The impact of light pollution on ecosystem services and human well-being

Overview

Life on our planet has evolved for millions of years in a rhythmic environment dictated by sunlight, moonlight and starlight. Consequently, organisms have developed adaptations to use light as a source of energy (eg photosynthesis), temporal information (eg circadian, circannual and circatidal rhythms) and spatial orientation (eg navigating using stars). However, the invention of artificial light, and specifically its widespread use in the outdoor and indoor environment, is increasingly recognised as a threat to these long-evolved biological processes [1].

In the last decade research on the ecological impacts of artificial light at night (ALAN) has blossomed. ALAN has been shown to affect genetic, physiological and behavioural responses of a wide-range of taxa [2]. Perhaps the most recognised impact is that on insects, and particularly on phototactic species which are attracted to artificial light sources where they suffer from high mortality due to increased predation, collision or exhaustion [3]. Effects on individual responses of insects have been recently highlighted to scale-up to population level consequences, providing one potential ecological mechanism to explain the insect apocalypse we are currently experiencing [4, 5].

Losing insects, among many other species that are known to be negatively affected by ALAN, has a cost for the healthy functioning of the natural environment, and consequently for the ecosystem services it provides [6]. Several insect species provide us with essential services. For instance, pollinators are key to maintain plant diversity and productivity, including that of crops. Insects also perform decomposition and pest control, other essential ecosystem services. Moreover, insects are often a key resource for taxa higher up on the food web, such as vertebrates, which also provide essential services to our society. Thus, ALAN may have an economic cost through the erosion of the natural environment, but this has never been quantified [7].

The erosion of green and blue spaces has been shown to impact not only biodiversity, but also human well-being [8]. These spaces, and particularly public ones in urban areas, represent the only regular daily opportunity for an increasing urban population to interact with nature. This interaction has been shown to have measurable physical and psychological benefits, and these benefits increase with increasing biodiversity [8]. If ALAN negatively affects biodiversity, then it is conceivable to hypothesise that it will also have detrimental impacts on human well-being. Moreover, light pollution may also have direct effects on well-being, for instance because it can interfere with the appreciation of the nocturnal natural environment (eg stargazing), with sensory perception and with sleep quality [9]. However, the indirect and/or direct relationship of ALAN with human well-being have been largely overlooked.

Despite the increasing evidence of the diverse impacts of ALAN, these impacts should be relatively easy to mitigate. Among effective mitigation strategies are: i) reducing the intensity of unnecessarily bright illumination, ii) shifting the colour spectrum towards red wavelengths, iii) turning off lights when and where they are not needed, iv) point illumination only where needed and never towards the sky [10]. The current widespread conversion of old incandescent illumination to energy and cost-efficient LEDs offers the chance to implement smart mitigation strategies, but this is too often a missed opportunity [11]. We argue that quantifying the net environmental and economic benefit of smart lighting will support policy-makers to legislate accordingly, and city councils to more widely adopt such strategies.

The aim of this project is to gain a holistic view of the effects of light pollution on biodiversity, ecosystem services and human well-being. Moreover, we also aim to quantify the effectiveness of alternative lighting strategies in reducing the environmental and socioeconomic costs of light pollution. Because of the transdisciplinary nature of the work, the student will be exposed to different research backgrounds and will interact with a diverse team of supervisors. This will offer the possibility to develop a highly relevant set of skills across ecology, environmental science and environmental economics. There will also be ample opportunities to develop the project in different directions by expanding the network of collaborators. For instance, additional economic and environmental benefits of minimising light pollution could be quantified, such as those derived by the reduced carbon footprint of producing and consuming less energy.

Methodology

This project uses fieldwork to conduct biodiversity and household surveys, spatial analysis of light pollution, and socioeconomic models to deliver on three major aims.

1. Quantify the impact of light pollution on the ecosystem services provided by insects

(a) Collate citizen science datasets on insect abundance and diversity in the UK (eg JNCC, Butterfly Conservation, iNaturalist).
(b) Assess the relationship between insect abundance/diversity and remote-sensing data on light pollution at the UK level.
(c) Perform insect biodiversity surveys in selected locations in Scotland, parallel to the household surveys (see aim 2 below).
(d) Based on these analyses, quantify the impact of light pollution on ecosystem services provided by insects [12].

II. Quantify the impact of light pollution on human well-being

(a) Household survey of a random sample of Scottish households. Use standard Subjective Well-Being (SWB) questions, accompanied by more specific questions on mental well-being (Edinburgh-Warwick scale). We also collect data on “standard” determinants of SWB such as employment status [13].
(b) Analyse the relationship between standard SWB metrics, questionnaire metrics and spatial light pollution data; Repeat this analysis using the mental well-being scale rather than SWB. Both these analyses will test, empirically, how variations in light pollution affect well-being.
(c) For a sub-set of households, an information treatment will be conducted in order to explain the effects of light pollution on different aspects of biodiversity. We use this treatment to test whether knowledge of ecological impacts increases or decreases the effects of light pollution on SWB [14].
(d) Using prescribing data for Scottish data zones, the student can investigate how prescribing rates for a class of anti-depressant drugs are affected by variations in light pollution. This will provide novel and complementary data on the mental well-being effects investigated in (1), and follows a similar approach to that of previous studies [15].

