11 Pressing Research Questions on How Light Pollution Affects Biodiversity

Abstract

Artificial light at night (ALAN) is closely associated with modern societies and is rapidly increasing worldwide. A dynamically growing body of literature shows that ALAN poses a serious threat to all levels of biodiversity—from genes to ecosystems. Many “unknowns” remain to be addressed however, before we fully understand the impact of ALAN on biodiversity and can design effective mitigation measures. Here, we distilled the findings of a workshop on the effects of ALAN on biodiversity at the first World Biodiversity Forum in Davos attended by several major research groups in the field from across the globe. We argue that 11 pressing research questions have to be answered to find ways to reduce the impact of ALAN on biodiversity. The questions address fundamental knowledge gaps, ranging from basic challenges on how to standardize light measurements, through the multi-level impacts on biodiversity, to opportunities and challenges for more sustainable use.

A Systematic Review for Establishing Relevant Environmental Parameters for Urban Lighting: Translating Research into Practice

“…Most of these studies concerning single light sources showed the impact of three different light parameters: (1) broad spectral distributions, including short, mid, and long wavelengths; (2) illuminance levels below 10 lx, and (3) CCTs of 3300-5300 K. Meanwhile, when multiple light sources were compared, only their spectral power distribution was considered. This supports the need for a consensus on measuring and reporting physical parameters of artificial light sources, as it is necessary to properly address the components of artificial light known to be stressors [273].…”

“…Yet, the light sources and physical parameters of the artificial light that induces changes in responses were not addressed to better comprehend the light-polluted scenarios that varied organism groups are exposed to [272]. Recently, Hölker et al addressed fundamental knowledge gaps, ranging from basic challenges on how to standardize light measurements, through the multi-level impacts on biodiversity, to opportunities and challenges for more sustainable use [273]. All these reviews gather crucial evidence on the night-time environment as a temporal niche in an ALAN context.…”

“…Firstly, these days, urban lighting focuses on mainly presenting the visual experience of nightscapes [33] as well as providing lighting for the safe passage of pedestrians or vehicles, often neglecting natural environments and biodiversity [15,273] and unintentionally polluting naturally dark skies [277]. Therefore, we postulate that lighting professionals involved in ULP should rethink their user-centered approach and become aware of ALAN research.…”

“…Furthermore, the exposure to weather and varied atmospheric conditions is rarely considered in research studies that provide evidence on a changed behavior or physiological change. Future ALAN research should include weather and varied atmospheric conditions (i.e., cloudy days and clear sky) and varied natural light conditions (i.e., lunar phases) when measuring the varied parameters of illuminated nightscapes, which can provide a better understanding of the exposed environment [54,273].…”

“…Translating research findings about ALAN implies that ULP must consider the night as a natural resource that needs protecting, with its inhabiting organisms, rather than only addressing tailored solutions for endangered species [34,273,276].…”