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Author (up) Bennie, J.; Davies, T.W.; Cruse, D.; Gaston, K.J.
Title Ecological effects of artificial light at night on wild plants Type Journal Article
Year 2016 Publication Journal of Ecology Abbreviated Journal J Ecol
Volume 104 Issue 3 Pages 611-620
Keywords Plants; wild plants; photobiology; Circadian; Ecophysiology; light cycles; light pollution; photoperiodism; photopollution; physiology; sky glow; urban ecology
Abstract 1.Plants use light as a source of both energy and information. Plant physiological responses to light, and interactions between plants and animals (such as herbivory and pollination), have evolved under a more or less stable regime of 24-hour cycles of light and darkness, and, outside of the tropics, seasonal variation in daylength.

2.The rapid spread of outdoor electric lighting across the globe over the past century has caused an unprecedented disruption to these natural light cycles. Artificial light is widespread in the environment, varying in intensity by several orders of magnitude from faint skyglow reflected from distant cities to direct illumination of urban and suburban vegetation.

3.In many cases artificial light in the nighttime environment is sufficiently bright to induce a physiological response in plants, affecting their phenology, growth form and resource allocation. The physiology, behaviour and ecology of herbivores and pollinators is also likely to be impacted by artificial light. Thus, understanding the ecological consequences of artificial light at night is critical to determine the full impact of human activity on ecosystems.

4.Synthesis. Understanding the impacts of artificial nighttime light on wild plants and natural vegetation requires linking the knowledge gained from over a century of experimental research on the impacts of light on plants in the laboratory and greenhouse with knowledge of the intensity, spatial distribution, spectral composition and timing of light in the nighttime environment. To understand fully the extent of these impacts requires conceptual models that can (i) characterise the highly heterogeneous nature of the nighttime light environment at a scale relevant to plant physiology, and (ii) scale physiological responses to predict impacts at the level of the whole plant, population, community and ecosystem.
Address Environment and Sustainability Institute, University of Exeter, Penryn, United Kimgdom; j.j.bennie(at)exeter.ac.uk
Corporate Author Thesis
Publisher Wiley Place of Publication Editor
Language English Summary Language English Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0022-0477 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number IDA @ john @ Serial 1350
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Author (up) Bennie, J.; Davies, T.W.; Cruse, D.; Inger, R.; Gaston, K.J.
Title Cascading effects of artificial light at night: resource-mediated control of herbivores in a grassland ecosystem Type Journal Article
Year 2015 Publication Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences Abbreviated Journal Philos Trans R Soc Lond B Biol Sci
Volume 2015 Issue Pages 20140131
Keywords Ecology; light pollution; photopollution; artificial light at night; biotic interactions; community-level; bottom-up effects; grasslands; herbivores; invertebrates; pea aphid; Acyrthosiphon pisum; plants; insects
Abstract Artificial light at night has a wide range of biological effects on both plants and animals. Here, we review mechanisms by which artificial light at night may restructure ecological communities by modifying the interactions between species. Such mechanisms may be top-down (predator, parasite or grazer controlled), bottom-up (resource-controlled) or involve non-trophic processes, such as pollination, seed dispersal or competition. We present results from an experiment investigating both top-down and bottom-up effects of artificial light at night on the population density of pea aphids Acyrthosiphon pisum in a diverse artificial grassland community in the presence and absence of predators and under low-level light of different spectral composition. We found no evidence for top-down control of A. pisum in this system, but did find evidence for bottom-up effects mediated through the impact of light on flower head density in a leguminous food plant. These results suggest that physiological effects of light on a plant species within a diverse plant community can have detectable demographic effects on a specialist herbivore.
Address Environment and Sustainability Institute, University of Exeter, Penryn TR10 9FE, UK; k.j.gaston@exeter.ac.uk
Corporate Author Thesis
Publisher Royal Society Place of Publication Editor
Language English Summary Language English Original Title
Series Editor Series Title The biological impacts of artificial light at night: from molecules to communities Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number IDA @ john @ Serial 1128
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Author (up) Bennie, J.; Davies, T.W.; Cruse, D.; Inger, R.; Gaston, K.J.; Lewis, O.
Title Artificial light at night causes top-down and bottom-up trophic effects on invertebrate populations Type Journal Article
Year 2018 Publication Journal of Applied Ecology Abbreviated Journal J Appl Ecol
Volume 55 Issue 6 Pages 2698-2706
Keywords Ecology; Animals; Plants
Abstract Globally, many ecosystems are exposed to artificial light at night. Nighttime lighting has direct biological impacts on species at all trophic levels. However, the effects of artificial light on biotic interactions remain, for the most part, to be determined.

