What happens to animals who venture beyond our gardens? It’s a dangerous world out there, but road ecologists are working to reconnect broken habitats. Ben Goldfarb’s captivating new book explains how.
“We inhabit a world as angular and broken as a corn maze, all edge and no heart.”—Ben Goldfarb, Crossings: How Road Ecology is Shaping the Future of Our Planet
On my bookshelf sits a bleached box turtle shell, about the size of the palm of my hand with a chunk torn from the side. The life story of the animal who once walked underneath this mangled armor is a mystery. I imagine she snacked on slugs and wild strawberries, spending her summers ambling through patches of urban forest and her winters deep in the ground under a warm layer of oak leaves. Maybe she narrowly avoided an encounter with a raccoon or fox during her first decade before her shell fully hardened.
But those are just guesses, as are any thoughts about how she died. Her ghostly remains were a gift from wildlife biologist Susan Hagood, who thought our turtle friend likely met her end by tractor, mower, or car. In the years since Susan gave me the shell in 2009, I’ve wanted to ask her more about it, but I can’t; two years later she also died, far too young, from cancer.
I’ve kept the shell to honor both Susan and the turtle I never knew, and as a reminder of all that we’ve lost and all that we still can save. Like the turtle’s death, Susan’s passing was untimely; at the age of 54 (only a year older than I am now), she had more plans to pursue. And like the turtle, she had a thick shell. She was kind and thoughtful, but she was also tough in a way that enabled her to take on formidable cultural and political barriers, testifying against everything from captive hunting of penned foxes to killing of coyotes under the guise of senseless “predator control.”
In her later years, Susan confronted more tangible barriers in the form of asphalt and concrete that sliced through the heart of wildlife habitat. Her devotion to saving animals from under vehicle wheels culminated in a PhD thesis about the impact of roads on genetic diversity. It also manifested in hands-on campaigns. In a rural pocket of Montgomery County, Maryland, where a park ranger had observed turtles hit repeatedly in the same small patch of road, Susan helped lead a crew of dozens of volunteers to erect silt fencing that diverted animals safely through an underground culvert. It worked, drastically reducing turtle mortality and also becoming a popular crossing for everyone from skunks to birds to chipmunks.
In another part of the county, Susan rescued turtles who had the misfortune of living in a forest doomed by an impending highway project. With the help of her turtle-tracking chocolate Lab, Drew, she and a team of field assistants scooped up hundreds of vulnerable animals and tagged and relocated them. The work was painstaking, and Susan knew their long-term survival was far from guaranteed; box turtles are wedded to their home ranges and may not survive in new environments, even when initially confined in large pens for long periods to acclimate to their new surroundings. But she also knew the turtles didn’t stand a chance once the bulldozers arrived.
“People ask me, ‘Why box turtles?’—and I have yet to come up with something that is satisfying to them and to me,” Susan told me as we drove to the site one day. “They’re so vulnerable, and they face such challenges in the world we’ve created, yet require so little of us to survive.”
I first got to know Susan while writing her story, “Turtle Trackers,” for the membership magazine of our employer at the time, the Humane Society of the United States. We discovered we had much in common—including the fact that both our fathers had been plant pathologists, a rare job we’d spent our lives fruitlessly trying to explain to others. Susan was now pursuing an arcane profession of her own and explaining it to me. Even the phrase “road ecology” was a recent invention, entering the U.S. vernacular just 15 years before. The pioneering wildlife overpass in Canada’s Banff National Park— the most famous ever built—was only a decade old.
For years I’d been well aware of the heartbreakingly high mortality rates caused by roads, forcing myself not to look away as the body counts of dead foxes, raccoons, squirrels and turtles accumulated where too many drivers raced along the rural roads guiding me to work. But thanks to Susan, I was inspired to learn more about population-level impacts. I read about how roads were inhibiting salamanders from returning to their natal ponds to breed. I spoke with researchers in southern California studying the dwindling genetic diversity of increasingly isolated populations of mountain lions who couldn’t or wouldn’t cross highways. I interviewed an ecologist in Florida who had managed to save more than 9,000 turtles from the crush of trucks and other vehicles before finally securing federal funding for a permanent tunnel system.
Fifteen years later, my six-inch-deep pile of notes, articles and studies from that research project still sits in a cabinet next to the shelves holding my broken turtle shell. Road ecology is underappreciated and critically important to curbing habitat loss and fragmentation, and I thought it deserved its own book. I was hoping one day to write it.
Last fall, Ben Goldfarb beat me to it, and I’m both relieved and grateful. His 2023 book, Crossings: How Road Ecology is Shaping the Future of Our Planet, is a gorgeously written, intricately reported masterpiece. I don’t know Goldfarb, but I came to love his poignant, perceptive writing when I read his first book, Eager: The Surprising Secret Life of Beavers and Why They Matter. He navigates complex worlds with compassion, insight, and imagination without ever getting in his own way.
