Agricultural practices in olive groves modify weeds floral traits and resources throughout the year

Lack of floral resources is suspected to be one of the factors involved in flower-visiting insect declines. Because agricultural landscapes are often poor in flowers, it seems crucial to assess weeds as floral resources to feed flower-visiting insects and to identify the factors that drive floral productivity, defined as floral biomass produced by the weed community. We monitored floral presence, productivity and traits in 16 olive groves from September 2021 to June 2022. The objectives were to understand to which extinct abiotic factors, among agricultural practices, pedoclimate and weather, determine floral productivity and to analyse the relationships between floral traits, floral presence and productivity. We found mowing frequency (2–3 per year on average) increased mean floral area and height, advanced flowering onset, and increased floral functional diversity and flowering species richness, which in turn increased floral presence and productivity. •Community level weeds floral traits are linked to flower productivity in olive groves.•Both weeds morphological and phenological traits are linked to flower productivity.•Weeds floral traits and flower productivity are modified by agricultural practices.•Low-regime mowing filters weeds communities producing more diverse floral resources that are available during a longer period.•Irrigation, fertilization and pedoclimate also impact weeds floral resources.