This Podcast Will Kill You - Special Episode: Ben Goldfarb & Crossings

Episode Date: August 6, 2024

Roads are essential to our modern lives, so much so that they largely exist in the background of our minds. When we do think of roads, we’re either complaining about traffic or celebrating them for enabling our restless need to explore. Can you imagine if all of the world’s 40 million miles of roads were suddenly erased? Chaos for humanity. But a boon perhaps to natural ecosystems. In Crossings: How Road Ecology is Shaping the Future of Our Planet, author Ben Goldfarb takes readers on a fascinating tour of the relatively recent science of road ecology. Even beyond their impact on roadkill, roads are powerful disruptors of natural ecosystems, bringing noise, pollution, and humans to natural areas and fragmenting landscapes. And as Goldfarb demonstrates, we are only just starting to reckon with the widespread effects of roads and integrate this knowledge into road design. After this fascinating conversation, you’ll never think of roads in the same way again! See omnystudio.com/listener for privacy information.

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Terms and conditions apply. Visit blueapron.com slash terms for more information. I'm Amanda Knox, and in the new podcast, Doubt, the case of Lucy Letby, we unpack the story of an unimaginable tragedy that gripped the UK in 2023. But what if we didn't get the whole story? Evidence has been made to fit. The moment you look at the whole picture, the case collapsed. What if the truth was disguised by a story we chose to book?

Oh, my God, I think she might be innocent. Listen to Doubt, the case of Lucy Lettby, on the IHeartRadio app, Apple Podcasts, or wherever you get your podcasts. I'm Clayton Eckerd. In 2022, I was the lead of ABC's The Bachelor. But here's the thing. Bachelor fans hated him. If I could press a button and rewind it all I would. That's when his life took a disturbing turn.

A one-night stand would end in a courtroom. The media is here. this case has gone viral. The dating contract. Agree to date me, but I'm also suing you. This is unlike anything I've ever seen before. I'm Stephanie Young. Listen to Love Trapped on the I Heart Radio app, Apple Podcasts, or wherever you get your podcasts.

Hi, I'm Aaron Welsh, and this is This Podcast Will Kill You. Welcome one and all to the TPWKY Book Club, where we get to read the most fascinating books in science and medicine, and then bombard the author. of those books with questions for almost an hour. It's one of my favorite parts of making this podcast. We've gotten into some super interesting topics so far this season, and there are even more fun books to come later this year. If you'd like to sneak a peek at the books we're featuring in the TPWKY Book Club this season, head over to our website, this podcast will kill you.com, where you can find a link under extras to our bookshop.org affiliate account, which includes the book club list showing all of the books we've already covered this and last season, and the other books will be covering

throughout the rest of this season. And of course, we love getting your book recommendations, so please keep sending them. There's always more room on my shelf. All right, let's get started with today's book club pick already. Conservation journalist and award-winning author Ben Goldfarb joins me to chat about his recent book Crossings, how road ecology is shaping the future of our planet. In Crossings, Goldfarb, whose previous book, Eager, delves into the secret lives of beavers, amazing, explores the varied impacts roads have on plants, animals, ecosystems, even human health. For something that many of us use on a daily basis, driving or biking to work or the grocery store, walking our dog alongside, taking a road trip, just living next to,

roads don't factor into our thoughts very much. They're just there, acting as the means by which we get to our destination. Of course, I'm sure we all have specific roads that hold special meaning for us. For instance, I did a good chunk of my PhD fieldwork along Pipeline Road in Gamboa and Panama. Some of my favorite, or at least most memorable, fieldwork times, happened along that road. Going for a run along the road at dusk with Motmott's collo. and koadis darting off into the forest, dragging for ticks and running into a wasp nest, dropping all of my gear to escape the stings, but then having to frantically run back in over and over again to retrieve all of my equipment piece by piece. But for the most part, when I think of Pipeline Road, or going to the Sun Road in Glacier National Park, or the road to my mom's house in Kentucky, where I spent most of my childhood, I think about, these roads in relation to myself, what they have allowed me to do or see or experience or the memories they conjure. I don't often think of what these roads are doing to the ecosystems they're

cutting through and how their construction utterly changed the life in that area. Or at least I didn't think about those things until I read Crossings. Crossings delves into the relatively recent field of road ecology, which seeks to measure the impacts of roads on ecosystems and develop solutions to mitigate those impacts. This goes way beyond roadkill or even constructing wildlife-only overpasses on busy highways. We're talking tunnels for toads, the hidden depths revealed by bug splatter on your windshield, habitat fragmentation, devastating charismatic megafauna populations, the health impacts of roads on humans disproportionately distributed. along lines of race and class.

There are so many dimensions of the effects roads can have on the land they transport us through and those that live in that land. And luckily, we have an excellent driver at the wheel for this road trip through the world of road ecology. I am so excited to share this fascinating conversation with you all, and I know that it'll change the way you think about the roads that make up the background of so much of our life. So let's get right into it. Ben, thank you so much for joining me today. I am so thrilled to chat with you about your amazing book crossings and all things road ecology. But before we get into the history of road ecology and the impacts of roads and all that jazz, first, what constitutes a road?

Does a hiking trail or bike path or wagon trail count? You know, dirt, gravel pavement, are there degrees of roads as it relates to effects on ecosystems? Yeah, Aaron, well, first of all, thanks for having me. And thanks for that kind of profound philosophical question. It's a really interesting one. I think that for the purposes of this book, you know, I was really defining a road as, you know, kind of a linear piece of infrastructure that conveys motorized vehicles, you know, so a bike path wouldn't be a road or a hiking trail, as you mentioned, would not be a road.

