Circadian disruption by light pollution: extent, health consequences and mitigation in songbirds

Urbanisation is increasing worldwide at an unprecedented rate and the majority of people now lives in urban areas. This process dramatically alters the spatial environment, fragmenting natural habitat and leading to biodiversity loss. However, a far-less appreciated effect of urbanisation is the modification of the temporal environment. Specifically, the presence of artificial light at night disrupts the natural alternation of light and darkness that organisms use to synchronise their daily, lunar and seasonal rhythms. Such rhythms are one of the most pervasive features of life on Earth, from bacteria to humans, evolved for millions of years in a world where cycles of light and darkness have been extremely predictable. Prominent examples are the activity patterns of animals, diel rhythms of hormones and metabolism, and seasonal reproduction. Studies in humans have linked disruption of circadian rhythms by artificial light at night to negative health consequences, including diabetes, obesity, cardiovascular disease and cancer. However, despite the increasing interest in the ecological effects of artificial light at night, we still lack an understanding of the extent to which it might cause circadian disruption also in wild species living in urban areas, what the outcomes of such disruption will be, and what we can do about it. As with other anthropogenic stressors, it is likely that species differ greatly in their responses. Hence, in this project we will firstly use state-of-the-art biotelemetry to assess how urban life affects circadian rhythms in a carefully selected range of wild bird species that differ in sensitivity to light. We will then experimentally test the effects of artificial light at night on targeted physiological pathways related to health in birds. Last, we will examine the potential for mitigating the effects of light pollution through partial night lighting, a strategy that is largely neglected in the context of circadian disruption, but that could provide both ecological and economic benefits. By integrating these approaches, our project will enable the most comprehensive understanding of both the scale and the mechanisms of the problem of light pollution to date, and explore the basis for a novel mitigation strategy.

The proposed project carries out fundamental research with high potential to generate impact during (general public, academic research) and beyond its duration (policy-making as well as general public and academic research).

Applied academic researchers will benefit from the outcomes of this project. In particular, conservation biologists will be informed about what songbird species are most affected by artificial light at night (ALAN) and what are the specific health consequences of circadian disruption due to ALAN. Moreover, we will also produce evidence on whether or not part-night lighting is an effective lighting strategy to minimise the circadian effects of ALAN.

The industry sector as well as policy-makers will be informed through the participation of PI Davide Dominoni (DD) and project partner Barbara Helm (BH) in specific focus groups such as the Loss of the Night Network (COST action LoNNe), which also organises bi-annual international conferences on ALAN that DD and BH regularly contributes to. Moreover, DD is also perfectly placed to reach the industry sector as he is an invited speaker at the next International Symposium of the Science and Technology of Lighting in Sheffield, UK. All team members regularly participate in local industry events such as the Industry Day organised at the University of Glasgow (UoG). Last, DD has strong ties with the Glasgow City Council (GCC) and in particular with the Biodiversity Officer Cath Scott. Miss Scott has expressed interest in the issue of light pollution for wildlife health and biodiversity and will co-organise with DD a workshop on the ecological and health problems associated to light pollution that will be crucial to liaise with urban planners at GCC. Given the recent scientific evidence that specific types of artificial lights sources matter to wildlife and human health, even small incremental advances in the recognition of this evidence from policy-makers have the potential to mitigate against some of the negative impacts of increasing light pollution.

The general public will benefit through new ways of engaging in an area of major interest, the ecological impact of light pollution, and will in turn inform future research directions. Dissemination of research ideas and results will enable the public to gain a better understanding of animal and human biology and why maintain natural circadian rhythms matter for health. This pertains especially to the young generation, who through their attraction to birds will become interested in ecology subjects. As most households in UK engage with birds through a range of different activities, including periodic recording of bird garden diversity, there is great scope to engage with the general public to explain best practices to increase bird diversity in urban areas, and the potential damaging effects of artificial lights on such biodiversity. Public engagement will be developed through collaboration with non-governmental organizations, especially with charities that are active in conservation and enhancement of the quality of life. These include the British Trust for Ornithology (BTO), Royal Society for the Protection of Birds (RSPB) and the Royal Society of Biology (RSB). Impact for charitable efforts can arise from heightened public interest through the project, but in particular through prospective implementation of the findings through policymakers. Finally, the project will impact the education of new generations on an universal issue such as light pollution, through regular visit to local schools and our participation at the Glasgow Science Festival, which attracts more than 10,000 visitors annually.