Una.Lecture | Living Lab Bienen, Biodiversität, urbane Nachhaltigkeit (Bees, Biodiversity, Urban Sustainability)
The Una.Lecture series kicked off in Berlin in November 2023 with a dynamic discussion as part of Berlin Science Week. The event introduced the importance of biodiversity and the crucial role of bees for biodiversity to an audience interested in science.
The event featured a panel discussion with Christian Dreher (Freie Universität Berlin), Sophie Lokatis (Deutsche Wildtier Stiftung), and Randolf Menzel (Freie Universität Berlin), who shared fascinating insights from their fields of research – from biochemistry to neurobiology to veterinary medicine – and explored how we as citizens can contribute positively to urban biodiversity.
Please note: This lecture was delivered in German. Both German and English subtitles are available.
Hello and welcome to this event and panel discussion titled “Living Lab: Bees, Biodiversity, and Urban Sustainability.” This event is part of Berlin Science Week and the Una Europa lecture series. Una Europa is an alliance made up of multiple universities. Today we will be asking how European university alliances can contribute to urban sustainability.
My name is Sabrina Walter, I’m a consultant and a trainer and I will be your host this evening – this afternoon, it’s dark out. I look forward to guiding us all through this discussion tonight. There I go again, I mean this afternoon.
Before I introduce our panel, I’ll be handing off for a brief welcome. After our official welcome, we’ll dive into the panel, which will last until 5:00 p.m. at the latest. Afterwards, we invite you to visit our exhibition in the basement. You will be able to speak with our panelists
As well as the researchers and experts involved in the exhibition. I also have a few things to note regarding our setup. As you may have seen, we are recording this event. If you share anything or ask a question and would prefer not to appear in the video,
Just let us know as much while you’re speaking. We will cut you from the recording. We also have someone here taking pictures. I hope you are all alright with this. If you would not like to appear in photos, again, just let us know. Allow me to hand it over for our brief introduction
To Herbert Grieshop, director of International Affairs at Freie Universität. We’re very happy you’ve joined us for one of the first events of Berlin Science Week, which I believe starts today – November 1, right? We’re thrilled to be in the School of Veterinary Medicine in this lovely building here in Düppel.
In case I forget, let me start by thanking everyone involved. As you can see, it takes quite a lot of people to organize this type of event. That’s the Una Europa team as well as everyone helping us secure this space. Plus the team behind the recording that’s being made today,
Giving us a video and photos for posterity. So thank you to everyone behind this. I am here representing Freie Universität for the Una Europa alliance. I know, you came for the bees and biodiversity and urban sustainability, but allow me to briefly mention Una Europa as the setting for this event.
So, I represent Freie Universität Berlin in this alliance, which is a network of ten universities plus us at Freie Universität. The other ten are the universities of Helsinki, Bologna, Complutense Madrid, Paris 1, Zurich, Leuven in Belgium, Leiden in the Netherlands, Edinburgh, and University College Dublin.
It’s a wonderful network with this motto, “Building the university of the future.” Our vision is to create a kind of pan-European university one day. For now, it remains a European network. This network collaborates on developing new degree programs, creating exchange opportunities for students and researchers and for all other university staff as well.
One of those new programs is a joint bachelor’s degree in European Studies. Another one that you’ll hear more about from Janina Taigel in a moment is a bachelor’s degree in sustainability, which is on topic for us today. This lecture series is a new event format that we’re kicking off today.
It’s not technically a lecture, but more of a talk or a panel discussion. Be that as it may, we’re holding these events across Europe. All Una Europa partners are holding public lecture events. Why? Because that European “university of the future” isn’t just for students and teachers, but for general society as well.
We want to be science communicators. Biodiversity is a great place to start: Two weeks ago, to my own surprise, Freie Universität announced next year as our year of biodiversity. This means that next year, in 2024, we’ll be having a number of events at Freie Universität that will be all about biodiversity.
Stay tuned for those. I look forward to an interesting panel and visiting the exhibition afterwards. I hope you all have a great afternoon here with us and am happy to pass it on to Janina Taigel, who will tell us more about biodiversity and Una Europa. Thank you. Thank you, and good afternoon.
I’m Janina Taigel from Freie Universität’s Unit for Sustainability and Energy Management. I’m also a coordinator at Una Europa for two sustainability working groups. They collaborate on new projects, such as the joint bachelor’s degree. I’m excited to be here today and want to give credit to my colleague Marie-Julie [Jacquemot] at Freie Universität.
We, and I myself, see sustainability as an essential international topic. We need to work together and exchange ideas about what is possible. I believe the approach “think global, act local” is quite valid. Thank you to everyone involved with this at Freie Universität. The whole reason that next year is our year of biodiversity
Is thanks in part to a student initiative. We have Sophie Lokatis here as one of our experts today. In Una Europa, we have a group of sustainability unit representatives. We hold regular meetings with all these representatives of the Una Europa universities where we can exchange ideas and experiences.