But it is kind of a fascinating issue because there are definitely wagon trails, for example, you know, these super wide, you know, often paved structures that were constructed in, you know, in the 1800s before the internal combustion engine and the automobile. I mean, certainly, you know, those were like roads in many particulars. So, you know, it's a difficult one to define. And, you know, maybe like the famous court definition of pornography. You just know it when you see it. Exactly.

All right. What is a road check? Got that answered. Now, what is road ecology? And how did you decide that you wanted to write a book about this field? So road ecology is the field of science that looks at all of the different ways that roads and other, you know, transportation infrastructure affect nature. So you've got, you know, and well, I'm sure we'll talk about all of these different relationships and connections. and connections, but everything from roadkill to the impacts of road noise pollution to all of the

road salt that we add as a de-icing chemical and turns our rivers and lakes into brackish estuaries. You know, you've got tire particles going into the environment and killing salmon in some cases. So road ecology is this big discipline that looks at all of those different relationships between roads and nature. It's this kind of emergent field of science that just examines the effects of our infrastructure on the natural world. And how did you come across road ecology? Like, when did you learn about it?

And then when did you start to feel so passionate about it that you're like, hey, you know what? This is absolutely worthy of at least one book. Yeah, it's a good question. You know, my interest in the field really goes back more than a decade to 2013. I was, you know, I'm an environmental journalist, and I report a lot on ecology and conservation biology. And I was in Montana writing about wildlife conservation. And I had the chance to go up on a wildlife overpass, this bridge that had been built over Highway 93, north of Missoula, to allow animals like grizzly bears and elk and moose and bobcats to cross this really busy highway. And, you know, I hadn't really thought much about roads before then. You know, they're just, they're such a daily part of our lives that they're sort of invisible

to us, I think. They're so ubiquitous. We don't really think about them much. And I was certainly guilty of that. But, you know, standing up on this wildlife overpass, you know, it just occurred to me really for the first time in some ways, I think, what a significant source of ecological change those roads are. And also how cool and inspiring it was.

was that scientists were trying to do something about it by building bridges and underpasses and tunnels and other structures that allow animals to kind of safely navigate this asphalt-covered world we've created. So it was really that experience of standing up on that wildlife overpass, watching traffic kind of flow beneath our feet. That was what got me thinking about this issue and eventually turned into the book. Let's take a quick break. And when we get back, there's still so much more to discuss. Dinner shows up every night, whether you're prepared for it or not. And with Blue Apron, you won't need to panic order takeout again.

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two orders plus free shipping with code this podcast 50. Terms and conditions apply. Visit blueapron.com slash terms for more information. Anyone who works long hours knows the routine. wash, sanitize, repeat. By the end of the day, your hands feel like they've been through something. That's why O'Keefe's Working Hands hand cream is such a relief. It's a concentrated hand cream that is specifically designed to relieve extremely dry, cracked hands caused by constant hand washing and harsh conditions. Working Hands creates a protective layer on the skin that locks in moisture. It's non-greasy, unscented, and absorbs quickly. A little goes a long way. Moisturization that lasts up to 48 hours. It's made.

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The nurse who should have been in charge of caring for tiny babies is now the most prolific child killer in modern British history. Everyone thought they knew how it ended. A verdict, a villain, a nurse named Lucy Leppie. Lucy Letby has been found guilty. But what if we didn't get the whole story. The moment you look at the whole picture, the case collapses. I'm Amanda Knox, and in the new podcast, Doubt the case of Lucy Letby, we follow the evidence and hear from the people that lived it, to ask what really happened when the world decided who Lucy Lettby was.

No voicing of any skepticism or doubt. It'll cause so much harm at every single level of the British establishment of this is wrong. Listen to Doubt, the case of Lucy Lettby, on the case of Lucy Lettby, on the case. iHeartRadio app, Apple Podcasts, or wherever you get your podcasts. Welcome back, everyone. I've been chatting with Ben Goldfarb about his book, Crossings, how road ecology is shaping the future of our planet. Let's get back into things. It's definitely something where, like, on the surface, you're like, oh, roads. And then once you start to dig deeper and deeper, you realize the effects are it's not just roadkill, it's not just

pollution. It's like all of these different aspects. And it's something that science has not really been thinking about in a formalized way for very long, but the sentiment behind road ecology, or at least the recognition that roads have an impact on wildlife and ecosystems is much older than like the formalized field itself. Could you briefly take us through the history of road ecology from these early observations to this growing realization that, hey, roads have an incredibly substantial impact on ecosystems, and maybe we should do something about it. Yeah, absolutely. So, you know, really the history of road ecology, even though the term itself, you know, wasn't coined until the 1990s, really begins, you know, with the proliferation of the car, right? In the early 1900s, cars are just

suddenly everywhere. They're exploding all over the landscape. And, you know, it's funny we think about America is having such a kind of a love affair with the car. But, you know, when cars first became abundant in the early 20th century, you know, most people hated the car, right? This is this kind of terrifying new technology that's overtaking city streets and, you know, kicking out all the kids playing stickball and running over pedestrians, you know, pedestrian death rates in the early 1900s were just astronomical, even much higher than they are today. And, you know, today they're still pretty high. So there were actually all of these protests against cars, you know, mothers and children out in the street, you know, protesting this, this terrifying new machine

that was overrunning American life. And that's really the kind of the intellectual tradition that road ecology emerges from in some ways. You know, in the 1920s and 30s, all of these wildlife biologists say, you know, hey, cars are killing all of these humans and they're destroying the fabric of American society in some ways, what are they doing to wild animals? And so you've got all of these biologists driving around places like Iowa and Illinois counting dead ground squirrels and garter snakes and woodpeckers and all kinds of other creatures, you know, saying quite explicitly, hey, you know, these cars are, you know, the roads are already stained with human blood, as one of these biologists put it, you know, and they're also stained with the blood of wild animals. And they're also

stained with the blood of wild animals. So that's really where road ecology comes from is this broader societal concern about cars overtaking American life. I mean, the term itself wasn't coined until the 1990s when a landscape ecologist named Richard Foreman at Harvard came up with the idea of road ecology. And that's kind of a cool story, too. Richard was, he was in his office one day with a bunch of his students. and he was looking at this big picture of a forest.

