BRINGING BACK BEAVERS!
Working with beavers to improve river health in the Roaring Fork Watershed.
ROARING FORK WATERSHED BEAVER INVENTORY!
Pitkin County Healthy Rivers is thrilled to announce our collaboration with the U.S. Forest Service on a project we hope will eventually lead to releasing beavers in suitable habitat in the headwaters of the White River National Forest.
Beavers, a keystone species, were once viewed as a nuisance and nearly eradicated from the Rocky Mountain west. Their numbers have yet to fully recover despite the fact they are universally recognized as having many benefits for river health. These range from improving overall stream and riparian ecology, to their potential to aid with our watershed's late season stream flow issues.
The first step will be to complete an inventory of where (on public national forest lands) beavers are currently thriving, while identifying areas (also on the forest, not private land) with similar characteristics where beavers could be successfully reintroduced in the future.
Pitkin County, through the Healthy Rivers program, is providing $50,000 that will fund two Forest Service seasonal workers to conduct the "boots on the ground" inventory beginning in summer 2023. Stay tuned for more news on this exciting project.
In the ecological community, there has long been broad acceptance that beavers are good for riparian ecosystems. Beavers are a “keystone” species in North America. They play a crucial role in biodiversity. Hundreds of species, including many threatened and endangered, rely either partly or entirely on beaver-created habitat. They assist with groundwater aquifer recharge, maintaining stream and river flow during dry late summer months, repairing incised and damaged stream channels, decreasing erosion, removing pollutants from surface and groundwater, and preserving open space. They also create and enhance opportunities for wildlife observation, fishing, photography, bird watching and quiet relaxation in nature.
Unfortunately, “keystone” status has done little to protect the beaver from the heavy hand of humanity. Historically, the North American beaver was viewed as a nuisance rodent who also had very valuable fur. This did not bode well for the species as homesteading ranchers and miners began to settle the Rocky Mountain west. Beaver were nearly extirpated by trappers in the late 1800’s and early 1900’s. Protections allowed North American beaver populations to rebound to an estimated 6–12 million by the late 20th century; still far fewer than the originally estimated 60–400 million North American beavers before the days of the fur trade. Prominent ecologists believe current beaver numbers are 2-20% of what they were historically.
Locally, the beaver remains underappreciated and misunderstood by many. Evidence indicates some landowners and agencies continue to perceive beavers primarily as a
nuisance that cause damage, or undesirable aesthetics, to private property. Irrigators have expressed concern that beavers (and stream restoration projects that promote
increased beaver activity) could negatively impact their ability to irrigate. Though recent literature has piqued the ecological community’s interest in pursuing beaver related river restoration projects, public understanding and support for the “where and why” of these projects is far from ubiquitous. Learning to understand and live with beavers is a concept still gaining traction.
In the wild, the lifespan of a beaver is ypically 10-12 years (up to 19-20 years in captivity). Beavers typically weigh 35- 65 pounds (up to 70 pounds) - much bigger than many people expect! Beavers do not hibernate in the winter. Beavers do not have the biological ability to lay dormant for long periods of time. Beavers remain active through the winter months, making adaptations and preparations to survive. This includes changes in diet, fur, habitat, and daily activity.
Why do Beavers build dams?
Water is the most important part of beaver habitat; they swim and dive in it, and it provides them a refuge from land predators which include mountain lions, wolves, coyotes, foxes, large raptors, and occasionally bears. Water restricts access to their homes and allows them to move building objects more easily. The water they impound also promotes the growth of many of the plant species they consume, such as willow, and other native riparian vegetation. Beavers cache food for the winter by building a submerged vegetation raft that is constructed of less desirable tree species and mud on top, with desirable food materials placed underneath. As beaver ponds freeze, the cache becomes frozen into the ice with food items remaining below ice level and accessible to beavers through winter.
what's with the teeth?
The beaver’s four front incisor teeth are incredibly strong, often compared to metal. They are strong because of the thick iron-rich coating on the exterior of their teeth. This iron layer is visibly orange and keeps their teeth stronger against mechanical stress than regular mammal teeth. Like all rodents, beavers have front teeth, called incisors, that never stop growing. To keep them in check, rodents must constantly gnaw on hard surfaces like wood. Beavers’ incisors can grow up to 4 feet per year. That is the size of most adult beavers’ bodies without the tail!
what's with the tail?
Contrary to popular belief, beavers do not use their tails to carry and pat down mud. However a beaver's long, flat tail does serve many uses. Beavers use their tails as rudders to steer in the water while swimming, to prop them up for balance when sitting, as leverage when carrying large branches and logs, and to slap the water as a warning signal.
family values and teamwork.
Beavers form monogamous pairs. The young stay with their parents for up to two years and help raise younger siblings. They live and work in colonies of 2 to 12 family members.
What can be done to help beavers successfully re-ESTABLISH?
