Special Episode: Ben Goldfarb & Crossings

00:00:44
Speaker 1: Hi, I'm Aaron Welsh and this is this podcast Will Kill You. Welcome, one and all to the t p w k Y Book Club, where we get to read the most fascinating books in science and medicine and then bombard the authors 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 dot com, where you can find a link under extras to our bookshop dot 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 planets. 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 field work times happened along that road. Going for a run along the road at dusk with Mottmot's calling and Coates, 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 bugsplatter 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?

00:05:48
Speaker 2: Yeah, Eron, First of all, thanks for having me, and thanks for that kind of profound philosophical question. It's a really interesting one. I know, I think that I think that for the purposes of this book, you know, I was really defining a road as you know, a 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 as you mentioned, would not be a road. But it is you know, kind of a fascinating issue because there are definitely wagon trails for example, you know, I mean these super wide, you know, often paved structures that were constructed and you know in the eighteen hundreds 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.

00:06:46
Speaker 1: Exactly. All right, what is a road check? That got that answered?

00:06:53
Speaker 2: Now?

00:06:54
Speaker 1: What is road ecology? And how did you decide that you wanted to write a book about this field?

00:07:00
Speaker 2: So road ecology is the field of science that looks at all of the different ways that roads and other 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, but everything from roadkill to the you know, the impacts of road noise pollution to all of the roads, salt that we add as a de icing chemical, and you know, 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, you know, kind of emergent field of science that just examines the effects of our infrastructure on the on the natural world.

00:07:50
Speaker 1: 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.

00:08:04
Speaker 2: Yeah, it's good. It's a good question. You know, my interest in the field really goes back more than a decade to twenty thirteen. 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 ninety three north of Missoula, to allow animals like grizzly bears and elk and moose and bobcats to cross this this really busy highway. And you know, I hadn't really thought much about roads before then. You know, they're just there's 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 signifigant source of ecological change those roads are, and also how cool and inspiring it 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 is really that experience of standing up on that wildlife overpass, you know, watching traffic kind of flow beneath our feet. That was what got me thinking about this issue and eventually turned into the book.

00:09:33
Speaker 1: Let's take a quick break and when we get back, there's still so much more to discuss Welcome back everyone. I've been chatting with Ben Goldfarb about his book Crossings. 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, you know, roads have an incredibly substantial impact on ecosystems and maybe we should do something about it.

00:10:56
Speaker 2: Yeah. Absolutely, So, you know, really the history of road ecology, know, the term itself, you know, wasn't coined until the nineteen nineties, really begins, you know, with the proliferation of the car, right you know, in the early nineteen hundreds. Cars are just suddenly everywhere. They're exploding all over the landscape. And you know, it's funny we think about America as having such a kind of a love affair with the car, but you know, when when cars first became abundant in the early twentieth 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 nineteen hundreds were just astronomical, even much higher than they are today, and you know today they're still pretty high. So there were actually these 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 roadyology emerges from. In some ways. You know, in the nineteen twenties and thirties, all of these wildlife biologists say, you know, hey, cars are killing all of these humans, and they're 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 were 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. So that's really where rody ecology comes from, is this broader societal concern about about cars overtaking American life. The term itself wasn't coined until the nineteen nineties 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. You know. 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, why they where they did, and suddenly he kind of looked at this, 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 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 in the nineteen nineties, was that hey, these you know, these structures are everywhere. We've got four million miles of road in the US alone, forty million miles around the world. What are they doing to our ecosystems? And that's really you know, where the formalized study of rood ecology emerged.

00:14:04
Speaker 1: 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, you know, 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 forests 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 a road impacts wildlife?

00:14:54
Speaker 2: Yeah, it's a great question, you know, and I think that I mean, look, ultimately, the answer is what you just said. You know, there were just so much any 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 tail deer or a raccoon or apossum by the side of the highway. Right, That's a very familiar site 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 that roads affect nature that you can't really see. You know, 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 six PPD and an ozone protection chemical which nobody had ever heard of. That chemical in the tire particles was killing cohost salmon in the Puget Sound Watershed, and it's 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 you know, 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 you know, the visible, conspicuous impacts like roadkill, but then you've got all of these other hidden, obscure impacts that really require, you know, dedicated scientific study to unravel.

