Dazzling lights are causing ecological chaos, disrupting plants' seasonal rhythms and their fragile relationship with pollinators.

耀眼的灯光引起了生态混乱,扰乱了植物的季节性节律,破坏了植物与传粉昆虫的脆弱关系。

One summer night in 2014, a group of biologists and ecologists staked out several streetlamp-lit suburban areas just outside Wallingford in the UK. While their nighttime presence may have prompted some concern of potential thievery among the locals, they were actually there to observe nocturnal moths going about their nightly pollinating routine.

2014年夏季的一个晚上,在英国沃林福德城外,一支由生物学家和生态学家组成的团队监视了多个有路灯照明的郊区。他们的夜间活动可能引起了当地居民对潜在盗窃的担忧,其实他们是去观察夜蛾在夜间的传粉路线。
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The scientists were studying how the streetlights affected the moths' behaviour. Their theory was that the artificial light at night would disrupt the moths' flight patterns enough that it would impede how much, or how well, they could pollinate.

科学家正在研究路灯对夜蛾行为产生的影响。他们认为,夜间的人造光源会打乱夜蛾的飞行模式,进而妨碍它们传粉的数量和效果。

Sure enough, of the hundreds of moths they observed, over 70% were drawn upwards towards the lights and away from the flowering plants, resulting in a noticeable reduction in plant pollination as well as the number of pollen types that were transported by the moths. This proved true across several different nocturnal moth species and over 28 varieties of plants, meaning the ripple effect could have wide-reaching consequences.

果不其然,在他们观察的数百只夜蛾中,70%以上被路灯吸引而飞离了有花植物,导致夜蛾的授粉量和种类显著减少。多种不同的夜蛾和超过28种植物都证明了这一点,这意味着连锁效应可能产生深远的后果。

This is just one narrow view into how light pollution is disrupting the natural world. Moths aren't the only pollinators impacted by dazzling city lights. Bees are also feeling the effects, along with all the plants they pollinate. As artificial lights disrupt how nocturnal pollinators interact with plants, their pollen output can be affected, which may, in turn, impact how well bees and other diurnal pollinators can fertilise them during the daytime.

这只是光污染打乱自然界的冰山一角。夜蛾不是唯一受到耀眼的城市光源影响的传粉昆虫,蜜蜂及其授粉的所有植物也会受到这种影响。由于人造光源打乱夜间传粉昆虫与植物的互动,它们的授粉量会受到影响,继而影响蜜蜂及其他日间传粉昆虫在白天为植物授精的效果。

Light pollution already encompasses about a quarter of the planet and continues to worsen, increasing by about 6% every year with growing urbanisation. Global light pollution has increased by at least 49% over 25 years.

光污染已经覆盖地球的四分之一,而且在继续扩大。随着城市化的发展,光污染每年扩大约6%。25年来,全球光污染至少增加了49%。

While its impacts are still being studied and vary widely across species, scientists do know light pollution is affecting how plants grow and reproduce. It disrupts their seasonal rhythms, their ability to sense and react to natural light, and their fragile relationship with pollinators. The more strained that relationship becomes, the more our food supply may be put in jeopardy. And just one broken lix could create unfathomable physiological consequences up and down the food chain.

尽管科学家仍在研究光污染的影响,而且对不同物种的影响有很大差异,但科学家知道光污染是如何影响植物生长和繁殖的。光污染打乱植物的季节性节律、感知能力、对自然光的反应、破坏植物与传粉昆虫的脆弱关系。彼此的关系越紧张,我们的粮食供应越有可能有危险。只要有一个环节断裂,就可能给整个粮食供应链带来难以预料的生理后果。

How plants sense the world

植物如何感受世界?

A primary reason light pollution, or artificial light at night, impacts most living things on this planet is that they have a circadian rhythm. This rhythm is the natural sleep-wake cycle that repeats every 24 hours and is governed by when it's light or dark. Most creatures, whether nocturnal or diurnal, carry out their living processes by this cycle, so when it is disrupted by, say, a perceived shorter nighttime, it can put undue stress on how internal systems function. And the longer that disruption goes on, the more potential there is for detrimental impacts.

