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Stone, E. L., Harris, S., & Jones, G. (2015). Impacts of artificial lighting on bats: a review of challenges and solutions. Zeitschrift für Säugetierkunde, .
Abstract: Light pollution is a major emerging issue in biodiversity conservation, and has important implications for policy development and strategic planning. Although research is now addressing the negative impacts of anthropogenic noise on biota, less attention has been paid to the effects of light pollution. Changes in lighting technology have led to a diverse range of emerging low energy light types and a trend towards the increased use of white light. Light pollution affects ecological interactions across a range of taxa and has adverse effects on behaviours such as foraging, reproduction and communication. Almost a quarter of bat species globally are threatened and the key underlying threat to populations is pressure on resources from increasing human populations. Being nocturnal, bats are among the taxa most likely to be affected by light pollution. In this paper we provide an overview of the current trends in artificial lighting followed by a review of the current evidence of the impacts of lighting on bat behaviour, particularly foraging, commuting, emergence, roosting and hibernation. We discuss taxon-specific effects and potential cumulative ecosystem level impacts. We conclude by summarising some potential strategies to minimise the impacts of lighting on bats and identify key gaps in knowledge and priority areas for future research.
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Aubé, M. (2015). Physical behaviour of anthropogenic light propagation into the nocturnal environment. Philos Trans R Soc Lond B Biol Sci, 370, 20140117.
Abstract: Propagation of artificial light at night (ALAN) in the environment is now known to have non negligible consequences on fauna, flora and human health. These consequences depend on light levels and their spectral power distributions, which in turn rely on the efficiency of various physical processes involved in the radiative transfer of this light into the atmosphere and its interactions with the built and natural environment. ALAN can affect the living organisms by direct lighting and indirect lighting (scattered by the sky and clouds and/or reflected by local surfaces). This paper mainly focuses on the behaviour of the indirect light scattered under clear sky conditions. Various interaction processes between anthropogenic light sources and the natural environment are discussed. This work mostly relies on a sensitivity analysis conducted with the light pollution radiative transfer model, Illumina (Aubé et al. 2005: Light pollution modelling and detection in a heterogeneous environment: toward a night-time aerosol optical depth retrieval method. In Proc. SPIE 2005, vol. 5890, San Diego, California, USA). More specifically, the impact of (i) the molecular and aerosol scattering and absorption, (ii) the second order of scattering, (iii) the topography and obstacle blocking, (iv) the ground reflectance and (v) the spectrum of light devices and their angular emission functions are examined. This analysis considers different behaviour as a function of the distance from the city centre, along with different zenith viewing angles in the principal plane.
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Bará, S. (2014). Naked-eye astronomy: optics of the starry night skies. Proc. SPIE 9289, 9289.
Abstract: The world at night offers a wealth of stimuli and opportunities as a resource for Optics education, at all age levels and from any (formal, non formal or informal) perspective. The starry sky and the urban nightscape provide a unique combination of pointlike sources with extremely different emission spectra and brightness levels on a generally darker, locally homogeneous background. This fact, combined with the particular characteristics of the human visual system under mesopic and scotopic conditions, provides a perfect setting for experiencing first-hand different optical phenomena of increasing levels of complexity: from the eye's point spread function to the luminance contrast threshold for source detection, from basic diffraction patterns to the intricate irradiance fluctuations due to atmospheric turbulence. Looking at the nightscape is also a perfect occasion to raise awareness on the increasing levels of light pollution associated to the misuse of public and private artificial light at night, to promote a sustainable use of lighting, and to take part in worldwide citizen science campaigns. Last but not least, night sky observing activities can be planned and developed following a very flexible schedule, allowing individual students to carry them out from home and sharing the results in the classroom as well as organizing social events and night star parties with the active engagement of families and groups of the local community. This contribution describes these possibilities and introduces some of the free resources available to put them in practice.
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Bará, S. (2014). Light pollution and solid-state lighting: reducing the carbon dioxide footprint is not enough. Proc. SPIE 8785, 8785.
Abstract: Public and private lighting account for a relevant share of the overall electric power consumption worldwide. The pressing need of reducing the carbon dioxide emissions as well as of lowering the lumen•hour price tag has fostered the search for alternative lighting technologies to substitute for the incandescent and gas-discharge based lamps. The most successful approach to date, solid-state lighting, is already finding its way into the public lighting market, very often helped by substantial public investments and support. LED-based sources have distinct advantages: under controlled conditions their efficacy equals or surpasses that of conventional solutions, their small source size allows for an efficient collimation of the lightbeam (delivering the photons where they are actually needed and reducing lightspill on the surrounding areas), and they can be switched and/or dimmed on demand at very high rates, thus allowing for a tailored schedule of lighting. However, energy savings and carbon dioxide reduction are not the only crucial issues faced by present day lighting. A growing body of research has shown the significance of the spectral composition of light when it comes to assess the detrimental effects of artificial light-at-night (ALAN). The potential ALAN blueshift associated to the deployment of LED-based lighting systems has raised sensible concerns about its scientific, cultural, ecological and public health consequences, which can be further amplified if an increased light consumption is produced due to the rebound effect. This contribution addresses some of the challenges that these issues pose to the Optics and Photonics community.
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Lyytimäki, J. (2015). Avoiding overly bright future: The systems intelligence perspective on the management of light pollution. Environmental Development, 16, 4–14.
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