00:17:06
Speaker 1: 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.

00:17:20
Speaker 2: Yeah, that's one of 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 taking years off of our lives, and it's having similar impacts on wildlife. Right. I 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 in Idaho did was they took a recording of traffic and 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 know, 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 you're not gaining as much calories and you're not as fit to complete your 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.

00:19:45
Speaker 1: Was that the study that used the noise recording from Going to the Sun Road.

00:19:51
Speaker 2: Yeah, it was. And I think that's I'm really glad you mentioned that, Eric, because I think that's a really important piece of this this research, right, is that as you know, as you say, the no 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 ninety 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 are 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.

00:20:33
Speaker 1: Yeah, that that really blew me away. It was sort of like this. The punchline at the end was like and 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 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?

00:21:17
Speaker 2: Yeah? Yeah, I think that's a 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 thirty five 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 hiss 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 that electrifying our vehicle fleet is not going to solve the problem of noise pollution, at least not in wild areas. I think 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 think, I do think that that electrification will 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 the electrification is going to do a whole lot.

00:22:31
Speaker 1: Let's take another quick break here. We'll be back before you know it. 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 I could also talk about noise pollution like all day, but I do want to. I want to get into a few of the other impacts of roads on ecosystems and wildlife, and one of the ones that you discussed 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. Twenty two, whose home ranges are quite big, bigger than these islands that have been created from these roads.

00:23:33
Speaker 2: Yeah. Yeah, it's such a good and difficult question to address. So, you know, I think the first thing that you have to remember is that, you know, roadkill is really, as we've been talking about, just just the tip of the iceberg here, right when it comes to how roads and traffic effect 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 highway 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 that's almost a bigger problem than roadkill itself, right there. You know, some 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 mass 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 the some of the poster species for this problem because you know, they're animals that range widely, so you know, it's it's very easy for their habitat to be fragmented by roads, and they tend to be, you know, somewhat wary of humans and traffics. They don't you know, they don't cross very readily. Uh. 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 one oh one and the four oh five and these other super highways. You know, ten 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 those highways. So as a result, you know, there's this little cluster of mountain lions and they can't they can't leave their little island of habitat, and no new mountain lions can enter the little island of habitat from other areas. So you know, these 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 mate it with their own daughters and granddaughters and even great grand daughter 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 and 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 one oh one that will theoretically connect those those mountain lions and the Santa Monica Mountains with mountain lions elsewhere in California. So the problem is being addressed, you know, in this big bridge. This will be completed by twenty twenty five, 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.

00:27:01
Speaker 1: 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.

00:27:39
Speaker 2: Yeah. Yeah, you know, I think 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, see 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 in collisions with large animals, right, So transportation departments, you know, are focused on preventing those dangerous crashes with with the big critters. But you know, nobody's ever totaled their car hitting a wood frog, right, so you know, so we kind of ignore I think those 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 their their 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 look, they're 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 can basically kill dozens or hundreds of these these you know, poor small animals that drivers don't really see. And you know, I think that you're your question about how you know death by roadkill kind of differs from death in nature is it 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 you know, those 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, these these 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.

00:30:40
Speaker 1: 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 and buckets or toads and 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 forgetting these these amphibians and reptiles safely to their destination.

00:31:11
Speaker 2: Yeah, that was That was one of my favorite experiences working on the book. Was was going to Portland, Oregon, where there's actually there's a frog shuttle. There's this little cohort of volunteers who go out, you know, on these warm, wet nights when northern red legged frogs migrate in Portland and they're all moving from uh, you know, this big patch of forest down to a wetland and unfortunately, you know, you've got Highway thirty right in the middle of of of those two habitats. So it's kind of a classic problem. And so you know, I spent a night with these guys, uh you know, just walking along the roadside along this kind of fence they had set up looking for frogs that had that had hopped up against the fence and we're 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 that kind of thing is it's it's wonderful, it's super heartwarming. Uh you know, in this case, it's definitely prevented that population from going extinct, which you know, which might have happened to other 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.

00:32:48
Speaker 1: Absolutely, you point out that it's awful to see so much roadkill, but at the same time, it's absence can be equally disturbing. Can you talk about that in the context of incts and the quote unquote windshield phenomenon.

