How artificial light threatens nature | DW Documentary

How artificial light threatens nature | DW Documentary

The big city at night darkness no longer exists in many places around the world the change was fast maybe too fast for our internal clocks organisms had adapted to the rhythm of day night in the seasons over millions of years we’ve only had artificial light for a few decades but it’s increasing

Exponentially more than 80% of the global population live with light pollution that dramatically impacts not only their health but also nature is our insatiable hunger for even more light worth the resulting diseases and The Disappearance of more and more Species France hooka heads a research group on light pollution and ecophysiology at Berlin’s Li nits Institute of freshwater ecology and Inland Fisheries unsurprisingly he views nightlife differently than Most when you look around it’s not just all the noise you’re also getting all the sensory input from the light sources it’s anything but a natural environment in evolutionary terms the only light visible at night came from the stars and the moon and these days if you look up

Here in Berlin for example you can hardly see any Starlight you can still make out a few of the stars but even on a clear night like this they’re hard to find do our nights have to be this bright much of the light is pointed

Upwards and is often of no use it’s a waste of both light and energy to be honest energy saving LED lights promised to reduce these effects but since they require so little electricity more and brighter lights are being used and that is now affecting Nature’s Own night

Life so rapidly that many animal and plant species can’t keep up their numbers are falling drastically as is their diversity research by France hulka and other International scientists highlight the dramatic impact on the biosphere and in 2021 the German bundist decided to begin regulating light Pollution since it was founded in 1988 the international dark sky Association has also been working to win back natural Darkness the DAR Peninsula on the German Baltic Coast hopes to win the association’s recognition but to become a dark sky Community or Star Park applicants must both prove how dark their area is and

What they’re doing to dim the lights Anto helel helps verify Applications we’ll be going to different spots to measure the sky brightness and find out how dark it really is here we want to measure several locations if possible to see how bright the radiation is outwards as well as the impact it’s so dark outside the villages on the peninsula that only special

Cameras can capture what light remains okay we’ll go here now Andreas hanel measures at new moon when nights are darkest he uses two digital cameras with fishee lenses and long exposure Times okay all right it’s on lights out we have to make it completely dark because I’m starting the observation the measuring one Moment we’ll have four minutes of exposure please keep it dark for now the cameras are pointed up at the sky they can then capture the entire night sky and any light source on the surrounding Horizon it’s uh we’re about to see the first image a series of 360° images are made of the night sky with a bright Horizon surrounding the black canopy like a circle of light we see all the different places that are light sources with an arch of light around them and the light

Scattering upwards we have light clouds above us which is why it’s relatively Bright Now this phenomenon when humidity and clouds reflect artificial light and Scatter it over huge areas is known as Sky Glow the bright outer edge of the 360 degree image shows that Sky Clow can be seen nearly everywhere on the horizon Andreas henel measures the brightness based on the photos he can then determine the quality of the darkness Sky brightness is pivotal to qualify as a dark sky Community an area must score above the 20 Mark the measurements are high enough at five locations on the outskirts but inside the villages excessively bright lights still prevent the darkness from Rolling In another problem is that we have a lot of nocturnal animals here but regardless of that it would be good if we had a place where we couldn’t see any artificial light sources in the sky these lights are brighter than all the stars up there and a star Park

Should try to eliminate bright light sources SE A bird’s eye perspective makes it clear how Street and house lighting cut through the night even on the dark Dar Peninsula a grid of artificial light now covers almost the entire planet growing by more than 2% every year but increasingly light pollution not only poses a problem for nocturnal creatures migratory Birds the Globe Trotters of the animal kingdom also suffer about 50 billion birds travel around the clock in Spring and fall to

Reach their breeding and wintering grounds eight key routs allow them to Traverse almost the entire planet Birds migrating the East Atlantic Flyway rely on the plentiful waden sea on Germany’s North Sea Coast millions of them rest Roost and feed here in Spring before moving on and dispersing through Scandinavia and the

Arctic they also need this pit stop in the fall when they head back South many migratory birds take a break on the island of shikaro to replenish their energy Reserves plenty of food for oyster catchers bar-tailed godwits little ringed clovers dunlins and many other species shikaro is part of the vodi national park a protected ecosystem in the German state of lower Saxony the mud

Flats are home to up to 12 million birds in both the spring and fall the Rangers observe and protect the annual visitors Peter sudbeck is the director of the national park and coordinates all conservation efforts in an area covering 3,500 km the migratory birds that come to the