We exposed experimental mesocosms containing combinations of grassland plants and invertebrate herbivores and predators to illumination at night over a 3‐year period to simulate conditions under different common forms of street lighting.

We demonstrate both top‐down (predation‐controlled) and bottom‐up (resource‐controlled) impacts of artificial light at night in grassland communities. The impacts on invertebrate herbivore abundance were wavelength‐dependent and mediated via other trophic levels.

White LED lighting decreased the abundance of a generalist herbivore mollusc by 55% in the presence of a visual predator, but not in its absence, while monochromatic amber light (with a peak wavelength similar to low‐pressure sodium lighting) decreased abundance of a specialist herbivore aphid (by 17%) by reducing the cover and flower abundance of its main food plant in the system. Artificial white light also significantly increased the food plant's foliar carbon to nitrogen ratio.

We conclude that exposure to artificial light at night can trigger ecological effects spanning trophic levels, and that the nature of such impacts depends on the wavelengths emitted by the lighting technology employed.

Policy implications. Our results confirm that artificial light at night, at illuminance levels similar to roadside vegetation, can have population effects mediated by both top‐down and bottom‐up effects on ecosystems. Given the increasing ubiquity of light pollution at night, these impacts may be widespread in the environment. These results underline the importance of minimizing ecosystem disruption by reducing light pollution in natural and seminatural ecosystems.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0021-8901 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number NC @ ehyde3 @ Serial 2086
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Author (up) Davies, T.W.; Bennie, J.; Cruse, D.; Blumgart, D.; Inger, R.; Gaston, K.J.
Title Multiple night-time light-emitting diode lighting strategies impact grassland invertebrate assemblages Type Journal Article
Year 2017 Publication Global Change Biology Abbreviated Journal Glob Chang Biol
Volume 23 Issue 7 Pages 2641-2648
Keywords Ecology; grasslands; LED
Abstract White light-emitting diodes (LEDs) are rapidly replacing conventional outdoor lighting technologies around the world. Despite rising concerns over their impact on the environment and human health, the flexibility of LEDs has been advocated as a means of mitigating the ecological impacts of globally widespread outdoor night-time lighting through spectral manipulation, dimming and switching lights off during periods of low demand. We conducted a three-year field experiment in which each of these lighting strategies was simulated in a previously artificial light naive grassland ecosystem. White LEDs both increased the total abundance and changed the assemblage composition of adult spiders and beetles. Dimming LEDs by 50% or manipulating their spectra to reduce ecologically damaging wavelengths partially reduced the number of commoner species affected from seven to four. A combination of dimming by 50% and switching lights off between midnight and 04:00 am showed the most promise for reducing the ecological costs of LEDs, but the abundances of two otherwise common species were still affected. The environmental consequences of using alternative lighting technologies are increasingly well established. These results suggest that while management strategies using LEDs can be an effective means of reducing the number of taxa affected, averting the ecological impacts of night-time lighting may ultimately require avoiding its use altogether.
Address Environment and Sustainability Institute, University of Exeter, Penryn, Cornwall, TR10 9FE, UK
Corporate Author Thesis
Publisher Wiley Place of Publication Editor
Language English Summary Language English Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1354-1013 ISBN Medium
Area Expedition Conference
Notes PMID:28139040 Approved no
Call Number LoNNe @ kyba @ Serial 1634
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Author (up) Kehoe, R.; Sanders, D.; Cruse, D.; Silk, M.; Gaston, K.J.; Bridle, J.R.; van Veen, F.
Title Longer photoperiods through range shifts and artificial light lead to a destabilising increase in host-parasitoid interaction strength Type Journal Article
Year 2020 Publication The Journal of Animal Ecology Abbreviated Journal J Anim Ecol
Volume in press Issue Pages in press
Keywords Ecology; Aphid; climate change; interaction; light pollution; parasitoid; photoperiod; range expansion; stability