We try to draft papers to raise awareness and present joint strategies. This will allow us to establish ourselves to a certain degree of influence across Europe and to effect change. We call this our Sustainability and Climate Protection Strategy. One of its key points is healthy, resilient nature on campus.
We really want to further this element. That’s the context in which we find ourselves here today. I’m very much looking forward to learning more about bees and what they can and do mean to life on campus and urban diversity. The concept of a Living Lab is under constant international discussion
Since it positions a campus not just as a place of study and research but as a proving ground for these ideas. I’m sure we’ll be hearing more about that. Allow me to give the floor back to our host. Thank you. I’m also looking forward to getting a close-up view
Of what’s going on at Freie Universität. Allow me to introduce our panel. Starting from the right, so your left, we have professor emeritus Randolf Menzel. He has been at Freie Universität since 1976 and helped establish the Institute of Neurobiology. He received the Leibniz Award of the German Research Council, among others,
For his work on the intelligence of bees. He also published a book titled The Intelligence of Bees and is one of our subject matter experts here today. In the middle is Dr. Sophie Lokatis. She earned her doctoral degree here on urban ecology under Jonathan Jeschke.
She then completed a postdoc position at iDiv in Leipzig. iDiv is the German Center for Integrative Biodiversity Research. Since this March, she’s been working with the German Wildlife Association for the project “Berlin in Bloom: More Bees for Berlin.” She also established an initiative in 2019 titled “Blooming Campus.”
This year, the initiative received the Berlin Nature Conservation Award. To my right is Christian Dreher, a researcher at the Institute of Veterinary Biochemistry. He has been at Freie Universität for nearly a year and helms the institute’s bee coordination unit. He’s an expert on bees and previously worked at the bee institute in Kirchhain
As an expert on beekeeping and led consulting and training projects there. That’s our panel for today, so let’s dive right in. Sophie Lokatis, your initiative received an award. What makes it so important to be considered for an accolade? The battery was low just now – can you hear me?
If I’m audible, that’s fine. The project started back in 2019 and I’m not sure if you’re all familiar with our campus, but it was your typical scene with crisply mowed lawns. Around this time of year, you’d see people with leaf blowers. It was a typical picture of pruned nature in the city.
This was right when Berlin declared the state of climate emergency, in 2019. We tried to tack onto that with our biodiversity initiative. But that didn’t work at all, so we turned into a working group around myself, Andreas Wanke from Sustainability and Energy Management, and Jens Rolff from zoology.
We wanted to tackle lawn mowing practices and how nature was handled on campus. Our goal was always to integrate biodiversity into the university’s sustainability strategy and to inspire a shift in thinking. I could go on, but… Please, go ahead. I hear it all started off a little scrappy,
With the makeshift sign you put up on lawns. I don’t know about scrappy, but it was definitely spontaneous. There’s some funny history there, Someone from the Institute of Biology got so annoyed at the early blooming plants constantly getting mowed back
That he just put up a sign that said, “Experiment in progress, please do not mow.” I saw that and had to laugh and then went to talk to my colleagues. We came up with the “experiment” in question afterwards.
I think I’m allowed to say that now since there really was an experiment in the end. We started monitoring the lawns, two master’s students got involved too. They compared it to data from other places around the world that had stopped mowing. So we were able to combine the project with research.
It’s fairly unique to combine science with a sustainability project, all on a university campus and closely tied to research. Rebecca, my successor as the Blooming Campus project lead has been doing great work incorporating teaching into the mix. Mr. Menzel, how would you say things have changed for bees on campus?
Well – I’m not sure my microphone is working. It is? Great. I think it’s a wonderful initiative. I used to constantly clash with the people responsible for tending the lawns. Especially later in the summer, since that’s when the goldenrods are in bloom. They’re essentially the last pollinating flower for bees to flock to.
It was always a chore until your initiative started. They had a job to do; they were employed by the university precisely in order to tidy up in preparation for winter. So we were fighting for that and suddenly, for reasons I didn’t understand at the time –
Turned out it was your initiative working in the background, which I didn’t understand until gleaning information about it later – we didn’t have to fight these battles anymore. The goldenrod stayed and flourished and the bees were able to collect pollen whenever the weather allowed.
Let me remind everyone here at this point that we say “bees,” but we’re not only talking about honeybees, but wild bees as well, the bumblebees and solitary, non-social bees. There are very very many of these, around 20,000 species worldwide.
We have roughly 400 species here in Germany, but there used to be way over 500. So your initiative is all about these, and not necessarily honeybees. I was fighting for the honeybees as well, since the plant in question was goldenrod, but honeybees don’t really need our help.
