NORTH COAST, Calif. – Beavers are burly.

Second only to the Australian capybara for being the largest rodent on the planet, male beavers can weigh in at over 70 pounds. (A few have even been cited at over 100 pounds!)

Although some people consider them a pest species that causes temporary flooding of areas adjacent area to their home, the ever-active North American Beavers (Castor canadensis) have actually been proven over and over again to be a boon to humankind in many ways.

In the last two or three years, projects and studies have been conducted throughout several Western states that conclusively prove that the beavers are actually 80 percent more effective (and less costly) at repairing and improving degraded stream systems than humans. And part of the reason for that is because the beavers instinctively know where the best places are to build their dams and lodges.

Although the beavers’ mechanism for finding suitable places to build their homes isn’t entirely understood by scientists (who tried to emulate the beavers’ efforts and were not very successful at producing the same beneficial results), it’s believed that a variety of factors are figured into the beavers’ mental calculations: the time of year, access to running water, the right kinds of trees, and vegetative food sources.

The beavers build their dams and lodges out of mud and the branches, sticks and twigs of trees they can harvest locally.

Although some people complain about this practice – because the downing of trees can be visually unpleasant – the beavers’ tree-cutting activities actually have a long-term benefit to both the felled trees and the surrounding environment.

Beavers don’t kill the trees they harvest. Rather, they cut the trees down with their sharp incisor teeth to just above ground-level, leaving the root system entirely intact.

In wildlife habitat restoration and management done by humans, this exact same process is call “coppicing.”

The majority of coppiced trees don’t die; they instead grow new healthier shoots from the severed stump, providing for long-term regrowth and reforestation.

This is part of the reason why beavers are considered to be a “keystone species” in the environment: their creation of new growth and water pathways and ponds actually increases the biodiversity in the areas in which they live.

Studies have proven that where beaver dams are allowed to exist naturally, waterfowl and fish populations increase, and become healthier and more diverse.

In Washington state, for example, studies proved that beavers – which do not eat fish – were a benefit to local trout and salmon populations, increasing smolt production from about 15 individuals per range to 1,170 fish.

A similar effect on waterfowl diversity was seen in Wyoming, where it was shown that waterways where beavers were present resulted in a 75 percent increase in the number and diversity of ducks.

Other benefits afforded by beavers and their construction sites include:

· An increase in the variety of vegetation which enhances bird habitat.

· The removal of toxins from local waterways by filtering out sediments, phosphates, and heavy nitrogen concentrations.

· A reduction in soil erosion (which can decrease flood dangers for people in surrounding areas).

· Helping to reestablish and increase riparian habitat which also aids in the interception of runoff, increasing soil nutrients, and providing habitat for a wide variety of plants and trees. Increased plant life has the added benefit of improving air quality as trees and plants naturally remove toxin form the air.

· Because the dams slow down the flow of water near them they help to recharged spent aquifers (raising the level of water stored underground for use during drought conditions).

So the big, burly beavers can actually be a boon to humankind. Working alongside humans they provide a natural workforce that has a documented history of improving air and water quality, growing underground water storage areas for future use, increasing biodiversity, and benefitting local populations of fish and waterfowl.

Mary K. Hanson is a Certified California Naturalist, author and nature photographer. She will be co-teaching a naturalist course for the public through Tuleyome in early 2018. Tuleyome is a501(c)(3) nonprofit conservation organization based in Woodland, CA. For more information visit www.tuleyome.org .