Leatherback hatchling sea-finding in response to artificial lighting: Interaction between wavelength and moonlight

Abstract

21Over the last decades, growing human populations have led to the rising occupation of 22 coastal areas over the globe causing light pollution. For this reason, it is important to assess 23 how this impact threatens endangered wildlife. Leatherback turtles (Dermochelys coriacea) 24 face many threats of anthropogenic origin including light pollution on nesting beaches. 25However, little is known about the specific effects. In this study we studied the effect of 26 different light wavelengths (orange, red, blue, green, yellow and white lights) on hatchling 27 orientation under the presence and absence of moonlight by analyzing: (i) the mean angle of 28 orientation, (ii) crawling duration, and (iii) track patterns. 29Hatchling orientation towards the sea was always better under controlled conditions. 30In the absence of moonlight, leatherback hatchlings were phototaxically attracted to the 31 experimental focus of light (misoriented) for the colours blue, green, yellow and white lights. 32Orange and red lights caused a lower misorientation than other colors, and orange lights 33 produced the lowest disrupted orientation (disorientation). On nights when moonlight was 34 present, hatchlings were misorientated under blue and white artificial lights. Crawling 35 duration was low for misoriented hatchlings and high for the disoriented individuals. Our 36 conclusion to this is that hatchlings can detect and be impacted by a wide range of the light 37 spectrum and we recommend avoiding the presence of artificial lights on nesting beaches. 38Additionally, actions to control and mitigate artificial lighting are especially important during 39 dark nights when moonlight is absent.

Multiple night‐time light‐emitting diode lighting strategies impact grassland invertebrate assemblages

“…The focus for limiting the ecological impacts of white LEDs has so far been on manipulating their spectra to avoid emitting wavelengths that disproportionately affect the environment (Pawson & Bader, ; Longcore et al ., ; Rivas et al ., ; Brüning et al ., ). In the current study amber LEDs, which completely avoided blue‐green wavelengths known to attract Lepidoptera (Van Langevelde et al ., ), did not mitigate the effects of white LEDs on grassland spiders, while beetles were less sensitive to amber compared to white LEDs.…”

Why artificial light at night should be a focus for global change research in the 21st century

“…The ecological benefits of dimming and part‐night lighting are not yet well explored (although see Azam et al., ; Day, Baker, Schofield, Mathews, & Gaston, ; Davies et al., ). A recent emphasis in the ecological literature has instead been on tailoring spectral power distributions to reduce known ecological impacts (Brüning, Hölker, Franke, Kleiner, & Kloas, ; Davies et al., ; van Geffen et al., ; Longcore et al., ; Pawson & Bader, ; Rivas, Tomillo, Uribeondo, & Marco, ; Spoelstra et al., ), despite this approach being less popular among lighting managers and engineers who often focus on the improved visual performance offered by broad‐spectrum lighting as a key selling point. These studies collectively present an inconsistent picture of whether spectral manipulation can be used to effectively mitigate the ecological impacts of ALAN.…”

“…The number of beetle taxa aggregating under white LED lighting can be reduced by switching to amber, but this has no discernible effect on the number of spider taxa that aggregate (Davies et al., ). Many animal responses are sensitive to short‐wavelength light (van Langevelde et al., ; Rivas et al., ; Spoelstra et al., ), while phenological responses in plants are most sensitive to the longer wavelengths recommended to avoid such effects (Bennie et al., ; Bennie, Davies, et al., ). Male caterpillars of the moth Mamestra brassicae reared under green artificial light reached a lower maximum mass, pupated earlier and obtained a lower pupal mass than those reared under red light (van Geffen, van Grunsven, van Ruijven, Berendse, & Veenendaal, ), while red light inhibited the attractiveness of a female pheromone lure to more adult males of the winter moth Operophtera brumata than did green light (van Geffen et al., ).…”

“…The number of beetle taxa aggregating under white LED lighting can be reduced by switching to amber, but this has no discernible effect on the number of spider taxa that aggregate (Davies et al, 2017). Many animal responses are sensitive to short-wavelength light (van Langevelde et al, 2011;Rivas et al, 2015;Spoelstra et al, 2017), while phenological responses in plants are most sensitive to the longer wavelengths recommended to avoid such effects .…”

Marine turtles are not fussy nesters: a novel test of small-scale nest site selection using structure from motion beach terrain information

“…Artificial night-light can alter the behaviour of female turtles that emerge to nest on beaches where the light environment is significantly changed (Salmon & Witherington, 1995; Mazaris, Matsinos & Pantis, 2009). Artificial lights can disorient hatchlings and increase the risk of predation (Limpus & Kamrowski, 2013; Rivas et al, 2015; Thums et al, 2016). Many urban beaches have seawalls and are being artificially nourished with sand, detrimentally affecting nesting female turtles and hatchlings (Brock, Reece & Ehrhart, 2009; Rizkalla & Savage, 2010; Fujisaki & Lamont, 2016).…”