There are plenty of beekeepers and other people who tend to them and can read the signs if there’s an issue. They can report those issues and talk to each other about them, meaning there’s already a very strong awareness in place there. Wild bees don’t enjoy the same attention. We don’t notice them disappearing.
I’m sure we’ll speak more about wild bees this afternoon, which are active at the height of summer and in fall. They are especially endangered by regular mowing, which is at its peak at this time in order to get rid of weeds on streets and roads and meadows.
This mainly endangers wild bees, which is why this initiative is so fantastic. I don’t have any data on this, I don’t know if you have statistics to back this up with research and show that there is a substantial change
To the wild bee population in Dahlem and whether you were able to save any species. I would love to know if there is any indication for that. – We definitely have data on that. – Really? Wonderful. Feel free to tell us more.
We started monitoring the areas in question very early on, right from the beginning. Even the first year showed really interesting results. Long-term data is very important too, but the initiative is still too new for that. Since you just mentioned wild bees, we tracked some rare ones on campus.
For example, we saw Tetraloniella dentata, which are specific to Berlin and Brandenburg and don’t really occur anywhere else in Germany. I photographed one myself as it was sitting on a cornflower just outside of the cafeteria on campus. All these species we were able to track are relevant for conservation efforts,
And we only ever saw them on the wild, unmowed lawns. That’s where we looked most – there’s not going to be a lot going on in grass that’s cut very short. We don’t have solid data on the population development yet,
But we know for sure that wild bees are coming to these unmowed areas. We also monitor the amount of actual biomass of animals in these areas, which has seen a massive increase. So there’s a number of indicators we have to show that this effort has a real effect.
The next step would be not just not mowing lawns and flowering areas, but actually creating habitats for a whole range of wild animals. Hedgehogs deserve some attention, too. How does your monitoring work? Is there anything similar we can do at home to see what kind of bees visit our gardens?
Some species of wild bee are fairly easy to recognize. Specifically, Tetraloniella dentata, at least the male ones. But other than that, you really need an expert to identify wild bees. Especially if you want to make sure you’re covering the entire spectrum of species.
We have an expert consultant for our wild bee monitoring efforts, too. The other types of data collection we do tend to be slightly chaotic. It has ups and downs since we try to tie it in to teaching and research.
So a lot of our data was collected as part of student projects or final theses, meaning it’s not always easily comparable. We’re aiming to create long-term monitoring systems that can be replicated. That’s a little hard to unify with busy everyday academia at a university
That sees a new set of students every three years who have their own new ideas. Obviously, we want to support any of the projects they come up with. So that’s what our monitoring looks like at the moment. There’s always someone with new research ideas for topics like pitfall traps or light contamination…
[Unintelligible – technical issues] There are two people working on butterfly monitoring, one of whom is Rebecca. In summer, they measure butterfly activity over a set period of time along a specific transect once a week. The data is then sent to the Center for Environmental Research in Halle
And joins other information in a large data pool that is collected with the same methods across the entire country. We’ve been doing this for three years now which is great, because there’s a dearth of data from urban transects.
We’re not as urban as it gets, but the data pool doesn’t have many of those. Since that area is underrepresented, it’s a great opportunity for student projects. There are also entire classes dedicated to working on the subject. I can’t speak to those much, though.
Rebecca will be able to tell you more at the exhibition, but all in all, it’s very diverse. You’ve got students spending three months in a lab counting samples from pitfall traps, or people focusing on photography. We’ve also got a citizen science project that has everyone taking pictures using iNaturalist.
All areas in question are mapped out and whenever anyone makes an observation, it gets added to the project, meaning we have quite a few different data sources. Not many hedgehog sightings so far, though. Mr. Dreher, as mentioned before, you lead – or you are – the bee coordination unit.
How does your work tie into the Blooming Campus initiative? Projects like this one benefit honeybees, too. Like we’ve just heard, there are big problems when it comes to wild bees. But it’s not like honeybees aren’t faced with their own issues. They’re just a little different compared to those of solitary species.
The majority of wild bees live solitary lives, unlike the honeybee, which forms large societies and is able to compensate for issues more easily. They can make up for environmental factors, such as a lack of flowering plants, very well. This makes it harder to tell for a beekeeper or another observer
If the bees are actually doing very well or not. Or if they’re doing very badly. A problem that isn’t too prevalent here in the city, but definitely present outside of it in more rural, agricultural areas is the marked lack of pollen as observed by beekeepers. At least for a certain amount of time.
That will certainly have adverse effects on the honeybee species. I helped ensure a larger number of flowering plants in the city. Or, at least, helped increase the already solid amount of plants in the city, especially compared to agricultural regions. Beekeepers can profit from this, and of course the bee colonies themselves.