And he was kind of expounding on all of the different features of this aerial photo. You know, here's where the water runs and here's, you know, where the animals live, and here's why the humans built their homes where they did. And suddenly he kind of looked at this road running right through the middle of the forest and said, you know, it's interesting. We know a lot about everything else in this picture ecologically. But we don't know much about that thing, that that, that, road because, again, I think that they're, you know, they are so abundant that we kind of take

them for granted or ignore them. And that was really the epiphany that led to this idea of road ecology in the 1990s was that, hey, these, you know, these structures are everywhere. We've got four million miles of road in the U.S. alone, 40 million miles around the world. What are they doing to our ecosystems? And that's really, you know, where the formalized study of road ecology emerged. As it turns out, the roads are doing a lot to ecosystems. And I think for most people, the first thing that comes to mind when asked about the impacts of roads on animals, or at least the first thing that came to mind for me, was roadkill,

which is a huge issue. But, you know, like we've kind of talked about, it's certainly not the only impact of roads. There's also noise pollution, other kinds of pollution. They create habitat for disease vectors. They cause erosion, fragment habitats, impede migration, allow access to forest for poaching or deforestation, and so many other things that you discuss in your book. And I won't ask you to go through each of these here, because that's what the book is for. But why is it important to consider this whole picture when asking how erode impacts wildlife? Yeah, it's a great question.

You know, and I think that, I mean, look, ultimately the answer is what you just said. there are just so many different connections and relationships. And a lot of them are really invisible to us in a lot of ways, right? You know, as you said, roadkill is I think the first thing that pops into people's mind when they think about the impacts of roads because roadkill is conspicuous. You know, we've all seen the dead white-tailed deer or a raccoon or a possum by the side of the highway, right? That's a very familiar sight to us. And I think we kind of blind ourselves to it in a lot of ways. But, you know, there's so many different ways. ways that roads affect nature that you can't really see. I often think about tire particles

as being a good example of this. You know, six million tons of tire particles enter the environment around the world every year, just an enormous amount of little plastic and rubbery bits bleeding from our vehicles and entering nature. And a couple of years ago, this big group of scientists in the state of Washington basically proved that it was these tire particles and specifically a chemical in them called 6pD, an ozone protection chemical, which nobody had ever heard of, that chemical in the tire particles was killing coho salmon in the Puget Sound watershed in just outside of Seattle in just enormous numbers, you know, that every year there were these big coho salmon die-offs, and that was all because of this obscure polysyllabic chemical that

nobody had ever heard of in tire particles, right? So that's just, you know, something that I think most, people never think about when it comes to the impacts of roads because you don't see it. You don't see all of those little microscopic tire particles entering nature. And unless you're actually walking along the stream, you don't see all of those dead fish. And yet, you know, this is this sort of biological apocalypse that's happening in some ways, at least, you know, in the watersheds that are affected. So, you know, I think that that's why it's important to consider the whole picture, as you put it,

because you've got the visible, conspicuous impacts like roadkill, but then you've got all of these other hidden, obscure impacts that really require dedicated scientific study to unravel. One of the ones that you mentioned in your book or discussed in your book was the impact of noise pollution and these soundscapes of roads. And I was hoping you could take us through the Phantom Road Study. Yeah, that's one of my favorite bits of road. ecological research and one of my favorite stories to tell in the book because I think it's so

revealing in so many ways. So, you know, noise pollution from roads, I think, is one of the biggest sort of unsung crises due to roads. Just, you know, I mean, first for human beings, right? We know that there's lots of scientific literature showing that, you know, road noise pollution is elevating our blood pressures and our heart rates and making us more susceptible to stroke and cardiac disease and diabetes. You know, road noise pollution is literally. literally taking years off of our lives. And it's having similar impacts on wildlife, right? I mean, really, road noise pollution is a form of habitat loss. You know, if you're a songbird who has to sing to attract a mate and, you know, your mate can't hear you over the rumble

of engines and tires, you know, you functionally can't live in that place, right? And so that was what this phantom road study that you mentioned was trying to get at is what is the impact of all of that road noise. So what these researchers, and I, Idaho did was they took a recording of traffic, and then they played the traffic recording through speakers in this roadless forest in Idaho. So you're, you know, you're stripping away all of the other variables, right? There's no physical road there. There's no traffic. All there is is just the noise of the traffic. And basically what they found was that many migrating songbirds avoided that area because they didn't like the road noise and that the songbirds who did stick around were in

worse body condition. They basically lost weight. And the reason for that is that if you're, if you're a little songbird, you know, you have to listen constantly for predators, right? You're at risk of being eaten all the time. And you have to, you know, keep an ear out for, you know, the flap of a hawk's wings or, you know, the rustle of a fox creeping through the brush. But, you know, if you can't hear those subtle acoustic signals over the noise of traffic, you have to look out for predators instead. And every minute that you're looking around for, you know, hawks and foxes is a minute that you're not feeding, right? So you're not gaining as much calories and you're not as fit to complete your migration. So that was what that Phantom Road study really showed,