光污染或夜间的人造光源会影响地球大多数生物,主要原因是生物具有昼夜节律。这种节律是自然的睡眠-苏醒周期,每24小时重复一次,并由白天或黑夜控制。大多数生物,无论日间还是夜间活动,都是依据这个节律来完成生命过程的。所以当昼夜节律被打乱时,例如明显感觉黑夜缩短,这会给内部系统如何运行造成过多的压力。打乱得越久,造成有害影响的可能性就越大。

Light pollution is negatively impacting many different species, including bumblebees

光污染对许多生物造成不利影响,包括大黄蜂。

Circadian clock disruptions can also affect regulating chemicals in humans, plants and animals, most notably melatonin, a molecule that is produced in response to darkness and helps regulate the circadian rhythm. "[It's] supposed to be elevated overnight, but light pollution suppresses melatonin, which, over time, can cause a whole sweep of negative health effects," says Valentina Alaasam, a researcher at the University of Nevada in the US. For humans, health impacts include an increased risk of sleep disorders, diabetes, depression, heart conditions, and breast cancer.

生物钟紊乱还会影响人类、植物、动物体内化学物质的调节,尤其是褪黑素,这种分子对漆黑环境做出反应,有助于调节昼夜节律。“褪黑素在夜晚应该升高,但光污染抑制褪黑素,久而久之会对健康造成大量的不利影响”,美国内华达大学研究人员瓦伦蒂娜·阿拉萨姆说道。对人类健康造成的不利影响包括:睡眠障碍、糖尿病、抑郁、心脏病、乳腺癌的患病风险增加。

The effects aren't all that dissimilar to jet lag. Say you're flying from London to New York. Since you're traveling to a place five hours behind your home base, you're effectively gaining five hours of either day or night (depending on when you're travelling), which throws your circadian rhythm off kilter. The resulting jet lag can leave you feeling foggy, sleep-deprived, and generally under the weather for several days. That's just the result of one circadian rhythm disruption. Now imagine you're a tree on the side of a city street constantly being exposed to artificial lights from street lamps, cars, and buildings. If your internal system always thinks it's daytime, it can turn your life upside down.

这种影响与飞行时差大同小异。例如你从伦敦飞往纽约,由于目的地比出发地晚了五个小时,你实际上延长了五个小时的白天或黑夜(取决于你什么时候出发)使你的昼夜节律失去平衡。飞行时差会让你感到迷糊、睡眠不足、连续多天身体不适,这就是昼夜节律紊乱的结果。现在想象你自己是城市街边的一棵树,经常暴露在路灯、汽车、建筑物的人造光源之下。如果你的内部系统认为这是白天,你的生活会完全颠倒。

"Plants are like animals in that they need a sleep cycle to process stuff, and what they do is they put attention on different activities at different times of the day. So they need to know the time of day," says Joanne Chory, professor at the Salk Institute for Biological Studies in San Diego, California.

“植物就像动物一样需要睡眠周期来处理活动,它们在一天中不同的时间里专注不同的生理活动,所以它们需要知道一天中的时间”,美国加州圣地亚哥索尔克生物研究所教授乔安妮·乔里说道。

Plants have photoreceptors, 13 that we know of, that they use to determine things like day length. This helps them know when to bloom and, for deciduous trees, when to drop leaves – arguably two of the most important events in a tree's calendar. Five of the photoreceptors absorb near-infrared light from the Moon and starlight, and eight absorb a type of UV light. By artificially extending the length of the day, light pollution can trigger these photoreceptors to the point where a plant's flowering pattern changes.