Studies have also shown that a more varied food selection significantly increases honeybees’ resistance to disease. Disease is a major problem that’s very common among honeybees. Strengthening their immunity levels benefits us too, of course. Can you tell us more about the kinds of diseases beekeepers are faced with?
The media has been reporting more and more on “bees dying.” Based on that, people used to – and still do – think that that means the honeybee population. That’s not quite the case, but honeybees do still have problems. You could even call it “dying” among honeybees,
Even though they’re quite resilient to outside influence and negative effects. While they’re threatened by external factors such as diseases, the difference is that honeybee colonies are tended by beekeepers, who do their best to take care of the bees. These aren’t wild bees anymore; there are actually very few wild species of honeybee.
Nearly all honeybee colonies are kept by beekeepers, who can step in in cases of disease or parasites. They’re able to counteract those or at least try to prevent them. Like I said, the honeybee population deals with other issues as well. Germany loses a certain amount of bee colonies each year.
It’s hard to pin down numbers, but I would say that we have roughly one million bee colonies in Germany per year. The percentage changes year over year, but in good years, we lose about ten percent. That number goes up to twenty to twenty-five percent in a bad year.
Some years or states have faced a loss of up to thirty-five or forty percent of bees. So even in a good year with few losses, if we lose ten percent of a million colonies, that’s one hundred thousand bee colonies dying every year, minimum.
That’s a huge number to compensate for or that are no longer available in the spring, meaning less cross-pollination. That’s definitely an issue. So the causes for population decrease in honeybees and wild bees are quite different. For honeybees, it’s mainly parasites – mainly one parasite, really.
The main cause of honeybee loss is Varroa destructor, the Varroa mite, which was introduced in the late 1970s. They’re the main problem. And that’s something that’s monitored here at the university too? – No. – No? Oh, then I misunderstood. Let me explain: There’s something called AFB monitoring,
Which tracks a disease called American foulbrood. There are other diseases, but the main threat to honeybee colonies is Varroa destructor. There are quite a few more diseases. One major one that is seen as the main disease in honeybees and is tracked on a national level is American foulbrood.
This is a bacterial disease, and I’m in charge of monitoring it here in Berlin. Alright, that clears that up. Mr. Menzel? I’d like to oppose Mr. Dreher here. If I throw in something contrarian, we can have a discussion. That will make everything a little more exciting.
Urban bees have a better life than rural bees. Not because city beekeepers are more highly skilled or more resilient than their rural counterparts, but because they aren’t exposed to the same factors that cause issues for bees in rural farm areas. Specifically, pesticide. Pesticides are less common in the city.
They’re sometimes used in gardening allotments. But for the most part, when urban bees harvest nectar for the honey that we collect, it’s from from flowering trees such as black locusts, chestnuts, and limes. In mid-July, when lime trees lose their flowers, the bees essentially go into winter mode, and beekeepers know to feed them.
That’s not the case in the countryside. Those bees have access to agricultural plants that also offer nectar sources such as rapeseed or potato flowers, or many others. These plants are either sprayed with pesticides or grown from seeds treated with neonicotinoids. Neonicotinoids are toxins that affect the brain.
They are much more common, stronger, and more concentrated in plants visited by bees in rural areas. As we were preparing for this event, Mr. Dreher said that there is no evidence of urban bees being better off than rural bees. As in, there is no sign of city bees being less threatened by neonicotinoids
Than bees in rural regions. Well, I checked the literature and made a little use of my international connections, and the situation is quite something. It’s true that there is next to nothing in terms of research on the fascinating question of whether urban or rural bee populations are healthier.
I found one single legitimate scientific study. It’s by a team of researchers at the institute for bee research in Celle. They ran a study over multiple years that used an ingenious concept. They compared three different groups of bees, not just the city and farm bees:
Urban bees; bees kept in nomadic beekeeping; and rural bees. The results were very clear. For all applicable parameters, as in health checkups, hibernation, amount of pesticides in the bee pollen or the honey, and their activity and efficiency while collecting pollen – for every single parameter, the team observed that urban bees
Are significantly healthier and better off than the others. I’m sure Mr. Dreher will have other studies to cite, allow me to go ahead and say so for you. I can tell you that other sources are simply incorrect. There’s a beekeeping magazine article on a study in Bavaria
That wasn’t conducted by scientists, but just a group of people that just took a glance at things and concluded there was no significant difference. Anyone even a little knowledgeable about statistics will know that, in order to conclude anything of significance, it’s not just about the size of the difference itself,
But about the amount of samples that were taken. In this case, the samples were so few that even for the Bavarian crops, which have over twice the amount of pesticide applied to them than elsewhere, the study concluded that there was no significant difference. So we need to look beyond the surface level.
I was also fascinated that, when asking my colleagues abroad, there turned out to be only a single study on the topic in Australia, which I wasn’t able to access. It seems like they haven’t compared urban and rural honeybees there. Thank you, Mr. Menzel, let’s put a pin in that.
