Does street lighting affect pollinators?

Increased urbanisation has led to increased night lighting.  ALAN (Artificial Light At Night), has an effect on natural life forms - plants, birds, insects and small mammals - suppressing or encouraging growth and activity.  Recent research has looked into ALAN's effect on pollination.
 
Researchers at Newcastle University compared night-pollinator visits to one plant species, White Campion Silene latifolia, under different night light conditions – lights on throughout the night (FN, full-night lighting), PN (part-night lighting) and no lighting. They expected that FN lighting would lead to fewer pollinator visits.  But in fact full-night lighting resulted in the most visits by pollinators (nocturnal moths in the most part). There was little difference in pollination between no light and part-night light conditions.

However, researchers were cautious in their response to the results. They surmise that pollination benefit for one plant species under full-night light does not mean all other species will benefit in the same way. The white flowers of Campion could be rendered brighter than other flowers around it in artificial light. They also stand taller than other surrounding species. These two factors could explain the increased pollinator visits.

The experiment also looked at the difference between sodium lighting (HPS) and modern LED lights. Firstly, researchers assessed pollination success by taking plants indoors in order to monitor the development of one or more seeds in the seed capsule. Seed count did not differ between HPS lights and LEDs when under FN lighting, but under PN lighting, seed count was higher under HPS lights and lower under LEDs.  This is relevant for councils who are replacing old sodium lighting with 'more efficient' LEDs.

See here for the full research paper.
Posted: 
Tuesday, 7 May 2019