This week we are talking about urban bees and how converting vacant lots into green spaces doesn't only benefit humans. With a few adjustments, green spaces can help support local bee populations. We're talking to Ohio State University reserachers about how to help urban bees thrive.
Mary Gardiner is a professor of entomology at the Ohio State University. Katie Turo is a post doctoral fellow in the department of ecology, evolution and natural resources at Rutgers University. Their latest study was recently published in the journal Conservation Biology.
The following is an unedited transcript.
Shoshannah Buxbaum 0:03 - This is undisciplined. I'm Shoshannah Buxbaum. For the past several years, scientists have been ringing the alarm bells about the rapidly declining bee population, and how the loss of these important pollinators are threatening our food supply. There's a lot of reasons from habitat loss to climate change and pesticides. Today we're talking about the sometimes overlooked but equally important city dwelling bees, and how urban green spaces can support their habitats. Ohio State University researchers wanted to know which conditions are best for city bees. So they created an experiment using vacant lots in Cleveland. They found that urban bee populations thrived in flowering prairies with native plants and areas with lots of surrounding green space. Joining me now are the study's co authors. Dr. Mary Gardiner is a professor of entomology at The Ohio State University, and Dr. Katie Turo, recently joined the Department of Ecology, evolution and natural resources at Rutgers University as a postdoctoral fellow, Dr. Mary Gardiner and Dr. Katie Turo, thanks for being here.
Mary Gardiner 1:03 - Thank you.
Katie Turo 1:04 - Thanks for having us for Shoshannah.
Shoshannah Buxbaum 1:06 - Okay, so to start off, this goes to both of you. Why is it so important to monitor urban the urban bee population we often think about the importance of bees in more rural areas, helping pollinate crops. What's so important about urban bees.
Katie Turo 1:23 - Well at the same time as we care about bees for pollinating rural farms and rural crops, there are still urban crops and urban farms that require pollination in cities as well. So in our study system in Cleveland, Ohio, there are over 235 community farms and gardens. And these community farms and gardens also depend on bees for their crop quantity and quality too. So there's a big urban agriculture industry across the world, as well as in our study region. Mary Gardiner 1:52 And Shoshannah urban habitats are quite floridly diverse. If you think about someone's yard space, they're often rich in floral plantings, in many cases are vacant lots were written in weedy plant resources for bees, and so many of these spaces can if they're managed properly, be really valuable habitat. The other reason it's really important to monitor urban areas for bees is cities are often where we pick up invasive species newly detect new detections of invasive species, or exotic species. And so it can also be really important from that kind of monitoring standpoint.
Shoshannah Buxbaum 2:30 - Okay, so this study is part of a larger project. So Mary, can you tell me a little bit about this overarching project that you developed in Cleveland in their vacant lots there?
Mary Gardiner 2:43 - Sure. So Katie's research was part of a larger project funded by the National Science Foundation, it was a career grant a five year project. And as part of that project, we installed a network of 60 some vacant lot habitats across the city of Cleveland, and eight different neighborhoods. And within a neighborhood we took eight vacant lots and working with the city we selected different types of potential bee habitat that ranged from existing weeding, vacant lot vegetation, Mone different time points, to transforming the lots into what we call pocket prairies, which were habitats seeded with native Ohio wildflowers and grasses. We sampled of many different types of insects within these habitats and examined how different habitat management influenced their community composition, abundance, and also metrics of health like reproductive success. And Katie collected data on bee populations and has published this article recently examining how these different habitats influenced bee reproductive success.
Shoshannah Buxbaum 3:56 - Yeah, so Katie, can you tell me a little bit about what you found which habitats were best for the bees?
Katie Turo 4:02 - Sure. So as Mary just mentioned, our overarching goal was to see how different habitats influence bees reproductive success, because reproduction is really an indicator of the population health to serve, we know that the bees are producing larvae and those populations are growing, we have an indicator about the health of those populations in general within the city. So my project looked into how turf grass versus a flowering lawn or a tall grass prairie and a flowering prairie would all impact bee reproductive success. And we found that for native bees, specifically, there was a connection between native prairie plantings within these urban habitats, and the overall reproductive health and success of these native bees too. So that's a really exciting connection that we were able to make.
