Beavers are a frequently maligned animal in our region. They are blamed for flooded basements, creating stagnant ponds that breed mosquitoes, and (in the town in which I live) declining water quality. While beavers may be a nuisance to homeowners, the value they provide to the greater ecosystem is immeasurable.
Recently, I visited Crooked Pond in Boxford – a pond that would not exist in its current state without beavers. Crooked Pond is fed by a number of small, seasonal streams, and by run-off from the steep hills that surround it. An old beaver dam at the east end of the pond retains this water, although holes in the dam allow for a modest stream to flow from under it. In a season where almost every other local body of water has run dry or is well below its normal limits, this pond and stream has more water in it now than had been present during the summer. Beavers require deep water to insure that their plunge holes (the “doors” to their lodge) remain underwater. Therefore during times of drought, they are especially attentive to maintaining their dams in order to insure maximum water retention.
These high water levels, while flooding the trails surrounding Crooked Pond, provide critical habitat for a plethora of plants and animals. During the summer months, the pond is filled with emergent aquatic plants that provide food and refuge for countless insects, amphibians, fish, and invertebrates. Birds that require cattails and buttonbush to nest flock to the area as do herons and osprey, which feed on those animals living below the surface. Students of mine have caught crayfish, leeches, dragonflies, minnows, snails, and countless other animals here. It is an area rich in biodiversity – a critical component of ecosystem resiliency.
Not only do beavers increase local biodiversity, they are also the only animal in our region that can actively manage their habitat (other than humans). In so doing, they create unique spaces that would not normally occur in a New England biome. The climax ecosystem in New England is forest. If we suddenly abandoned this area, all of our yards, playing fields, farms, and other open spaces would eventually become forested. The only naturally occurring fields in New England are a by-product of beaver activity. Beavers generally abandon their pond after about 10 years, or once their prime food and construction materials have been exhausted. Once the pond is abandoned, the dam falls into disrepair, breeches, and the pond drains. What is left behind is a large mud flat, rich in alluvial soil; prime growing substrate for many fast-growing plants, like grasses, sedges, and other annuals, which in turn provide homes for butterflies, mice, snakes… well, you get the idea.
So while it may be frustrating that your favorite hiking trail is flooded, or that your basement takes on a little water in the spring, or that there are a few more mosquitoes than you remember, it’s a small price to pay to live in an area rich in biodiversity. For while we humans often think we stand apart from nature, we are really no more than a piece in a very complex puzzle. And when we try to jam a piece into a space where it doesn’t fit, or remove a piece altogether, things often don’t turn out very well for anyone.