Can macroplastics affect riparian vegetation blooming and pollination? First observations from a temperate South-European river

•Macroplastics entrapped by riparian vegetation in Aniene river (central Italy).•First field observation of macroplastics covering vegetation’s flowers.•Macroplastics on vegetation may threaten bud emissions and flower blooming.•We deduced that the ecosystem service of pollination was partially reduced.