Mr. Dreher, any thoughts on this? Yes, you’re correct, of course. There aren’t very many studies, specifically, on the subject. But there is quite reliable data to be found from projects such as monitoring programs. For example, the German bee monitoring program has been running for decades at this point.
Practically every research institute on bees in Germany is part of this program. It’s run on a state level, meaning that every German state has one main bee research institute that works closely with beekeeping businesses and monitors the honeybee population.
They operate with the goal of recording the amount of plant protectant traces and pathogens. And they’re working to find out the cause of colony losses in winter. As I said, the program has been around for some time. Don’t get me wrong, I agree with you that many plant protectants
Have negative effects on bee colonies and on insects in general. Please don’t misunderstand me there. This monitoring also works with sampling residue amounts. These show a clear difference for bee colonies in urban areas that feature very little to no agricultural activity:
The amount of plant protectant residue found in those cases is essentially zero. It’s shocking to see what they’ve found in rural agricultural areas: Some of these plant protectants contain up to twenty-three active components. Traces of those can be found in the bee pollen. Obviously, honeybees come into direct contact with these agents,
Bringing them back into the hive. I strongly assume that other wildlife that visits flowering plants, like wild bees or other insects, come into contact with these substances, too. But if we try to find a link between winter colony losses and these agents, we can’t establish any kind of statistical correlation between the two,
At least not in years past. So every time the data is reviewed every two years and conclusions are reached, the German bee monitoring program – formed, remember, by all state institutes – finds that plant protectants play no significant part in winter colony loss. This doesn’t mean that they have no negative effects.
That’s where the bee colonies’ capacity for counteracting problems comes in. They’re able to compensate for the strain already put on them by these agents. Another thing I’d like to point out – the bee institute in Mayen conducts extensive surveys about winter colony loss.
These surveys provide solid data and are held across all German-speaking regions. It focuses on Germany and sees very high participation rates in the realm of about 15,000 survey replies every year. So we’ve got roughly 15,000 replies’ worth of data each year and if we compare the metropolitan data from Berlin, Bremen, and Hamburg
With more rural states – specifically, with colony loss data from those states – then there is no significant difference to be determined. To be concrete, looking at Berlin and Brandenburg, there was basically no difference between them this year, at least none of any statistical significance.
If anything, Berlin reported worse winter colony loss than Brandenburg. – May I… – I think this may be an issue we can’t solve today. So I’d like to direct the conversation toward a different aspect. Could you tell us more about your research on bees’ memory? What are the effects of pesticides on them?
Where are pesticides used and where could we find them in the city? Why are they used in those places? With pleasure. Just let me add that there’s a difference between conducting monitoring in which you’re looking for a certain correlation and conducting a research study that uses control groups of bees
That are studied in a way that is appropriate for the statistical results. The experiments need to be conceived for that. Monitoring data tells us nothing about differences between urban and rural bees because it’s based on random, selective factors along with many others.
This data is of no help to conclude anything about issues in either location. I don’t believe bee monitoring can be used for this. I would say that what we need for that is an appropriately designed study, as the researchers put it. A balanced study that includes control groups.
The neonicotinoids aren’t the only agent that needs to be studied. We need to include glyphosates as well; that’s a type of herbicide. But let me start with the neonicotinoids. All these agents have complicated names that sound like they’re related to the brain. There’s one molecule in particular behind this all,
And that’s the nicotinic acetylcholine receptor, for you scientists. This receptor is found in strategic places of the bees’ brains and helps them perform particularly complex tasks, such as navigating, learning, or using their social communication in the form of waggle dances to exchange information and experiences among one another.
The studies done on this topic were all conducted in a way that show precise dose-response curves over a specific amount of time. This lets us compare unaffected colonies and individual bees with those colonies and individual bees that are indeed affected by these agents.
And we can see that – well, we need to differentiate here between the neonicotinoids that are banned in the European Union and those that are permitted. I won’t bore you with their names right now but they’re so toxic that it’s not really up for debate.
There’s an interesting case when we look at one called Thiacloprid. This one was only banned very recently. Farmers are allowed to use up any remaining amounts they have of it and they’re also allowed to import it from Poland. It’s still around in other countries, too. Thiacloprid isn’t necessarily fatal to bees.
To give you an idea of the numbers, a bee would need to collect ten thousand nanograms to give it a fifty percent likelihood across a group of multiple bees to die within twenty-four hours. How many times would a bee need to visit a flower to collect that much?
I have no concept of the amounts here. Yes, I see what you mean. They’d need to… Well, we can estimate that because we’ve checked: We used rose petals, extracting the nectar and comparing it with the amount of bee visits. For the rose, which is fairly rich in nectar,
The bee will have to visit up to one hundred times to collect it all. That number went up when it was collecting the extracted nectar. The more interesting question there is how much they collect over a longer period of time, not just in a single visit.
