ALAN pollution monitor

Many cities across the world are known to “come alive” at night, with street lights and business signs illuminating the city, giving it an entirely different feel than during the day. However, the increase in artificial light at night (ALAN) is becoming a global concern, especially for migrating bird populations. To determine the effect of ALAN pollution patterns in urban bird populations habitats, Xue et al. (2020), used JL1-eB satellite imagery and land use land cover remote sensing techniques to create an ALAN pollution map over Hangzhou, China. Main bird habitats were designated based on how favourable each pixel’s land use is for hosting bird habitats; for example, woodland would be more favourable than grasslands and would be even more favourable if it is adjacent to other woodland designated pixels. These habitat nodes were then superimposed onto the map along with high probability corridors and connectivity paths that were generated via Circuitscape, a software that uses circuit theory to model functional connectivity and the potential flow in a heterogeneous landscape. They found that habitats suffered from fragmentation and uneven distribution, despite most habitats experiencing fairly light ALAN pollution. It was the corridors that were found to experience uneven amounts of ALAN pollution, from low to quite high, which can confuse birds entirely and cause them to crash into high rises. As a solution, it is recommended that more trees be planted in existing urban green spaces to increase woodland cover and habitat range and that generally more green patches are created. The later recommendation might be difficult to achieve in the capital and most populous city in Zhejiang province. Recognizing this, Xue and his colleagues provide alternative measures, such as turning off ALAN in the busiest corridors and replacing light fixtures with LED since they have a larger spectrum and are more easily recognizable to birds. This study only covers one major light polluting urban center, but its techniques for identifying main bird habitats and corridors could be applied to most other areas on Earth. This study shows that humans must remember that we live amongst many other creatures and that our actions have far more effect on their way of life than it even has on ours. We have a responsibility to change our habits so our cities are mutually beneficial for all beings.

Xue, X., Lin, Y., Zheng, Q., Wang, K., Zhang, J., Deng, J., Abubakar, G.A. and Gan, M., 2020. Mapping the fine-scale spatial pattern of artificial light pollution at night in urban environments from the perspective of bird habitats. Science of The Total Environment, 702, p.134725.



Climate Change, Ecological Monitoring, Lifestyle, Monitoring, Pollution, Visual Technologies