is that, you know, even the noise of traffic without the vehicles themselves is hugely detrimental to many, many species. Was that the study that used the noise recording from going to the Sun Road? Yeah, it was. I think that's, I'm really glad to you mentioned that, Eric, because I think that's a really important piece of this research, right, is that as, you know, as you say, the noise of traffic that they were using, you know, it wasn't a recording from, you know, Broadway in New York City or, you know, I-90, a giant interstate highway, right? It was, as you said, it was going to the Sun Road, which is kind of the main road in Glacier National Park, a protected area, right? And yet, you know, even our protected areas, our national parks have lots of traffic. running through them. So, you know, if animals aren't safe from road noise pollution in a national park, you know, where are they, where are they safe? I think that that really goes to show just how pervasive and widespread this problem is. Yeah, that really blew me away. It was sort of like this, the punchline at the end was like, and I've been on going to the Sun Road and I would absolutely describe it as like a beautiful, slow, scenic byway where everyone's stopping for, you know,

looking at mountain goats and it's wonderful. But at the same time, to see the impact or to learn of the impact of that road was huge. And there's another point you brought up about the difference in like electric vehicles versus, you know, gas vehicles, gas powered vehicles, and how at a certain point, there's really no difference between them or the difference goes away because of just the sound of tires on the road. And it was just like, what can we do about this? Yeah.

Yeah. I think that's a great point because people always say, well, you know, isn't this problem going to go away once, you know, the entire fleet of vehicles in this country is electrified. And, I mean, as you say, you know, the answer is really no, because once you get to 35 miles an hour or so, you know, the primary source of noise from cars is not the engine. It's, it's the tires. You know, so when you hear like the hits of a highway off in the distance, you know, what you're hearing is almost entirely tire noise. And, you know, and tires have actually gotten quieter over time, which is, you know, which is definitely a good thing.

But, you know, it's impossible to make them silent, right? So, you know, it's true that electrifying our vehicle fleet is not going to solve the problem of noise pollution, at least not in wild areas. I think it will be helpful in cities, you know, where the traffic is generally going at lower speeds. And, you know, road noise pollution is a big problem for human health. You know, I do think that electrification will help to some extent in urban areas. but, you know, for wildlife in rural places where, you know, the roads are mostly highways rather than, you know, little urban streets, yeah, I don't think that electrification is going to do a whole lot.

Let's take another quick break here. We'll be back before you know it. Anyone who works long hours knows the routine. Wash, sanitize, repeat. By the end of the day, your hands feel like they've been through something. That's why O'Keeffe's working hands hand cream is such a relief. It's a concentrated hand cream that is specifically designed to relieve extremely dry, cracked hands caused by constant hand washing and harsh conditions.

Working hands creates a protective layer on the skin that locks in moisture. It's non-greasy, unscented, and absorbs quickly. A little goes a long way. Moisturization that lasts up to 48 hours. It's made for people whose hands take a beating at work, from health care and food service to salon, lab, and caregiving environments. It's been relied on for decades. by people who wash their hands constantly or work in harsh conditions because it actually works.

O'Keefs is my hand cream of choice in these dry Colorado winters when it feels like my skin is always on the verge of cracking. It keeps them soft and smooth, no matter how harsh it is outside. We're offering our listeners 15% off their first order of O'Keefs. Just visit O'Keef's company.com slash this podcast and code this podcast at checkout. In 2023, a story gripped the UK, evoking horror and disbelief. A nurse who should have been in charge of caring for tiny babies is now the most prolific child killer in modern British history. Everyone thought they knew how it ended.

A verdict, a villain, a nurse named Lucy Leppie. Lucy Letby has been found guilty. But what if we didn't get the whole story? The moment you look at the whole picture, the case collapses. I'm Amanda Knox, and in the new podcast, Doubt the case of Lucy Lettby, we follow the evidence and hear from the people that lived in, to ask what really happened when the world decided who Lucy Lettby was. No voicing of any skepticism or doubt.

It'll cause so much harm at every single level of the British establishment of this is wrong. Listen to Doubt, the case of Lucy Lettby on the Iheart Radio app, Apple Podcasts, or wherever you get your podcasts. I'm Clayton Eckerd, and in 2022, I was the lead of ABC's The Bachelor. Unfortunately, it didn't go according to plan. He became the first Bachelor to ever have his final rose rejected. The internet turned on him. If I could press a button and rewind it all I would.

But what happened to Clayton after the show made even bigger headlines. It began as a one-night stand and ended in a courtroom, with Clayton at the center of a very strange paternity scandal. The media is here. This case has gone viral. The dating contract. Agree to date me, but I'm also suing you. Please search for it.

This is unlike anything I've ever seen before. I'm Stephanie Young. This is Love Trapped. This season, an epic battle of He Said She Said, and the search for accountability in a sea of lies. Listen to Love Trapped on the IHeart Radio app, Apple Podcasts or wherever you get your podcasts. Welcome back, everyone.

