Light pollution: spatial analysis and potential ecological effects in rural Ireland

Increasing use of artificial light at night has led to many areas across the globe being exposed to light conditions above the natural background level. Research is only now uncovering the impacts of ‘ecological light pollution’ on the environment. Artificial light at night can disrupt circadian rhythms, cause interference with orientation and migration, alter predator/prey interactions and affect other behaviour and physiological features. Intercalibration of Defense Meteorological Satellite Program’s Operational Linescan System images shows that night light emissions in Ireland have increased significantly from 1995 to 2010. In this period, artificial light has spread into previously dark rural areas, including County Mayo where 28% of land surface is designated for habitat and species conservation purposes. To investigate light pollution in rural areas, examination into the conservation area of Owenduff/Nephin Beg Complex was undertaken. Spatial analysis of light measurements taken from Sky Quality Meters surrounding the site were overlaid with species distribution records to determine the proximity of protected species to sources of artificial light at night. Light measurements from the area show pristine night skies according to International Dark Sky Association standards, with one site indicating the presence of localised light pollution. Further work is required to determine if any potential adverse ecological impacts on protected species in the locality are occurring from artificial light at night. The findings of this study provide a foundation for ecological light pollution effects assessment in Ireland. Further work is required to establish the temporal and spatial scales of artificial light in Irish rural areas and determine the specific effects on species present there.