The role of weeds in field margins in supporting wild pollinators in Mediterranean cereal agroecosystems

Concerns about a global decline in pollinators have called for more knowledge about the drivers of wild pollinator abundance and diversity. In this study we observed pollinator foraging activity in 27 field margins, from 2014-2016, in order to investigate the role of native weeds in supporting wild pollinators in Mediterranean cereal agroecosystems. In total, 175 different plant species were identified and 1,959 wild pollinators were observed foraging on margin flora. The most visited floral species were Papaver rhoeas L. (251 pollinator visits), Torilis arvensis (Huds.) (229 visits) and Malva sylvestris L. (141 visits). Pollinator abundance increased with flower abundance, vegetation height and floral diversity. Pollinator visits increased initially with open flower richness, but began to decrease when high richness likely resulted in lower densities of individual species.