I'm here chatting with Ben Goldfarb about his book Crossings. Let's get into some more questions. I definitely want to touch on the human health stuff in a bit, but first, and I could also talk about noise pollution like all day, but I do want to get into a few of the other impacts of roads on ecosystems and wildlife. And one of the ones that you discuss in your book is, how roads turn the landscape into fragments, essentially these islands. What does that fragmentation mean for the large carnivores, such as the mountain lion P-22,

whose home ranges are quite big, bigger than these islands that have been created from these roads? Yeah, it's such a good and difficult question to address. So I think the first thing that you have to remember is that, you know, road kill. is really, as we've been talking about, just the tip of the iceberg here, right, when it comes to how roads and traffic affect nature. And, you know, I think in many cases, a bigger problem than roadkill is this barrier effect, right? There's, you know, so many busy highways have so much traffic that animals don't even attempt to cross, right? So they're not being killed by cars. They're just, as you say, you know, kind of trapped in these little islands of habitat surrounded by this, you know, these oceans of kind of impassable highways. And that's almost a bigger problem than roadkill itself, right? There are, you know, some terrible stories that I encountered and tell in this book of, you know, of herds of deer and elk and antelope and other species that have actually starved en masse because they can't cross the highway to access, you know, the really good habitat, right? So, you know, again, they're not being hit by cars. They're just being prevented from moving around the landscape.

And, you know, large carnivores, as you said, Aaron, are sort of the, some of the postings. species for this problem because, you know, they're animals that range widely. So, you know, it's very easy for their habitat to be fragmented by roads. And they tend to be, you know, somewhat wary of humans and traffic. So they don't, you know, they don't cross very readily. And, you know, those mountain lions that you mentioned in Southern California outside of Los Angeles are a really good example of this. So the situation there is that there's this little population of mountain lions that live in the Santa Monica Mountains, and they're surrounded by some of the busiest freeways on Earth. You know, you've got the 101 and the 405 and these other super highways, you know, 10 lanes

of traffic conveying hundreds of thousands of cars every day. And it's, you know, all but impossible for these animals to cross those highways. So as a result, you know, there's this little cluster of mountain lions and they can't leave their little island of habitat. And no. And no. No new mountain lions can enter the little island of habitat from other areas. So, you know, this little cluster is basically stuck, you know, breeding with each other, right? And, you know, there have been stories of male mountain lions who have mated with their own daughters and granddaughters and even great-granddaughters because they just can't find unrelated mates on this little island. And as a result, the populations become very inbred over time. They're starting to suffer genetic defects.

They've entered what scientists call an extinction vortex, this kind of long-term doom spiral, if nothing is done to help them. But, you know, fortunately, something is being done to help them. You know, at the start of our conversation, I was talking about, you know, these wildlife bridges that allow animals to cross highway safely. And, you know, right now there's a very large and famous bridge being built over the 101 that will theoretically connect those mountain lions and the Santa Monica Mountains with Mountie Mountains with Mountie. lions elsewhere in California. So the problem is being addressed, you know, and this big bridge will be completed by 2025. And, you know, the hope is that the animals use it. And there's enough kind of connectivity there that, you know, new mountain lions can enter the population and kind of refresh that stagnant gene pool. Many of these road ecology conservation projects have been

focused on charismatic megafauna like bears and cats. And I, you know, I love charismatic megafauna too. But for the most part, a lot of these projects have overlooked these more abundant species like reptiles and amphibians that are much more likely to be struck and killed by vehicles. What population level impacts have we seen with some of these species? And this part I found really interesting that you discussed was how death by roadkill differs from death in nature. Yeah. Yeah, you know, I think you're exactly right that those, you know, those reptiles and amphibians, we haven't really done much to help them. And, you know, I think the reason for that is that, look, you know, we, I think understandably tend to be focused on preventing roadkill with large animals like deer and elk and moose that will, you know, mess you up when you hit them, right? Nobody wants to hit a big critter. That's how you, you know, total your car. And actually, hundreds of drivers die every year. And, and, you know, you know, collisions with large animals, right? So transportation departments, you know, are focused on preventing those dangerous crashes with the big critters. But, you know, nobody's ever totaled their car

hitting a wood frog, right? So, you know, so we, we kind of ignore, I think, those smaller animals in many cases, which is problematic because, you know, as you say, there are these enormous population-level impacts on those reptiles and amphibians. You know, these are animals that are incredibly susceptible to roadkill, in part because, you know, the amphibians especially are, they're migratory, right? You know, on those warm, wet spring nights, you know, you've got in some places thousands of frogs and toads and salamanders all migrating from kind of the upland forests down to their breeding ponds to mate. And, you know, the issue is that we tend to build our roads in the low-lying places where it's easy to construct roads. And those are also the places

where, you know, the water collects and the amphibians go to breed, right? So so many, there are so many populations of amphibians out there that have been just totally demolished by roadkill because, you know, they're, look, they're all on the march at night. You know, they're not the brightest animals. They're not very responsive to traffic. You know, they're all crossing the road at once. And, you know, even a few cars can basically kill dozens or hundreds of these poor, small animals that drivers don't really see. And, you know, I think that your question about how, you know, death by roadkill kind of differs from death in nature is a really good one. And it, you know, definitely applies to these, you know, these frogs and salamanders because, you know,

you think about in nature, right, generally predators are taking out the, you know, the sick, the old, the weak, you know, kind of the most susceptible, vulnerable members of the population. whereas cars don't discriminate like that, right? They're just going to crush everything in their path, including those old, big, fertile females that frog and salamander populations really need to survive. So the strongest and most reproductively important members of the population are being killed by cars in a way they aren't being killed by natural predators.

And so, you know, there aren't just lots of amphibians getting hit. You know, it's the very individuals within the population that they need that are getting crushed. So I think that's a big part of why, you know, why roads and traffic are so pernicious. That chapter where you talked about these more abundant species, reptiles and amphibians, is filled with, you know, these really sad stories of dozens or hundreds of animals being killed by cars in one night. But it's also filled with this amazing imagery of people carrying frogs in buckets or toads in buckets or these toad tunnels or frog tunnels. I can't remember which is which,

but just these incredible creative solutions that people have come up with for getting these amphibians and reptiles safely to their destination. Yeah, that was one of my favorite experiences working on the book was going to Portland, Oregon, where there's actually a frog shuttle. There's this little cohort of volunteers

who go out on these warm, wet nights when northern red-legged frogs migrate in Portland and they're all moving from, you know, this big patch of forest down to a wetland. And unfortunately, you know, you've got Highway 30 right in the middle of those two habitats. So it's kind of a classic problem. And so, you know, I spent a night with these guys, you know, just walking along the roadside, along this kind of fence they had set up, looking for frogs that had hopped up against the fence and were, you know, sort of waiting for a ride.

