By Gary Martin
We live in Masham where we can step out our back door to seemingly endless forests and fields. I love to walk, and one of my winter routes takes me through a marshy area with a long, straight drainage ditch. It’s great when everything is frozen. The rest of the year it’s pretty wet and tangled with brush and dead trees and hard to get through, unless you’re a dog. On a snowshoe this past winter, I noticed what looked like a large beaver house under the snow. Two weekends ago, I donned rubber boots to investigate.
Beavers had built a wide, low dam which created a small pond. The diligence with which the beavers had engineered the structure was amazing. Big trees, little trees, branches, and mud – all went into an impressive watertight structure with a spillway that kept the water at a level perfect for beavers.
I didn’t expect it to last. I have grown accustomed to expressions of hatred for beavers, including, sadly, from people who love the forests and fields as much as I do. I went back this past weekend to find what I expected: shotgun shells, the dam partly dismantled, and two bloated beavers belly-up in what was left of the pond. The scene had a spooky feeling. Even the dog was sombre.
Giardia is a common waterborne parasite that causes diarrhoea in humans and other animals around the world and is known here as ‘beaver fever’ because we generally assume it comes from beaver feces. Now, some studies blame livestock and humans for infecting beavers. In other words, the relationship – and the cause of the illness – might be the reverse of ‘common knowledge’. It may be that human interactions with ecology (for example, improperly treated sewage and livestock near waterways) are poisoning the wildlife. Sound familiar?
It seems to me that people who hate beavers are concerned about immediate threats – flooded farmland or homes and giardia in their drinking water. I can’t argue with protecting farmland and homes and water. But the incident that sparked my concern has some troubling elements. First, the area is a long way from any housing and will likely remain so. Second, the beavers were not stopping the ditches from draining the fields surrounding the marsh. Exactly the same amount of water flows in and out of a beaver pond.
Beavers have evolved over millions of years to serve an ecological function. Beaver ponds enlarge water surfaces, slowing water down so it can replenish the water table. Beaver ponds and marshes are essentially large filters for the water you drink, and they create habitat for amphibians, waterfowl, fish, and aquatic plants. Each time we meddle, the clock ticks for humans.
As I stood pondering those wondrous builders floating dead in their home, I saw ‘beaver fever’ from the beaver’s point of view. I questioned whether we and our guns belong. And that ticking clock got a little louder.
Gary Martin, Ph.D., is with the Department of Geography and Environmental Studies at Carleton University