The ecological impacts of nighttime light pollution: a mechanistic appraisal

Abstract

The ecological impacts of nighttime light pollution have been a longstanding source of concern, accentuated by realized and projected growth in electrical lighting. As human communities and lighting technologies develop, artificial light increasingly modifies natural light regimes by encroaching on dark refuges in space, in time, and across wavelengths. A wide variety of ecological implications of artificial light have been identified. However, the primary research to date is largely focused on the disruptive influence of nighttime light on higher vertebrates, and while comprehensive reviews have been compiled along taxonomic lines and within specific research domains, the subject is in need of synthesis within a common mechanistic framework. Here we propose such a framework that focuses on the cross-factoring of the ways in which artificial lighting alters natural light regimes (spatially, temporally, and spectrally), and the ways in which light influences biological systems, particularly the distinction between light as a resource and light as an information source. We review the evidence for each of the combinations of this cross-factoring. As artificial lighting alters natural patterns of light in space, time and across wavelengths, natural patterns of resource use and information flows may be disrupted, with downstream effects to the structure and function of ecosystems. This review highlights: (i) the potential influence of nighttime lighting at all levels of biological organisation (from cell to ecosystem); (ii) the significant impact that even low levels of nighttime light pollution can have; and (iii) the existence of major research gaps, particularly in terms of the impacts of light at population and ecosystem levels, identification of intensity thresholds, and the spatial extent of impacts in the vicinity of artificial lights.

The effects of light pollution on biological rhythms of birds: an integrated, mechanistic perspective

“…Some studies have investigated changes in reproductive physiology, although shifts in egg laying date were mostly reported (Chamberlain et al 2009 ; Deviche andDavies 2013 ).…”

“…Indeed, several species, especially in Europe, have been shown to advance lay date in urban and suburban areas (Chamberlain et al 2009 ; Deviche andDavies 2013 ). However, at present, only two studies tested the hypothesis that these shifts in lay date are caused by light pollution.…”

Ground-based hyperspectral analysis of the urban nightscape

“…In its broadest sense, this term encompasses the undesired side-effects associated with the production and use of artificial light, especially at nighttime (Falchi et al, 2011;Bará, 2013Bará, , 2014. Excessive or misdirected light leads to unnecessary energy waste and increased greenhouse gas emissions (Gallaway et al, 2010;Kyba, 2014), and poses, according to recent findings, nonnegligible threats to the nocturnal environment (Hölker et al, 2010;Gaston et al, 2013Gaston et al, , 2015 as well as potential health hazards (Cho et al, 2015;Haim and Zubidat, 2015;Stevens et al, 2013).…”

Global Trends in Exposure to Light Pollution in Natural Terrestrial Ecosystems

“…The intrusion of artificial light into ecosystems is of concern because there is evidence that this can have profound effects on wildlife, including plants, invertebrates, fish, amphibians, reptiles, birds and mammals [3][4][5][6][7][8], and may have effects on key ecological processes and ecosystem services [9]. Artificial light alters the natural daily, monthly and seasonal rhythms of light and dark under which species have evolved and obscures the view of the night sky that animals may use as cues for navigation; it can disrupt natural circadian rhythms, alter the activity patterns of diurnal and nocturnal animals, interfere with movement and migration in many species, and alter the timing of key events such as flowering, budburst and reproduction.…”