III. Evaluate the effectiveness of alternative lighting strategies to minimise the environmental and socioeconomic costs of light pollution

(a) Identify a small set of alternative lighting strategies and interventions aimed at reducing the financial costs to local authorities of street lighting.
(b) Quantify the social (environmental and well-being) costs or benefits of each of these interventions based on the results found for objective I and II.

Project Timeline

Year 1

Y1—Months 0-6: Kick-off meeting, PhD training, reading group, experimental design, biodiversity fieldwork
Y1—Months 7-12: Analyse field data, modelling of ecosystem services

Year 2

Y2—Months 0-6: Finish analysing field data and ecosystem services models, secondment to Stirling for training on household surveys
Y2—Months 7-12: Perform household surveys, collect remote-sensing light pollution data

Year 3

Y3—Months 0-6: Analyse well-being data in relation to light pollution
Y3—Months 7-12: Further analysis and manuscript and chapter writing, conference presentations

Year 3.5

Y3.5—Months 0-6: Submit thesis, work on further manuscripts

Training
& Skills

The studentship provides an opportunity to develop skills in cutting-edge research techniques consistent with NERC’s identified priority areas. For example, numeracy will be developed through engagement with ecological and socioeconomic modelling, as well as spatial ecology related to the analysis of remote-sensing light data. Exposure to best practice for fieldwork and statistical modelling will provide the student both breadth and depth of advanced skills for a career in the biosciences. The student will be encouraged and supported in identifying external training opportunities such as spatial ecology courses (e.g. through the IBAHCM Spatial Ecology special interest group). The supervisory team will offer fieldwork training on biodiversity (Dr Dominoni), environmental economics and economic tools for conservation (Prof Hanley), as well as household surveys and well-being analyses (Prof Hanley and Dr Oliver). Extensive skill development in survey design will be complemented with exposure to GIS modelling methodologies. The student will be embedded within a highly collegiate postgraduate environment at IBAHCM that offers both formal and informal mentoring, access to seminars and more informal discussion groups. The student and supervisors will take advantage of the physical proximity of Glasgow and Stirling to facilitate progress meetings and laboratory exchange visits, thus widening the student’s network of contacts, colleagues and collaborators. The student will also be encouraged to independently develop their own specialties and interests related to the project, and expand the network of collaborators nationally and/or internationally.

References & further reading

[1] Hölker et al. Light pollution as a biodiversity threat. Trends Ecol. Evol. 25, 681–682 (2010).

[2] Dominoni et al. Artificial light at night as an environmental pollutant: An integrative approach across taxa, biological functions, and scientific disciplines. J. Exp. Zool. Part A 329 (2018).

[3] Altermatt et al Reduced flight-to-light behaviour of moth populations exposed to long-term urban light pollution. Biol. Lett. 12, 20160111 (2016).

[4] Knop et al. Artificial light at night as a new threat to pollination. Nature (2017).

[5] Boyes et al. Street lighting has detrimental impacts on local insect populations. Sci. Adv., 7, 8322–8347 (2021).

[6] Noriega et al. Research trends in ecosystem services provided by insects. Basic Applied Ecol, 26, 8–23. (2018).

[7] Gallaway et al. The economics of global light pollution. Ecol. Econ. 69, 658–665 (2010).

[8] Fuller et al. Psychological benefits of greenspace increase with biodiversity. Biol. Lett. 3, 390–394 (2007).

[9] Dominoni et al. Why conservation biology can benefit from sensory ecology. Nat. Ecol. Evol. 4, 502–511 (2020).

[10] Gaston et al Reducing the ecological consequences of night-time light pollution: options and developments. J. Appl. Ecol. 49, 1256–1266 (2012).

[11] Kyba et al. Artificially lit surface of Earth at night increasing in radiance and extent. Sci. Adv. 3, e1701528 (2017).

[12] Crossman et al. A blueprint for mapping and modelling ecosystem services. Ecosyst. Serv. 4, 4–14 (2013).

[13] Dallimer et al. Quantifying Preferences for the Natural World Using Monetary and Nonmonetary Assessments of Value. Cons. Biol., 28, 404–413 (2014).

[14] Needham et al. What is the causal impact of information and knowledge in stated preference studies? Res. Ene. Econom., 54, 69–89 (2018).

[15] McDougall et al Neighbourhood blue space and mental health: A nationwide ecological study of antidepressant medication prescribed to older adults. Land. Urban Plann., 214, 104132 (2021).

Further Information

Applications: for information on the application process and the IAPETUS2 DTP please see: https://www.iapetus2.ac.uk/how-to-apply/.

This project is in competition with others for funding, and success will depend on the quality of applicants. Funding includes tuition fee waiver for Glasgow University, a competitive stipend, and research support. To express interest please first contact Dr Davide Dominoni (Davide.Dominoni@glasgow.ac.uk) by early January 2022, including a paragraph detailing your reasons for applying and how your experiences fit the project.

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