New Lighting at Train Stations Reduces Light Stress for Insects

A newly tested LED light drastically reduces the attraction of flying insects at railway stations. This has been demonstrated by the BALIN research project under real-world conditions at the Westhavelland Nature and Star Park. Coinciding with today’s Earth Night, which aims to take a stand against excessive artificial light outdoors, this is a promising result for the protection of insects.

At six rural railway stations in Westhavelland, researchers from the Leibniz Institute for the Analysis of Biodiversity Change (LIB), together with their project partners, demonstrated at six rural railway stations in Westhavelland that amber-coloured 1800 K LED lights attract around 40 to 50 per cent fewer insects and up to 75 per cent less biomass compared with current standards. “We were thus able to demonstrate under real-world conditions at railway stations that the choice of light source – and in particular its spectral composition – plays a decisive role in attracting flying insects,” explains Carmen Ludreschl, a researcher at the LIB working on the BALIN project. The impetus for the joint study came from Deutsche Bahn, which is seeking ways to make its lighting more insect-friendly. The findings were recently published in the journal *Biological Conservation*.

The results at a glance

• The amber-coloured 1800 K LED attracted significantly fewer insects than the current standard (cool white 4000 K LED) and the old high-pressure sodium vapour lamps (2000 K).
• The number of species affected fell by between 10 and 20 per cent with the 1,800 K LED – including endangered and legally protected species.
• Although high-pressure sodium vapour lamps emit a visually ‘warmer’ light (2000 K), they attracted insects to a similar extent as cool-white 4000 K LEDs.
• Even the optimised 1,800 K LED attracted more insects than unlit control sites. There is no such thing as truly insect-friendly artificial light – switching it off remains the best option. Where this is not an option, such as at railway stations, suitable light colour and emission spectrum, dimming and shielding can reduce the impact on insects.
  

From the laboratory to practice: Deutsche Bahn is making the switch

Deutsche Bahn has already responded to the findings: all the platforms studied, as well as one additional station, have been permanently converted to the new 1800 K LEDs. Furthermore, the light source has been included in DB InfraGO AG’s official luminaire selection list. The retrofit demonstrates a new understanding of sustainability that focuses not only on climate protection but also on the conservation of biodiversity: Although the amber-coloured LEDs consume slightly more electricity than conventional cool-white 4000 K LEDs, they offer measurable added value for biodiversity. A positive side effect: in informal surveys, some customers found the warmer light more pleasant.

Legal hurdles are slowing down the nationwide roll-out

However, a nationwide roll-out across all stations is currently complicated for Deutsche Bahn. On the one hand, current EU lighting standards and safety guidelines only permit the use of 1800 K LEDs on uncovered platforms at present. Furthermore, Section 46a of the Federal Nature Conservation Act (protection of animals and plants from the effects of lighting) is still subject to a pending statutory instrument. As long as the legal requirements remain unclear, long-term planning and further retrofitting will be difficult for Deutsche Bahn. There are also currently no new calls for research proposals on the subject of light pollution.

Setting an example for gardens and local authorities on Earth Night

The initiators of the project, which was funded under the Federal Programme for Biological Diversity, hope it willset an example far beyond the rail sector. Just in time for today’s ‘Earth Night’, the researchers emphasise that light pollution throws the entire ecosystem out of balance. If insects lose their sense of direction due to light and, as a result, some of them perish, they are no longer available as food for birds or bats and can no longer pollinate.

These findings can be directly applied to the private sphere. “Even with solar lamps, you should ensure they are not left on unnecessarily throughout the night,” emphasises Ludreschl. The same applies in your own garden: adjust the colour of the light, shield the lights, dim them or, ideally, switch them off.