Agricultural management intensity determines the strength of weed seed predationDaouti, Eirini; Feit, Benjamin; Jonsson, Mattias;
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 dis-turbances 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 in-tensity 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.
Carabid species; Agricultural intensity; Poa annua; Arable plants; SEM path analysis
Published inAgriculture, Ecosystems and Environment 2022, volume: 339, article number: 108132
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