Wen sea in Spring have flown four to 5,000 km many have flown non-stop for 5 days it’s hard to picture that distance the body fat they burn as their own aviation fuel along this great migration route which for many birds only ends at breeding grounds and other 5,000 km

North there’s only one point which has enough food for them to make the journey while also preparing them to breed successfully in the Arctic the Wen sea the birds are only here for three or four weeks in Spring some for five depending on the conditions and their

Energy needs but in this short time they’ll gain between 50 and 100% of their body weight depending on size and Species it’s also impressive how migratory birds can optimize their flight routes and find their way across huge distances they rely on the Earth’s magnetic field as a compass and navigate by using the Sun during the day and the stars at Night that’s how it’s always been even along the East Atlantic Flyway but animals are becoming increasingly disoriented because of the nocturnal lights coastal towns Harbors oil rigs even ships now light up the root the artificial lighting diverts many birds from their ideal Root the detours waste precious energy and some birds end up dying at Sea We assume and can see that an artificial light source is attractive and draws flying birds in just as it would us that can lead to collisions Birds used to collide with lighthouses for example but now they collide with wind turbines or other light sources because they’re tempted by them and diverted from their

Roots and so light pollution at Sea should of course be seen as a serious hurdle that has to be eliminated when migratory birds fly under cloud cover in bad weather they can no longer use the stars and moon for orientation making artificial lights especially dangerous researchers can only estimate

How many birds collide with light sources at sea or that crash due to exhaustion before disappearing into the deep but studies on land suggest that the number on the oceans is in the millions I think the current change in light will affect the ecology and individual species in ways we can’t even

Imagine today we need to broaden our research to give us the scientific and fact-based knowledge to make conservation decisions allowing us not only to convince others but also to act as quickly as possible or even preemptively when it comes to light pollution the light smog is not only affecting flight

Behavior other behavioral changes have also been found in a variety of Animals the night jar commutes between Africa and Europe ecologist Ruben Evans noticed that the birds show different hunting behavior in the naturally Dark Nights in Africa than in the illuminated nights of Western Europe he traps them near the hog kimpen National Park in Belgium as part of long-term

Studies he uses special Nets to avoid harming the birds we need to catch these Birds because we try to invest individual behaviors in response to light conditions in order to do this we need to catch individuals in order to put tracking devices on them and this

Way we can study how they fly where they fly to where they eat how much they eat where they incubate the eggs this loudspeaker admits the call of a male night jar Reuben Evans uses it to lure both competing males and curious females it’s windy there he

Is now it’s a waiting game to see if a bird gets caught there he is so there is a Niger sitting there yeah right above the it’s a [Applause] Mele these nigers they are so fascinating um most people have never seen them most people have only heard them or seen like a dark shade somewhere flying and being able to to unravel their ecology like the influence of light on their behavior how they breed how they forage where

They eat what they eat it’s it’s so fascinating and it’s a privilege to do it he began researching the lives of night jars in Africa and Europe over 12 years ago he documents their behavior in different places comparing and looking for any [Applause] changes this one is a nice meale I think that it’s a adult from uh last year and we also have two uh two two birds uh young birds from last year so it’s a relatively good evening what is very important to know is that these nigars they are uh visual

Predators and they they need light in order to detect prey against a a Bright Horizon or a a light sky so they need light to detect prey but also to fly under natural circumstances that would this would mean that as soon as there is no moon above

The horizon or there is no more Daylight these birds they cannot do anything they have to sit still they have to wait until there is light again the biologist gently attaches transmitters to the bird’s bodies ensuring their natural movements aren’t impeded he also attaches an accelerometer a device that lets them

Know remotely when the birds are resting flying or pouncing on insects under natural circumstances uh moonless nights and cloudy nights are the most dark scenarios that you could can imagine but here in Western Europe they are among the most light conditions that you can imagine so these birds they can

Be active whenever they Want our data show that these birds in Mongolia and Africa they they don’t fly when there is no Moonlight but here in Western European countries when it’s cloudy for example the nights are even more brighter or lighter than during full moon conditions the big question is whether Sky glow

Facilitates these nigars and that is also my hypothesis that nigers when they are subjected to Sky glow are able able to use this as some sort of artificial light source an artificial Moon and that they are able to be active at moments when they shouldn’t be active night jars are different they