In Crossings, Goldfarb makes the case that roads are “not merely a symptom of civilization but a distinct disease” with far-reaching consequences, halting animal migrations while spreading everything from invasive species to pandemic-causing pathogens: “Name an environmental problem, and it’s exacerbated by the access that roads provide and the incentives they create.” The killing fields of roads, Goldfarb writes, are “an overlooked culprit in our planet’s current mass die-off, the sixth major extinction in its history.”
Through Goldfarb’s research, we learn of salmon in the Pacific Northwest who are unable to pass through a seemingly endless tangle of culverts that are too small, too jammed with debris and sediment, or too filled with rushing water—and of the successful legal efforts of Native tribes to dismantle or replace these structures and make way for a “Salmon SuperHighway” in Oregon. We discover why the navigational abilities of mule deer, “unsurpassed cartographic geniuses,” stopped short at the roadside along I-80 in Montana until the state installed wide, inviting underpasses along with fencing to guide the deer to safety. Without such help, deer were often either hit or deciding not to brave the wall of traffic at all—a slow death sentence for a species that evolved to eat in the mountains in the warm season and spend winters foraging in the valleys.
Roads, Goldfarb explains, undo age-old behaviors that are integral to survival: “Whereas other ungulates stray widely, mule deer remain faithful to their inherited pathways. Deer migration isn’t merely a movement pattern but a form of culture, transmitted from doe to fawn like family lore. And when roads thwart their treks, the loss is as thorough as the erasure of a language.”
Exploring the rise of roads as a dominating force in modern society, Goldfarb travels through time and across lands, tracing the racial injustices of 20th-century highway development as well as the U.S. Forest Service’s labyrinthine roads that still scar many remote ecosystems even as they crumble. He introduces readers to road ecologists, transportation planners, wildlife rehabbers, and advocates trying to mitigate the losses across the American West, Florida, New York, Alaska, Wales, Brazil, Costa Rica, and Tasmania. Tallying the destruction that ripples out beyond our usual sightlines as we cruise down the highway, Goldfarb writes: “The essential insight of road ecology is this: roads warp the earth in every way and at every scale, from the polluted soils that line their shoulders to the skies they besmog. They taint rivers, invite poachers, tweak genes. They manipulate life’s fundamental processes: pollination, scavenging, sex, death.”
Among the less visible consequences, Goldfarb considers noise pollution to be perhaps the “most vexing.” Roads have hard edges, but their effects can be borderless, with noise acting like “a toxic plume that drifts from its source like sewage” and emptying the landscape of wildlife even miles deep into adjacent lands. As I also wrote in my own book Wildscape, even (and maybe especially?) the smallest and least mobile creatures like monarch caterpillars are stressed by road noise.
One of the many tragedies of roads is that they can encourage attractive early-successional habitat for wildlife while also killing those animals in large numbers, and Goldfarb wrestles with the popular idea of planting wildflowers for monarchs along the very highways that may further imperil them. Larger animals like hawks, vultures, and coyotes are also at risk of succumbing to an ecological trap: though they benefit in the short term from scavenging killed animals, they might not make it off the shoulder alive. This roadside “necrobiome” has another consequence: complacency. Removal of carrion by animal cleanup crews “airbrushes our roadsides,” Goldfarb writes, “camouflaging a crisis by devouring it.” We humans rarely see the full accounting of the messes we’ve made.
Sometimes collisions with animals are unavoidable for even the most careful driver, but as Goldfarb notes, reduced speeds could avert many more accidents. That’s not too much to ask, especially on my street, where a couple of neighbors and their visitors routinely drive twice the 25-miles-per-hour speed limit and have hit squirrels, turtles, rabbits, owls and deer—without even bothering to stop.
Years ago, as Susan Hagood described a recent rescue of dozens of turtles from an area where forest was being cleared for new soccer fields, she told me how much it wore on her to find dead hatchlings, shell fragments and carcasses of turtles mauled by construction equipment: “They keep me up at night, these turtles. You’re just haunted by the ones you couldn’t find.”
I’m haunted, too, by the splayed animals I’ve come across and tried to help—too late, after they’ve already been crushed by the relentless churn of humanity. Just last night I found a hit and eviscerated squirrel in the road right in front of our house, with only her tail left. Though so many of us are working hard to create habitat within our own patches of lands, the animals know no borders. I hope as many as people as possible will read Crossings, take it to heart, slow down, spread the word, and advocate for a world where our own freedom of movement doesn’t subsume that of all the other organisms in our path.
Related Articles:
“Roadside Assistance”: Millions of animals die in the road, and many suffer serious injuries after colliding with cars. How can we help? Read the tips.
“Slow Down for Owls”: Daylight Savings Time had ended a few days before. But there was just one problem: This little screech owl living on our road didn’t know how to turn the clocks back and adjust her timing for increased traffic. Read the story.
“Turtle Trackers”: When I interviewed Susan Hagood for this All Animals magazine article 15 years ago, she sparked my interest in the then-nascent field of road ecology. Read the story.