates most strongly reduced population growth of A. myosuroides, although both vertebrates and invertebrates were needed to prevent it entirely.Synthesis and applications. We showed that weed seed predation by vertebrate and invertebrate seed predators is key for reducing the population growth of winter annual weeds like A. myosuroides in intensively managed agroecosystems. Therefore, protection of weed seed predators is essential for making management of unwanted vegetation less dependent on chemical and mechanical measures. [ABSTRACT FROM AUTHOR]

Agricultural intensification both increases disturbances at the field level and reduces habitat heterogeneity at the landscape level and this can have detrimental effects on biodiversity-driven ecosystem services. A few studies have shown that agricultural intensification can diminish the ecosystem service of weed seed predation, but it is not known to what extent availability of crop and non-crop habitat can provide disturbance refugia for weed seed predators and how those effects cascade to ecosystem service provisioning. Using data from 13 fields in Southern Sweden, we first combined diet preference traits, activity density and metabolic theory, in order to develop a metric that approximates the community strength of seed predation. We then explored how the impact of field management intensity and habitat refugia on seed card predation rates mediated by weed seed availability and the metric of community strength of seed predation. We found that increasing field management intensity directly reduced seed card predation rates and weed seed availability and that reduced weed seed availability in turn impaired the community strength of seed predation. This suggests an indirect mechanism by which field management limits seed predator potential for weed seed predation. We found no evidence that either crop or non-crop refugia can increase seed card predation rates or community strength of seed predation during disturbances in the crop. Consequently, weed seed predation can be promoted by reducing disturbances at the field level, regardless of the availability of disturbance refugia in the landscape. Reduction of field management intensity can directly increase weed seed predation and indirectly seed predator communities' potential for weed seed predation by increasing weed seed availability. Future research is needed to explore if supporting a diversity of non-competitive weeds to enhance seed availability can improve the suppression of dominant and competitive weed species. [Display omitted] • We developed a novel metric approximating the strength of weed seed predation. • Seed card predation rates and seed availability were reduced by field disturbances. • Disturbance refugia had no direct or indirect effect on weed seed predation. • Weed seed availability increased predator community strength of weed seed predation. • Reduced field management intensity can promote weed seed predation. [ABSTRACT FROM AUTHOR]