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Shier, D. M., Bird, A. K., & Wang, T. B. (2020). Effects of artificial light at night on the foraging behavior of an endangered nocturnal mammal. Environmental Pollution, in press, in press.
Abstract: Modification of nighttime light levels by artificial illumination (artificial light at night; ALAN) is a rapidly increasing form of human disturbance that affects natural environments worldwide. Light in natural environments influences a variety of physiological and ecological processes directly and indirectly and, as a result, the effects of light pollution on species, communities and ecosystems are emerging as significant. Small prey species may be particularly susceptible to ALAN as it makes them more conspicuous and thus more vulnerable to predation by visually oriented predators. Understanding the effects of disturbance like ALAN is especially important for threatened or endangered species as impacts have the potential to impede recovery, but due to low population numbers inherent to at-risk species, disturbance is rarely studied. The endangered Stephens’ kangaroo rat (SKR), Dipodomys stephensi, is a nocturnal rodent threatened by habitat destruction from urban expansion. The degree to which ALAN impacts their recovery is unknown. In this study, we examined the effects of ALAN on SKR foraging decisions across a gradient of light intensity for two types of ALAN, flood and bug lights (756 vs 300 lumen, respectfully) during full and new moon conditions. We found that ALAN decreased probability of resource patch depletion compared to controls. Moreover, lunar illumination, distance from the light source and light type interacted to alter SKR foraging. Under the new moon, SKR were consistently more likely to deplete patches under control conditions, but there was an increasing probability of patch depletion with distance from the source of artificial light. The full moon dampened SKR foraging activity and the effect of artificial lights. Our study underscores that ALAN reduces habitat suitability, and raises the possibility that ALAN may impede the recovery of at-risk nocturnal rodents.
Keywords: Animals
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Falchetta, G., Pachauri, S., Byers, E., Danylo, O., & Parkinson, S. C. (2020). Satellite Observations Reveal Inequalities in the Progress and Effectiveness of Recent Electrification in Sub-Saharan Africa. One Earth, in press.
Abstract: Energy poverty is widely diffused and persistent in sub-Saharan Africa. Even in areas that formally have electricity access, power consumption and supply reliability are largely inadequate. Yet, most institutional statistics fail to capture these different dimensions and rely on rapidly outdated and unwieldy household surveys. In this study, we process high-resolution population distribution maps (including demographic and migration trends), satellite-measured nighttime light, and settlement information for sub-Saharan Africa. This allows us to derive multi-dimensional estimates of electricity access over space and time and compare them with a set of published records. Our results reveal wide inequalities in the pace and quality of electrification, which cannot be observed in existing statistics. We show that the pace of electrification must more than triple to fulfill SDG 7.1.1 and discuss why electrification policy could fall short if aimed solely at boosting electricity connections.
Keywords: Remote Sensing
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Cisse, Y. M., Russart, K., & Nelson, R. J. (2020). Exposure to dim light at night prior to conception attenuates offspring innate immune responses. PLoS One, 15(4), e0231140.
Abstract: Functional circadian timekeeping is necessary for homeostatic control of the immune system and appropriate immune responsiveness. Disruption of natural light-dark cycles, through light at night (LAN), impairs innate and adaptive immune responses in nocturnal rodents. These altered immune responses are associated with disrupted endogenous gene transcriptional and endocrine cycles. However, few studies have addressed the multigenerational consequences of systemic circadian rhythm disruption. We hypothesized that parental exposure to dim LAN (dLAN) would alter innate immune and sickness responses to an endotoxin challenge in adult offspring gestated and reared in dark nights. Adult male and female Siberian hamsters were exposed to either dark nights (DARK) or dLAN (~5 lux) for 8 weeks, then paired, mated, and thereafter housed under dark nights. Maternal exposure to dLAN prior to conception impaired febrile responses and increased splenic il-1 production in response to LPS in male offspring. Paternal pre-conception dLAN dampened offspring tnf-alpha expression in the hypothalamus, reduced serum bactericidal capacity, and dark phase locomotor activity. These changes occurred despite offspring being conceived, gestated, and reared under standard dark night conditions. Overall, these data suggest that dLAN has intergenerational effects on innate immunity and sickness responses.
Keywords: Animals
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Ludtke, L. E. (2020). Sleep, disruption and the ‘nightmare of total illumination’ in late nineteenth and early twentieth-century dystopian fiction. Interface Focus., 10(3), 20190130.
Abstract: This article addresses the charge that the introduction of the electric light in the late nineteenth century increased disruptions to the human body's biological processes and interfered with the oscillating sleeping–waking cycle. By considering the nineteenth century research into the factors that motivate and disrupt sleep in concert with contemporary discussions of the physiology of street lighting, this article exposes how social and political forces shaped the impact of artificial light on sleep and, more perniciously, on bodily autonomy. As a close reading of artificial light in three influential dystopian novels building on these historical contexts demonstrates, dystopian fiction challenges the commonplace assumption that the advent of the electric light, or of widespread street lighting in public urban spaces, posed an immediate or inherent threat to sleep. Beginning with H. G. Wells's The Sleeper Awakes (1899), in which the eponymous sleeper emerges from a cataleptic trance into a future in which electric light and power are used to control the populace, representations of artificial light in early dystopian fiction of the late nineteenth and early twentieth centuries depict a nightmare of total illumination in which the state exerted its control over the individual. In Aldous Huxley's Brave New World (1932), constant artificial illumination plays a vital role in the chemical and behavioural conditioning undergone by individuals in a post-Fordian world. George Orwell intensifies this relationship between light and individual autonomy in Nineteen Eighty-Four (1949), where access to electric current (and thus light) is limited at certain times of the day, brownouts and electrical rationing occur intermittently, and total illumination is used to torture and reprogram individuals believed to have betrayed Big Brother.
Keywords: Literature; Society; History
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Leonard, J. P., Tewes, M. E., Lombardi, J. V., Wester, D. W., & Campbell, T. A. (2020). Effects of sun angle, lunar illumination, and diurnal temperature on temporal movement rates of sympatric ocelots and bobcats in South Texas. PLoS One, 15(4), e0231732.
Abstract: Sympatric ocelots (Leopardus pardalis) and bobcats (Lynx rufus) in South Texas show substantial overlap in body size, food habits, and habitat use. Consequently, we explore whether temporal niche partitioning may explain ocelot and bobcat coexistence. We investigated the influence of sun angle, lunar illumination, and maximum diurnal temperature on temporal movement rates of sympatric ocelots (n = 8) and bobcats (n = 6) using a combination of high-frequency GPS locations and bi-axial accelerometer data. We demonstrated that accelerometer data could be used to predict movement rates, providing a nearly continuous measure of animal activity and supplementing GPS locations. Ocelots showed a strong nocturnal activity pattern with the highest movement rates at night whereas bobcats showed a crepuscular activity pattern with the highest movement rates occurring around sunrise and sunset. Although bobcat activity levels were lower during the day, bobcat diurnal activity was higher than ocelot diurnal activity. During warmer months, bobcats were more active on nights with high levels of lunar illumination. In contrast, ocelots showed the highest nocturnal activity levels during periods of low lunar illumination. Ocelots showed reduced diurnal activity on hotter days. Our results indicate that ocelot and bobcat coexistence in South Texas can be partially explained by temporal niche partitioning, although both felids showed periods of overlapping activity during nocturnal and crepuscular periods.
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