Environment & Sustainability Institute, University of Exeter, Penryn, Cornwall TR10 9FE, UK.
Integr Comp Biol. 2021 Oct 4;61(3):1098-1110. doi: 10.1093/icb/icab145.
Artificial light at night (ALAN) and its associated biological impacts have regularly been characterized as predominantly urban issues. Although far from trivial, this would imply that these impacts only affect ecosystems that are already heavily modified by humans and are relatively limited in their spatial extent, at least as compared with some key anthropogenic pressures on the environment that attract much more scientific and public attention, such as climate change or plastic pollution. However, there are a number of reasons to believe that ALAN and its impacts are more pervasive, and therefore need to be viewed from a broader geographic perspective rather than an essentially urban one. Here we address, in turn, 11 key issues when considering the degree of spatial pervasiveness of the biological impacts of ALAN. First, the global extent of ALAN is likely itself commonly underestimated, as a consequence of limitations of available remote sensing data sources and how these are processed. Second and third, more isolated (rural) and mobile (e.g., vehicle headlight) sources of ALAN may have both very widespread and important biological influences. Fourth and fifth, the occurrence and impacts of ALAN in marine systems and other remote settings, need much greater consideration. Sixth, seventh, and eighth, there is growing evidence for important biological impacts of ALAN at low light levels, from skyglow, and over long distances (because of the altitudes from which it may be viewed by some organisms), all of which would increase the areas over which impacts are occurring. Ninth and tenth, ALAN may exert indirect biological effects that may further expand these areas, because it has a landscape ecology (modifying movement and dispersal and so hence with effects beyond the direct extent of ALAN), and because ALAN interacts with other anthropogenic pressures on the environment. Finally, ALAN is not stable, but increasing rapidly in global extent, and shifting toward wavelengths of light that often have greater biological impacts.
夜间人工光照（ALAN）及其相关的生物影响通常被认为主要是城市问题。尽管这远非微不足道，但这意味着这些影响仅影响那些已经受到人类强烈改造的生态系统，并且其空间范围相对有限，至少与一些吸引更多科学和公众关注的关键人为环境压力相比是如此，如气候变化或塑料污染。然而，有一些理由相信，ALAN 及其影响更为普遍，因此需要从更广泛的地理角度而不是从本质上的城市角度来看待。在这里，我们依次讨论了在考虑 ALAN 的生物影响的空间普遍性程度时需要考虑的 11 个关键问题。首先，由于可用遥感数据源的局限性以及如何处理这些数据，ALAN 的全球范围可能本身就经常被低估。其次和第三，更孤立（农村）和移动（例如，车辆前照灯）的 ALAN 源可能具有非常广泛和重要的生物影响。第四和第五，海洋系统和其他偏远地区的 ALAN 的发生和影响需要更多的考虑。第六、第七和第八，越来越多的证据表明，天空辉光和长距离（因为有些生物可能从这些高度观察到它）的低光照水平下的 ALAN 会产生重要的生物影响，所有这些都会增加发生影响的区域。第九和第十，ALAN 可能会产生间接的生物影响，这可能会进一步扩大这些区域，因为它具有景观生态学（改变运动和扩散，因此其影响超出了 ALAN 的直接范围），并且因为 ALAN 与环境的其他人为压力相互作用。最后，ALAN 不是稳定的，而是在全球范围内迅速增加，并向具有更大生物影响的光波长转移。