Shoshannah Buxbaum 4:56 - Can you expand a little bit about that? What you mean by a native bee and also like the role of native species, native plants in the area.
Katie Turo 5:06 - So when we think of a bee, someone says the bees are in decline. The first image that seems to pop up in people's head is a honeybee. Right. And honey bees are great. We love Honey, I have no problems with honeybees, I would like them to have healthy populations as well. But if you think about a honeybee, they're kind of like cows, and compared to other wild bees. So they're an agricultural bee, like they're managed by people, they have a product, but they're not native bees native to this region. Honey bees are from Europe. So they weren't originally in native North America. Honey bees came over with people as they moved from Europe to North America. So the native bees that we were looking into have always been in this area, they typically have particular relationships with native plants, because they co evolved over time. So they have these unique intricate relationships with native plants, or sometimes they don't care and they can just eat a whole bunch of things. And there's not that relationship. This is an exciting find for us, because some Urban Studies have found that native bees don't care if native plants are in the city. They'll feed upon many of the ornamentals, or exotic weeds that are just growing in a city. Those are great resources, too. But in our study, we found that the native bees within our region really did have more of this connection with the native plants too, because we saw an increase in native larvae being within the native bee nests that we looked at. And we also saw that there was a unique composition of native bees present in habitats in which native plants were planted.
Shoshannah Buxbaum 6:40 - Yeah, and so one of the other things that you found too, is the importance of having interconnected green spaces. Can you talk a little bit about I mean, when we think of a bee nest, like how much space is that taking up? And also, why is it important for them to have a lot of green space surrounding their nest area.
Katie Turo 6:58 - So again, if we think about bees, people's typical entry point when they're thinking about bees is the honeybee, I mean, pet your hive. But most native bees are not social like that. Most native bees are solitary, and they nest with one maternal Bee, and then a range of smaller larvae, so maybe like five to 12 larvae within one small cavity, or within the ground. So most native bees are solitary, there's just one reproductive individual. And most native bees are also ground nesting, so you won't even see their nest, they look kind of like ant mounds from the top of the ground. And then underneath, there's a tunnel that digs down into the earth. So native bees have different habitat requirements to and in order to have a healthy population of bees, they need things like food and shelter and other reproductive individuals that they can encounter. So having a large habitat sometimes important to find all those particular habitat prerequisites for reproduction to occur. So in our study, we found that a large patch of urban green space was really critical for native bees. And that's probably because of the interplay of these different factors that impact reproduction, such as food, so were they able to find the pollen in the nectar that they like and are attracted to. So maybe that was native plants. shelter, were they able to find the nesting materials that they require in order to create a nesting construct one, so some bees take mud and make partitions in between different cells where they lay their eggs and a pollen ball. And so they need some mud or they need some leaves to make these partitions within their long tunnel or their long cavity of a nest. So we need nesting materials. And we also need the ability to encounter other reproductive individuals. So all these things combined, what we found that it was really important that there was a large green space available in order to have an increased number of native larvae with when our trap nests, which was our study tool in order to look at the types of bees and the numbers of bees that were nesting in a particular habitat.
Shoshannah Buxbaum 9:12 - Is there anything for either of you that was surprising about your findings?
Mary Gardiner 9:16 - Well, one thing and this was actually in one of Katie's other great papers, just the diversity of bees that live within the city of Cleveland and use vacant lots. So we found about 20% of Ohio's bee fauna, which consists of 500 species, use these vacant lots for habitat and so understanding, you know, what factors influence their health is really important because we're not talking about one or two species. Here, we're talking about 20% of Ohio's bees. And so with this study, she's able to look at the reproductive success of a subset of those that nest in cavities. Of course, there are many species that nest in the soil or in wood or other habitats and different factors might influence their health and reproductive success too. And so you know, that is a, an area for a lot of future work.
