{"id":118505,"date":"2026-11-06T02:43:00","date_gmt":"2026-11-06T01:43:00","guid":{"rendered":"https:\/\/www.sonnenseite.com\/?p=118505"},"modified":"2026-11-05T15:45:18","modified_gmt":"2026-11-05T14:45:18","slug":"mitigating-the-ecological-consequences-of-light-pollution","status":"publish","type":"post","link":"https:\/\/www.sonnenseite.com\/en\/science\/mitigating-the-ecological-consequences-of-light-pollution\/","title":{"rendered":"Mitigating the ecological consequences of light pollution"},"content":{"rendered":"\n
Limits for light emissions and \u201cdark corridors\u201d can help<\/p>\n\n\n\n
Light pollution is one of the fastest-growing and least-regulated environmental changes worldwide. It disrupts biological processes at all levels \u2013 from genes to entire ecosystems \u2013 and contributes significantly to global biodiversity loss. A recent review article, in which the Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB) participated, addresses the ecological consequences of artificial nighttime lighting. Based on a comprehensive assessment of the impacts on organisms on land and in water, the authors identify priorities for research and management. The article was published in \u201cNature Reviews Biodiversity\u201d.<\/p>\n\n\n\n
Over the past decade, the night sky has brightened by an average of nearly 10 percent per year. According to projections, by 2052, half of the Earth\u2019s land area will be affected by light pollution. Since large cities are concentrated near important natural areas such as coastal regions and freshwater bodies, and light pollution is reaching even seemingly untouched habitats, the natural day-night rhythm has changed for many animals and plants. \u201cThe light-dark cycle is one of the most stable environmental signals throughout evolution. A change in this signal due to light pollution therefore has far-reaching consequences for biodiversity,\u201d said Dr Ashton Dickerson, the article\u2019s lead author.<\/p>\n\n\n\n
Suppression of the \u201csleep hormone\u201d melatonin has been demonstrated in all vertebrate groups<\/h4>\n\n\n\n
It is well known that the release of melatonin in all vertebrate groups \u2013 that is, birds, mammals, amphibians, reptiles, and fish \u2013 is suppressed by light pollution. On average, by 36 percent.<\/p>\n\n\n\n
Plants are also affected by light pollution, as their seasonal rhythms are shifted: urban trees bud earlier and lose their leaves later. Research shows that light pollution influences the lengthening of the urban growing season more strongly than air temperature \u2013 especially toward the end of the growing season. Other documented consequences include changes in animal behavior throughout the day-night cycle. For example, some bird species begin singing earlier in the day.<\/p>\n\n\n\n
Light attracts insects or reef fish \u2013 and can act as a barrier for migratory animals<\/h4>\n\n\n\n
Light pollution also alters the spatial distribution of animals by attracting or driving them away. Insects, fish, birds, and mammals are all affected. Flying insects are the most obvious example; the nocturnal swarms that gather around streetlights are well known. Numerous studies document this increase in the density of flying insects and their predators, e.g. spiders, near streetlights. Predatory reef fish also become more concentrated around illuminated corals, altering community composition. Other vertebrates often exhibit the opposite pattern: pumas, for example, avoid brightly lit habitats, as do migratory birds. Shorebirds show altered distribution patterns on nesting beaches, and eels veer off their migration routes near illuminated bridges. \u201cTaken together, these responses lead to a redistribution of species into aggregation hotspots and alternative habitats. This results in the formation of novel communities with no historical precedent,\u201d said Dr Franz H\u00f6lker, co-author of the article and head of the IGB research group \u201cLight Pollution and Ecophysiology.\u201d<\/p>\n\n\n\n
Building on policy measures, such as the national Insect Protection Act<\/h4>\n\n\n\n
According to the authors, there is still a need for better integration of ecological findings into lighting regulations and land-use planning. \u201cThere is still a gap between scientific knowledge and the protection of biodiversity,\u201d summarized Franz H\u00f6lker. Some policy implementations already recognize light pollution as a threat to biodiversity. For example, the \u201cConvention on Migratory Species\u201d adopted the \u201cInternational Light Pollution Guidelines\u201d at COP 14 in 2024; Australia implemented the \u201cNational Light Pollution Guidelines for Wildlife\u201d in 2023; and Germany introduced the so-called \u201cInsect Protection Act\u201d in 2021 (Section 41a BNatSchG).<\/p>\n\n\n\n
A hierarchical mitigation approach to address the ecological impacts of light pollution<\/h4>\n\n\n\n
Based on scientific findings regarding various species and contexts, the authors propose a four-tiered, hierarchical mitigation approach. In the first tier, light sources are permanently removed unless there is a justified need for them. In the second tier, spatial confinement is achieved with custom optics or shielding and luminous flux is reduced via dimming. The third level addresses temporal restrictions, such as limiting operating hours using timers and motion sensors. Finally, the fourth level involves spectral adjustment.<\/p>\n\n\n\n
Establishing limit values for light emissions<\/h4>\n\n\n\n
Major obstacles to effective regulation relate to proving relevant environmental damage and establishing a causal link: Most applicable environmental laws require, on the one hand, proof that the light emission in question causes a relevant impact and, on the other hand, that the light emission and the responsible operator can be identified. \u201cSince it is often difficult to establish concrete environmental damage and identify those responsible, lawmakers could introduce evidence-based emission limits tailored to the specific type of lighting and its context of use,\u201d said Dr Andreas Jechow, a professor at Brandenburg University of Applied Sciences and co-author of the study.<\/p>\n\n\n\n
This solution would circumvent questions regarding the relevant harm and the causal relationship and establish clear, enforceable obligations. In particular, emission limits can be considered by manufacturers, retailers, and lighting designers, thereby reducing light pollution even before the lighting is installed.<\/p>\n\n\n\n
Creating protected areas: \u201cdark corridors\u201d and shielding lights<\/h4>\n\n\n\n
In addition to emission control, planning tools and spatial protection concepts offer specific ways to ensure improved protection against light pollution. One approach, for example, is the creation of \u201cdark corridors\u201d to connect important biotopes \u2013 an approach that complements existing frameworks for habitat connectivity, such as Natura 2000.<\/p>\n\n\n\n
The authors feel it is important to emphasize that this is not about neglecting the benefits of artificial light for people\u2014above all, the sense of security it provides in the dark. New lighting concepts, such as those already implemented in some municipalities such as Fulda (Germany) or along Florida\u2019s Gulf Coast (USA), show that ecological and societal requirements for public lighting can be reconciled.<\/p>\n\n\n\n