植物拥有视细胞,它们利用我们已知的13种视细胞来确认昼长等事情。这有助于它们知道何时开花,落叶树知道何时落叶,可谓树木生涯中最重要的两件事。5种视细胞吸收月亮和星光中的近红外光,8种视细胞吸收某种紫外光。如果人为延长白昼时间,光污染会触发这些视细胞,使植物的开花模式发生改变。

"Plants will get stressed out under [artificial] light. They can photosynthesise more, and because they are there's more stress," says Brett Seymoure, an ecologist and assistant professor of biological sciences at the University of Texas at El Paso. "It's just like a bodybuilder who's just always working out." When a plant photosynthesises, they're taking in energy, and if they're doing that all the time, it can be overwhelming and create a reactive type of oxygen that kills the plant.

“植物在人造光源下会承受巨大压力。它们进行更多的光合作用,因为它们承受着更大的压力”,德克萨斯大学埃尔帕索分校的生物学家布雷特·西摩说道。“就好比健美运动员不停地锻炼”。植物的光合作用是在摄取能量,不停地进行光合作用会使植物筋疲力尽,产生的一种活性氧导致它们死亡。

Couple that with warmer winters and longer summers due to climate change, and you end up with trees growing well out of their natural rhythm, which can ultimately weaken them.

再加上气候变化导致冬季变暖和夏季延长,树木生长最终完全脱离自然节律,削弱它们的生命力。

Seasonal changes

季节性变化

Blooming or budbursts typically happen in the spring with the arrival of warmer temperatures coinciding with longer days and more UV rays. However, Seymour says light pollution is scrambling those cues for plants. "The seasonal changes of plants have been affected by artificial light at night," says Seymoure. "They do budbursts sooner or they hold onto their leaves longer, and that's because the photoperiod, which is the ratio of daytime to nighttime, is being masked by artificial light at night."

开花或发芽通常发生在暖春,也正是白天变长和紫外线增加的时候。但西摩表示,光污染在扰乱植物接收这些信号。“植物的季节性变化已经受到夜晚人造光源的影响”,西摩说道。“它们提前发芽或延迟落叶,因为夜晚的人造光源掩盖了光周期,即昼长和夜长的比例”。

Even ambient light that radiates miles out from a city can disrupt the circadian rhythms of plants and animals

即使是从城市向外辐射数英里的环境光也会扰乱植物和动物的昼夜节律。
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One study that analysed 13 years of budburst data from deciduous trees in the UK found that budburst happened up to 7.5 days earlier in areas that were brighter at night due to light pollution. Budburst can also change when trees drop their leaves in the autumn because, again, artificial light interferes with the perceived photoperiod of shortening days as winter approaches.

一项研究分析了英国落叶树13年的发芽数据,发现在光污染导致夜晚更亮的地区,落叶树的发芽时间提前了7.5天。发芽的提前也改变了秋天的落叶时间,同样是因为随着冬天的临近,人造光源扰乱了落叶树感知昼长越来越短的光周期。

Normally, as days grow shorter, deciduous trees stop the production of chlorophyll, the primary pigment used in photosynthesis, and pull nutrients out of their leaves, which is why they change colour and eventually fall to the ground. "But since they're just constantly bombarded by street lights, they don't get that photoperiod, so they're going to hold on to their leaves a lot longer, and they could lose all those leaves that have this chlorophyll which is actually very energetically costly," says Seymoure.

随着昼长越来越短,落叶树通常停止产生叶绿素(用于光合作用的主要色素),并停止从树叶中提取养分,这就是树叶变色并最终落在地上的原因。“但由于落叶树一直受到路灯的照射而无法感知光周期,所以落叶时间延迟很多,它们可能掉光所有含叶绿素的树叶,这实际上会耗损巨大能量”。

Light pollution disrupts pollinators' circadian rhythms as well as their general life patterns, which ultimately impedes plant reproduction. Several studies, the UK moth study included, have found that nocturnal pollination is diminished under artificial lights. A 2017 study found that nocturnal plant-pollinator interactions were 62% lower in brightly lit areas than in non-illuminated ones. When those interactions shrink, plants aren't as stimulated to produce pollen, which leaves less pollen for diurnal pollinators like bees.

