Rapid assessment of lamp spectrum to quantify ecological effects of light at night

Abstract

For many decades, the spectral composition of lighting was determined by the type of lamp, which also influenced potential effects of outdoor lights on species and ecosystems. Light-emitting diode (LED) lamps have dramatically increased the range of spectral profiles of light that is economically viable for outdoor lighting. Because of the array of choices, it is necessary to develop methods to predict the effects of different spectral profiles without conducting field studies, especially because older lighting systems are being replaced rapidly. We describe an approach to predict responses of exemplar organisms and groups to lamps of different spectral output by calculating an index based on action spectra from behavioral or visual characteristics of organisms and lamp spectral irradiance. We calculate relative response indices for a range of lamp types and light sources and develop an index that identifies lamps that minimize predicted effects as measured by ecological, physiological, and astronomical indices. Using these assessment metrics, filtered yellow-green and amber LEDs are predicted to have lower effects on wildlife than high pressure sodium lamps, while blue-rich lighting (e.g., K ≥ 2200) would have greater effects. The approach can be updated with new information about behavioral or visual responses of organisms and used to test new lighting products based on spectrum. Together with control of intensity, direction, and duration, the approach can be used to predict and then minimize the adverse effects of lighting and can be tailored to individual species or taxonomic groups.

Artificial light at night causes top‐down and bottom‐up trophic effects on invertebrate populations

“…This shift towards exposure to short‐wavelength light has caused concern for human health (West et al., ) and ecological systems (Davies et al., ). Known ecological responses to light at night vary in their sensitivity to different wavelengths, although many responses appear to be more sensitive to “blue” light (Longcore et al., ). Our results suggest that the response of an ecosystem to changes in the intensity and spectra of artificial light in the environment may be complex and mediated through multiple physiological pathways and trophic levels.…”

“…Our results suggest that great care should be taken to consider both the physiological and ecological pathways through which the impacts of artificial light are realized. Plants, and hence specialist herbivores, are likely to be susceptible to higher wavelength light, particularly the red/far red ratio (Bennie et al., ; Briggs, ; Cathey & Campbell, ), while many physiological pathways such as cryptochrome and melatonin, and behaviours such as insect phototaxis are most sensitive to lower wavelength blue light (Longcore et al., ). Species that are able to utilize artificial light for vision, are likely to respond to broad wavelength “white” light.…”

The impact of artificial light at night on nocturnal insects: A review and synthesis

“…Exposure to blue light at night is known to cause insomnia and increased disease risk in humans (American Medical Association, ). However, the effects of this widespread spectral shift on other organisms have only recently attracted the attention of researchers (Davies et al, ; Donners et al, ; Gaston, Visser, & Hölker, ; Justice & Justice, ; Lewanzik & Voigt, ; Longcore et al, ; Pawson & Bader, ; Plummer, Hale, O'Callaghan, Sadler, & Siriwardena, ; Somers‐Yeates, Hodgson, McGregor, Spalding, & Ffrench‐Constant, ; Spoelstra et al, ; van Grunsven et al, ; van Langevelde, Grunsven, Veenendaal, & Fijen, ; Wakefield, Broyles, Stone, Jones, & Harris, ).…”

Connecting spectral radiometry of anthropogenic light sources to the visual ecology of organisms

“…() and Longcore et al . () have devised theoretical models to determine how specific light sources overlap with the full range of visual sensitivities for organisms. These studies have established an understanding of how different spectra of light sources overlapped with different visual systems, however, these studies combine the overall visual range of organisms and do not investigate artificial light at the photoreceptor level.…”

“…Although numerous studies have investigated behavioral responses to different light sources (Langevelde et al, 2011;van Grunsven et al, 2014;Longcore et al, 2015;Spoelstra et al, 2017), few studies have investigated varied spectral signatures in the environment, see Davies et al (2013); Donners et al (2018); Longcore et al (2018). Davies et al (2013) found that low-pressure sodium lamps emitted the smallest proportion of the light spectrum to which animals are sensitive, whereas metal halides (MH) lamps emitted the largest proportion.…”