And then we would pick them up, put them in the buckets, and, you know, drive them from point, A to point B, so they wouldn't have to face traffic. So, you know, that kind of thing is, it's wonderful. It's super heartwarming. In this case, it's definitely prevented that population from going extinct, which, you know, which might have happened otherwise. But it's also an imperfect solution, right? And that would be a place where, you know, ideally, I think you'd see some kind of wildlife crossing structure, right, an underpass probably that would allow those animals to cross the road safely without humans having to intervene. But, you know, again, the problem is that, you know, it's easy to convince a transportation department to, you know, build an underpass for deer

because that underpass will, you know, prevent dozens of crashes and probably save human lives. You know, it's harder to convince a government agency to spend a couple million dollars on a frog crossing, right? Absolutely. You point out that it's awful to see so much roadkill, but at the same time, its absence can be equally disturbing. Can you talk about that in the context of insects and the quote-unquote windshield phenomenon? Yeah, certainly. So, you know, I mean, if that's the thing about roadkill, as you pointed out, right, is that, yes, it's this terrible form of death and, you know, biodiversity decline,

but it's also an indicator, right? When, you know, when species are abundant, you know, we tend to hit a lot of them on the road, right? That's why you see a lot of white-tailed deer and gray squirrels and raccoons, right? common creatures that crossroads a lot and unfortunately get hit. So, you know, when all of a sudden you stop seeing roadkill, that can be, you know, a troubling sign that a once abundant species is no longer quite so abundant, right? And, you know, in the context of the windshield phenomenon, you know, that's what we're seeing with insects, right? And this is this, you know, widely observed, you know, somewhat anecdotal. But I think increasingly there's, you know, there's peer-reviewed

research demonstrating this is true, which is basically the idea that it used to be that when we would drive around our roads, especially in rural areas, we would hit a lot of insects, right? And your windshield would be totally smudged with, you know, dead bees and wasps and flying ants and beetles and all kinds of critters, right? All of those insects. And that was obviously sad. but it also indicated that there were a lot of insects flying around for us to hit. And now what many, many people all over the world have observed is that we don't hit as many insects as we used to. You go on a long road trip and you don't have to squeegee off the windshield at the end of it because you just haven't been hitting all of those bugs. And that's a really

troubling sign. It suggests that maybe there aren't as many insects out there to be hit. So, you know, it's that sort of thing that, I mean, the roadkill is, yes, it's this tragedy. It is this form of biodiversity decline and collapse for some species. But, you know, it's also this indicator phenomenon that tells you a lot about the natural world. And, you know, in this case, it's telling us that our insect populations are probably collapsing. So we've touched on a lot of the ways that roads have negatively impacted animals and ecosystems. but one area that I found really fascinating that you explored in your book was how roads can create habitats or resources. Can you tell me about the necrobium?

Yeah, definitely. I think that's an important point, right, is that roads, yes, they destroy ecosystems, but they're also ecosystems in their own right, in a sense, that there are just so many of them that they're kind of this landscape type that many species have learned to take it advantage of. And, you know, one really good example of that, you know, are scavengers, right? You know, you've got crows and magpies and ravens and bald eagles and golden eagles and coyotes and vultures, you know, all of these different species that eat carrion and have learned to eat roadkill, you know, and that's what the necrobion is, right? That's sort of a wonderful, relatively novel ecological term for this whole community of animals and, you know, and plants

and fungi and other organisms that have kind of learned to take advantage of carcasses, of, you know, of dead animals, which are these kind of amazing resources in their own right. And, you know, the roadside is this very rich and abundant necrobium, right? There's lots that, unfortunately, there are lots of dead animals out there, but, you know, They're also resources. The problem is that they're dangerous resources, right? You could imagine, you know, if you're a bald eagle and you sit down on a dead deer and, you know, fill your belly with venison, well, you know, you're a couple pounds heavier at the end and it's harder to achieve liftoff. So when you take off, you know, you're at risk of being hit by, you know, the oncoming 18 wheeler yourself, right?

So, you know, the road, yes, it is this ecosystem. It's, you know, it's this resource potentially for scavengers, but it's also a really dangerous resource. And there's a risk of, you know, creating a kind of an ecological trap, this situation where you lure animals in with the promise of food and then you kill them. So, you know, what some researchers, like a guy named Steve Slater with a group called Hawkwatch have proposed is that, you know, we could go around taking these carcasses, this roadkill, and dragging those carcasses away from the shoulder, you know, and if you just pull them 40 feet off the road,

then, you know, all of these animals that really depend on roadkill now can kind of eat their fill safely without getting hit themselves. So that's kind of a cool way that you could, you know, you can take these, you can take this necrobium, take these carcasses and, you know, make them a really safe and productive resource for especially Golden Eagles, you know, a species that really has come to depend on roadkill. It's amazing how many different approaches you could or should take when it comes to roads and protecting wildlife. And part of that is because, or the main reason, is because the effects of roads on wildlife is context dependent. It depends on where the road is, how traveled it is, which animal species you're studying or plant species or fungal species. It depends on other factors. and it makes it challenging, if not impossible, to create a one-size-fits-all solution for rows.