Shoshannah Buxbaum 10:11 - Can you speak a little bit about what these urban bees are up against? Like, what threats are they facing that may be different than like honeybees when we think about, like colony collapse, I know where like, you know, 90% of bees sort of disappeared for like a variety of different reasons. But our urban bees dealing with a different set of issues than like honey bees, or other types of bees?
Mary Gardiner 10:35 - Well all be is kind of deal with a plethora of challenges or stressors in their lives. In urban bees, they have to face habitat, fragmentation to an extreme extent, right, there's a lot of roads and parking lots and, and broken up green spaces that they have to traverse and survive within and crossing. There also can be contamination in cities. So you know, in agricultural areas, it's well established that pesticides can pose a threat to bees. In cities, they're also pesticides being used by you know, residential homeowners using pesticides in their green spaces, so that can be a threat to urban bees. There's also heavy metal contamination in some cities with a post in post industrial city cities where smelting took place. Along roadways, areas like this can have high concentrations of lead and other contaminants. And our lab has also demonstrated that exposure to those heavy metals can have a negative consequence for bee health.
Katie Turo 11:43 - Specifically for Reproductive Health to heavy metals really does impact colony growth for bumble bees and even larval size two, I believe Sara has found that in our lab, so heavy metals are a unique stressor that maybe some more agricultural bees might not encounter. But generally, it seems to be pretty in tandem, that the same stressors would impact both rural bees and urban bees, because these are large issues such as climate change and habitat fragmentation and loss. So it's likely that all bees encounter them.
Shoshannah Buxbaum 12:18 - Yeah. And like the heavy metal issues, I'm thinking about–I had done some reporting about urban bird rescues in New York City and how a lot of a lot of pigeons and hawks and other birds that live in this city will have lead poisoning because of the soil there is really in high concentrations of lead, which is not just a problem in New York City, but a lot of a lot of places. So it doesn't just affect bees, it affects kind of like the whole ecology.
Mary Gardiner 12:45 - The very thing that eats them.
Shoshannah Buxbaum 12:46 - Right. Exactly.
Mary Gardiner 12:48 - And eats spiders and grasshoppers and other insects and invertebrates that are also encountering soil lead and soil contamination. So yes, this is, you know, urban conservation is a really, really important area for conservation growth. But we must be mindful of heavy metals and heavy metal remediation tactics as well when doing this work. Yeah. And so what what sort of got you interested in specifically looking at the vacant lots in Cleveland for your lab, you've done tons of research, not just on bees, but on other insects? What motivated you to say like, oh, let's look at these vacant lots? Well, I think my major motivation was that the vacant lots are widely viewed as blight. And they are very challenging habitats for people to live near and for cities to manage. And I was really excited about how they, on the other side could potentially represent a positive because you're going from a very highly densely packed urban area to one that's reclaiming its green space. And so in a rare sense, you know, although there are hundreds of vacant lots cities, most cities are growing. So in these cities that are shrinking or losing population, we kind of have a bit of an ecological duel over in a certain sense. Now, we're not going to get back to what the city was, you know, post urbanization or anything like that, right? We have these green spaces back that we didn't have. And so what should we do with these? What would be best? How should we manage them to support the biodiversity that can thrive within this fragmented urban environment? And I just thought that was really exciting and important. I also like to work with communities and do community science, and co created science. And so this was the perfect opportunity to do that.