Abstract Many organisms are experiencing changing daily light regimes due to latitudinal range shifts driven by climate change and increased artificial light at night (ALAN). Activity patterns are often driven by light cycles, which will have important consequences for species interactions. We tested whether longer photoperiods lead to higher parasitism rates by a day-active parasitoid on its host using a laboratory experiment in which we independently varied day length and the presence of ALAN. We then tested whether reduced nighttime temperature tempers the effect of ALAN. We found that parasitism rate increased with day length, with ALAN intensifying this effect only when the temperature was not reduced at night. The impact of ALAN was more pronounced under short day length. Increased parasitoid activity was not compensated for by reduced lifespan, indicating that increased day length leads to an increase in total parasitism effects on fitness. To test the significance of increased parasitism rate for population dynamics, we developed a host-parasitoid model. The results of the model predicted an increase in time-to-equilibrium with increased day length and, crucially, a threshold day length above which interactions are unstable, leading to local extinctions. Here we demonstrate that ALAN impact interacts with day length and temperature by changing the interaction strength between a common day-active consumer species and its host in a predictable way. Our results further suggest that range expansion or ALAN induced changes in light regimes experienced by insects and their natural enemies will result in unstable dynamics beyond key tipping points in day length.
Address College of Life and Environmental Sciences, University of Exeter, Penryn, Cornwall, UK
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0021-8790 ISBN Medium
Area Expedition Conference
Notes PMID:32858779 Approved no
Call Number GFZ @ kyba @ Serial 3107
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Author (up) Kehoe, R.C.; Cruse, D.; Sanders, D.; Gaston, K.J.; van Veen, F.J.F.
Title Shifting daylength regimes associated with range shifts alter aphid-parasitoid community dynamics Type Journal Article
Year 2018 Publication Ecology and Evolution Abbreviated Journal Ecol Evol
Volume 8 Issue 17 Pages 8761-8769
Keywords Animals; Ecology
Abstract With climate change leading to poleward range expansion of species, populations are exposed to new daylength regimes along latitudinal gradients. Daylength is a major factor affecting insect life cycles and activity patterns, so a range shift leading to new daylength regimes is likely to affect population dynamics and species interactions; however, the impact of daylength in isolation on ecological communities has not been studied so far. Here, we tested for the direct and indirect effects of two different daylengths on the dynamics of experimental multitrophic insect communities. We compared the community dynamics under “southern” summer conditions of 14.5-hr daylight to “northern” summer conditions of 22-hr daylight. We show that food web dynamics indeed respond to daylength with one aphid species (Acyrthosiphon pisum) reaching much lower population sizes at the northern daylength regime compared to under southern conditions. In contrast, in the same communities, another aphid species (Megoura viciae) reached higher population densities under northern conditions. This effect at the aphid level was driven by an indirect effect of daylength causing a change in competitive interaction strengths, with the different aphid species being more competitive at different daylength regimes. Additionally, increasing daylength also increased growth rates in M. viciae making it more competitive under summer long days. As such, the shift in daylength affected aphid population sizes by both direct and indirect effects, propagating through species interactions. However, contrary to expectations, parasitoids were not affected by daylength. Our results demonstrate that range expansion of whole communities due to climate change can indeed change interaction strengths between species within ecological communities with consequences for community dynamics. This study provides the first evidence of daylength affecting community dynamics, which could not be predicted from studying single species separately.
Address College of Life and Environmental Sciences University of Exeter Penryn Cornwall UK
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2045-7758 ISBN Medium
Area Expedition Conference
Notes PMID:30271543; PMCID:PMC6157684 Approved no
Call Number NC @ ehyde3 @ Serial 2100
Permanent link to this record
 

