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Lewanzik, D., Voigt, C. C., & Minderman, J. (2016). Transition from conventional to light-emitting diode street lighting changes activity of urban bats. J Appl Ecol, 54(1), 264–271.
Abstract: Light pollution is rapidly increasing and can have deleterious effects on biodiversity, yet light types differ in their effect on wildlife. Among the light types used for street lamps, light-emitting diodes (LEDs) are expected to become globally predominant within the next few years.
In a large-scale field experiment, we recorded bat activity at 46 street lights for 12 nights each and investigated how the widespread replacement of conventional illuminants by LEDs affects urban bats: we compared bat activity at municipal mercury vapour (MV) street lamps that were replaced by LEDs with control sites that were not changed.
Pipistrellus pipistrellus was the most frequently recorded species; it was 45% less active at LEDs than at MV street lamps, but the activity did not depend on illuminance level. Light type did not affect the activity of Pipistrellus nathusii, Pipistrellus pygmaeus or bats in the Nyctalus/Eptesicus/Vespertilio (NEV) group, yet the activity of P. nathusii increased with illuminance level. Bats of the genus Myotis increased activity 4·5-fold at LEDs compared with MV lights, but illuminance level had no effect.
Decreased activity of P. pipistrellus, which are considered light tolerant, probably paralleled insect densities around lights. Further, our results suggest that LEDs may be less repelling for light-averse Myotis spp. than MV lights. Accordingly, the transition from conventional lighting techniques to LEDs may greatly alter the anthropogenic impact of artificial light on urban bats and might eventually affect the resilience of urban bat populations.
Synthesis and applications. At light-emitting diodes (LEDs), the competitive advantage – the exclusive ability to forage on insect aggregations at lights – is reduced for light-tolerant bats. Thus, the global spread of LED street lamps might lead to a more natural level of competition between light-tolerant and light-averse bats. This effect could be reinforced if the potential advantages of LEDs over conventional illuminants are applied in practice: choice of spectra with relatively little energy in the short wavelength range; reduced spillover by precisely directing light; dimming during low human activity times; and control by motion sensors. Yet, the potential benefits of LEDs could be negated if low costs foster an overall increase in artificial lighting.
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Tan, M. (2016). Use of an inside buffer method to extract the extent of urban areas from DMSP/OLS night-time light data in North China. GIScience & Remote Sensing, 53(4), 444–458.
Abstract: Defense Meteorological Satellite Program (DMSP)/Operational Linescan System (OLS) night-time imagery provides a valuable data source for mapping urban areas. However, the spatial extents of large cities are often over-estimated because of the effect of over-glow from night-time light if a fixed thresholding technique is used. In the work reported here, an inside buffer method was developed to solve this issue. The method is based on the fact that the area over-estimated is proportional to the extent of the lit area if a fixed threshold is used to extract urban areas in a region/county. Using this method, the extents of urban areas in North China were extracted and validated by interpretations from Landsat Thematic Mapper images. The results showed that the lit areas had a significant linear relationship with the urban areas for 120 representative cities in North China in 2000, with an R2 value of over 0.95. This demonstrates that the inside buffer method can be used to extract urban areas. The validation results showed that the inside buffer model developed in 2000 can be directly used to extract the extent of urban areas using more recent night-time light imagery. This is of great value for the timely updating of urban area databases in large regions or countries.
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Xie, Y., & Weng, Q. (2016). World energy consumption pattern as revealed by DMSP-OLS nighttime light imagery. GIScience & Remote Sensing, 53(2), 265–282.
Abstract: Remotely sensed nighttime light (NTL) from the Defense Meteorological Satellite Program (DMSP) Operational Linescan System (OLS) provides a spatially consistent and cost-effective mean to estimate energy consumption pattern. While previous researches have documented the application of NTL to predict electric power consumption (EPC) with varying degrees of success, few have systematically studied the possible factors affecting the EPC-NTL relationship. Moreover, no substantial research effort has been made to relate overall energy consumption (OEC) to NTL. This study investigated key factors governing the EPC/OEC-NTL relationship by examining the influences of affluence, urbanization, technology, temperature, and NTL pattern. Results show that EPC increased with higher per capital GDP, urbanization rate, and high-technology exports, and lower agricultural development, both globally and regionally. Meanwhile, EPC generally reduced with higher temperature and more agglomerate human activities. A strong OEC-NTL relationship was found; but the influencing factors to the OEC-NTL relationship varied across regions due to the natures of energy use. These factors must be considered especially for the studies of less-affluent regions where NTL was undetectable by the DMSP-OLS sensor.
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Sun, C., & Lian, Z. (2016). Sensitive physiological indicators for human visual comfort evaluation. Lighting Res. & Tech., 48(6), 726–741.
Abstract: Three physiological factors (melatonin levels, tear mucus ferning quality and degree of asthenopia) were examined for their relationship to visual comfort. A lighting environment was created where the illuminance, illuminance uniformity and correlated colour temperature could be adjusted. A three-factor and three-level orthogonal experiment with 24 subjects was designed and carried out. The results indicated that the selected environmental factors had different impacts on the physiological factors. With the illuminance increasing, the melatonin level decreased significantly and the tear mucus ferning quality was improved. However, there is no general influence of illuminance uniformity and correlated colour temperature on the physiological parameters, only differential effects among the three levels were found.
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Pocock, T. (2016). Advanced lighting technology in controlled environment agriculture. Lighting Research and Technology, 48(1), 83–94.
Abstract: There is a recent awareness of the importance of plants in our everyday lives. Light is a requirement for plants and serves two important roles. It provides energy for growth and provides information that elicits plant responses including, among others, plant shape, pigmentation, nutritional content and resistance to stress. Light is paradoxical to plants, it is a requirement however, in excess it is damaging. Plants sense and interpret light through many families of photoreceptors and through the energy state of the photosynthetic apparatus. Light emitting diodes (LEDs) are quickly replacing traditional light sources for human applications, and currently there is effort being put into tailoring these technology platforms for the plant community. Potential plant sensing pathways and the spectral effects on pigmentation and photochemistry in red lettuce are described.
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