Davies, T. W., Bennie, J., Inger, R., Hempel de Ibarra, N., & Gaston, K. J. (2013). Artificial light pollution: are shifting spectral signatures changing the balance of species interactions? Global Change Biologyology, 19(5), 1417–1423.
Abstract: Technological developments in municipal lighting are altering the spectral characteristics of artificially lit habitats. Little is yet known of the biological consequences of such changes, although a variety of animal behaviours are dependent on detecting the spectral signature of light reflected from objects. Using previously published wavelengths of peak visual pigment absorbance, we compared how four alternative street lamp technologies affect the visual abilities of 213 species of arachnid, insect, bird, reptile and mammal by producing different wavelength ranges of light to which they are visually sensitive. The proportion of the visually detectable region of the light spectrum emitted by each lamp was compared to provide an indication of how different technologies are likely to facilitate visually guided behaviours such as detecting objects in the environment. Compared to narrow spectrum lamps, broad spectrum technologies enable animals to detect objects that reflect light over more of the spectrum to which they are sensitive and, importantly, create greater disparities in this ability between major taxonomic groups. The introduction of broad spectrum street lamps could therefore alter the balance of species interactions in the artificially lit environment.
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Davoudian, N. (2017). Background lighting clutters: how do they affect visual saliency of urban objects? International Journal of Design Creativity and Innovation, 5(1-2), 95–103.
Abstract: The current study aims to create some general guidance for designers to better understand the impact of background lighting in their design and as a result minimize its effect on the visual saliency of urban objects. There are few studies about how lighting clutters can affect and decrease the visual saliency of illuminated urban objects at night. Lack of information in this area has resulted in increasing luminance to be recognized as one of the main tools to enhance the saliency of urban objects at night. To address this matter a study was performed to investigate the effect of proximity of lighting clutters on visual saliency of urban objects. A forced choice pair comparison method was employed, in which two test images of an urban object in different conditions of luminance contrast and proximity of light patterns were compared. Test participants reported in which image the target appeared more salient. Results show there is a progressive increase in saliency value by increasing the gap between the target and the background lighting when the luminance contrast of the target is three or higher. However, the critical area around the object with the highest effect lies between 0.5° and 1° visual angle. Removing light patterns beyond that point creates negligible effect. The findings of this study could inform development of future models of visual recognition in the road environment, models which can address the important effects of environmental context in addition to photometric variables (luminance and contrast) that are the only factors considered in traditional models of ‘Visibility Level.’
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Davoudian, N., Raynham, P., & Barrett, E. (2014). Disability glare: A study in simulated road lighting conditions. Lighting Research & Technology, 46(6), 695–705.
Abstract: Disability glare is associated with veiling luminance caused by light from bright sources being scattered within the eyes of observers, thereby reducing retinal luminance contrast. This study compares the reduction in observers’ performance in the presence of glare with veiling luminance in the eye, calculated using a non-subjective method. A total of 42 observers performed a target detection task in the presence of a glare source in conditions similar to street lighting at night. Luminance contrast thresholds were measured for each observer under different levels of glare. Results show that, while veiling luminance has a significant effect on the performance of observers, its effect is lower than expected from contrast loss. Furthermore, the performance of observers over the age of 50 is unaffected by increasing the glare level.
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Dominoni, D. M., Halfwerk, W., Baird, E. et al. (2020). Why conservation biology can benefit from sensory ecology. Nature Ecology & Evolution, 4, 502–511.
Abstract: Global expansion of human activities is associated with the introduction of novel stimuli, such as anthropogenic noise, artificial lights and chemical agents. Progress in documenting the ecological effects of sensory pollutants is weakened by sparse knowledge of the mechanisms underlying these effects. This severely limits our capacity to devise mitigation measures. Here, we integrate knowledge of animal sensory ecology, physiology and life history to articulate three perceptual mechanisms—masking, distracting and misleading—that clearly explain how and why anthropogenic sensory pollutants impact organisms. We then link these three mechanisms to ecological consequences and discuss their implications for conservation. We argue that this framework can reveal the presence of ‘sensory danger zones’, hotspots of conservation concern where sensory pollutants overlap in space and time with an organism’s activity, and foster development of strategic interventions to mitigate the impact of sensory pollutants. Future research that applies this framework will provide critical insight to preserve the natural sensory world.
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Dominy, N. J., & Melin, A. D. (2020). Liminal Light and Primate Evolution. Annu. Rev. Anthropol., 49(1).
Abstract: The adaptive origins of primates and anthropoid primates are topics of enduring interest to biological anthropologists. A convention in these discussions is to treat the light environment as binary—night is dark, day is light—and to impute corresponding selective pressure on the visual systems and behaviors of primates. In consequence, debate has tended to focus on whether a given trait can be interpreted as evidence of nocturnal or diurnal behavior in the primate fossil record. Such classification elides the variability in light, or the ways that primates internalize light in their environments. Here, we explore the liminality of light by focusing on what it is, its many sources, and its flux under natural conditions. We conclude by focusing on the intensity and spectral properties of twilight, and we review the mounting evidence of its importance as a cue that determines the onset or offset of primate activities as well as the entrainment of circadian rhythms.
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