And you touched on this a bit in terms of, you know, how a lot of places will prioritize these charismatic megafauna or just like larger animals or animals that are more risky to humans if a car hits one of them. But how can we prioritize these different features of road design to have as little impact on an ecosystem as possible. Yeah, it's, you know, it's such an important question, especially given that we're entering what scientists have called the infrastructure tsunami, this kind of wave of new construction around the world, right? And, you know, and here in the U.S., you know, our highway network is mostly built already, right? We're not really building a lot of giant

new interstates or anything like that. But, you know, other countries like Nepal and Myanmar and Kenya and Brazil, you know, they're building major new highways right now. And, and, you know, of course, those highways are, you know, they're important for human flourishing in a lot of ways, right? You know, infrastructure and roads, you know, they're how we get to schools and hospitals. And that's how farmers get their goods to market and so on, right? There are lots of human benefits of, you know, of kind of this infrastructural connectivity. And, you know, I think it would be incredibly unjust to, you know, prevent other countries from building. roads as we have. But, you know, we also need, as you say, to kind of encourage those design techniques

that don't destroy nature, right? Because we know that, you know, these countries like Nepal and Myanmar and Brazil are incredibly biodiverse and that, you know, this new construction is hugely dangerous and risky for tigers and elephants and gorillas and, you know, giant ant eaters. I mean, you know, name a species of charismatic megafauna and, you know, new infrastructure is one of the the primary threats to its survival. So, you know, I think that the most important thing we can do is just avoid those critical habitats, right? You know, as, look, when we, when we built, you know, the interstate highways here in the United States, you know, we just plowed them through every ecosystem we came upon, right? We, you know, we cleaved old growth forests and wetlands and,

you know, deserts and all kinds of other systems that, you know, are so important for biodiversity. And, you know, I think it's, I think it's crucial that, you know, other countries don't make the same mistake. You know, I think that's the kind of the first, sort of the first step in road building now is just how do we spare those really crucial habitats that are going to be essential for, you know, for the survival of wildlife. And I think that really starts with data, right? You can't, you know, you can't protect habitats unless you know where the wildlife lives. And, you know, there are so many wonderful road ecologists and wildlife biologists in, you know, in all of those countries, many of whom I met while working on this book, who are doing exactly that, you know, who are putting satellite collars on, you know, on tigers and ant eaters and other other critters just trying to figure out, you know, where are the critical habitat areas, where are the movement corridors that these animals are transiting through. And how can we avoid building roads, you know, in the places that are going to be most catastrophic. for wildlife. There are some amazing innovative design features that you discuss in your book in terms of like looking ahead to the future as we construct roads, as we incentivize the incorporation of

wildlife protective design. But in the U.S., you know, when we already have, for instance, all of these roads, especially, you know, like the Forest Service roads that go through miles and miles and miles of already biodiverse habitat. What has worked in terms of taking these existing road structures and then incorporating different features like, you know, I know that in your book, I think you mentioned that the signs warning humans about wildlife don't really seem to work. Animals get used to the reflectors that warn them away from roads. What has worked? You know, what are some of the design features that have worked well with existing? road structures.

Yeah, you know, I think it really does come down to building more of these wildlife crossing structures, you know, giving animals an opportunity to cross the road safely. And, you know, the design of those structures really depends on the species you're trying to help, right? You know, look, every organism has its own ecological niche, you know, its own habitat requirements, you know, its own sort of sensory experience of the world. And you have to think about that, you know, when you, when you, when you, build these structures. You know, one really good example of that is in Wyoming, you know,

which is a very good state when it comes to this sort of thing. They've built lots of these crossings. And, you know, what they've found out is that, is that, you know, mule deer will very happily go through underpasses and, you know, box culverts and other structures that go under the road, whereas other species like pronghorn, antelope, you know, really have to go over the highway, right? And that's because antelope, you know, they have an ink, incredible vision. They're amazingly far-sighted. They're also the fastest terrestrial animal in North America. They're just incredibly good runners. So, you know, that's an organism. They don't want to be in a, you know, a tight little culvert. You know, they want to be out on top of a bridge

where they can see their surroundings for, you know, for many miles in every direction and, you know, be able to run away from predators if they have to, right? So you really have to think about, you know, the organism that you're trying to help, you know, when when you build these structures. But, you know, I think a really important point about these crossings is that, you know, they're good for humans as well, right? And that's a big part of, you know, why you see so many being built around the world now is that, you know, there's lots of data basically showing that, you know, even a, you know, a $5 million overpass, you know, prevents enough of these dangerous, expensive crashes involving wildlife to, you know, to pay for its own costs over

time. So, you know, I think, I think that that's one of the things that's really, you know, catalyzing a lot of the interest in, you know, in these crossings is, yes, they're, you know, they're good conservation tools. You know, there's lots of data and evidence showing that they work. But, you know, they're also really good for human safety and, you know, for our own, our own bottom line. So I think that's, you know, when I think about the future of, you know, of roads and wildlife, you know, I think it's going to involve a lot more of these crossings, you know, built with more ecological sensitivity, thinking, you know, differently about the kinds of organisms we're trying to help and what it will take to help them. And, you know, that's,

that's really the best tool we have at our disposal to help mitigate this problem. Most of your book focuses on the impact of roads on ecosystems, but you also bring up in one of my favorite chapters how roads impact humans as well and how those impacts are disproportionately distributed across lines of race and class in the U.S. What are some of the health effects of living near roads and how is this discrimination literally built into the way that cities were planned? Yeah, it's such an important issue and, you know, one that I really try to explore in the book. So look, I mean, the health impacts of roads on humans are vast, right?