00:33:04
Speaker 2: Yeah, certainly, so, you know that. I mean, that's the thing about about roadkill is, 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 tail deer and gray squirrels and raccoons, right, common creatures that cross roads a lot and unfortunately get hit. So you know, when 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 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 you know, it used to be that when we would drive aroun around you know, our roads, especially in rural areas you know, are we would hit a lot of insects, right and your you know, 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, all of those insects, and that was obviously sad, but you know, it also indicated that there were a lot of insects flying around for us to hit. And you know, now what many, many people all over the world have observed is that we don't hit as many insects as we used to do. You know, you you go on a long road trip and you know you don't have to squeegeye off the windshield at the end of it because you just haven't, you know, been hitting all of those bugs. And that's a really troubling sign, right, It suggests that maybe there there aren't as many insects out there to be hit. So you know, it's 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.

00:35:08
Speaker 1: So we've 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 necrobiome?

00:35:28
Speaker 2: Yeah, definitely, you know, and I think that's an important point, right, is that is that roads, Yes, they destroy ecosystems, but they are also ecosystems in their own right in a sense that there are just so many of them that they're you know, kind of this landscape type that you know, that that many species have learned to take 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 that eat carrion and have learned to eat roadkill. Uh, you know, and and that and that's what the necrobiome is, right. That's that's sort of a wonderful, relatively novel ecological term for this whole community of animals. Uh. And you know, and and plants and and uh and fungi and other other organisms that have kind of learned to take advantage of of carcasses of you know, of dead animals, which are these these kind of amazing resources in their own right. Uh. And you know the roadside is this very rich and abundant necro biome. Right, there's lots of Unfortunately, there are lots of dead animals out there, but you know they're also resources. The problem is that they're they're dangerous resources. Right. You could imagine, you know, if you're a bald eagle, uh, you know, and you sit down on a dead deer, uh, and you know fill your belly with venison. Well, you know, you're a couple pounds heavier at the end, and it's it's harder to achieve liftoff. So when you take off, you know, you're at risk of being hit by a you know, the oncoming eighteen wheeler yourself, right, So you know the road, Yes, it is this ecosystem, it's 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 hawk Watch 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 forty feet off the road, then you know, all of these 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 necrobiome, 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.

00:38:03
Speaker 1: 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 roads. And you touched on this a bit in terms of, you know, how a lot of places will prioritize these charismatic megafaunnel or just like larger animals or animals that are more at 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.

00:39:00
Speaker 2: Yeah, it's you know, it's 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 and here in the US, uh, 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 Mienmar and Kenya and Brazil, you know, they're 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 they're how we get to schools, and hospitals, and that's how they're how farmers get their goods to market and so on. Right, there are lots of human benefits of you know, I kind of this infrastructural connectivity. And you know, I think it would be incredibly unjust to you know, prevent other countries from from building roads as we have. But you know, we also need, as you say, to of encourage those design techniques that don't destroy nature, right because we know that you know, these countries like Nepal and Yenmar and Brazil are incredibly biodiverse, and that you know, this new construction uh is hugely dangerous and risky for tigers and elephants and gorillas and you know, giant ant eaters. I mean, you know Nama Nama species of charismatic megafauna, and you know new infrastructure is one of the primary threats to its 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 Ash, look, when we when we built you know, the interstate highways here in in 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 uh, you know, other other countries don't make the same mistake, you know. I think that's the kind of the first the 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, you know where the wildlife lives. And you know, there there are so many wonderful rhad ecologists and wildlife biologists and 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 on tigers and ant eaters and and other other criators just trying to figure out, you know, where are the critical habitat areas, where are the movement corridors that these animals are transitting through and how can we avoid building roads you know in the places that are going to be most catastrophic for wildlife.

00:41:52
Speaker 1: There are some amazing innovative design features that you discuss in your book in terms of like looking ahead to the few. Sure, as we construct roads, as we incentivize the incorporation of wildlife protective design. But in the US, 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?

