Hale James

Ecological Light Pollution in the Gantrisch Naturpark
Ökologische Lichtverschmutzung im Naturpark Gantrisch

Project Number: CH-6257
Project Type: Research_Project
Project Duration: 06/01/2017 - 03/16/2018 project completed
Funding Source: other ,
Leading Institution: Institute of Ecology and Evolution, University Bern
Project Leader: Dr. James Hale

related to this project.
for which the project has a relevance.


Research Areas:
Landscape

Disciplines:
environmental sciences

Keywords:
  • Light
  • Street Lighting
  • Strassenbeleuchtung
  • Light pollution
  • Lichtverschmutzung
  • LED
  • Biodiversity
  • Dark Corridor
  • Biodiversität

    Abstract:
    Outdoor artificial lighting is known to disrupt many ecological communities. Lighting emissions are getting stronger, expanding and becoming dominated by white LEDs. Switzerland has some of the darkest skies in Europe, and areas such as the Gantrisch Naturpark potentially hold rare and valuable examples of dark habitats.
    There are many ways to measure lighting emissions within the park. Most useful from an ecology perspective are VIIRS satellite images, ISS photography and lamp inventories. VIIRS data for the past 3 years show seasonal variation but no obvious yearly trend. One ISS image is useful for identifying causes of emissions in the north of the park.

    It was possible to secure street lamp inventories for the majority of the park. Additional lamp surveys were undertaken in areas of high emissions and near to sensitive habitats – many sources of problem lighting are not from street lamps. Lighting associated with railways, outdoor sports areas, banks and other businesses, schools, hospitals and retirement homes, churches, garages and gas-stations often involves poorly shielded floodlights, advertising signs or globe/sphere type lamps.

    A more complete inventory could be created and maintained with a citizen science approach. Through a literature review we identified evidence for light-sensitive species and habitats; artificial lighting can have impacts though direct illumination, by magnifying horizontally polarized light signals, and by obscuring monthly lunar lighting cycles. The most directly relevant research papers related to bats and aquatic insects. The lack of research on other mammals is particularly concerning, given their strong tendency towards nocturnal activity. For other taxa, a lack of research evidence does not imply that no impacts exist. In most cases there is sufficient justification for a precautionary approach involving restricting lighting near to key habitats. There is good evidence to suspect impacts on aquatic habitats and grasslands.

    A spatial indicator of ecologically relevant light pollution was developed based on a visibility analysis of VIIRS bright lighting locations. This was further refined to identify core dark zones that could be the focus of additional protection, enhancement and darkening projects. Most of the Swiss biotopes of national importance that are found within the park are already located within dark viewshed areas. However, high percentages of amphibian spawning areas and fens are subjected to lit viewsheds caused by lighting from Plaffeien and Belp.

    Experimental research in summer 2017 revealed that LED lighting within 80 m of river edges can impact adult Ephemeroptera, Trichoptera and Diptera. Surveys of main river sections identified numerous lighting sources needing mitigation. Passerine bird migration is known to be impacted by artificial lighting and we identified a zone within the park which would benefit from lighting restrictions in this context.

    A series of recommendations are outlined, including the application of a broad precautionary approach to lighting near to priority species and habitats, and public engagement to raise awareness of the unique nature of the dark habitats and best lighting practice. A particularly clear opportunity for addressing ecological light pollution is to reduce lighting adjacent to streams, rivers and ponds and to focus habitat improvements on the existing dark network of aquatic habitats.

    Leading questions:
  • What is the current state of artificial lighting in the Naturpark Gantrisch?
  • What species and habitats could be damaged by this lighting?
  • What action can be taken to reduce impacts
  • What core dark habitats should be protected?

    Publications:
    Hale, James et al. 2018. Ecological light pollution in the Gantrisch Naturpark. Project-Report. Conservation Biology Division, University of Bern.
    pdf Abstract (in German)


    Last update: 1/25/19
    Source of data: ProClim- Research InfoSystem (1993-2024)
    Update the data of project: CH-6257

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