Over the past few years, we have been gathering evidence for a novel biogeographic theory inspired by the abundance of new research emerging within the fields of chronobiology, light pollution, and biogeography. We synthesized this knowledge to describe a potential latitudinal gradient in organism’s vulnerability to light pollution, grounded in the evolution of circadian rhythms. We are excited to announce that a preprint of our paper, Circadian Histories: Latitudinally Determined Responses to Light Pollution is now available.
Light follows a similar biogeographic pattern to temperature, with seasonally fixed cycles around the equator to highly divergent summer and winter cycles at higher latitudes. With the rapid increase in artificial light at night across the globe, organisms must navigate novel photoperiods for the first time in their recent evolutionary history, with consequences for circadian timing. Natural photoperiod variation follows a latitudinal gradient, which has resulted in a corresponding latitudinal gradient of circadian sensitivity to photoperiodic change. This prompts an exploration of how latitudinally determined evolutionary adaptations to the historic photoperiod, termed “circadian histories,” might influence biogeographic patterns of vulnerability to light pollution as well.
Victoria E. Amaral 