How much of this toxic agent do they collect over multiple days or weeks? Are they harmful? Not fatal, but harmful. The results are, and this can be traced to a specific molecular mechanism, that these substances are harmful at as low doses as forty nanograms per bee.
What do you mean by “harmful”? Could you explain that? It means that they can’t find their way home or they’re unable to perform their waggle dance. Or that they’re unable to learn and contribute to a reduction of efficiency that is normally so typical for bee colonies.
And of course it is the case that thanks to the beekeepers’ fantastic efforts, such effects can go unnoticed. It doesn’t necessarily mean that colony will die, either immediately or during the winter, and it could just be a mere correlation. But it remains an enormous strain put on the bees.
Their capability to resist the Varroa mites has been proven to suffer under this, too. So has their larval development. As proven by your own former institute in Kirchheim. These non-fatal effects are overlooked by those responsible for this at the European level, the EFSA in Parma.
They only look at death rates, which means all these other issues are ignored. And that leads to major damage – let me just finish this sentence – because when we look at wild bees, we see that they are far more susceptible to pesticide damage than honeybees on a per-dose level.
This is because they use the nectar themselves. They need it for energy to fly, and for their offspring along with pollen. But they also eat more nectar than honeybees do when they spit it back out again to produce honey. All of this is well-researched, especially for what we call
The standard solitary bee, which is the mason bee… Thank you, I’d like to touch on Ms. Lokatis’ project again. Keeping in mind what we’ve learned, what does that mean for the Berlin in Bloom and Blooming Campus projects? Including what we now know about pesticides,
That are sometimes found in plants from home improvement stores. Well I can’t speak for honeybees but I would agree that cities are often better habitats for wild bees than highly cultivated farmland. The use of pesticides is just one reason for this. Another point that is worth discussing
And relevant to the topic of “biodiversity” we are talking about today is that honeybees are working animals and cannot really be included within the concept of “biodiversity” or at least not in the traditional sense of the phrase because they have been domesticated. There used to be wild honeybee colonies in Central Europe
And honeybees were their own unique, wild species that would settle large colonies in hollow trees. Nowadays they have been cultivated and form part of our cultural history. It’s important to keep that in mind. That’s why I wanted to emphasize that we need to consider these aspects from biodiversity research
When we talk about biodiversity if we want to draw meaningful conclusions. Of course I don’t want honeybees to be exposed to harmful pesticides but we should remember these nuances and that our actions also affect wild animals And in this case, wild bees. In cities, one of the most effective
Things you can do to promote flying, wild pollinators is to increase the number of flowering plants not just native plants, but a broad range of species with nectar-rich pollen so that you can cater to a wide variety of pollinators and that means not just wild bees.
You can trust me on this one, I’m part of a project on wild bees! There are many more pollinators than just honeybees or wild bees, there are many different groups e.g., hoverflies, many species of wasps, beetles are also important pollinators. There are a number of studies regarding agricultural pollination
That are starting to mention wild bees as pollinators. Many studies in recent years have shown that moths are incredibly important pollinators, for example, and people simply hadn’t thought to research them. There is often this focus on honeybees because they are such an integral part of our culture
Which isn’t a bad thing. But we can’t forget to take these other groups into account. This is why it is so interesting that wild bees and bees do so well in cities compared to other groups of insects while other groups of insects tend not to do so well.
Wild bees do surprisingly well in cities. But pollinators such as butterflies struggle a lot more in cities. They have a much more complicated life cycle, meaning you can’t simply plant more flowers and install some insect hotels, things are a bit more complicated. What do you mean “more complicated?”
Well – the problem is that even if you were to create habitats that were perfect for various species, you would be faced with additional factors in cities. For example the “heat island effect,” i.e., that cities are warmer than the areas surrounding them. This means that for
Insects like butterflies, if it is too warm during the winter months, they cannot – Okay, so there is this article about butterflies. It says that when winters are too mild, butterflies wake up early and expend too much energy. But that is not my field of expertise.
That’s what I mean by additional factors. There’s heat, and then there’s high levels of nitrogen, i.e., even if we reduce the amount of pesticides in cities, we are surrounded by cars, and dogs marking their territory and this is a very new ecosystem, a human-made ecosystem that some
Animals and plants can adapt well to and others can’t. And bees are able to adapt surprisingly well. Thank you for emphasizing that important point, that we are talking about the mass extinction of insects; there is a lot more at stake. Like you said, our keyword is biodiversity.
By removing plant life we are also increasing the temperatures of cities. What would you say to people in private households? What can we do to help insects in our local cities, or in Berlin? I’ve written a pamphlet on how to promote wild bees in your garden. You can collect a copy downstairs.