Sometimes beavers need a little help to get established, or re-established, in an area that is otherwise suitable but may initially be lacking one or more critical components of sustainable beaver habitat. Many areas of our watershed that were once great beaver habitat have been damaged in some way that makes it unappealing, or impossible, for beavers to reinhabit those areas without a little help. Beavers need both suitable food and dependable water resources for continued success in an area. Decades of cattle grazing may have removed vegetation. Water diversion projects, road and railroad grades, and other human influences may have de-waterred streamflows, cut off natural floodplains, and channelized streamflows. Some level of revegetation or ecological restoration to reestablish a food source may be critical to repopulating an otherwise suitable location with beaver. Construction of analog dams can also give pioneering beavers a foot-hold in getting reestablished in an area.
what ARE the costS of COEXISTING with beavers VS. REMOVING THEM?
Beavers are peaceful animals that, when treated thoughtfully, can make great neighbors. Their work can also have undesirable impacts on private property, including flooding and changes to vegetation. Coexistence is often less costly than attempting to remove them. Removing “nuisance” beavers tends to be a short-term fix as others will normally migrate into the empty habitat. Beaver kits need to stay with their parents for two years, and any removal of adults risks leaving dependent youngsters behind. Orphaned beaver babies have been known to swim up to humans for help, and, if then taken to a wildlife rehabilitator, that person must devote considerable time, energy and expense raising them over two years. Furthermore, when active beavers are taken away, their dams disintegrate without constant repairs and the ponds drain. Some pond residents, such as herons, will be able to migrate, but many fish and other creatures will die. Neighbors of such destroyed ponds are often dismayed by the loss of life left behind.
Beavers Eat fish. (FALSE!)
False. Beavers are 100% herbivorous. They eat the bark, shoots and leaves of woody (predominantly broadleaf) trees and shrubs along with herbaceous plants including aquatic vegetation. They store branches and twigs in underwater food caches to eat in the winter. As ‘choosy generalists,’ their diet consists of many species of woody, herbaceous, and aquatic plants.
Beavers multiply RAPIDLY LIKE "RODENTS". (FALSE!)
It’s true that beavers are rodents. They become sexually mature at around 20 months but they often do not reproduce until age 2 or 3. A mated pair typically has between 2 and 6 babies, called kits, once per year. That’s it. Beavers live in family groups with a breeding pair and offspring from the current and previous year. Even the youngsters from the previous year (appropriately called yearlings) hang around and help care for the new generation. At 2 years old, young beaver disperse to find their own territories.
Beavers are bad for fish. (FALSE)
It is important to keep in mind that beavers and fish have coexisted for at least a million years. The question of whether beavers are good for fish, or not, is highly site specific. It depends on the location, species of fish, and a variety of ecological and anthropogenic influences on the area. In the Roaring Fork Watershed, beavers' ability to retain and slow the release of headwaters snowmelt, thus enhancing late season streamflows, provides a huge overarching benefit to not only our fish, but all of our riverine flora and fauna.
"BEAVER" FEVER. (MISNOMER)
Giardia is the name commonly used to describe several species of one-celled animals responsible for a common type of water-borne intestinal illness. Though the parasite is commonly referred to as ‘beaver fever,’ beavers are not often the original source. Humans pick up the disease by swallowing the resting stage of Giardia, the cyst. Cysts are hardy little tablets that exit an infected animal's body along with feces and can survive for a month in cool water. Beavers contribute, but get far too much credit for spreading Giardia. The science says other species, including humans and livestock, may be much more to blame. Three-hundred million Giardia cysts may be present in one milligram of human feces.
BEAVERS QUICKLY DESTROY AN AREA AND MOVE ON TO THE NEXT. (FALSE!)
In addition to being professional hydro-engineers, beavers are master gardeners! Beaver foraging and damming activity actually serves to promote the growth of many of the plant species they consume, such as willow and other native riparian vegetation. Beavers can fell large trees (>1m diameter) but prefer saplings to eat the bark, branches and leaves. Most tree felling and feeding takes place within 20m of the water’s edge but they will range further if options are limited. Beavers have the effect of naturally coppicing trees resulting in more, not less, growth of woody vegetation.
BEAVERS BELONG IN THE HEADWATERS, NOT MY BACKYARD. (FALSE!)
In the Roaring Fork Watershed, human development has heavily encroached on much of the beaver's historic habitat. Beavers prefer slow moving water with a gradient of 1 – 2%. Beavers prefer to use slower moving streams, typically with a gradient or steepness of one percent, though they have been recorded using streams with gradients as high as 15 percent. Beavers are found in wider streams more than narrower ones. They also prefer areas with no regular flooding. Sound like some place you know? Many of our valley bottoms were once the domain of the beaver!
BEAVERS ARE MESSY. (IT's ALL ABOUT PERSPECTIVE)
Messiness is certainly in the eye of the beholder. That said, beavers are indisputably one of nature's most organized engineers and builders. Their dam building skills have been creating order out of chaos, and building the foundations of riparian communities for over 12-million years! Whether you see their work as ordered, or messy, the vitality they create is one of nature’s great marvels.