光污染会扰乱传粉昆虫的昼夜节律和正常的生活模式,最终阻碍植物繁殖。多项研究,包括英国对夜蛾的研究发现,夜间授粉量在人造光源下有所减少。2017年的一项研究发现,照明区与无照明区相比,植物与传粉昆虫的夜间互动减少了62%。当互动减少时,植物得不到那么多刺激来产生花粉,留给蜜蜂等昼间传粉昆虫的花粉就会变少。

Just like jet lag affects humans, light pollution can also stress pollinators' bodies by reducing their sleep and recovery time, ultimately making it harder for them to pollinate and reproduce.

正如飞行时差会影响人类,光污染也会给传粉昆虫的身体造成压力,减少它们睡眠和恢复体能的时间,最终使它们授粉和繁殖变得更加困难。

Light pollution even impacts migration by attracting insects (and other flying animal species) away from their natural, intended path and into dangerous and often deadly scenarios. "[It] has been shown to disorient [bird] migration routes and change where species breed or overwinter," says Alaasam. These migratory changes can potentially impact plants that are pollinated by birds or plants that get their seeds dispersed by birds.

光污染甚至会影响迁移,吸引昆虫(及其他飞行物种)脱离天然的预定路线,陷入危险且通常致命的境地。“事实证明光污染会使(鸟类)迷失迁移路线,改变它们的繁殖或过冬地点”,阿拉萨姆说道。这些迁移上的改变可能影响那些由鸟类授粉或散播种子的植物。

In terms of insects, Seymoure calls this attraction to light the "trap effect" which is "where the insects come to the lights but they never pollinate because they're just too busy flying around in the light," says Seymoure. Other pollinators, such as certain species of beetles, are photophobic, and simply avoid vegetation under artificial light; this is the "repel effect". Around one-third of bugs that are attracted to artificial light at night don't survive past the morning, according to a review of 229 studies Seymoure co-authored, either due to predation, exhaustion, or hunger.

西摩将光源吸引昆虫的现象称为“陷阱效应”,“昆虫飞向光源但根本不进行传粉,因为它们忙于绕着光源飞行”,西摩说道。还有些传粉昆虫怕光,比如某些种类的甲虫,它们在人造光源下完全避开植物,这被称为“排斥效应”。由西摩合著的有关229项研究的报告显示,在夜晚被人造光源吸引的昆虫中,约有三分之一活不到早晨,原因包括捕食、疲惫、饥饿。

'Insect apocalypse'

昆虫末日

Pollinator populations are steadily declining, and ecologists like Seymoure fear it's the result of a confluence of stressors, including light pollution, chemical pollution, climate change, and habitat loss. Insects are an essential keystone to life on this planet, and as we lose them, the species domino effect becomes clearer. For example, if honeybees native to the US die out, all the species of plants they pollinate could follow, with no other intervention – that's 80% of flowering plants. The US Department of Agriculture estimates those plants account for 25% of the food Americans eat today.

传粉昆虫的数量在逐步下降,西摩等生态学家担心这是多种压力因素共同作用的结果,包括光污染、化学污染、气候变化、生境丧失。昆虫是地球生命的重要基石,随着我们失去它们,物种的多米诺效应会更加明显。例如,如果美国本土的蜜蜂灭绝,在没有其他干预的情况下,依靠它们授粉的植物都可能随之灭绝——约占开花植物的80%。美国农业部预测,这些植物占美国人当今粮食的25%。

"Around 200 million years ago, flowering plants and insects started to co-evolve with each other. If you start to alter either the behaviour of the insect or the behavioural physiology of the plant, you're going to affect both of them," says Seymoure. "[With light pollution] you have this new weird situation that's going to have consequences for everything on this planet because pretty much everything depends on insects and flowering plants – 80% of our crop species are pollinated by insects."