Create small structures. At the Blooming Campus initiative we have discovered that you can often make a big difference just by getting a small group together. You start seeing things differently. One example is hedgehogs. They need certain structures in gardens; And when it comes to these typical garden walls that you see in Dahlem
Their concrete bases make it very difficult for wildlife to move around. Once you start thinking about these animals and their habitats, you start seeing how hostile Berlin is to hedgehogs and you can come up with ideas Maybe we could put a small hole here, maybe we could leave this pile of leaves, etc.
My suggestion would be to choose your favorite group and focus on them. If everyone did this… Exactly. Do we have any questions from the audience for our podium experts? I wanted to ask about the air in cities. We can’t really call it healthy these days,
We have CO2, other pollutants, air pollution. Maybe factories also play a role. What are the effects of this? And has this been researched? Who would like to answer? Mr. Dreher? I can give it a go. There aren’t too many studies on the subject.
We have monitoring projects like the one from Oberursel in Hessen. It monitors the air at Frankfurt Airport and we can assume here that there may be high levels of air pollution. I mean of course we have different levels of pollution in big cities. In the city we don’t usually have any agriculture
And any attempt to protect plants can only take place in small-scale allotments with a limited repertoire of resources. We have other pollutants at work. Now, you mentioned exhaust gas. CO2 isn’t a pollutant in itself, it is a trace gas and doesn’t really contribute to air pollution.
But it is, for example, possible that heavy metals play a role here or certain hydrocarbons produced during combustion. What little data we have suggest that this is not a big problem, at least when you look at the products, or bee products. You can find surprisingly little evidence of pollutants in honey,
Or no evidence of pollutants at all. This means that honeybees are clearly able to withstand and filter out a lot for example, any particles or any heavy metals. So I don’t think there is cause for alarm. Can I chime in for a second? There have been some studies carried out in China.
Beijing, for example, is a city that suffers from extremely high levels of dust. Research carried out there has found that a very dusty environment affects the respiratory system. Bees breathe differently than we do, relying on tube-like organs called tracheae. Scientists have shown that these organs can become clogged by dust
Which affects energy metabolism. We have yet to discover whether this has an ecological effect, as far as I know, because there are so many parameters, including in Beijing, between urban and rural areas but the point remains that the oxygen consumption and energy efficiency of these animals
If you were to put them in a measuring device and ask: “How well can you fly with X amount of oxygen?” then they are worse off. Thank you. Do we have any more questions? Was anything hard to understand? This isn’t about understanding but more about another topic.
I was wondering: If honeybees and wild bees have very different problems, are there any factors at work here that influence each other? There are lots of honeybees and fewer and fewer wild bees. Is there any research that has investigated this aspect? I’ll have a go at answering!
Can I just check – the question is about competition between solitary bees? I looked this up before because I knew I’d be sitting between two honeybee experts. Very good, well, this is a topic that we haven’t discussed yet I think that was the general idea, right…?
– Competition between honeybees and… – Yes, what does the research say, is there competition, etc. Yes. Yes, okay. A number of individual studies have been carried out over the past 40 years including a current study that, although it isn’t a proper meta-analysis,
But rather a review that sums up the results of previous research. And there are also individual studies on the subject. Some are very experimental in nature which, as we have heard, is very important where researchers placed wild bee nests near domesticated beehives
Or further away and they found that the growth curve of the wild bee nest flattened out considerably, meaning that the wild colony developed much more poorly than they would had no other bees been nearby. And it has been observed on many occasions that
Gardens or nature reserves that are home to many bee colonies are home to fewer species in total. It is often said that more research is required and more research is indeed taking place. When you look at all the studies that have been carried out
I believe around 60% demonstrate negative effects to different degrees of severity while only a few demonstrate a slightly positive effect, or none at all. And the big factors here are: Is the honeybee used in the study native to the area?
Here in Central Europe there is a very long history between humans and honeybees. But it is only when we try to industrialize beekeeping that we have this competition. Although if we are talking about industrialization, I think there is a rule of thumb, apparently, when it comes to beekeeping
That you shouldn’t have more than ten colonies in one place. I don’t know if that’s true. It’s hard to generalize. Yes, but the point is that the concentration of bees in one place is important although I’ve also been in allotments that only had four colonies and I hardly saw any wild bees
And I am someone who always looks for wild bees when I am out and about. If there are only honeybees in the area then I know I won’t be taking any good photos because all you can see are honeybees visiting the plants.
This is something that I have experienced personally but it is also reflected in the research, however it is important to remember this historic relationship between humans and honeybees; we have a cultural landscape that is so diverse and can supply so much that competition shouldn’t exist.
Unfortunately it does exist because other factors are also at play. We had one last question that I would like to address… is it still relevant? Yes, I think so, because it ties back to urban life and emissions. It’s more another answer than a question.
