The effect of artificial light on plants/wildlife - Page 1
Forum section: electronics / general

author: Zero999
author_rank: Super Contributor
timestamp: January 25, 2025, 07:36:46 pm
content: TLDR: Artificial light is messing with the seasonal cycle of plants.I was cycling to work yesterday and had to stop because something fell out of my bag. I noticed one the one of the nearby bushes still has leaves and flowers growing near the lamps and the rest are completely dormant. I thought it was strange but didn't have time to stop to take a picture, so I took one on the way back home, when the light was on and another one today in daylight, with the light off.It's an LED lamp, not incandescent, so I don't think it produces enough heat to keep the plant growing. It's more likely the light is fooling the plant into thinking it's summer, so it hasn't gone dormant. We have had some cold weather, with lows of -7°C and according to the Met Office, this month has been slightly colder than average, with an average temperature of 3°, highs of 6°C and lows of freezing, but it hasn't been enough to damage the plant or stop it growing. Yes, I know it's nothing compared to America and we've had much colder weather before.It's a dasiphora fruticosa, a hardy plant native to northern Eurasia.https://en.wikipedia.org/wiki/Dasiphora_fruticosa?useskin=vectorI've read about artificial lighting causing problems for wildlife, but this is the first time I've seen it affect a plant.

author: Zero999
author_rank: Super Contributor
timestamp: January 25, 2025, 07:37:59 pm
content: With the light off, you can see the green parts corellate well with light exposure. The lamp is on all night and has a sensor.

author: Analog Kid
author_rank: Super Contributor
timestamp: January 25, 2025, 08:17:36 pm
content: Certainly looks like a problem to me. How serious a problem I can't say.Just another second-order effect of the Hue-mon cancer metastasizing over the planet, I guess.

author: SiliconWizard
author_rank: Super Contributor
timestamp: January 25, 2025, 11:08:52 pm
content: Yes, it does mess with insects and birds as well.

author: Analog Kid
author_rank: Super Contributor
timestamp: January 25, 2025, 11:18:56 pm
content: Those circadian rhythms are pretty goddamn important.Mess with them and ...

author: Marco
author_rank: Super Contributor
timestamp: January 25, 2025, 11:59:42 pm
content: Quote from: Analog Kid on January 25, 2025, 08:17:36 pmNature had no problem with cancer before humans either ... it's cancer all the way down.

author: Zero999
author_rank: Super Contributor
timestamp: January 26, 2025, 03:35:09 pm
content: Yes, it's not good, but in this case it isn't devastating either. It's only a small part of the plant which has been affected. The main issue I can think of is, if there is a spell of extremely cold weather, it will kill the parts of the plant which haven't gone dormant, which will cut it back, but it will recover in the spring.It's still interesting how this plant's grow cycle appears to be more influenced by day length and light levels, than temperature.We do need to think more about nature and light pollution. Old sodium lamps weren't so bad. Perhaps street lamps should move to monochromatic LED lamps. It would be easy to mimic the spectrum of sodium lights.

author: Haenk
author_rank: Super Contributor
timestamp: January 26, 2025, 04:00:52 pm
content: I'd also wager a guess here: Maybe it is the radiation of heat from the lamp, that keeps the plant un-dormant near the lamp. Of course it is not a lot of heat, but might keep the plant above 4oC or so. The light might help, but usually they need UV light to grow.

author: Siwastaja
author_rank: Super Contributor
timestamp: January 26, 2025, 04:12:24 pm
content: Quote from: Haenk on January 26, 2025, 04:00:52 pmYou are off by many orders of magnitude. Heat from a LED lamp, outdoors, nearly a meter apart, in free air could maybe heat the plants by 0.04degC. Maybe.

author: Zero999
author_rank: Super Contributor
timestamp: February 02, 2025, 05:26:50 pm
content: Yes. It's definitely the light which is causing this. The lamp itself hardly gets warm.

author: jpanhalt
author_rank: Super Contributor
timestamp: February 02, 2025, 06:04:25 pm
content: The effect is known, and so far, the US EPA seems to giving "light pollution" a pass. I hope it stays that way. Lighted streets and paths help humans and probably decrease crime.

author: Zero999
author_rank: Super Contributor
timestamp: February 02, 2025, 06:14:35 pm
content: Quote from: jpanhalt on February 02, 2025, 06:04:25 pmIs there any strong evidence to suggest that?I'm not against street lighting. I'm more doubtful it affects crime, but it probably reduces the chance of cyclists and pedestrians being injured on the road.There are ways light streets, which minimise disruption to wildlife. Sodium street lights were good in that they emitted a narrow spectrum, which is nothing like natural light and is much less likely to interfere with plants and animals. Being a longer wavelength it's also less likely to affect night vision and interfere with human sleep.

author: jpanhalt
author_rank: Super Contributor
timestamp: February 02, 2025, 07:07:09 pm
content: Quote from: Zero999 on February 02, 2025, 06:14:35 pmYes. That's why I moved 42 miles West of Cleveland to a rural area without street lights shortly after I retired. It wasn't the light pollution that bothered me.