Don’t seem to be harmed by light pollution they seem to use it to their advantage but the question of whether artificial light is good or bad for nature is not just about individual species but the entire Ecosystem in Northern Germany the huffle river flows through the vest huleen Nature Park an official dark sky reserve a place where Darkness has been cultivated since 2014 but street lights even interfere with the natural nightlife here especially that of insects ecologist Sophia johanneson is investigating the damage her ongoing research project

Known as tat street light is looking at the effects of artificial light on the insect po ulation especially near natural bodies of water she traps insects buzzing around the light and can then identify them in her laboratory the huffle is about 2 to 300 met away and we want to know whether the

Aquatic insects are also attracted by these street lights and if so to what extent because aquatic insects are extremely sensitive to brightness and have like other insects adapted to Nature’s daily rhythms and because aquatic insects are a life source for the fish and all the other creatures that live in the huffle Half many flying insects that move at night are closely linked with aquatic ecosystems their lives often begin as larvae below the water surface mosquito larvae take about 10 days to hatch as soon as it unfolds its wings it starts looking for a partner to reproduce it can then lay its own eggs

In the [Applause] water a few days later the life cycle begins a new but permanently Bright Nights can disrupt the search for a partner the street lights work like a magnet or an irresistible attraction for insects especially flying insects they think it’s the moon or the Stars so

They’re drawn towards it and constantly try to readjust themselves flying disoriented around the light above especially around its source many insects birds and other animals use the Stars to navigate when looking for food and Partners but just a few lamps can act as false moons and endanger the insects even in the protected vest haand Star Park Sophia johanneson is looking into a phenomenon known as the vacuum cleaner effect where lights suck insects from the Environment the confused insects try to fly away but are always drawn back to the lamp they eventually become exhausted and die but a closer look reveals that these lights aren’t a danger to every species for some they’re more like a well-lit all you can eat Buffet spiders especially emerge from the dark undergrowth to spin their webs where there is light and plenty of insects even if individual species might benefit from artificial light more research is needed to determine the long-term Effects the more insects that die on Street lamps before reproducing means fewer individuals in the Next Generation every night the lights in our streets deprive the ecosystem of living creatures that are an integral part of it food chain the number of flying insects in Germany has fallen by more than 75% over

The past three decades a loss especially for the birds feeding on Them research in the vest huffle land Nature Park is looking at how artificial lighting affects biodiversity and biological processes these insect traps are part of the tatort street light project the findings should help create nature-friendly Street lamps to better protect the insect World insects are also being collected counted and preserved in three other areas in Germany the samples are then sent to France hulka in his Berlin laboratory at The libbets Institute of freshwater ecology and Inland Fisheries there an entire team of experts identifies and analyzes the animals the study isn’t complete but the

Loss in both the numbers and diversity of insects is already clearly visible many of the moths are protected species including the garden tiger moth it’s always a shame to find them here and see how sensitive they are to light but you also realize that these are all potential plant pollinators that can no

Longer do their job more than half of all insects are nocturnal just like their dial relatives they play an important role as pollinators butterflies flit from flower to flower during the day and moths at night but their dark habitat is often divided by lanterns and illuminated streets making any foray into

Neighboring territory a risky [Applause] Venture this often puts potential mating Partners Out Of Reach light pollution that fragments habitats is just one piece of a bigger puzzle a puzzle scientists around the world are trying to piece together to discover why nocturnal insect populations are declining you can easily catch 400 bugs

By hanging up a passive air trap like this by a street lamp on a warm summer night and it of course adds up we have about 9 million spots with Street Lighting in Germany and if you multiply those by 400 for a summer night it brings us to over 1 billion insects that

Are lured out of their habitats in a single night by these 9 million vacuum cleaners to keep the analogy France hulka’s research shows that light pollution also affects aquatic ecosystems about 50% of the world’s human population now lives Closer Than 3 km to a body of water where people live

There is water and where people live there is also light some of the light reflects off the surface of the water but a lot of artificial light still reaches deeper in rivers and lakes what you see here is a strong illumination of the surface around the riverbank even though there’s no real

Reason to illuminate the water here but you see how far it goes and without having measured it I can guarantee that this strong light will affect the fish fish have long since adapted to Darkness at Night at his Institute France hilka is conducting Behavioral Studies to better understand how artificial light affects Fish we use these Guppies to investigate to what extent social behavior is altered but also how risk-taking and general activity are affected by nighttime light and we observed increased nocturnal activity when there were lights whether from Sky glow or continuous daylight but the interesting thing was that the willingness to take