Okay good, are there any other questions from the audience? Then maybe we could take a minute for each of you to make a concluding remark? – Could I maybe address what was just said? – Of course. – Because I agree. Research is so divided on the subject.
I find two things particularly interesting when it comes to this topic. One is this question regarding competition between honeybees and wild bees. You have to be mindful of seasonal variations. In spring there is so much nectar and pollen available that it is hard to find anywhere where honeybees present a real threat.
This is a conclusion that is often made but they fail to mention that this can become a real problem in summer and fall. And this matches the observations made in recent years in which solitary bees, or wild bees, are increasingly coming under threat and are disappearing or in danger of disappearing.
These are primarily the wild bees that are active in summer and fall. For me, this is a scenario that needs to be taken into account when reading the literature. Maybe people are doing this but this needs to happen for every study.
We need to determine whether these studies are taking place throughout the year or at least throughout the growing season and whether they differentiate between spring, summer, and fall. What would you two like the audience to take away from this discussion? – Ms. Lokatis. – Bees are great!
Having any wild animals in the city is great. We have a lovely exhibition downstairs where you can see some things on display. I highly recommend you take a look. And in response to the earlier question of what can people do in their gardens to help wildlife,
My tip would be to start by looking and, based on what you see, to start thinking how you can help. For example, if I see a species of wild bee that I don’t recognize I start researching it and what it needs. This is usually the first step toward getting involved with the subject
And seeing what you can do in your own garden. Or if you don’t have your own garden you can take things into your own hands by organizing something at your university or in your district. There are a lot of opportunities to get involved these days
For example, through Urban Gardening, or by adopting a tree in your local area or by advocating for change on a local level. – Thank you. Mr. Dreher? – I’d like to quickly circle back. I think this problem of honeybees and wild bees… they are simply different animals.
Once we start speaking of competition we lose sight of what’s important. I think it is important that conservationists and beekeepers work together to achieve the most effect. As already mentioned, the available studies don’t agree; in my opinion there are too few studies that are truly valid and useful for evaluating whether competition exists
And that provide proof of this. Making generalized statements is always dangerous and incorrect. There are so many species; they cannot all be in competition with one another. There would have to be overlap between evolutionary niches, there would have to be temporary pollen shortages
Because any type of competition would really have to be for food. It’s not like honeybees actively attack wild bees or prevent them accessing flowers. – Oh but sometimes they do exactly that! *Laughter* I should emphasize that the data are incredibly varied.
We don’t have a lot of data but what we have is quite conclusive. The German Wildlife Association for example, says that honeybee colonies should not be placed within a three-kilometer radius of nature reserves. This is something we haven’t discussed at all.
And then with regard to what Mr. Menzel said about less competition taking place in spring. Honeybees primarily visit mass pastures and this becomes a problem when the plants there finish blooming and beekeepers don’t move the colonies, meaning that the honeybees then swarm to the wild plants that are used by wild bees.
So in this case we need to raise awareness among beekeepers to remove their hives from at-risk areas. *Laughter* I think I know which studies… …I mean, of course we could keep going back and forth about the studies – I believe… – I’m afraid we don’t really have time for that.
The situation is simply not so clear and I know that many species or most species have no biological reason to generate such competition but I don’t want to get into that again. The biological reason is that wild bees are usually active for only a few weeks of the year.
This means they can only collect nectar from some plants. Honeybees are active all year and they don’t mind where they get their pollen. That’s why they like these mass pastures where everything blooms at once but they are also very flexible when compared to wild bees. – Yes, I know.
– Mr. Dreher, 20 seconds and then I will have to end the discussion, if you have any final remarks. Like I said, I don’t think it’s productive when conservationists and beekeepers are at odds with each other. I believe the main problem with the decline in wild bee numbers
Is not competition from other bees, but a loss or fragmentation of habitat through agriculture or through the use of certain pesticides, as Mr. Dreher already mentioned. An even bigger problem is the deposition of pollutants in the soil through agriculture or nitrogen dioxide pollution, as well as climate change.
These are the main problems facing pollinators, not the competition between wild bees and honeybees. Thank you all very much. I have learned a lot today and I would like to thank you for the range of perspectives you have presented. I think we have all seen that there are many perspectives at work here
And we couldn’t address them all tonight. Nevertheless we have been able to take a look at a human-made problem. We have brought nature out of balance. Biodiversity is suffering because of human interference and I would like to thank you for your input this evening,
And for the tips that we can try out at home in our gardens or on our windowsills. I am looking forward to the exhibition and would like to extend an invitation once more to everyone here to visit the exhibition downstairs where you can also continue the discussion if you so wish.
Thank you everyone, thank you to the organizers, and thank you Berlin Science Week! *Applause*