Patterns of weed co-occurrence at the field and landscape level

International audienceQuestion Are patterns of weed co-occurrence structured or random? Do these patterns differ at the field and landscape scales? Are co-occurrence patterns related to the effect of environmental filters and/or competition? Location France. Methods Weed communities were surveyed in 3008 4-m2 plots, i.e. 32 plots per field in 94 winter-wheat fields located in the same landscape. We estimated patterns of species co-occurrence (C-score) at the field and landscape level. Additional characteristics of weed communities (degree of habitat specialization, competitive ability) and sampled fields (within-field and among-fields environmental heterogeneity) were used to interpret observed co-occurrence patterns at both scales. Results Non-randomness was detected in