Risks that is the willingness to leave their hiding places and expose themselves to Predators also increased during the day when there was light at night there was a spillover effect into the day so to speak the hormone melatonin which also affects humans when it gets dark is partly responsible for this change in

Behavior France hulka compares the control of melatonin production in the body to the different rules rolls within an orchestra you could say that the body cells are like the musicians and although the whole score is coated into their DNA and these are very good musicians they still need a conductor

And that’s our Master Clock and in US you’ll find it just about here the suprachiasmatic nucleus fish also have a Master Clock many animals in fact almost all organisms have such a central pacemaker in their bodies and that’s the Conductor this Master Clock also influences melatonin production which determines the sleep wake cycle in humans and allows us to sleep at night when it gets light and The receptors on our retina pick up light melatonin production is suppressed we have a complex control system in the center of of our brain the

Pineal gland only releases melatonin again when it gets dark and little if any Light reaches the eyes tiredness loss of appetite decreased body temperature and low blood pressure are among the effects of an increased melatonin level this is not exclusive to humans almost all vertebrates react similarly many Studies have confirmed

This in fish who are particularly sensitive to artificial light after Sunset even small amounts of light lower their melatonin levels impacting their immune defense reproduction and Growth the typical solar Spectrum during the day is dominated by Blue that’s why for example many terrestrial vertebrates are so sensitive to Blue it’s a bit different with fish the waters we’re looking at the spray in Berlin for example are very turbid this means that here the blue wavelengths are absorbed

Relatively quickly while red and yellow wavelengths travel much further and we found that melatonin production is reduced no matter which color we have on the light blue green red they react to all different colors but nocturnal species above water have adapted their Vision to the light of the stars and the

Moon but humans have changed both the brightness and the colors of the night a disruptive Factor impeding the night vision of many animals scientists in the faua forest in the Netherlands are using a colorful experimental set up to investigate how different lights affect nature they’ve set up lamps in different

Colors deliberately disrupting the night’s Darkness for more than 10 years ecologist Camille sper has been observing which wavelengths have the greatest impact on the natural behavior of animals place a light in an area uh which is normally a pristine dark natural environment uh you place those lights there and from the moment that

There it starts changing uh populations around it different animal species are affected in different ways depending on the color of the light white light mixes all wavelengths and is visible to a large number of animals red lacks the blue spectrum that nocturnal animals are used to so the light appears less bright to

Them green light with its high blue content shines brightest for nocturnal species with a correspondingly strong effect what we know about the green light is that um it actually shies away many nocturnal species even more so than for example white light and that has to do with the the eye sensitivity of

Nocturnal species they’re relatively blue sensitive and relatively little red sensitive modern LED technology allows us to control the wavelengths of the lights and make them less harmful to Wildlife like bats that have a Flyway where uh lights that actually cross this Flyway and these lights may actually

Block these bats from using this Flyway now if you illuminate the uh location with a red light then bats may continue to use this Flyway uh and that may be a very effective way in mitigating the impact of light but not every species reacts in

The same way W mice will avoid any place with light but birds will stay in white light and sleep less each light affects the natural environment in different ways these effects are subtle but can affect entire ecosystems over a long period of time far beyond the area where the light

Shines all these effects on species they interact and and and and and an effect on one species may carry over to an effect on another species uh the so-called cascading effects in the ecosystem so even if you’re a species like like a bird being active in

The day you may suffer from these lights because your insect bra species disappear from your environment because they need to night the forage so yeah uh many things can happen to an ecosystem and many things will happen at different levels and will Cascade through these different Levels this is bad it’s a mishmash of colors totally over the top 4,000 kin you can see that the blue Peak is much Higher the villages on the DAR Peninsula need to adjust their street lighting if they want to qualify as a dark sky Community it’s way too bright like lighting for a billboard not very efficient a real Catastrophe Andreas hanel shows a village official where there is still too much light Illuminating the night sky so this is a filter that allows you to create a spectrum it’s looking good you can see the LED lamp has a very strong blue color which is typical and a characteristic of LED

Lights if we measure right now and do a real test we can get a reading right away and see its color temperature now we’ll measure here right by the ground and now you can see the Spectrum here we have 18 Lux it’s relatively bright here half the light would be