author: Zero999
author_rank: Super Contributor
timestamp: February 02, 2025, 07:20:12 pm
content: Quote from: jpanhalt on February 02, 2025, 07:07:09 pmWhy do you think it has anything to do with street lighting?There are many reasons why some areas have higher crime rates, than others. It's simplistic to blame it on the lack of lighting.

author: Njk
author_rank: Frequent Contributor
timestamp: February 03, 2025, 07:38:45 am
content: Who else is doing that and why it's necessary? There are many species such as big mammals, who're apparently smarter than humans, because they have bigger brain which evolved over longer time. Some of them are also living in packs where one individual takes advantage of the others. But they're not took that to the extreme by using the industrial way. Which suggests that it's not the only way and maybe not the best one in the long term. Perhaps humans are too stupid and short-minded to understand this. Especially the champions.

author: tszaboo
author_rank: Super Contributor
timestamp: February 03, 2025, 09:09:06 am
content: Quote from: Zero999 on February 02, 2025, 07:20:12 pmI'm 100% sure that crime is caused by people and criminals, and not street lighting.

author: voltsandjolts
author_rank: Unknown
timestamp: February 03, 2025, 09:48:02 am
content: https://www.bbc.com/future/article/20230308-how-light-pollution-disrupts-plants-sensesQuote

author: 5U4GB
author_rank: Super Contributor
timestamp: February 03, 2025, 10:01:41 am
content: Quote from: Zero999 on February 02, 2025, 06:14:35 pmNope, and in fact it does the opposite by lighting the way for criminals and creating an excuse for them to be there. For example if you're a teenager vandalising a school you bring along a football and if you hear someone coming, kick it around the brightly-lit sports field for an informal night game of sportsball, perfectly legit. If its unlit and you're flashing a torch around it's a lot less legit and a great way to draw attention to yourself.Same with many other situations, e.g an office building at night with all windows lit. Put on overalls and carry some sort of cleaning equipment and you can go anywhere you want and no-one will bat an eyelid. OTOH with no windows lit, nothing attracts attention like a light flashing around as you try and find your way in the dark.There's whole field of architecture and town planning behind this, look up CPTED, crime prevention through environmental design.

author: jpanhalt
author_rank: Super Contributor
timestamp: February 03, 2025, 11:34:11 am
content: OK contrarian trolls,https://newarkcollaborative.org/blog/can-street-lighting-reduce-crimeQuotePlus many other including Google AI.

author: Zero999
author_rank: Super Contributor
timestamp: February 03, 2025, 07:23:07 pm
content: It's pointless to compare crime in one area to another because there normally numerous confounding variables. Perhaps well-lit areas have less crime because the authorities have more money to spend on lighting? Or maybe more well-lit streets are generally in urban areas which have higher crime rates?Has anyone done randomised trials regarding street lighting?Quote from: voltsandjolts on February 03, 2025, 09:48:02 amI'm interested to see what happens. It's been a bit milder this week, but temperatures are forecast to drop from mid-week onwards. The plant might eventually go dormant, or be damaged. When spring comes, the parts of the plant nearer to the light will start greening first, unless they've been killed by the frost. I'll post an update, in spring.

author: jpanhalt
author_rank: Super Contributor
timestamp: February 03, 2025, 07:42:37 pm
content: Quote from: Zero999 on February 03, 2025, 07:23:07 pmSo, why ask for evidence? Every place is different. Install working lights and see what happens. If crime goes up because criminals can see their targets better, then turn them off. Criminals in the US apparently are not affected by that factor. There's more street crime at night than during the day, so we leave streets lights on. It makes common sense. QuoteNow, that's silly.

author: Zero999
author_rank: Super Contributor
timestamp: February 03, 2025, 08:25:01 pm
content: Quote from: jpanhalt on February 03, 2025, 07:42:37 pmThe problem is that's not what's normally done. When they install street lighting, they typically do other things as well and even if they don't, crime rates can fluctuate for other reasons. You have to randomly do it in other areas to prove that any change in crime is caused by the lighting. It's a scientific method which is not silly. It's a way to establish whether or not a measure is effective or not. It's done in other fields such as medicine and agriculture and doing the same for street lighting is sensible.

author: jpanhalt
author_rank: Super Contributor
timestamp: February 03, 2025, 09:42:21 pm
content: Quote from: Zero999 on February 03, 2025, 08:25:01 pmIt's silly from several standpoints.You have asserted that "every place is different." One way to address that is a randomized "cross-over" study. How will you in any non-totalitarian government do a cross-over study?Secondly, the criminals will know its a study and may adjust their tactics accordingly. Thus, it needs to be done "blind." But, how do you do a blind study with lights? Surly, most criminals in each study area will know whether the lights are on or off.And finally, how are you going to get consent from the occupants/residents of those areas to cooperate freely as subjects? Any coercion is a violation of general ethical standards. Those harmed as victims could sue for damages in the US, but most politicians here would not be so dumb as to try it. California has tried "soft on crime" and defund police social experiments with bad results for the political advocates. Those experiments aren't going to fly in most other areas.