“大约2亿年前,开花植物和昆虫开始共同进化。如果你开始改变昆虫的行为或植物行为的生理机能,两者都会受到影响”,西摩说道。“光污染会使你面临新的奇怪处境,对地球上的一切都会造成后果,因为几乎一切都依赖昆虫和开花植物——80%的农作物依靠昆虫授粉”。

By artificially extending the length of the day, light pollution can cause changes in a a plant's flowering pattern

光污染人为地延长昼长,这会改变植物的开花方式。

Plants and pollinators rely on temperature and light changes to know how, and when, to carry out their life processes. As the planet warms and light pollution grows, these processes will be thrown more and more off-balance, and it's unclear if the affected species will adapt fast enough to survive.

植物和传粉昆虫依靠温度和光照的变化来判断如何以及何时开展生命活动。随着全球变暖和光污染的日益严重,这些活动将越来越失去平衡,尚不确定受影响物种的适应速度是否足以生存下去。

"Light pollution and climate change are making these cues [light and temperature] less reliable and causing some ecological chaos," says Alaasam.

“光污染和气候变化使这些信号(光照和温度)不那么可靠,引发一定程度的生态混乱”,阿拉萨姆说道。

Despite all of this, there are pollinators that aren't as negatively affected by light pollution. In fact, some have evolved to use it to their advantage. One study that looked at "city moths" from 10 different populations found that they'd adapted not to fly to artificial light at night. "Moths that had been exposed to artificial light over the last 20 to 50 years no longer had the genes that allowed them to fly to the light," says Seymoure.

尽管如此,有些传粉昆虫没有受到太多光污染的不利影响。事实上,有些传粉昆虫通过进化将光污染为己所用。一项观察了10种“城市飞蛾”的研究发现,它们适应了在夜晚不会飞向人造光源。“在过去的20-50年里,暴露在人造光源下的飞蛾已经失去飞向光源的基因”,西摩说道。

Pollinating bats also seem to have found a positive loophole. Not only do artificial lights illuminate the bugs they like to eat, but a 2022 study found they also increased pollination due to more fruit and seeds on the artificially illuminated trees (a potential result of excessive blooming). That may only be a temporary boon, however. As Seymoure fears, too much artificial light exposure could be overtaxing trees, weakening them over time.

传粉的蝙蝠似乎也发现一个有利的漏洞。人造光源不仅照亮了蝙蝠爱吃的小虫子,2022年一项研究发现,人造光源还增加了授粉量,这是因为人工照亮的树木结出了更多的果实和种子(可能是过度开花的结果)。但这可能只是暂时的福利,西摩担心树木暴露在太多的人造光源下可能负担过重,久而久之变得虚弱。

Many other insect species have never been attracted to light, so they aren't directly affected by light pollution. However, that doesn't mean they aren't indirectly impacted in other ways. For example, bees aren't attracted to light, but they're negatively affected by light pollution because the plants they pollinate aren't as stimulated to produce pollen by nocturnal pollinators who are driven away by artificial lights.

许多其他种类的昆虫根本不受光源的吸引,所以没有受到光污染的直接影响,但并不意味着不受其他方面的间接影响,例如:蜜蜂不受光源的吸引,但受到光污染的不利影响,因为蜜蜂传粉的植物得不到夜间传粉昆虫那么多刺激来产生花粉,夜间传粉昆虫被人造光源赶跑了。

It might seem like these small changes won't have sweeping effects, but all these changes can also save money through lower energy costs too. This might help convince your office manager, landlord or city council to cut back on light pollution, says Alaasam.

这些细微的变化似乎不会产生广泛的影响,但这一切变化可以通过降低能源成本来节省资金。这可能有助于说服你的办公室经理、业主、市议会来减少光污染,阿拉萨姆说道。

These changes are starting to happen more and more in small, eco-conscious pockets of the world. The more communities start reaping the benefits, then perhaps others will follow suit, drawn like, forgive the expression, a moth to a flame.

世界上有环保意识的小地方已开始发生这些变化。越多的社区获益,请原谅我的措辞,也许其他社区会像飞蛾扑火般纷纷效仿。