Crossings: How Road Ecology Is Shaping the Future of Our Planet

by Ben Goldfarb

Early colonists described rivers that “ran silver” with spawners; at fords in Virginia, wrote one nineteenth-century traveler, herring were so multitudinous “that it is almost impossible to ride through, without treading on them.” Now it’s our planet’s highways that gleam with chrome travelers, not our waterways.

Eventually they return to their natal rivers, attuned to magnetic fields and familiar smells, and power upstream. They cease to eat; their organs deteriorate. Some swim hundreds of miles inland and thousands of feet upslope, halting at last in high deserts fragrant with sage. With vigorous tail-sweeps, females excavate gravel nests and deposit sticky orange eggs. Males joust for primacy and contribute milt with spasmodic shivers. Mission accomplished, they die. Their carcasses nurture eagles, bears, otters, mice; the nitrogen and phosphorus inhered in their flesh nourish the insects that will comprise the matter of their fry. Their life cycle is a circular economy, a perpetual reincarnation. A salmon never dies—she’s merely recycled.

“Really,” he fumed, “we should have the whole salmon.” His fury was justified. For thousands of years Krise’s Squaxin Island ancestors, the People of the Water, had plied the southern end of Puget Sound, the glacier-chiseled arm of the Pacific that elbows into western Washington. Theirs was a world of tidal flats and brackish rivers, one that collapsed the line between land and sea. They hunted elk and gathered clams, but salmon were their staple, a food as sacred as it was nourishing. The People of the Water harpooned salmon with obsidian points, endured winter on their dried flesh, honored their seasonal return with First Food ceremonies. They carved salmon petroglyphs, inscribing their devotion upon the earth.

And then there was stormwater. The rain that pummeled Washington’s concrete skin—its roads, driveways, parking lots—rushed downhill to the Sound, carrying with it a toxic brew of motor oil, transmission fluid, gasoline, copper, and other automotive tinctures. Deadliest of all, though no one knew it then, were the particulates shed by tires. Scientists would eventually pin decades of coho salmon die-offs on 6PPD-quinone, a chemical that manufacturers apply to tires to protect them from ozone. We’d paved the earth for cars, then used them to poison it.

Nearly twenty years of struggle came down to an hour of argument. Samuel Alito grappled with the semantic difference between a “substantial degradation” of salmon and a “large decline”; Stephen Breyer expounded on the history of fish-passage law; Neil Gorsuch and Elena Kagan made common cause on esoteric points of treaty interpretation. It was over by noon.

By contrast, there are something like two million culverts just waiting for a few cheap tweaks to convert them into crossings. Adding an elevated concrete ledge turns a half-flooded box culvert into a boulevard for bobcats. Replacing rocky abutments with forgiving dirt can coax elk beneath a bridge.

Like reforestation, species reintroductions, and the planting of oyster reefs, it’s part of what the historian Thomas Berry described as humanity’s Great Work: “moving the human project from its devastating exploitation to a benign presence.”