Raap Thomas, Sun Jiachen, Pinxten Rianne, Eens Marcel
Department of Biology, Behavioural Ecology and Ecophysiology Group, University of Antwerp, Wilrijk, Belgium.
Department of Biology, Behavioural Ecology and Ecophysiology Group, University of Antwerp, Wilrijk, Belgium.
Behav Processes. 2017 Nov;144:13-19. doi: 10.1016/j.beproc.2017.08.011. Epub 2017 Sep 1.
Light pollution or artificial light at night (ALAN) is an increasing anthropogenic environmental pollutant posing an important potential threat for wildlife. Evidence of its effects on animal physiology and behaviour is accumulating. However, in order to effectively mitigate light pollution it is important to determine which factors contribute to the severity of effects of ALAN. In this experimental study we explored whether there are seasonal-dependent effects of ALAN on sleep in free-living great tits (Parus major), an important model species. Additionally, we looked at whether light intensity determined the severity of effects of ALAN on sleep. We therefore exposed animals to artificial light inside the nest box (3lx) in December (winter) and February (pre-breeding season). Results from February were compared with the results from a previous study in February, using a lower light intensity (1.6lx). We found little evidence for a season-dependent response. Effects of ALAN hardly differed between high and low light intensity. ALAN disrupted sleep with as main effect a decrease in sleep duration (≈-40min) as animals woke up earlier (≈-24min). However, compared to a natural dark situation sleep onset was delayed by high but not by low light intensity of ALAN. Our study underlines earlier found disruptive effects of ALAN on sleep of free-living animals. While we found no conclusive evidence for seasonal or light intensity-dependent effects of ALAN, additional experimental work using lower light intensities might show such differences. Examining potential management options is crucial in mitigating disruptive effects of light pollution, which will be an important focus for future studies.
光污染或夜间人造光（ALAN）是一种日益严重的人为环境污染物，对野生动物构成重要的潜在威胁。其对动物生理和行为影响的证据正在不断积累。然而，为了有效减轻光污染，确定哪些因素会导致ALAN影响的严重程度很重要。在这项实验研究中，我们探讨了ALAN对自由生活的大山雀（Parus major）睡眠是否存在季节性依赖效应，大山雀是一种重要的模式物种。此外，我们还研究了光强度是否决定了ALAN对睡眠影响的严重程度。因此，我们在12月（冬季）和2月（繁殖前期）将动物置于巢箱内的人造光（3勒克斯）环境中。将2月的结果与之前2月的一项使用较低光强度（1.6勒克斯）的研究结果进行比较。我们几乎没有发现季节性依赖反应的证据。高、低光强度下ALAN的影响几乎没有差异。ALAN扰乱了睡眠，主要影响是睡眠时间减少（约-40分钟），因为动物醒来更早（约-24分钟）。然而，与自然黑暗环境相比，高ALAN光强度会延迟睡眠开始时间，而低光强度则不会。我们的研究强调了早期发现的ALAN对自由生活动物睡眠的干扰作用。虽然我们没有找到ALAN存在季节性或光强度依赖效应的确凿证据，但使用更低光强度的额外实验工作可能会显示出这种差异。研究潜在的管理方案对于减轻光污染的干扰作用至关重要，这将是未来研究的一个重要重点。