We've talked about noise pollution, which is, you know, literally taking years off of our lives. You know, you've got, of course, air pollution, which is a huge problem. You've got, you know, obviously pedestrian death, you know, which is a gigantic issue in the U.S. and is actually becoming more of a problem. You know, for many, many years, pedestrian fatalities due to cars were declining. And, you know, in the last decade or so, you know, they've really been on the rise for, you know, for reasons that are kind of complex and hard to figure out. So you've got all these different problems.

You know, we think about roads and cars, I think, as being, you know, these fundamentally positive things. And, you know, we tend to associate them with, you know, human mobility and freedom. And yet they're really, you know, curtailing our lives. all kinds of different ways. So, you know, roads are affecting us, just as they're affecting wild animals, but they're obviously not affecting all of us equally, right? I think that's a really important point as well, because, you know, so many roads in urban areas were built in ways that deliberately targeted communities of color. You know, in the middle of the 20th century, as the interstate highways were being built, you know, all of these, quote unquote, urban reformers,

you know, basically wanted to get rid of all of the communities of color. And so, you know, that they considered undesirable. And, you know, these new freeways that were being built were the way they could accomplish that. You know, so in, I mean, practically every American city, you know, from Minneapolis to Miami to Los Angeles, to Memphis, to New York City, you know, roads were built in ways that basically wiped out or displaced communities of color very, very intentionally. And as a result, you know, today, those communities still experience the legacy of those problems. We know that people of color are much more susceptible to asthma and, you know, cancers associated with air pollution and other problems that roads create. And, you know, and these urban freeways have really been tools of long-term segregation. You know, you just think about how a giant viaduct running through the middle of a city kind of cleaves the city in half and effectively destroys the connectivity of that city, just as it destroys the connectivity of a mountain.

mountain lion population. So, you know, I think that's a really important point to bear in mind is that, you know, roads and these giant highways that were built in the middle of the 20th century, you know, they kind of inadvertently fragmented natural ecosystems, but, you know, I think they very deliberately fragmented human communities and urban ecosystems. And we're still living with the consequences of that kind of racist and catastrophic planning. In the first few months of the COVID pandemic, the world shut down, right? We experienced a remarkable cessation of human activity across the board. People stayed at home.

People didn't drive their cars. Shipping slowed. Air travel declined. It was a very drastic, very dramatic change. What did this anthropos show us about restoring ecosystem health? Yeah. You know, it's, well, first of all, it was really the, you know, the kind of the greatest, or at least biggest inadvertent experiment in history of road ecology, right? I mean, what happens when you, you know, shut down traffic for a few months? Well, animals respond in all kinds of ways, right? We saw much more, we saw many more creatures moving into urban areas, you know, mountain lions, you know, walking down the street, you know, in some California cities, for example. Obviously, roadkill rates, dramatically declined for all kinds of species.

You know, there's basically, there's one study in Maine showing that, you know, twice as many frogs and salamanders survived their spring migration because, you know, there were no cars to hit them, right? So we know that this was, you know, an enormous benefit to wildlife as disastrous as it was, of course, for us humans. One of my favorite studies that I think, you know, reveals a lot about, you know, just how dramatically we've affected animals' lives with our roads and traffic was done on white crown sparrows in the Bay Area around San Francisco. And basically what these researchers

showed is that they recorded the songs of white crown sparrows, these birds who like so many songbirds, of course, sing to attract mates. And what they found was that without the noise of traffic around, you know, these male sparrows were able to sing much more intricate, complex songs, right? Because, you know, for years, they'd been basically screaming to be heard over the, you know, the noise of traffic. And when you have to, you know, scream all the time, you can't really sing a great song, right? But, you know, without, without all of that kind of low-frequency rumble of traffic masking their song, you know, they're able to, again, sing these much more elaborate songs that kind of veered into lower registers. They were able to express sort of the

full complexity of their vocal range in a really interesting way. So to me, what that shows is that, you know, look, we've done so much, obviously, to harm animals with roads and traffic, and yet, you know, we haven't destroyed them, right? They're still, you know, living amongst us just sort of waiting for their opportunity to flourish again. And, and, and, and, you know, and, you know, And obviously, you know, we'd never, you know, wish another pandemic or, you know, total cessation of human movement upon anyone. That was, you know, that was obviously a horrific couple of years. And it's, you know, still ongoing in a lot of ways. And yet, you know, if we can figure out ways to more deliberately pull back traffic, you know, whether that means potentially closing some roads seasonally to accommodate wildlife or, you know,

removing some roads from the landscape as, you know, the Forest Service is doing in many places. You know, these animals are, they're still around, they're still amongst us, just, you know, waiting for their chance to thrive. Ben, thank you so much for such a wonderful conversation. You know, one of the things that I absolutely love about this podcast is how it has exposed me to new ideas or concepts that sometimes completely change the way that I see the world. Like how now I let my dog sniff to his heart's content or his nose's content on our dog walks, thanks to Ed Yong and his book An Immense World. Or how I will never drive or walk along a road or especially scenic highway and not think about how that road has changed the life around it.

And if you want to learn more and have your road view challenged, check out our website, this podcast will kill you.com, where I'll post a link to where you can. can find crossings as well as a link to Ben's website. And don't forget, you can check out our website for all sorts of other cool things, including but not limited to transcripts, quarantini and placebo-rida recipes, show notes and references for all of our episodes, links to merch, our bookshop.org affiliate account, our goodreads list, a firsthand account form, and music by Bloodmobile. Speaking of which, thank you to Bloodmobile for providing the music for this episode and

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