00:42:47
Speaker 2: 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, they're they're every look, every 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, uh, you know when you when you build these structures. You know one one really good example of that, uh is in Wyoming, you know where, which is a very good state when it comes to this sort of thing. You know, they've built lots of these crossings, and you know what they've found out is that is that you know, mule deer uh 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 uh, you know, really have to go over the highway, right, And that's because antelope uh, you know, they have incredible vision. They're amazingly far sighted. Uh. They're also the fastest uh terrestrial animal in North America. They're they're just you know, incredibly good runners. So you know that's a that's an organism. They don't want to be in a you know, a tight little culvert. You know, they want be out on top of a bridge where they can see their surroundings for you know, for many miles in every direction and and uh, you know, be able to run away from predators, uh if they have to, Right, So you really have to think about, uh, you know, the the organism that you're trying to help. Uh, you know, when when you build these these structures. But you know, I think a really important point about these these crossings, uh is that you know, they're 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 around the world now, is that there's lots of data basically showing that you know, even a you know, a five million dollar overpass, uh, you know, prevents enough of these dangerous, expensive crashes involving wildlife to you know, to pay for its own its own costs over over time. So you know, I think I think that that's that's one of the things that's really you know, catalyzing a lot of the interest in you know, in these crossings is is, yes, they're you know, they're good conservation tools. You know, there's lots of data and evidence showing that they work. Uh, 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 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, uh, you know, differently about the kinds of organisms we're trying to help and what it will take to help them, and uh, you know, that's that's really the best tool we have at our disposal to help mitigate this problem.

00:45:31
Speaker 1: 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 US. 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.

00:46:01
Speaker 2: Yeah, it's it's uh, it's you know, that's such an important issue and and you know, one that I really try to explore in in the book. So look, I mean the health 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. Uh. You know, you've got of course air pollution, which is a huge problem. You've got uh you know, obviously pedestrian death, you know, which is which is a gigantic issue uh in the US and is actually becoming more of a problem. You know, for for many, many years, pedestrian fatalities due to cars we're declining, and 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. Uh. You know, we we think about roads and cars I think as being you know, these fundamentally positive things, and 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 and 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 twentieth 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 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 experienced the legacy of those problems. You know, we know that, you know, the people of color are much more susceptible to asthma and you know, cancers associated with with air pollution and other problems that roads create. And you know, and these 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 that city. Just as you know, as it destroys the connectivity of a mountain lion population. So, you know, I think that's a really important A really important point to bear in mind is that, you know, roads and these these giant highways that were built in the middle of the twentieth century. You know, they 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 of that, that kind of racist and catastrophic planning.

00:48:59
Speaker 1: 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 anthropause show us about restoring ecosystem health?

00:49:26
Speaker 2: Yeah, you know, it's well, first of all, it was really the you know, the kind of the greatest or least biggest inadvertent experiment in history of rhode ecology. Right, I mean, what happens when you you know, shut down traffic for a few months will 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 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 that 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 US humans. One of my favorite studies that I think, you know, reveals a lot about 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. Uh. And you know, basically, what these researchers showed is that they you know, so they recorded the songs of white crown sparrows. Uh. You know, these birds who, like you know, so many songbirds of course, sing to attract to attract mates. Uh. 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 this the 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 uh, you know, without without all of that kind of low frequency rumble of traffic, uh masking their their song, you know, they're able to to again sing these these much more elaborate songs that kind of veered into lower registers, that they were able to express sort of the full complexity of their their vocal range uh in a really interesting way. So you know, to me with that shows is that you know, look, we've 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 uh to flourish again. And and obviously you know we we'd never you know, wish another pandemic or you know, total cessation of human movement upon anyone that was a 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 for the from the landscape, as you know the Forest Services is doing in 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.

00:52:46
Speaker 1: 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 noses content on our dog walks thanks to Edyong 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 roadview challenged. Check out our website This podcast will kill You dot com, where I'll post a link to where you 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, quarantining and placebar reader recipes, show notes and references for all of our episodes, links to merch our bookshop dot org, affiliate account, our Goodreads list, a first hand account form, and music by Bloodmobile. Speaking of which, thank you to Bloodmobile for providing the music for this episode and all of our episodes. Thank you to Leana Squillacci and Tom Bryfogel for our amazing audio mixing, and thanks to you listeners for listening. I hope you liked this bonus episode and are a loving being part of the TPWKY book Club. A special thank you, as always to our fantastic, generous patrons. We appreciate you so so very much. Well, until next time, keep washing those hands