EFFECTS OF ROAD DUST ON THE POLLINATION AND REPRODUCTION OF WILDFLOWERS

Premise of research. Dust particles and pollen grains are similar in size. Dust deposition might therefore influence the pollination and reproduction of flowering plants. Little is known about such effects, however, despite more general interest in ecological effects of dust.Methodology. We used observational and experimental methods to explore whether dust generated by traffic on unpaved roads affects the amounts of pollen received and numbers of seeds produced by four species of native wildflowers in the western United States.Pivotal results. Flowers of Nuttall’s larkspur (Delphinium nuttallianum), scarlet gilia (Ipomopsis aggregata), Lewis flax (Linum lewisii), and sulphur paintbrush (Castilleja sulphurea) growing 1–2 m from a road received substantially more dust and less pollen than those growing 40–50 m away. We observed the same pattern when we transplanted individuals of the first two species into pots and placed pots near to compared with far from a road. Experimental “hand dusting” of scarlet gi...