Beavers Welcome (a field note)
I have always had a soft spot for the underdogs of the wildlife world. The ones who get a bad rap, yet provide numerous benefits to the land and habitat for other species. As I wander our property on Kelly Creek outside Bozeman, Montana—notebook in hand—I begin to pay closer attention to the creek and wonder about beavers, a keystone species that used to live here. Is it possible that this stream, now intermittent used to be perennial, and the overgrown vegetation is a result of their absence? If so, what would it take for them to return?
The creek that runs through our 15 acres is small yet mighty in the spring, flowing strong and reduced to a trickle by the end of summer. It is fed from snow runoff. It is small, about 4-6 feet wide and 12 inches deep in the deepest pools formed by naturally fallen trees and twigs. The creekbed is mostly soft and silty with some sporadic rocky bottom areas. The banks are steep. Most of the creek is inaccessible in the summer due to overgrown vegetation, including; aspens, willows, and prunus shrubs, all ideal for beaver food and building material. There is also plenty of deadwood that would serve as a readily accessible building material.
We know that the forest on our property could use a proper cleanup and who better to help than our beaver friends! Beavers are ecosystem engineers providing many benefits to the land. For us, this could involve cleaning up dead woodpiles and thinning an overgrown forest, increasing habitat for wildlife, increasing water base flows, recharging and elevating the water table, improved nutrient cycling, filtering pollutants, and fire mitigation.
My initial concern for the viability of beaver habitat on our property is the lack of water. However, according to The Beaver Restoration Guidebook, beavers prefer small-medium sized, low-gradient streams with less than 6% slope that flow through unconfined valleys. Water is essential for beavers and can be in the form of a stream, river, lake, or pond, as long as there is a year-round supply. Currently, I am not sure if the stream would constitute for a year-round supply. However, if the beaver built a dam in the spring, would it carry enough capacity through the year? Judging from our neighbor's property about a half-mile mile downstream, the answer is yes—their stream, once a trickle transformed into a multilayered pond and lush wetland.
The overall consensus of our surrounding neighbors is that there was ample presence of beavers in previous decades, with colonies present every half-mile up and down the drainage. It is hard to pinpoint when and why exactly the beavers on our property and higher up had gone. Some say the highest dam blew out one year. Others say cattle grazing was a factor, and some say the continued killing sent them away. Maybe it was a culmination of all these things.
This brings me to another and even more critical consideration, the cultural carrying capacity. Luckily, we live in an area with mostly wildlife-friendly neighbors. By wildlife-friendly, I mean welcoming and tolerant of all species. I have been collecting stories and opinions from our neighbors, some of whom have been here 30 years or more. One neighbor recounted sandhill cranes returning after the return of the beavers. Some people do not like that they cut down trees. However, as one of our neighbors put it—they are not killing the forest, only changing it. They act as rotational farmers, and when they cut down trees and move them around, they are also planting more as they go. The neighborhood directly downstream from us has a long history of conflict with beavers, the main complaint being the flooding of their road. For years, they killed the beavers only to have them return to this ideal habitat. In recent years they installed a culvert under the road and voila, the flooding stopped, and the two could coexist.
The North American beaver (Castor canadensis), has a unique adaptation to manipulate their surroundings. The skull is broad and thick with chisel-like incisors that grow continuously. This allows it to chew and fell trees while its forelimbs allow it to carry branches, rocks, and mud for building shelter. Yet, how does that manipulation fit with modern society? In addition to flooding, beavers can do a lot of damage to property, including the destruction of cultivated trees, damming of culverts, or just aesthetic interruptions to an otherwise planned landscape. Personally, we are less interested in a human-designed landscape and curious about what a fully intact ecosystem would look like and what we can do to support that process. Luckily for us, and the beavers, we live in an area mostly surrounded by people who feel the same.
We have two intermittent ponds near our property, both last about two months in the spring and invite ducks and frogs. I am hopeful that a more permanent wetland area would encourage these and other waterfowl and amphibians to come and stay longer. Already, this land is abundant with wildlife, including black bears, mountain lion, moose, elk, deer, fox, weasel, bunnies, and numerous songbirds and raptors. I imagine the improvements brought by beaver would not only further support the existing species but also attract an even more diverse ecosystem.
So now that we are convinced that beavers would be a welcome addition to the land, how do we invite them in? Our options are; 1. Do nothing and wait and see if they repopulate from downstream, 2. Entice them by manipulating the habitat, or 3. Capture "problem beavers" from another location and relocate them here. After filling out the Methow Beaver Project Release Site Score Card, which evaluates food and building sources, water cover, stream discharge, and gradient, floodplain structure, mud substrate, and human/grazing impact—we score a 62, which falls in the range of "good habitat" on a scale of poor-excellent. This is encouraging and suggests that with beavers only a half-mile downstream and plenty of suitable habitat, for now, we can wait and see.