author: Zero999
author_rank: Super Contributor
timestamp: February 03, 2025, 10:21:36 pm
content: Quote from: jpanhalt on February 03, 2025, 09:42:21 pm1) Yes, every place is different, but if you do it randomly, then the differences between places will average out. Pick a load of random post codes and you should get an average crime rate.2) Don't publicise it.3) How is it unethical? We don't know whether more light = more crime or less light = more crime. There's no coercion involved. I'm not talking about banning people from choosing to light their own properties, but whether or not the publicly owned street lights are on or not.Defunding the police was a completely different matter. It was pushed by political activists and the result was predictable. How many victims sued the authorities for that?

author: Analog Kid
author_rank: Super Contributor
timestamp: February 03, 2025, 10:31:08 pm
content: Quote from: jpanhalt on February 03, 2025, 11:34:11 amHmmmm; just for comparison, look at recent incidents in San Francisco (probably occurs elsewhere as well) where car break-ins regularly occur in broad daylight on well-traveled streets with onlookers witnessing it.I seriously doubt that lighting/no lighting is going to affect the behavior of these kinds of motherfuckers much at all, if they're able to walk up to a car, casually break the rear window, reach in and grab stuff, then take off in a getaway car.

author: jpanhalt
author_rank: Super Contributor
timestamp: February 03, 2025, 10:48:53 pm
content: SFO (San Francisco/Oakland) are garbage dumps. When retail theft of less than about $1000 was effectively made legal (i.e., not prosecuted) what happened? Did you watch? Hasn't that law now been repealed? Brazen criminals are allowed to roam free in California. Californians voted for it. That has no bearing on whether in civilized areas, street lights inhibit street crime at night.

author: Kleinstein
author_rank: Super Contributor
timestamp: February 03, 2025, 11:17:33 pm
content: The effect of street lights on plants should be relatively local (a few meters). It needs quite some light to have an effect. So I would not worry that much about the plants.It's much more severe with animals, like insects and a few brids. The lights (especially the blue part from LED lights) attracts most insects and this can reduce the insects over quite some distance (miles) around a light. The yellow sodium light was relatively good in this respect. However LEDs are just worse in the yellow part of the spectrum.In some areas they start to have rules to limit the light polution. E.g. turn the lights off at night, less blue contend and limiting the angle to more the area actually wanted to be lit.

author: Zero999
author_rank: Super Contributor
timestamp: May 05, 2025, 07:01:33 pm
content: I just thought I’d post an update. I took this picture on the 22nd April. Interestingly the situation has reversed. The parts of the plant exposed to the lamp haven’t greened, whilst the rest of the plant has. I suspect the frost killed the parts which didn't go dormant. It’ll probably recover later in the season.

author: u666sa
author_rank: Frequent Contributor
timestamp: May 06, 2025, 12:57:20 pm
content: It is obvious that UV from the lamp has an effect on photosynthesis of the plant. What if you get "UV filter film" and insert it inside the lamp? That would cut the UV coming out of the lamp and depending on how much UV it will cut, there could be visible effect on your plant.

author: Gyro
author_rank: Super Contributor
timestamp: May 07, 2025, 11:52:16 am
content: Quote from: u666sa on May 06, 2025, 12:57:20 pmUV from an ordinary LED lamp? ... I don't think so!

author: SiliconWizard
author_rank: Super Contributor
timestamp: May 07, 2025, 12:39:31 pm
content: LEDs (apart from the specialized UV ones) emit very very little UV.But the idea that UV play a major role in photosynthesis is, as it seems, wrong. The bulk of photosynthesis reactions comes from the energy from visible light, and marginally infrared.UV's principal role for plants seems to be mostly in killing parasites like fungi, so it helps the plant grow in practice, but not by direct photosynthesis.So the first thing to determine is how much energy/m^2, here with a source very close to ground, some artificial light generates compared to, say, moderate sunlight.And, of course, its spectrum too. But LED-based lighting now tends to have a relatively wide spectrum and is thus probably much more efficient for photosynthesis than incandescent light bulbs.

author: NE666
author_rank: Frequent Contributor
timestamp: May 07, 2025, 12:50:53 pm
content: Quote from: Zero999 on May 05, 2025, 07:01:33 pmI suspect that this is the answer.I'm seeing similar effects on plants in my own garden, from 'indistinct' season transitions. i.e. a prolonged summer heat, or resurgence of higher temperatures towards the end of the traditional UK summer season, is stimulating some species into two growth and flowering cycles, only to get cut down when the winter frost and shorter day lengths inevitably arrive.

author: watchmaker
author_rank: Unknown
timestamp: May 07, 2025, 01:56:13 pm
content: I bought Mary a couple of the LED grow lights; wow do they suck up power!But she is seeing an impact after they germinate. She sez you have to remove the light for 8 hours a day.Dewey

author: themadhippy
author_rank: Super Contributor
timestamp: May 07, 2025, 02:45:34 pm
content: Quotetry it the ole skool way with 400w high pressure sodium's if you want a power drainQuoteonly in the veg stage,once you get to flowering its a 12 on 12 off cycle