It really started in the early 1600s, when the first European fur traders arrived in North America and basically went about ransacking the continent’s beavers. Europeans trapped beavers out of every single river, stream, lake, and pond they found, or traded for pelts with Native people. And as beavers vanished the wetlands they created dried up. Streams eroded. Untold millions of acre of watery habitat was lost. By the time the second wave of farmers showed up a few decades later, North America had been permanently transformed by the fur trade. Colonists came to internalize this much drier, beaver-less landscape as natural. It’s a classic case of the “shifting baseline syndrome,” as ecologists say; every generation accepts a bit more environmental degradation as natural. We lost countless beaver-created ponds and wetlands without realizing the extent of the destruction.
As a result, when we envision a stream as a clear, clean, straight, shallow, narrow thread running through the landscape, we forget to include the network of ponds and wetlands and side channels that beavers would have created. It wasn’t until the last couple of decades, really, that scientists started taking a second look at landscapes and recognizing that they’re missing one of their primary ecological actors. Aquatic ecosystems would have been much more complex than they are today.
Those trappers obviously saw beavers a commodity. But as you write, there emerged a hostility to beavers even after the fur trade disappeared.
We tend to feel hostile towards animals that cohabitate well with us. Beavers, in some ways, are a lot like us. Just as we modify our own surroundings to maximize our food and shelter, beavers are relentlessly driven to change their environment as well. The problem is that their vision of a healthy landscape doesn’t jibe with ours. We like to build towns and farms and roads in floodplains, while they like spreading water all over those floodplains. The inevitable result is conflict, and, in most cases, the offending beavers get killed. We’re consistently hostile to this animal that’s nearly as bold and ingenious as we are.
How exactly do beavers transform the land? And what did North American landscapes look like before the fur trade?
The classic beaver behavior that every school kid knows, of course, is that they build dams. The purpose of those dams is to create ponds and wetlands that provide shelter. A beaver on land is a slow, fat, waddling snack for wolves and bears and cougars. By contrast, beavers are incredibly powerful and agile swimmers. So building dams increases the extent of the watery habitat in which they’re safe.
In so doing, they inadvertently create huge amounts of habitat for other creatures as well. Water is life: In the American West, wetlands cover just 2 percent of the land area but support 80 percent of the biodiversity. It’s hard to name an animal that doesn’t benefit from beaver-built habitats in some way. Frogs and salamanders breed in beaver ponds. Juvenile trout and salmon use ponds as rearing habitat. Waterfowl forage in beaver ponds and even nest directly atop beaver lodges. Moose hang out in beaver ponds to cool off. Woodpeckers will use dead trees killed by rising water levels. There’s just this incredible array of species that has evolved to take advantage of beaver engineering.
While beavers were nearly wiped out, you also call them one of the great success stories of the conservation movement. How have populations recovered so successfully over the past century?