Enough Lux is a measurement unit for illuminance even at nine Lux as Andreas hannel recommends the sidewalk would still be about 50 times brighter than on a night with a full moon the color of a light is decisive when assessing its environmental impact if you look at the

Spectrum now you see that the blue Peak has a color temperature of 2800° and that’s how it should be the Kelvin unit of measurement is used to determine the general color impression of a light source light that registers above 5,000 de Kelvin for example appears as a rather old

Blue it has a yellow orange glow below 3000° Kelvin and is more pleasant to the human eye Andreas Han’s measurements show officials how they can improve their lighting if you want to reduce the light you have to do it on a large scale in other words it’s best to do it in an

Entire Village at once otherwise you won’t see the effect but at the same time we also want to show that the lighting is still good in these towns that it doesn’t somehow mean we have to switch everything off just reduce it according to our nocturnal needs small measures can have a big

Effect the most harmful lights are those with very bright cold colors shining in all directions they also waste a lot of power trap insects and Dazzle passers by less illuminance through darker light helps a lot since a warmer light below 3000° Kelvin is much less harmful to insects and other Animals but the most important thing of all is targeted lighting if we Shield lamps and direct the light only where it is needed nocturnal beings will be less affected and we can once again gaze at stars above the growing effects of light pollution mean we have to act quickly even if the

Research isn’t yet complete and dark sky Park coordinator Sabina Frank is doing just that in the central German Town of fua her interest in light pollution was peaked a few years ago when she noticed some Chestnut trees that still had leaves on them in November I realized that the trees

Couldn’t drop their leaves I don’t think anyone ever noticed that but I saw it and thought something was wrong I always check the trees in the fall to see how they’re positioned whether there’s a light next to them and if they’re able to drop their leaves I have a thousand

Photos of trees that are struggling because of the Light Sabina Fran’s photos clearly show that the branches closest to the Street Lamp are still covered in leaves even though winter is just around the corner the trees should have already parted with them to avoid damage from frost the street lights between the trees are clearly interfering with natural

Cycles plants react more to light radiation than to heat the intensity duration and availability of sunlight give them the information they need to Survive telling them when they need to grow absorb water and drop their leaves but street lights trick branches into believing it’s a different time of year and so over the course of many years the artificial light can lead to massive Frost damage I actually took the photos and

Went to City Hall where I showed them to the city’s planning officer the woman who is responsible for everything that is built here and she was like what she couldn’t believe her own eyes everyone was very concerned at first because these trees are loved by residents and they need to be healthy

But it has to be said Fula took action by changing all the street lamps in the entire city this was the beginning of a complete transformation of nocturnal fua the city made numerous changes to become the first official Dark Sky City in Germany people in fua never used to think about light pollution but now they join Sabina Fran in saying lights out stars on lights out night on

Light can be deadly. Many animals and plants are threatened by artificial light. Numerous organisms have found their evolutionary niche in the dark of night, and now have to adapt to bright nights. Not all of them succeed.

More than half of all animals are nocturnal. Their sensory organs, their behavior, their orientation and their metabolism are adapted to darkness, moonlight and starlight. But in today’s modern world, countless artificial light sources create something called light smog. This light pollution is generated in cities, villages and industrial areas. It comes from advertising billboards, roads and paths – and even from space.

Artificial light disturbs the natural way of life of animals and plants, destroys biotopes and, not least, eliminates biodiversity. Indeed, light pollution has recently been recognized by experts as a possible main cause of global species extinction.

However, the urgency of the issue is still underestimated by the general public and politicians. As part of a citizen science project, people all over Germany are helping to catch, identify and count aquatic insects in the country’s largest light pollution field experiment.

Franz Hölker, ecologist at the Leibniz Institute of Freshwater Ecology and Inland Fisheries in Berlin and his research team want to find out how many insects end up in the street lamp death trap. Peter Südbeck, head of the Wadden Sea National Park in Germany, still one of the darkest regions in Europe, has been observing a worrying change in the behavior of migratory birds for some time.

The Wadden Sea is a global transportation hub for shipping traffic, but also a resting and feeding place for millions of birds. Drilling platforms, ships and light smog cause the birds to stray from their route. More and more become so exhausted they can no longer make it to their vital resting place. The film is a night-time journey through the work of scientists who have set themselves the task of bringing darkness back to nature – and to us humans.

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