Shoshannah Buxbaum 14:46 - So Katie, how did you sort of get interested in this type of research and get involved in Mary's lab? K
atie Turo 14:54 - Well, in undergrad I took an entomology course and was interested in the subject broadly, but I've worked at Penn State and Michigan State University and different B labs and just found them really fascinating creatures. It's not often in science. And typically we're working in molecular biology labs, it's not often that you get to hold the creature in your hands and see all of its features. And the really, the biodiversity of bees is just fascinating. but also their role within the ecosystem is also equally fascinating, too. It's critical for crop pollination. So I've worked with apples and in native prairies in Michigan, too. So that just led me to question like what happens in other habitats that are human dominated, because typically agricultural habitats are human dominated, but that has a unique set of challenges. And a city where it's human dominated. It's, it's a whole other type of challenges that the bees are going to encounter, and that we could be a frontier of science and see how urban conservation might contribute to helping global populations, because a huge amount of land in the world is really set aside in cities at this point. And that's continuing to grow because most cities are expanding. I do think it's interesting, though, at the same time that more cities are expanding. Our research really pointed out that large green spaces were critical to success and health of native bee populations. So that does indicate that not every city is a key candidate for native bee and urban bee conservation. Those cities such as legacy cities, such as Cleveland, or Detroit, where we conducted our research in Cleveland have unique opportunities, because they've lost some land that was held and urban houses and residential properties, and an industry to reclaim that land for green space. And that has unique opportunities for bees and urban bee conservation.
Shoshannah Buxbaum 16:50 - How can you use what you've learned in Cleveland to help other city other legacy cities, as you said that are having population decline? Like how can they sort of look at what you've learned and help implement that in other cities?
Katie Turo 17:03 - Well, we've written a couple papers about this topic of how best to do urban conservation, because we learned a lot of lessons about what works well within a community. And the first step is really to ask, what does the community want, because this is different working within an urban environment than working in an agricultural or more woody woodland environment, where there's not a lot of people that you encounter. Here in the urban environment, we are working in people's backyards, and people have opinions. They have differing aesthetic perspectives about what looks nice in the city, and what would help their community. So as scientists, we shouldn't be going into the city and saying, This is what you need. This is what the bees need, you should do this, we need to go and ask those communities, what would help your community? How can we be a part of that and maybe incorporate some of those needs that we've learned that bees required to have healthy, successful populations. So I think that that was a key takeaway for us throughout this research is that it's critical to co create community projects, and really be part of a community development process. And that also requires that we work beyond our particular disciplines, too, because we need to be working with other sociologists, other people, and like urban landscape design, to make sure that what we're doing is more long lasting, too, because this project in particular, that we did in Cleveland, Ohio, was intended to be a short term project where we looked at low maintenance, habitat designs that could reduce mowing and the costs of mowing for city and maybe have some ecological benefit as well. We learned a lot, but those cities are those vacant lots included in this research have now been reclaimed by the city. And they're not being maintained as the specific habitat designs that we had created in Cleveland, because they were never given the structure for management that they would require for a long term success. So if someone is interested in doing urban community development and incorporating conservation into that, I think they should think about long term who is going to manage these habitats. What do the people want? What kind of structure Do we need both fiscally and also on the ground to to connect with people? Because this is in people's backyards, and we want to be supporting our neighbors?
Shoshannah Buxbaum 19:21 - Yeah, it's not as simple as saying like, okay, like, this is what bees need. You know, we've researched this, like, here's a cookie cutter plan that you just throw into any city, it's a lot more collaborative.
Katie Turo 19:35 - Collaborative, but also each city has its unique city context to and history. And so we especially don't want to be going in and saying, Look at this neighborhood, a lot of people have left, it's got so much green space, but in reality, those people who are left in those neighborhoods are maybe minority communities and we're displacing them to put an urban green space there and that's definitely not what our intent or what we recommend to so instead of having that perspective of, we're going to be scientists and come in and save the city for the bees. We need to be thinking, what do people here want? What would help those communities?
Shoshannah Buxbaum 20:10 - That's a really important factor in making some of these projects happen. And I was also thinking about, you know, people that maybe live in more densely populated cities or you know, suburban areas where they maybe have a big garden in the back or yard or something like that. Are there things that people can just do on their own property to sort of help the bees? There's research for about monarch butterflies that people can even planting like a small amount of milkweed, for example, can help the monarchs along their migration paths? Is there something similar that people can on their own property, say, like, Oh, I can, you know, maybe devote part of my yard to something that's going to attract bees and help them?
