title: Light pollution is associated with earlier tree budburst across the United Kingdom.
abstract: The ecological impact of night-time lighting is of concern because of its well-demonstrated effects on animal behaviour. However, the potential of light pollution to change plant phenology and its corresponding knock-on effects on associated herbivores are less clear. Here, we test if artificial lighting can advance the timing of budburst in trees. We took a UK-wide 13 year dataset of spatially referenced budburst data from four deciduous tree species and matched it with both satellite imagery of night-time lighting and average spring temperature. We find that budburst occurs up to 7.5 days earlier in brighter areas, with the relationship being more pronounced for later-budding species. Excluding large urban areas from the analysis showed an even more pronounced advance of budburst, confirming that the urban 'heat-island' effect is not the sole cause of earlier urban budburst. Similarly, the advance in budburst across all sites is too large to be explained by increases in temperature alone. This dramatic advance of budburst illustrates the need for further experimental investigation into the impact of artificial night-time lighting on plant phenology and subsequent species interactions. As light pollution is a growing global phenomenon, the findings of this study are likely to be applicable to a wide range of species interactions across the world.
authors.affiliation: Centre for Ecology and Conservation, University of Exeter, Penryn TR10 9EZ, UK rf222@exeter.ac.uk.
authors.forename: Richard H
authors.identifier: 0000-0001-5385-9888
authors.initials: RH
authors.lastname: Ffrench-Constant
authors.affiliation: Centre for Ecology and Conservation, University of Exeter, Penryn TR10 9EZ, UK.
authors.forename: Robin
authors.initials: R
authors.lastname: Somers-Yeates
authors.affiliation: Environment and Sustainability Institute, University of Exeter, Penryn TR10 9EZ, UK.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Bennie
authors.affiliation: College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter EX4 UY, UK.
authors.forename: Theodoros
authors.identifier: 0000-0001-8697-1518
authors.initials: T
authors.lastname: Economou
authors.affiliation: Centre for Ecology and Conservation, University of Exeter, Penryn TR10 9EZ, UK.
authors.forename: David
authors.initials: D
authors.lastname: Hodgson
authors.affiliation: Spalding Associates (Environmental) Ltd, 10 Walsingham Place, Truro TR1 2RP, UK.
authors.forename: Adrian
authors.initials: A
authors.lastname: Spalding
authors.affiliation: Centre for Applied Zoology, Cornwall College Newquay, Newquay TR7 2LZ, UK.
authors.forename: Peter K
authors.identifier: 0000-0001-6337-5254
authors.initials: PK
authors.lastname: McGregor
mesh_terms: D008029:Lighting; D018515:Plant Leaves / Q000254:growth & development; D012621:Seasons; D013696:Temperature; D014197:Trees / Q000502:physiology*; D006113:United Kingdom
keywords: light pollution; phenology; species interactions; temperature; tree budburst; urban heat islands