 
Author (up) Sanders, D.; Kehoe, R.; Cruse, D.; van Veen, F.J.F.; Gaston, K.J.
Title Low Levels of Artificial Light at Night Strengthen Top-Down Control in Insect Food Web Type Journal Article
Year 2018 Publication Current Biology : CB Abbreviated Journal Curr Biol
Volume 28 Issue 15 Pages 2474-2478.e3
Keywords Ecology; Animals
Abstract Artificial light has transformed the nighttime environment of large areas of the earth, with 88% of Europe and almost 50% of the United States experiencing light-polluted night skies [1]. The consequences for ecosystems range from exposure to high light intensities in the vicinity of direct light sources to the very widespread but lower lighting levels further away [2]. While it is known that species exhibit a range of physiological and behavioral responses to artificial nighttime lighting [e.g., 3-5], there is a need to gain a mechanistic understanding of whole ecological community impacts [6, 7], especially to different light intensities. Using a mesocosm field experiment with insect communities, we determined the impact of intensities of artificial light ranging from 0.1 to 100 lux on different trophic levels and interactions between species. Strikingly, we found the strongest impact at low levels of artificial lighting (0.1 to 5 lux), which led to a 1.8 times overall reduction in aphid densities. Mechanistically, artificial light at night increased the efficiency of parasitoid wasps in attacking aphids, with twice the parasitism rate under low light levels compared to unlit controls. However, at higher light levels, parasitoid wasps spent longer away from the aphid host plants, diminishing this increased efficiency. Therefore, aphids reached higher densities under increased light intensity as compared to low levels of lighting, where they were limited by higher parasitoid efficiency. Our study highlights the importance of different intensities of artificial light in driving the strength of species interactions and ecosystem functions.
Address Environment and Sustainability Institute, University of Exeter, Penryn, Penryn, Cornwall TR10 9FE, UK
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0960-9822 ISBN Medium
Area Expedition Conference
Notes PMID:30057304 Approved no
Call Number GFZ @ kyba @ Serial 2518
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Author (up) Sanders, D.; Kehoe, R.; Tiley, K.; Bennie, J.; Cruse, D.; Davies, T.W.; Frank van Veen, F.J.; Gaston, K.J.
Title Artificial nighttime light changes aphid-parasitoid population dynamics Type Journal Article
Year 2015 Publication Scientific Reports Abbreviated Journal Sci Rep
Volume 5 Issue Pages 15232
Keywords Ecology; animals; plants
Abstract Artificial light at night (ALAN) is recognized as a widespread and increasingly important anthropogenic environmental pressure on wild species and their interactions. Understanding of how these impacts translate into changes in population dynamics of communities with multiple trophic levels is, however, severely lacking. In an outdoor mesocosm experiment we tested the effect of ALAN on the population dynamics of a plant-aphid-parasitoid community with one plant species, three aphid species and their specialist parasitoids. The light treatment reduced the abundance of two aphid species by 20% over five generations, most likely as a consequence of bottom-up effects, with reductions in bean plant biomass being observed. For the aphid Megoura viciae this effect was reversed under autumn conditions with the light treatment promoting continuous reproduction through asexuals. All three parasitoid species were negatively affected by the light treatment, through reduced host numbers and we discuss induced possible behavioural changes. These results suggest that, in addition to direct impacts on species behaviour, the impacts of ALAN can cascade through food webs with potentially far reaching effects on the wider ecosystem.
Address Environment &Sustainability Institute, University of Exeter, Cornwall Campus Penryn, Cornwall, TR10 9EZ, United Kingdom
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2045-2322 ISBN Medium
Area Expedition Conference
Notes PMID:26472251; PMCID:PMC4607942 Approved no
Call Number LoNNe @ kyba @ Serial 1290
Permanent link to this record