Katie Turo 20:54 - Definitely, and we don't mean to imply that larger cities can't be beneficial for bees, there are bees living in New York City like even though it's a large city, so there is stuff you could do locally to help your local because and lots of bees are small and don't move beyond like one to 200 meters in their life in that radius. So where you're at, there are very, there are many bees that you could help that maybe wouldn't get any help beyond what you locally could do in your backyard. So what our study really indicated was, native bees were beneficial for native bee reproduction, or native plants are beneficial for native bee reproduction. But at the same time, we've also found that bees regardless if they're native or exotic feet on weeds that are in the city, so these exotic plants like red clover or chicory or dandelions, those types of flowers if you just stop mowing your lawn will be so beneficial to the bees in your local neighborhood. Or if you like a lawn, like just delay your mowing schedule. Maybe instead of like one week or two weeks, you wait three weeks to mow your lawn, you get to be a little lazy with it, which is a great benefit. And at the same time, it'll benefit those local bee populations to theirs offices. So that's on the food aspect, you can plant more native plants you can plant or leave weeds in your lawn alone. But you could also consider some nesting materials too. So a lot of these are ground nesting. If you do use a lot of heavy mulch, those ground nesting bees can't access the soil as easily. Bare patches of Sandy ground available for those these don't use pesticides as much as possible. And if you're going to stay spray pesticides don't do it at the same time the bees are flying in your yard because they're definitely going to encounter those chemicals then.
Shoshannah Buxbaum 22:41 - Right? Yeah, no, the pesticides are a big issue. I was just reading in preparation of how much pesticides really have impacted the bee population.
Mary Gardiner 22:51 - And it can be, you know, something that people maybe don't realize, maybe they think they're just putting down her fertilizer. But there can be pesticides mixed with that fertilizer, just because you buy a pesticide yourself at a big box store, you know, home improvement store. That doesn't mean it's safe for bees. I think people have a sense that if it's something that we can buy, as you know, non commercial applicators, that it's somehow more safe for bees, but unfortunately that you know, that's not necessarily the case, though. I think avoiding pesticide use is probably one of the top things right behind providing habitat but you if you provide habitat, you got to go pesticide free so that you're not bringing these in and then exposing them.
Shoshannah Buxbaum 23:35 - Yeah, that's so important. I think people aren't necessarily thinking about everything that they put in their garden of affecting not just the plants, but also things like bees and other insects that are going to be in their garden as well.
Mary Gardiner 23:52 - Right.
Shoshannah Buxbaum 23:53 - To close us out here. Mary just wanted to get your sort of final takeaways of what you hope that cities can take away from your research of vacant spaces, and just what you hope this type of research will help other cities when they're trying to come up with some ecologically friendly green space plans.
Mary Gardiner 24:14 - Well, it's it's been a really exciting thing in the past year, many groups, both groups of citizens and also cities have contacted me. For more information about the pocket prairies that they're looking to put these in or looking to try out a pocket prairie on a vacant lot within their city are several vacant lots. And so we are seeing this type of habitat spread in other post industrial cities in the state. And so you know, I'm happy to meet with anybody to give them all of our information and advice on what we found worked and didn't work. Any community group that's looking to do this. It's a lot of fun. It's a lot of hard work, but I think that it can be really a beneficial win win for community and bees if we do it right.
Shoshannah Buxbaum - 25:02 Dr. Gardiner and Dr. Turo, thank you so much for being here.
Mary Gardiner 25:06 - Thanks for having us.
Shoshannah Buxbaum 25:07 - Dr. Mary Gardiner is a professor of entomology at The Ohio State University. Dr. Katie Turo is a postdoctoral fellow in the Department of Ecology, evolution and natural resources at Rutgers University. Their latest study was recently published in the journal conservation biology. undisciplined is a production of Utah public radio with support from the College of Humanities and Social Sciences at Utah State University. And if you happen to live in Utah, you can listen to us every Thursday at 10:30am on up er, if you miss us, then you can listen to every episode of undisciplined wherever you get your podcast. Our producer is Clayre Scott. And our theme music is little idea by Benjamin Tisso. And I'm Shoshanna Buxbaum, thanks for listening, now go have big ideas.