Preventing areas from being artificially lit
Faced with progressive loss of dark areas, it is important to protect those that remain and where possible, recover others. Arguably the simplest approach to managing night-time light pollution is to prevent areas from being lit in the first place, limit the installation of lighting devices or remove lighting devices where these are already in place – ‘exclusion, reduction and removal’. When carried out over very large areas, this will prevent or localize the problem of night-time light pollution, at least for those organisms that do not disperse or migrate over longer distances. However, diffuse illumination from artificial skyglow may remain an issue, even tens and possibly hundreds of kilometres from light sources.
There is clearly potential for applying such an ‘exclusion, reduction and removal’ management approach much more widely and this should include water bodies and areas of high conservation value. Furthermore, the proposed introduction of night-time light pollution to an area could become a routine component of Environmental Impact Assessments.
A precautionary and sensible strategy in urban landscapes might be to maintain unlit areas of all sizes wherever possible. Ecological thresholds of unlit areas will vary with the mobility and individual sensitivity of species. It is important to determine just how important such dark refuges are, and their adequacy, for the maintenance of organisms in urban environments. At large spatial extents, the protection or creation of natural unlit areas has received most attention in the context of establishing International Dark Sky Places (including parks, reserves and communities) with a particular goal of limiting skyglow, and preventing loss of visibility of stars and other celestial bodies.
There are a number of initiatives to identify and maintain presently dark areas and to encourage communities to reduce their overall levels of artificial light at night:
International Dark Sky Association (IDSA)
Loss of the Night Network (LoNNe)