The excessive use of artificial light at night, also known as light pollution, is a hot topic in biological research and nature conservation. In Germany, however, there is still a lack of awareness of the importance of the problem and the need to implement appropriate protection measures for protected species. In a review article, therefore, essential findings from scientific studies on the effects of artificial light on bats were summarized, legal bases on which protective measures can be demanded were discussed and recommendations for practical protective measures were given.

Bats are nocturnal and are considered endangered, are strictly protected by law and are severely affected by light pollution. It is therefore important to avoid and reduce the negative effects of artificial light.

The study shows that bat species such as Myotis, Plecotus or Rhinolophus species, which mainly move in the protection of vegetation, are most sensitive to artificial light. Species that move in free airspace, such as Pipistrellus, Eptesicus or Nyctalus species, are more tolerant of light.

The negative effects can be mitigated by appropriate shading, dark corridors, time limitation of lighting, low illuminance or reddish-yellowish spectrum of light color, for example when it comes to hunting habitats or transfer routes. However, the lighting of roosts is a significant impairment for all species, regardless of the illuminance or colour of light.

Original article:

Zschorn, M., Fritze, M. (2022): Light pollution and bat conservation – current knowledge, need for action, and recommendations for practice. Naturschutz und Landschaftsplanung 54 (12), 16-23. https://doi.org/10.1399/NuL.2022.12.01

Overview about measures to reduce negative effects of artificial light on bats (in German):

Massnahmen_All-in-a-nutshell


Supplementary material (overview of the effect of artificial light on native bat species):

Tabelle_Zschorn_Fritze

Lighting situation in a residential area in Greifswald. On the left side there are street lamps with bat-friendly reddish-warm light, on the right side bluish-cold light colors that attract many insects and at the same time have a disturbing effect on bats. Photo: M.Fritze
Schematic, model-like representation of a man-made landscape with different habitats, which are also used and populated by bats. The areas shown in dark green represent near-natural areas such as forests and historical cultural landscapes, where bats’ roosts and feeding areas are often located. Light green areas symbolize agricultural land, meadows and parks that are used as food habitats. Blue are water surfaces that are essential for drinking, but also for as a source of food. Shown in yellow are the areas that are irradiated with artificial light at night – settlements and paths. The red arrows symbolize how often bats can come into conflict with the light (illustration: © Maria Zschorn).
Light pollution and bat protection – current state of knowledge, need for action and recommendations for practice