Data from: Artificial light at night causes top-down and bottom-up trophic effects on invertebrate populations

1. Globally, many ecosystems are exposed to artificial light at night. Nighttime lighting has direct biological impacts on species at all trophic levels. However, the effects of artificial light on biotic interactions largely remain to be determined. 2. We exposed experimental mesocosms containing combinations of grassland plants and invertebrate herbivores and predators to illumination at night over a three-year period to simulate conditions under different common forms of street lighting. 3. We demonstrate both top-down (predation controlled) and bottom-up (resource controlled) impacts of artificial light at night in grassland communities. The impacts on invertebrate herbivore abundance were wavelength dependent and mediated via other trophic levels. 4. White LED lighting decreased the abundance of a generalist herbivore mollusc by 55% in the presence of a visual predator, but not in its absence, while monochromatic amber light (with a peak wavelength similar to low pressure sodium lighting) decreased abundance of a specialist herbivore aphid (by 17%) by reducing the cover and flower abundance of its main food plant in the system. Artificial white light also significantly increased the food plant’s foliar carbon to nitrogen ratio. 5. We conclude that exposure to artificial light at night can trigger ecological effects spanning trophic levels, and that the nature of such impacts depends on the wavelengths emitted by the lighting technology employed. 6. Policy implications Our results confirm that artificial light at night, at illuminance levels similar to roadside vegetation, can have population effects mediated by both top-down and bottom-up effects on ecosystems. Given the increasing ubiquity of light pollution at night, these impacts may be widespread in the environment. These results underlines the importance of minimising disruption of natural ecosystems by reducing light pollution into natural and semi-natural ecosystems.26-Jun-2018

1. 全球范围内，众多生态系统均暴露于夜间人工光照环境中。夜间照明对各营养级（trophic level）的物种均存在直接生物学影响。然而，人工光照对生物间相互作用的影响在很大程度上仍有待探明。
2. 本研究开展了为期三年的夜间光照暴露实验，将包含草原植物、无脊椎草食动物与捕食者组合的中型生态实验系统（mesocosms）置于不同常见街道照明的模拟光照条件下。
3. 研究证实，夜间人工光照对草原群落存在自上而下（捕食调控）与自下而上（资源调控）两类影响。无脊椎草食动物的丰度所受影响具有波长依赖性，且通过其他营养级介导产生。
4. 白色发光二极管（Light Emitting Diode, LED）照明在存在视觉捕食者的情况下，可使广食性草食性软体动物的丰度降低55%，而在无捕食者时则无此效应；单色琥珀光（峰值波长与低压钠灯相似）则通过降低系统内其主要寄主植物的盖度与花部丰度，使专食性草食性蚜虫的丰度降低17%。此外，人工白光还会显著提升寄主植物的叶片碳氮比。
5. 本研究结论表明，夜间人工光照暴露可引发跨营养级的生态效应，且此类影响的性质取决于所采用照明技术的发射波长。
6. 政策启示：本研究结果证实，夜间人工光照在照度与路边植被所处水平相当的情况下，可通过自上而下与自下而上的作用对生态系统产生种群层面的影响。鉴于夜间光污染日益普遍，此类影响可能在环境中广泛存在。上述研究结果凸显了通过减少进入自然与半自然生态系统的光污染，以降低对自然生态系统干扰的重要性。
2018年6月26日